Arch Sex Behav (2014) 43:483–491 DOI 10.1007/s10508-013-0232-8
ORIGINAL PAPER
Sex and Cultural Differences in Spatial Performance Between Japanese and North Americans Maiko Sakamoto · Mary V. Spiers
Received: 21 December 2011 / Revised: 5 October 2012 / Accepted: 10 October 2013 / Published online: 20 December 2013 © Springer Science+Business Media New York 2013
Abstract Previous studies have suggested that Asians perform better than North Americans on spatial tasks but show smaller sex differences. In this study, we evaluated the relationship between long-term experience with a pictorial written language and spatial performance. It was hypothesized that native Japanese Kanji (a complex pictorial written language) educated adults would show smaller sex differences on spatial tasks than Japanese Americans or North Americans without Kanji education. A total of 80 young healthy participants (20 native Japanese speakers, 20 Japanese Americans-non Japanese speaking, and 40 North Americans-non Japanese speaking) completed the Rey Complex Figure Test (RCFT), the Mental Rotations Test (MRT), and customized 2D and 3D spatial object location memory tests. As predicted, main effects revealed men performed better on the MRT and RCFT and women performed better on the spatial object location memory tests. Also, as predicted, native Japanese performed better on all tests than the other groups. In contrast to the other groups, native Japanese showed a decreased magnitude of sex differences on aspects of the RCFT (immediate and delayed recall) and no significant sex difference on the efficiency of the strategy used to copy and encode the RCFT figure. This study lends support to the idea that intensive experience over time with a pictorial written language (i.e., Japanese Kanji) may contribute to increased spatial performance on some spatial tasks as well as diminish sex differences in performance on tasks that most resemble Kanji. M. Sakamoto (&) Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, Saga 849-8501, Japan e-mail: [email protected] M. V. Spiers Department of Psychology, Drexel University, Philadelphia, PA, USA
Keywords Visuospatial ability Sex differences Japanese Written language Kanji characters
Introduction Research on sex differences in spatial performance, which has primarily been studied within an American and European context, has suggested that spatial visualization tasks (e.g., Mental Rotations Test: MRT) (Linn & Petersen, 1985; Voyer, Voyer, & Bryden, 1995), spatial perception tasks (e.g., Judgment of Line Orientation: JOLO) (Collaer & Nelson, 2002), and spatial organization tasks (e.g., Rey Complex Figure Test: RCFT) (Mitrushina, Boone, Razani, & D’Elia, 2005) are often performed better by males while object location memory tasks (e.g., Brief Visuospatial Memory Test-revised: BVMT-R) are generally performed better by females (Rahman, Wilson, & Abrahams, 2003; Silverman, Phillips, & Silverman, 1996; Spiers, Sakamoto, Elliott, & Baumann, 2008; Tottenham, Saucier, Elias, & Gutwin, 2003). The RCFT is a task that requires both spatial organization skills and ability to memorize locations of parts. The literature suggests that sex differences in the RCFT are generally in favor of males (for reviews, see Mitrushina et al., 2005; Strauss, Sherman, & Spreen, 2006); however, variation in RCFT performance has also been found related to handedness (D’Andrea & Spiers, 2005; Weinstein, Kaplan, Casey, & Hurwitz, 1990) and experience in math and science (Vlachos, Andreou, & Andreou, 2003). Regarding cultural differences in spatial performance, various researchers have reported that Asians (i.e., Japanese and Chinese) perform better than North Americans and Europeans on various spatial tests, including the MRT, JOLO, RCFT, and object location memory tests (Flaherty & Connolly, 1995; Isomura, 2002; Lynn, 1987; Nagoshi & Johnson, 1987; Silverman et al., 1996; Wang, 1994). For example, in an early study,
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Nagoshi and Johnson (1987) reported that Japanese Americans raised in Hawaii performed better than European Americans on spatial and perceptual speed tasks in spite of the fact that the two groups had similar cultural backgrounds, including socioeconomic status and educational levels. Lynn, Hampton, and Bingham (1987) found that Japanese had significantly higher scores on spatial relations tests than British and American participants although cultural and educational differences among the three groups were not taken into account as possible factors that might have influenced performance. Regarding possible cultural or experiential factors, Flaherty and Connolly (1995) focused on the impact of the written language called Kanji (漢字), which consists of Chinese characters that the Japanese adapted hundreds of years ago. This written language relies on pictorial characters rather than letters. In Japanese, approximately 1,100 complicated Kanji characters are used in daily life; therefore, children must memorize 100–200 pictorial characters per year. Some characters look alike, requiring extremely clear delineation and years of practice to avoid misinterpretation. These 1,100 characters are required for the level of fluency necessary to read newspapers and literature in Japanese and are generally mastered by the ninth grade. In their study, Flaherty and Connelly did not find significant performance differences on spatial object location memory tasks between low level (e.g., third to forth grade) Japanese Kanji educated participants and Europeans with no knowledge of Kanji. However, in order to evaluate the full impact of Kanji on spatial performance, the level of knowledge of Kanji would be better assessed at the fully literate ninth grade level. In addition to the possible impact of having a pictorial written language, Japanese learning strategies for visual information may also impact spatial performance. The vigorous Kanji training, which includes visual processing skills, formation of images, and attention to detail involved in learning these complex symbolic characters throughout life, may facilitate higher level processing of pictorial information in general (Bond, 1980; Gitterman & Sies, 1992). For instance, there are specific rules and an inherent order in writing Kanji characters: top to bottom and left to right. Japanese students are constantly drilled on these rules throughout their school years and calligraphy is judged by the beauty, details, and spatial balance within and between Kanji characters. As a result, Japanese students may develop strong spatial learning strategies in general. Only a few studies have systematically considered spatial learning strategies in Asians versus Westerners. In one study, when Japanese participants memorized the locations of objects, they showed no signs of vocalization either covertly or overtly whereas Europeans often verbalized to remember the locations of objects (Flaherty & Connolly, 1995). Gro¨n, Schul, Bretschneider, Wunderlich, and Riepe (2003) also found significant Chinese versus Caucasian differences in fMRI activation of brain areas on the same spatial location memory task. Chinese
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participants who use Kanji characters outperformed the Caucasian individuals and primarily activated the dorsal (i.e., “where”) stream whereas the ventral (i.e., “what”) stream was primarily activated in the Caucasian group. This suggests that the visual information traveled from the primary visual cortex to posterior parietal cortex in Chinese individuals while the same information was processed between the primary visual cortex and the inferior temporal cortex in Caucasian cohorts on the same object location memory tasks. It is important to note that object location memory requires both object identification (ventral) and spatial location (dorsal) skills (Postma, Kessels, & van Asselen, 2008); however, neural activation in dorsolateral prefrontal cortex has been significantly associated with subsequent memory for object locations (Hampstead, Stringer, Stilla, Amaraneni, & Sathian, 2011; Sommer, Rose, Weiller, & Bu¨chel, 2005). The greater activation of the dorsal area in Chinese participants may account for their recall of more object locations compared to the Caucasians. Thus, Chinese and Japanese cultures showed differences from Western cultures both in their behavioral strategies and in neural activation. The other area of interest in spatial performance is related to the suggestion that sex differences among Asians may not be as large as their North American counterparts. For instance, when Chinese students’ spatial, verbal, and mathematical abilities were compared to North American students, Chinese students outperformed North American students on spatial performance tasks; moreover, the sex differences were smaller for the Chinese sample than for the North American sample (Wang, 1994). Similarly, smaller sex differences were found in a Japanese group compared to a North American group when performance on the delayed recall (DR) of the RCFT was evaluated (Isomura, 2002). Given that both Japanese and Chinese use the pictorial written language Kanji, which requires visuospatial memory and visual organization and is used everyday throughout their lives, it is possible that the experience of Kanji may be an important factor in decreasing the sex differences in spatial tasks. Unlike previous studies, the current study aimed to investigate three cultural groups: native Japanese with advanced Kanji education, Japanese Americans without Kanji, and North Americans without Kanji. Since the interest was in long and intensive exposure to a complex pictorial written language and its impact on visuospatial performance, native Japanese participants’ high level of knowledge in Kanji would be also required. Additionally, this study aimed to assess whether sex differences would be diminished on spatial tasks in a culture where both sexes have high levels of practice with the pictorial Kanji language. In this study, it was hypothesized that (1) native Japanese would outperform Japanese Americans and North Americans on spatial performance tests and (2) in general males would perform better than females on male favoring tasks (MRT and RCFT) and females would outperform males on female favoring tasks (2D and 3D Object Location Memory Tests)
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Table 1 Demographic characteristics of the sample Native Japanese (n = 20)
Japanese Americans (n = 20)
North Americans (n = 40)
Males (n = 10) M (SD)
Females (n = 10) M (SD)
Males (n = 10) M (SD)
Females (n = 10) M (SD)
Males (n = 20) M (SD)
Females (n = 20) M (SD)
Age (years)
21.2 (1.9)
20.6 (1.3)
22.1 (3.5)
21.5 (2.3)
20.3 (2.0)
20.5 (3.3)
Education (years)
14.9 (2.2)
14.5 (2.4)
14.3 (2.3)
14.0 (1.9)
14.0 (1.4)
14.0 (1.9)
but this would interact with group, such that native Japanese participants with Kanji education would show smaller sex differences on spatial tasks than North Americans or Japanese Americans without Kanji education.
Method
Participants’ demographic characteristics are shown in Table 1. There were no significant differences in age or years of education among the three cultural groups, age: F(2, 74) = 2.03, education: F(2, 74)\1, and between males and females, age: F(1, 74)\1, education: F(1, 74)\1. This study was approved by the Drexel University Institutional Review Board (IRB). Written informed consent was obtained from all participants after the research procedure had been fully explained to them.
Participants Measures Twenty Native Japanese (10 males and 10 females), 20 Japanese Americans (10 males and 10 females), and 40 North Americans (20 males and 20 females) participated in this study. The native Japanese and North American were recruited at Drexel University in Philadelphia, PA, and Japanese American participants were recruited through the Japan America Society in Greater Philadelphia (JASGP). Individuals were between the ages of 18 and 35 years and able to read and speak their native language (e.g., Japanese for the native Japanese and English for the Japanese American and North American). Native Japanese participants were required to have at least a ninth grade level Kanji education measured by a Kanji examination, to be able to speak Japanese more fluently than English, and to not have lived in the United States for more than 1 year. Japanese American and North American participants were required to have no exposure to Kanji education, to read and speak English at a level of proficiency (ninth grade level), to be more fluent in spoken English than Japanese, and to not have lived in Japan or China for more than 1 year. Native Japanese had Japanese ancestry in both parents, Japanese Americans had Japanese ancestry (75 % of Japanese American had Japanese ancestry in both parents and 25 % had one parent who was Japanese and the other was either Chinese or Korean), and the North American sample was selected to have Western European ancestry in both parents. Individuals who were left handed, had a history of head injury, trauma, or severe medical problems (both physical and mental), were diagnosed with learning disabilities, were taking medications whose side effects might influence spatial performance, and had previously taken any of the spatial tests that were used in this study were going to be excluded from participation. Two potential participants who met the criteria were excluded from the current study.
Based on the prior research related to sex differences and crosscultural studies of visuospatial differences between Westerners and Asians, the visuospatial tasks below were chosen for this study. Mental Rotations Test (MRT) Spatial orientation ability and strategy use was assessed using the Vandenberg MRT (Peters et al., 1995). A line drawing of a three-dimensional figure was presented and participants were asked to determine which of four alternatives would accurately represent the stimulus figure if it were rotated in space. Two of the alternatives were correct and two incorrect for each item. Scores were based on the number of items in which both choices were correct. The Vandenberg MRT is composed of 24 items and the range of scores is from 0 to 24 for each form. Rey Complex Figure Test (RCFT) The RCFT (Osterrieth, 1944; Rey, 1941, 1964) served as a measure of visuospatial organization strategy and incidental memory for visual material. Participants were shown a complex figure to copy. It was then removed and drawn from memory without prior warning. A delayed-recall trial was administered after 30 min. Participants’ copy attempts were scored for organizational strategy using the continuation and symmetry measures described by Bennett-Levy (1984), with a maximum score of 36. Higher “strategy points” indicate use of a more holistic strategy. The number of features recalled in the
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immediate- and delayed-recall trials (i.e., accuracy) was also scored. A maximum of two points, one for accuracy and one for placement, were allocated to each scoring unit (18 units, max score = 36).
tests in Japanese and Japanese American and North American participants completed all tests in English.
2D Object Location Memory Tests
To test the hypotheses, 2 (Sex) 9 3 (Culture: Japanese, Japanese American and North American) MANOVAs were conducted for male favoring tasks (MRT and RCFT) and female favoring tasks (2D and 3D Object Location Memory Tests). Planned comparisons were conducted to test specific hypotheses regarding the interaction of sex differences with culture for specific tests.
Flaherty and Connolly’s (1995) experimental object location memory tests that showed cultural differences were adapted with different objects. The object location memory tests had two subtests. One subtest used small familiar objects that are commonly used in daily life, such as a pair of scissors, a water bottle, a glue stick, and so on. The other subtest used stones that were in different colors, sizes, and shapes. The familiar objects were placed on a white card divided into 20 squares, in a 5 9 4 row matrix. In the case of the stones, they were placed in a 3 9 4 row matrix, which had 12 squares. Participants were exposed to these objects/stones for 25 s and asked to remember each location. The maximum score for each subtest was 20 points for familiar objects and 12 points for stones. 3D Object Location Memory Test The grocery shopping Virtual Reality Spatial Object Location Test (VRSOLT) is an experimental real world object location memory task developed using a commercial virtual reality software package (VR Worlds, Psychology Software Tools, Inc., Pittsburgh, PA). It was designed to measure incidental object-location memory for common grocery store items as well as efficiency of route through a 3D virtual grocery store (Spiers et al., 2008). In this task, participants were instructed to locate and retrieve 12 specifically listed grocery items and scored on the following criteria: (1) ability to correctly place each of the 12 items, plus 4 incidental memory items, on a 2D map following the VR task; (2) their “efficiency of route,” defined as the number of aisle entries in the retrieval of the original 12 items; and (3) completion time. These measures were administered and scored by two experimenters. In order to assure inter-rater reliability, they independently scored and compared the results. These comparisons were repeatedly done before the actual data collection and showed high agreement. Participants’ level of acculturation was not assessed in this study. Currently available acculturation questionnaires (e.g., Ward & Kennedy, 1994) would not answer our specific questions regarding language learning and spatial strategies in different cultures. All test instructions, the demographic questionnaire, and informed consent form were carefully translated and backtranslated by three individuals who were fluent in both English and Japanese. Native Japanese participants completed all
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Data Analysis
Results Table 2 shows test performance of each cultural and sex group. On male favoring tasks (MRT and RCFT), the Wilks Lambda multivariate test of overall differences among groups was statistically significant, indicating that males performed better than females (p \ .001) and the Japanese group performed better than the Japanese American and North American groups (p\.001). In terms of the female favoring tasks (2D and 3D object location memory tests), the Wilks Lambda multivariate test of overall differences among groups was statistically significant, indicating that females performed better than males (p\.001), and the Japanese group performed better than the Japanese American and North American groups (p \ .001). Further analyses of individual tasks were then conducted to more closely examine main effects and interactions for each task (see Table 3). Male Favoring Tasks On the MRT, there was no significant difference between the native Japanese group and the Japanese American group (d = .27). However, the North American group performed more poorly than the native Japanese (p = .002, d = .71) and Japanese American groups (p = .04, d = .49). As expected, males performed better than females (p\.001, d = 1.23). On the RCFT Immediate Recall (IR), the Japanese group performed significantly better than the Japanese American (p \ .001, d = .88) and North American groups (p \ .001, d = 1.03), but there was no significant difference between the Japanese American and North American groups (d = .29). Males performed significantly better than females (p = .002, d = .73). Follow up testing of our specific hypothesis related to smaller sex differences in native Japanese Kanji educated participants gave some support to the hypothesis that the Japanese group did not show significant sex differences on IR, F(1, 18)\1, d = .29, whereas the other two groups did
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Table 2 Test performance on visuospatial tasks Native Japanese (n = 20)
Japanese Americans (n = 20)
North Americans (n = 40)
Males (n = 10) M (SD)
Females (n = 10) M (SD)
Males (n = 10) M (SD)
Females (n = 10) M (SD)
Males (n = 20) M (SD)
Females (n = 20) M (SD)
15.1 (3.81)
9.9 (2.69)
14.3 (4.30)
8.4 (2.17)
10.9 (4.35)
7.7 (3.18)
IR
28.4 (3.54)
27.1 (2.14)
25 (2.79)
21.5 (2.54)
24.7 (5.04)
21.8 (3.39)
DR
27.9 (4.10)
26.8 (2.26)
23.5 (2.98)
21.8 (2.99)
23.3 (5.69)
20.2 (3.13)
Strategy
27.3 (3.77)
28.8 (2.04)
25.3 (4.62)
21.5 (3.14)
24.5 (3.76)
20.4 (5.53)
2D Location memory 20 Familiar objects
14.7 (3.33)
17.7 (1.95)
12.1 (4.12)
15.6 (1.9)
11.1 (3.55)
13.2 (2.40)
12 Non-familiar objects
7.6 (2.46)
10.4 (1.35)
8.3 (2.63)
9.6 (2.46)
8.2 (2.74)
8.9 (2.90)
Accuracy
12.9 (1.2)
14.4 (1.51)
11.3 (2.11)
13.6 (1.51)
11.3 (2.27)
13.4 (1.73)
Efficiency
12.2 (2.74)
10.2 (2.48)
15.3 (3.30)
13.2 (2.15)
14.9 (3.97)
12.4 (3.19)
Completion time (s)
258.6 (39.15)
312.7 (39.15)
251.0 (48.92)
311.6 (57.09)
255.1 (65.64)
306.4 (76.68)
MRT RCFT
VRSOLT
show sex differences, Japanese Americans: F(1, 18) = 5.84, p = .004, d = 1.38, North Americans: F(1, 38) = 4.33, p = .04, d = .67. However, this conclusion must be tentative as the overall sex by group interaction for IR did not reach significance, F(2, 74)\1, η2 = .06. On the DR portion of the RCFT, the Japanese group recalled the figure significantly better than the Japanese American group (p\.001, d = 1.08) and the North American group (p \ .001, d = 1.05), but there was no significant difference between the Japanese American and North American groups (d = .20). A significant sex difference was found in the expected direction with males performing better than females (p = .02, d = .58). On post hoc tests, the Japanese group did not show significant sex differences on DR, F(1, 18) \ 1, d = .24, while the other two groups did: Japanese Americans: F(1, 18) = 5.96, p = .03, d = .62; North Americans: F(1, 38) = 4.63, p = .04, d = .70. However, again this hypothesis is tentative as the sex by group interaction did not reach significance, F(2, 74)\1, η2 = .06. Regarding the copying strategy or approach to the RCFT, the native Japanese group used a more holistic or spatial approach to copy the figure than the Japanese American group (p = .001, d = 1.08) and the North American group (p\.001, d = 1.10). There was no significant difference between the Japanese American and North American groups (d = .38). There was a significant sex difference whereas males earned more holistic strategy points than females (p = .036, d = .49). On this task, a significant interaction between sex and cultural groups was found, F(2, 74) = 3.18, p = .04, η2 = .10. There was no sex difference in the native Japanese group, F(1, 18) = 1.22, p = .28, d = .52, while a sex difference was found in the Japanese American, F(1, 18) = 4.54, p = .047, d = 1.00, and the North American groups, F(1, 38) = 7.30, p = .01, d = 0.88.
Female Favoring Tasks On the 20-familiar object location task, the native Japanese group was able to reproduce the highest number of 20 locations among three groups, performing better than the Japanese American (p = .02, d = 1.25), and North American (p\.001, d = 1.33) groups, while the Japanese American and the North American groups performed similarly (p = .06, d = .54). A significant sex difference was found in the expected direction with females performing better than males (p \ .001, d = .62). While no cultural group difference was found for the 12 object location task, there was a sex difference (p = .01, d = .56). As we expected, females remembered more objects than males did. On accuracy of item placement recall of 16 items of the grocery shopping VRSOLT, the native Japanese participants outperformed the Japanese American (p = .04, d = .68) and the North American participants (p = .01, d = .66). There was no significant difference between the Japanese American and North American groups (d = .06). Similarly, in terms of efficiency, the Japanese entered aisles significantly fewer times than the Japanese Americans (p = .003, d = 1.15) or the North Americans (p = .005, d = .74) to collect all items. There was no difference in efficiency between the Japanese American and North American groups (d = .16). There were no differences in completion time, which indicated that all three groups spent a similar length of time in the virtual grocery store (d = .04). In terms of sex differences on the VRSOLT, the female participants recalled more item locations than the male participants (accuracy: p\.001, d = .85), and females found and selected items significantly more efficiently in the virtual grocery store than males (p = .004, d = .71). When comparing the completion time, female participants across all groups
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Table 3 Results of ANOVA and post hoc tests on cultural and sex differences on spatial tests F
p
Group comparison
MRT Cultural
5.84
.004
J = JA[NA
Sex
31.65
\.001
M[F
Cultural
12.75
\.001
J[JA = NA
Sex DR
10.81
.002
M[F
Cultural
14.45
\.001
J[JA = NA
Sex
6.09
.02
M[F
Cultural
12.30
\.001
J[JA = NA
Sex
4.57
.036
M[F
RCFT IR
Strategy
20 Familiar object location memory test Cultural
12.38
\.001
J[JA = NA
Sex
16.59
\.001
F[M
12 Unfamiliar object location memory test Cultural
\1
ns
Sex
7.11
.01
F[M
3.71 20.38
.03 \.001
J[JA = NA F[M
VRSOLT Accuracy Cultural Sex Efficiency Cultural
5.63
.005
J[JA = NA
Sex
8.96
.004
F[M
Completion time Cultural
\1
ns
Sex
14.98
\.001
F[M
J native Japanese, JA Japanese Americans, NA North Americans, M males, F females
spent significantly more time collecting the grocery items than male participants in the virtual grocery store (p\.001, d = .42).
Discussion Native Japanese participants with a high level of Kanji education outperformed both Japanese Americans with no Kanji education and North American English speakers on all spatial tasks except for the MRT (where both Japanese groups outperformed North Americans). Given that the native Japanese outperformed Japanese Americans on the majority of tasks, and both Japanese groups had similar ancestry, an argument
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can be made that experiential cultural differences between the groups may account for many of the performance differences on the spatial tasks employed here. In addition, the diminishment of sex differences on the RCFT in the native Japanese Kanji educated group suggests an influence of intensive pictorial language experience for this task. First, experiential cultural differences may relate to the intensive practice over years by native Japanese Kanji educated people. Ninth grade education requires a high level of Kanji training. Some complicated characters comprise 30 or more strokes. As previous studies have suggested (Bond, 1980; Gitterman & Sies, 1992), the vigorous visual training, such as the visual processing skills, formation of images, and attention to details involved in constant learning and use of complex symbolic characters on a daily basis may lead to the native Japanese superiority on most of the visuospatial tasks in this study and may partly explain the difference in findings between this study and previous work in which there was no significant difference in spatial object location memory between cultures for lower levels of Kanji education despite apparent differences in strategy (Flaherty & Connolly, 1995). In addition to the influence of Kanji itself, other general educational systems must be considered. Japanese children’s better performance than Westerners in mathematics has been well reported (Iben, 1991; Stevenson, Lee, & Stigler, 1996; Witman et al., 1997). Researchers found that, when comparing educational achievement in North American and Japanese youth of the same age, Japanese students were two grade levels ahead of North American students. Considering the Japanese children’s higher performance in mathematics, it may be that the Japanese raised in this system, as our native Japanese group was, would outperform the Japanese Americans and North Americans on most spatial measures, as well as many measures related to math. On one measure, the MRT, which is strongly associated with geometry, Japanese Americans performed similarly to native Japanese and Japanese Americans outperformed North Americans. Sociological and anthropological studies have reported that East Asian parents’ beliefs in academic achievement, especially mathematics, are stronger than those of North American parents (Chen & Stevenson, 1995; Ginsberg, Choi, Lopez, Netley, & Chi, 1997; Stevenson, Chen, & Lee, 1993). East Asian children, including Japanese children, are encouraged to devote more time to do math homework and are challenged to do more difficult math problems by their teachers and parents (Chen & Stevenson, 1989; Stigler & Hiebert, 1999). Therefore, even though the Japanese American participants in this study did not participate in the Japanese educational system, they might have attained a higher level of spatial achievement related to their parent’s encouragement of educational achievement (Chen & Stevenson, 1995; d’Ailly, 1992). It is also possible that the Japanese Americans had high achievement motivation on the math-like
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task, the MRT (Heil & Jansen-Osmann, 2008; Voyer et al., 2006). Finally, the native Japanese in this study were international students who were studying overseas and therefore they might have been academically superior and have higher motivation than participants in other cultural groups. While all participants across three cultural groups were college students whose IQ generally falls in the above average range, and there were no group differences in years of age and education, participants’ global intelligence was not systematically compared. However, since intelligence tests are highly culturally specific (i.e., generally North American in origin) and are strongly correlated with educational attainment, cognitive equivalence across cultural groups using IQ tests is difficult to determine. Future research is needed to tease out the effects of general educational attainment and rigor, motivation to achieve, and a focus on intensive spatial practice on spatial task performance. Regarding the hypothesis of smaller sex differences in Asians, we found significant sex differences across all cultural groups; therefore, this hypothesis was not supported across most tasks, except with the task that could be considered most like Kanji, the RCFT. Thus, the hypothesized interaction that native Japanese with Kanji education would show smaller sex differences on spatial tasks than Japanese Americans or North Americans without Kanji education was suggested only in the case of the RCFT. These findings were partially consistent with Isomura’s (2002) study in which reduced sex differences were found in the Japanese group but only in the DR portion of the RCFT. It is important to note that, in this study, only Japanese Americans and European Americans were compared. The Japanese Americans showed significantly smaller sex differences only in DR of the RCFT as compared to European Americans, but it is unknown to what degree the Japanese American participants were exposed to Kanji education. Unlike that study, the current study included not only Japanese Americans but also the native Japanese who had intensive Kanji experience. Furthermore, we evaluated the RCFT strategy, measuring one’s approach for drawing the complex figure, and found smaller sex differences in strategy in addition to IR and DR in our native Japanese group only. Since the RCFT is the most Kanjilike test in form and execution, compared to the rest of the tests used in the present study, Kanji education may be an important factor here. In addition to recording strategy points, it was qualitatively observed that all native Japanese participants copied and reproduced the Rey figure in a very similar way-left to right, top to bottom, and bigger outlines to smaller details in the figure while the other two cultural groups (Japanese American and North American) demonstrated a variety of strategies. This particular style and specific order is taught to learn Kanji characters in the Japanese education system. Because both Japanese males and females have an equally long history
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of Kanji education, the sex difference in IR, DR, and strategy on the RCFT might be diminished. In regard to sex differences found on the RCFT, it is important to reiterate that studies of Western participants have suggested variability in performance. Some studies have shown strong sex differences, often favoring makes, while others have shown none (for review, see Mitrushina et al., 2005; Strauss et al., 2006). The results of the current study support previous suggestions that performance differences on the RCFT are not simply characterized by sex and may involve other factors, such as culture, educational experience, and handedness (D’Andrea & Spiers, 2005; Vlachos et al., 2003; Weinstein et al., 1990). The most robust sex differences in spatial performance were evident in the spatial visualization task (MRT) and spatial location memory tasks (2D and 3D object location memory tests) regardless of cultural group membership. A number of studies suggest that brain organizing hormones play an important role in sex-related spatial performance (Bibawi, Cherry, & Hellige, 1995; Janowsky, Oviatt, & Orwoll, 1994), and particularly that testosterone increases overall spatial ability; therefore, males, as a group, might outperform females on many spatial tasks (Janowsky et al., 1994). Additionally, males’ brains are reportedly more specialized and localized for spatial function (Gur et al., 2000). Neural activation studies also suggest that males and females implement different cognitive strategies (Jordan, Wu¨stenberg, Heinze, Peters, & Ja¨ncke, 2002), which may relate to the results seen in the current study. In summary, this study suggests that sex and cultural differences in spatial performance exist, and yet experiential, educational, and cultural differences may increase or decrease the magnitude of the group and sex differences in some tasks. In particular, individuals with a native Japanese Kanji educational background showed decreased sex differences on some aspects of the RCFT but not on the MRT or spatial location memory tasks. There were a few limitations to this study. Due to the stringent inclusion and exclusion criteria and the location of this study, the recruitment of participants, especially native Japanese and Japanese Americans, was challenging and resulted in a small sample size. As a result, statistical power to detect interactions may have been reduced. However, effect sizes for interaction terms were between small to medium, which suggests that meaningful significant differences at this level may not be found even if we increased the sample size. Second, as mentioned above, a question regarding the group equivalence still remains. Even though the three cultural groups were comparable in terms of age and education, they might not be entirely equivalent on cognitive, motivational or other cultural measures. Additionally, since only young and healthy participants were recruited for this study, it is important for future studies to investigate sex and cultural differences in spatial performance with clinical populations or participants in different age groups.
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To date, norms and interpretations of many spatial tests in achievement, intellectual, and neuropsychological assessments are still keyed to Western culture. The results of this study suggest that, even for spatial tests that have traditionally been characterized as less culture bound because of their non-verbal nature, the importance of culture and experience should not be minimized and warrants further exploration.
References Bennett-Levy, J. (1984). Determinants of performance on the ReyOsterrieth Complex Figure Test: An analysis, and a new technique for single-case assessment. British Journal of Clinical Psychology, 23, 109–119. Bibawi, D., Cherry, B., & Hellige, J. B. (1995). Fluctuations of perceptual memory asymmetry across time in women and men: Effects related to menstrual cycle. Neuropsychologia, 33, 131–138. Bond, M. H. (1980). The psychology of the Chinese people. Hong Kong: Oxford University Press. Chen, C., & Stevenson, H. W. (1989). Homework: A cross-cultural examination. Child Development, 60, 551–561. Chen, C., & Stevenson, H. W. (1995). Motivation and mathematics achievement: A comparative study of Asian-American, CaucasianAmerican, and East Asian high school students. Child Development, 66, 1215–1234. Collaer, M. L., & Nelson, J. D. (2002). Large visuospatial sex difference in line judgment: Possible role of attentional factors. Brain and Cognition, 49, 1–12. d’Ailly, H. H. (1992). Asian mathematics superiority: A search for explanation. Educational Psychologist, 27, 243–261. D’Andrea, E., & Spiers, M. V. (2005). The effect of familial sinistrality and academic experience on cognition in right-handed women. Neuropsychology, 19, 657–663. Flaherty, M., & Connolly, M. (1995). Space perception, coordination and a knowledge of Kanji in Japanese and non-Japanese. Psychologia, 38, 229–237. Ginsberg, H. C., Choi, Y. E., Lopez, L. S., Netley, R., & Chi, C. Y. (1997). Happy birthday to you: Early mathematical thinking of Asian, South American and U.S. children. In T. Nunes & P. Bryant (Eds.), Learning and teaching mathematics: An international perspective (pp. 163–207). Hove, UK: Psychology Press. Gitterman, M. R., & Sies, L. F. (1992). Nonbiological determinants of the organization of language in the brain: A comment on Hu, Qiou and Zhong. Brain and Language, 43, 162–165. Gro¨n, G., Schul, D., Bretschneider, V., Wunderlich, A. P., & Riepe, M. W. (2003). Alike performance during nonverbal episodic learning from diversely imprinted neural networks. European Journal of Neuroscience, 18, 3112–3120. Gur, R. C., Alsop, D., Glahn, D., Petty, R., Swanson, C. L., Maldjian, J. A., … Gur, R. E. (2000). An fMRI study of sex differences in regional activation to a verbal and a spatial task. Brain and Language, 74, 157–170. Hampstead, B. M., Stringer, A. Y., Stilla, R. F., Amaraneni, A., & Sathian, K. (2011). Where did I put that? Patients with amnestic mild cognitive impairment demonstrate widespread reductions in activity during the encoding of ecologically relevant object-location associations. Neuropsychologia, 49, 2349–2361. Heil, M., & Jansen-Osmann, P. (2008). Gender differences in math and mental rotation. European Journal of Developmental Science, 2, 190–196. Iben, M. F. (1991). Attitudes and mathematics. Comparative Education, 27, 135–151.
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Arch Sex Behav (2014) 43:483–491 Isomura, A. J. (2002). Verbal and spatial explicit memory performance among Japanese Americans and European Americans: Gender and ethnic differences. Dissertation Abstracts International, 63-B(6), 3034. Janowsky, J. S., Oviatt, S. K., & Orwoll, E. S. (1994). Testosterone influences spatial cognition in older men. Behavioral Neurosciences, 108, 325–332. Jordan, K., Wu¨stenberg, T., Heinze, H.-J., Peters, M., & Ja¨ncke, L. (2002). Women and men exhibit different cortical activation patterns during mental rotation tasks. Neuropsychologia, 40, 2397–2408. Linn, M. C., & Petersen, A. C. (1985). Emergence and characterization of sex differences in spatial ability: A meta-analysis. Child Development, 56, 1479–1498. Lynn, R. (1987). The intelligence of the Japanese. Bulletin of British Psychological Society, 30, 69–72. Lynn, R., Hampton, F., & Bingham, R. (1987). Japanese, British, and American adolescents compared for Spearman’s g and for verbal, numerical, and visuospatial abilities. Psychologia, 30, 137–144. Mitrushina, M., Boone, K. B., Razani, J., & D’Elia, L. F. (2005). Handbook of normative data for neuropsychological assessment. New York: Oxford University Press. Nagoshi, C. T., & Johnson, R. C. (1987). Cognitive abilities profiles of Caucasian vs Japanese in the Hawaiian Family Study of Cognition. Personality and Individual Differences, 8, 581–583. Osterrieth, P. A. (1944). Le test de copie d’une figure complex: Contribution a l’etude de la perception et de la memoire. Archives de Psychologie, 30, 286–356. Peters, M., Laeng, B., Latham, K., Jackson, M., Zaiyouna, M., & Richardson, C. (1995). A redrawn Vandenberg and Kuse Mental Rotations test: Different versions and factors that affect performance. Brain and Cognition, 28, 39–58. Postma, A., Kessels, R. P. C., & van Asselen, M. (2008). How the brain remembers and forgets where things are: The neurocognition of object-location memory. Neuroscience and Biobehavioral Reviews, 32, 1339–1345. Rahman, Q., Wilson, G. D., & Abrahams, S. (2003). Sexual orientation related differences in spatial memory. Journal of the International Neuropsychological Society, 9, 376–383. Rey, A. (1941). L’examen psychologique dans les cas d’encephalopathie traumatique. Archives de Psychologie, 28, 286–340. Rey, A. (1964). L’examen clinique en psychologie. Paris: Presses Universitaires & France. Silverman, I., Phillips, K., & Silverman, L. K. (1996). Homogeneity of effect sizes for sex across spatial tests and cultures: Implications for hormonal theories. Brain and Cognition, 31, 90–94. Sommer, T., Rose, M., Weiller, C., & Bu¨chel, C. (2005). Contributions of occipital, parietal and parahippocampal cortex to encoding of object-location associations. Neuropsychologia, 43, 732–743. Spiers, M. V., Sakamoto, M., Elliott, R. J., & Baumann, S. (2008). Sex differences in spatial object-location memory in a virtual grocery store. CyberPsychology & Behavior, 11, 471–473. Stevenson, H. M., Chen, C., & Lee, S. (1993). Mathematics achievement of Chinese, Japanese, and American children: Ten years later. Science, 259, 53–58. Stevenson, H. M., Lee, S., & Stigler, J. M. (1996). Mathematics achievement of Chinese, Japanese, and American children. Science, 231, 693–698. Stigler, J. W., & Hiebert, J. (1999). The teaching gap: Best ideas from the world’s teachers for improving education in the classroom. New York: Free Press. Strauss, E., Sherman, E. M. S., & Spreen, O. (2006). A compendium of neuropsychological tests: Administration, norms, and commentary (3rd ed.). New York: Oxford University Press. Tottenham, L. S., Saucier, D., Elias, L., & Gutwin, C. (2003). Female advantage for spatial location memory in both static and dynamic environments. Brain and Cognition, 53, 381–383.
Arch Sex Behav (2014) 43:483–491 Vlachos, F., Andreou, G., & Andreou, E. (2003). Biological and environmental influences in visuospatial abilities. Learning and Individual Differences, 13, 339–347. Voyer, D., Butler, T., Cordero, J., Brake, B., Silbersweig, D., Stern, E., & Imperato-McGinley, J. (2006). The relation between computerized and paper-and-pencil mental rotation tasks: A validation study. Journal of Clinical and Experimental Neuropsychology, 28, 928–939. Voyer, D., Voyer, S., & Bryden, M. P. (1995). Magnitude of sex differences in spatial abilities: A meta-analysis and consideration of critical variables. Psychological Bulletin, 117, 250–270. Wang, X. (1994). Gender differences in spatial, verbal, and mathematical abilities for Chinese students: A cross-cultural comparison. Unpublished doctoral dissertation, University of Iowa.
491 Ward, C., & Kennedy, A. (1994). Acculturation strategies, psychological adjustment, and sociocultural competence during cross-cultural transitions. International Journal of Intercultural Relations, 18, 329–343. Weinstein, C. S., Kaplan, E., Casey, M. B., & Hurwitz, I. (1990). Delineation of female performance on the Rey-Osterrieth Complex Figure. Neuropsychology, 4, 117–127. Witman, N. C., Nohda, N., Lai, M. K., Hashimoto, T., Iijima, Y., Isoda, M., & Hoffer, A. (1997). Mathematics education: A cross-cultural study. Peabody Journal of Education, 72, 215–232.
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ORIGINAL PAPER
Sex and Cultural Differences in Spatial Performance Between Japanese and North Americans Maiko Sakamoto · Mary V. Spiers
Received: 21 December 2011 / Revised: 5 October 2012 / Accepted: 10 October 2013 / Published online: 20 December 2013 © Springer Science+Business Media New York 2013
Abstract Previous studies have suggested that Asians perform better than North Americans on spatial tasks but show smaller sex differences. In this study, we evaluated the relationship between long-term experience with a pictorial written language and spatial performance. It was hypothesized that native Japanese Kanji (a complex pictorial written language) educated adults would show smaller sex differences on spatial tasks than Japanese Americans or North Americans without Kanji education. A total of 80 young healthy participants (20 native Japanese speakers, 20 Japanese Americans-non Japanese speaking, and 40 North Americans-non Japanese speaking) completed the Rey Complex Figure Test (RCFT), the Mental Rotations Test (MRT), and customized 2D and 3D spatial object location memory tests. As predicted, main effects revealed men performed better on the MRT and RCFT and women performed better on the spatial object location memory tests. Also, as predicted, native Japanese performed better on all tests than the other groups. In contrast to the other groups, native Japanese showed a decreased magnitude of sex differences on aspects of the RCFT (immediate and delayed recall) and no significant sex difference on the efficiency of the strategy used to copy and encode the RCFT figure. This study lends support to the idea that intensive experience over time with a pictorial written language (i.e., Japanese Kanji) may contribute to increased spatial performance on some spatial tasks as well as diminish sex differences in performance on tasks that most resemble Kanji. M. Sakamoto (&) Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, Saga 849-8501, Japan e-mail: [email protected] M. V. Spiers Department of Psychology, Drexel University, Philadelphia, PA, USA
Keywords Visuospatial ability Sex differences Japanese Written language Kanji characters
Introduction Research on sex differences in spatial performance, which has primarily been studied within an American and European context, has suggested that spatial visualization tasks (e.g., Mental Rotations Test: MRT) (Linn & Petersen, 1985; Voyer, Voyer, & Bryden, 1995), spatial perception tasks (e.g., Judgment of Line Orientation: JOLO) (Collaer & Nelson, 2002), and spatial organization tasks (e.g., Rey Complex Figure Test: RCFT) (Mitrushina, Boone, Razani, & D’Elia, 2005) are often performed better by males while object location memory tasks (e.g., Brief Visuospatial Memory Test-revised: BVMT-R) are generally performed better by females (Rahman, Wilson, & Abrahams, 2003; Silverman, Phillips, & Silverman, 1996; Spiers, Sakamoto, Elliott, & Baumann, 2008; Tottenham, Saucier, Elias, & Gutwin, 2003). The RCFT is a task that requires both spatial organization skills and ability to memorize locations of parts. The literature suggests that sex differences in the RCFT are generally in favor of males (for reviews, see Mitrushina et al., 2005; Strauss, Sherman, & Spreen, 2006); however, variation in RCFT performance has also been found related to handedness (D’Andrea & Spiers, 2005; Weinstein, Kaplan, Casey, & Hurwitz, 1990) and experience in math and science (Vlachos, Andreou, & Andreou, 2003). Regarding cultural differences in spatial performance, various researchers have reported that Asians (i.e., Japanese and Chinese) perform better than North Americans and Europeans on various spatial tests, including the MRT, JOLO, RCFT, and object location memory tests (Flaherty & Connolly, 1995; Isomura, 2002; Lynn, 1987; Nagoshi & Johnson, 1987; Silverman et al., 1996; Wang, 1994). For example, in an early study,
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Nagoshi and Johnson (1987) reported that Japanese Americans raised in Hawaii performed better than European Americans on spatial and perceptual speed tasks in spite of the fact that the two groups had similar cultural backgrounds, including socioeconomic status and educational levels. Lynn, Hampton, and Bingham (1987) found that Japanese had significantly higher scores on spatial relations tests than British and American participants although cultural and educational differences among the three groups were not taken into account as possible factors that might have influenced performance. Regarding possible cultural or experiential factors, Flaherty and Connolly (1995) focused on the impact of the written language called Kanji (漢字), which consists of Chinese characters that the Japanese adapted hundreds of years ago. This written language relies on pictorial characters rather than letters. In Japanese, approximately 1,100 complicated Kanji characters are used in daily life; therefore, children must memorize 100–200 pictorial characters per year. Some characters look alike, requiring extremely clear delineation and years of practice to avoid misinterpretation. These 1,100 characters are required for the level of fluency necessary to read newspapers and literature in Japanese and are generally mastered by the ninth grade. In their study, Flaherty and Connelly did not find significant performance differences on spatial object location memory tasks between low level (e.g., third to forth grade) Japanese Kanji educated participants and Europeans with no knowledge of Kanji. However, in order to evaluate the full impact of Kanji on spatial performance, the level of knowledge of Kanji would be better assessed at the fully literate ninth grade level. In addition to the possible impact of having a pictorial written language, Japanese learning strategies for visual information may also impact spatial performance. The vigorous Kanji training, which includes visual processing skills, formation of images, and attention to detail involved in learning these complex symbolic characters throughout life, may facilitate higher level processing of pictorial information in general (Bond, 1980; Gitterman & Sies, 1992). For instance, there are specific rules and an inherent order in writing Kanji characters: top to bottom and left to right. Japanese students are constantly drilled on these rules throughout their school years and calligraphy is judged by the beauty, details, and spatial balance within and between Kanji characters. As a result, Japanese students may develop strong spatial learning strategies in general. Only a few studies have systematically considered spatial learning strategies in Asians versus Westerners. In one study, when Japanese participants memorized the locations of objects, they showed no signs of vocalization either covertly or overtly whereas Europeans often verbalized to remember the locations of objects (Flaherty & Connolly, 1995). Gro¨n, Schul, Bretschneider, Wunderlich, and Riepe (2003) also found significant Chinese versus Caucasian differences in fMRI activation of brain areas on the same spatial location memory task. Chinese
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participants who use Kanji characters outperformed the Caucasian individuals and primarily activated the dorsal (i.e., “where”) stream whereas the ventral (i.e., “what”) stream was primarily activated in the Caucasian group. This suggests that the visual information traveled from the primary visual cortex to posterior parietal cortex in Chinese individuals while the same information was processed between the primary visual cortex and the inferior temporal cortex in Caucasian cohorts on the same object location memory tasks. It is important to note that object location memory requires both object identification (ventral) and spatial location (dorsal) skills (Postma, Kessels, & van Asselen, 2008); however, neural activation in dorsolateral prefrontal cortex has been significantly associated with subsequent memory for object locations (Hampstead, Stringer, Stilla, Amaraneni, & Sathian, 2011; Sommer, Rose, Weiller, & Bu¨chel, 2005). The greater activation of the dorsal area in Chinese participants may account for their recall of more object locations compared to the Caucasians. Thus, Chinese and Japanese cultures showed differences from Western cultures both in their behavioral strategies and in neural activation. The other area of interest in spatial performance is related to the suggestion that sex differences among Asians may not be as large as their North American counterparts. For instance, when Chinese students’ spatial, verbal, and mathematical abilities were compared to North American students, Chinese students outperformed North American students on spatial performance tasks; moreover, the sex differences were smaller for the Chinese sample than for the North American sample (Wang, 1994). Similarly, smaller sex differences were found in a Japanese group compared to a North American group when performance on the delayed recall (DR) of the RCFT was evaluated (Isomura, 2002). Given that both Japanese and Chinese use the pictorial written language Kanji, which requires visuospatial memory and visual organization and is used everyday throughout their lives, it is possible that the experience of Kanji may be an important factor in decreasing the sex differences in spatial tasks. Unlike previous studies, the current study aimed to investigate three cultural groups: native Japanese with advanced Kanji education, Japanese Americans without Kanji, and North Americans without Kanji. Since the interest was in long and intensive exposure to a complex pictorial written language and its impact on visuospatial performance, native Japanese participants’ high level of knowledge in Kanji would be also required. Additionally, this study aimed to assess whether sex differences would be diminished on spatial tasks in a culture where both sexes have high levels of practice with the pictorial Kanji language. In this study, it was hypothesized that (1) native Japanese would outperform Japanese Americans and North Americans on spatial performance tests and (2) in general males would perform better than females on male favoring tasks (MRT and RCFT) and females would outperform males on female favoring tasks (2D and 3D Object Location Memory Tests)
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Table 1 Demographic characteristics of the sample Native Japanese (n = 20)
Japanese Americans (n = 20)
North Americans (n = 40)
Males (n = 10) M (SD)
Females (n = 10) M (SD)
Males (n = 10) M (SD)
Females (n = 10) M (SD)
Males (n = 20) M (SD)
Females (n = 20) M (SD)
Age (years)
21.2 (1.9)
20.6 (1.3)
22.1 (3.5)
21.5 (2.3)
20.3 (2.0)
20.5 (3.3)
Education (years)
14.9 (2.2)
14.5 (2.4)
14.3 (2.3)
14.0 (1.9)
14.0 (1.4)
14.0 (1.9)
but this would interact with group, such that native Japanese participants with Kanji education would show smaller sex differences on spatial tasks than North Americans or Japanese Americans without Kanji education.
Method
Participants’ demographic characteristics are shown in Table 1. There were no significant differences in age or years of education among the three cultural groups, age: F(2, 74) = 2.03, education: F(2, 74)\1, and between males and females, age: F(1, 74)\1, education: F(1, 74)\1. This study was approved by the Drexel University Institutional Review Board (IRB). Written informed consent was obtained from all participants after the research procedure had been fully explained to them.
Participants Measures Twenty Native Japanese (10 males and 10 females), 20 Japanese Americans (10 males and 10 females), and 40 North Americans (20 males and 20 females) participated in this study. The native Japanese and North American were recruited at Drexel University in Philadelphia, PA, and Japanese American participants were recruited through the Japan America Society in Greater Philadelphia (JASGP). Individuals were between the ages of 18 and 35 years and able to read and speak their native language (e.g., Japanese for the native Japanese and English for the Japanese American and North American). Native Japanese participants were required to have at least a ninth grade level Kanji education measured by a Kanji examination, to be able to speak Japanese more fluently than English, and to not have lived in the United States for more than 1 year. Japanese American and North American participants were required to have no exposure to Kanji education, to read and speak English at a level of proficiency (ninth grade level), to be more fluent in spoken English than Japanese, and to not have lived in Japan or China for more than 1 year. Native Japanese had Japanese ancestry in both parents, Japanese Americans had Japanese ancestry (75 % of Japanese American had Japanese ancestry in both parents and 25 % had one parent who was Japanese and the other was either Chinese or Korean), and the North American sample was selected to have Western European ancestry in both parents. Individuals who were left handed, had a history of head injury, trauma, or severe medical problems (both physical and mental), were diagnosed with learning disabilities, were taking medications whose side effects might influence spatial performance, and had previously taken any of the spatial tests that were used in this study were going to be excluded from participation. Two potential participants who met the criteria were excluded from the current study.
Based on the prior research related to sex differences and crosscultural studies of visuospatial differences between Westerners and Asians, the visuospatial tasks below were chosen for this study. Mental Rotations Test (MRT) Spatial orientation ability and strategy use was assessed using the Vandenberg MRT (Peters et al., 1995). A line drawing of a three-dimensional figure was presented and participants were asked to determine which of four alternatives would accurately represent the stimulus figure if it were rotated in space. Two of the alternatives were correct and two incorrect for each item. Scores were based on the number of items in which both choices were correct. The Vandenberg MRT is composed of 24 items and the range of scores is from 0 to 24 for each form. Rey Complex Figure Test (RCFT) The RCFT (Osterrieth, 1944; Rey, 1941, 1964) served as a measure of visuospatial organization strategy and incidental memory for visual material. Participants were shown a complex figure to copy. It was then removed and drawn from memory without prior warning. A delayed-recall trial was administered after 30 min. Participants’ copy attempts were scored for organizational strategy using the continuation and symmetry measures described by Bennett-Levy (1984), with a maximum score of 36. Higher “strategy points” indicate use of a more holistic strategy. The number of features recalled in the
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immediate- and delayed-recall trials (i.e., accuracy) was also scored. A maximum of two points, one for accuracy and one for placement, were allocated to each scoring unit (18 units, max score = 36).
tests in Japanese and Japanese American and North American participants completed all tests in English.
2D Object Location Memory Tests
To test the hypotheses, 2 (Sex) 9 3 (Culture: Japanese, Japanese American and North American) MANOVAs were conducted for male favoring tasks (MRT and RCFT) and female favoring tasks (2D and 3D Object Location Memory Tests). Planned comparisons were conducted to test specific hypotheses regarding the interaction of sex differences with culture for specific tests.
Flaherty and Connolly’s (1995) experimental object location memory tests that showed cultural differences were adapted with different objects. The object location memory tests had two subtests. One subtest used small familiar objects that are commonly used in daily life, such as a pair of scissors, a water bottle, a glue stick, and so on. The other subtest used stones that were in different colors, sizes, and shapes. The familiar objects were placed on a white card divided into 20 squares, in a 5 9 4 row matrix. In the case of the stones, they were placed in a 3 9 4 row matrix, which had 12 squares. Participants were exposed to these objects/stones for 25 s and asked to remember each location. The maximum score for each subtest was 20 points for familiar objects and 12 points for stones. 3D Object Location Memory Test The grocery shopping Virtual Reality Spatial Object Location Test (VRSOLT) is an experimental real world object location memory task developed using a commercial virtual reality software package (VR Worlds, Psychology Software Tools, Inc., Pittsburgh, PA). It was designed to measure incidental object-location memory for common grocery store items as well as efficiency of route through a 3D virtual grocery store (Spiers et al., 2008). In this task, participants were instructed to locate and retrieve 12 specifically listed grocery items and scored on the following criteria: (1) ability to correctly place each of the 12 items, plus 4 incidental memory items, on a 2D map following the VR task; (2) their “efficiency of route,” defined as the number of aisle entries in the retrieval of the original 12 items; and (3) completion time. These measures were administered and scored by two experimenters. In order to assure inter-rater reliability, they independently scored and compared the results. These comparisons were repeatedly done before the actual data collection and showed high agreement. Participants’ level of acculturation was not assessed in this study. Currently available acculturation questionnaires (e.g., Ward & Kennedy, 1994) would not answer our specific questions regarding language learning and spatial strategies in different cultures. All test instructions, the demographic questionnaire, and informed consent form were carefully translated and backtranslated by three individuals who were fluent in both English and Japanese. Native Japanese participants completed all
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Data Analysis
Results Table 2 shows test performance of each cultural and sex group. On male favoring tasks (MRT and RCFT), the Wilks Lambda multivariate test of overall differences among groups was statistically significant, indicating that males performed better than females (p \ .001) and the Japanese group performed better than the Japanese American and North American groups (p\.001). In terms of the female favoring tasks (2D and 3D object location memory tests), the Wilks Lambda multivariate test of overall differences among groups was statistically significant, indicating that females performed better than males (p\.001), and the Japanese group performed better than the Japanese American and North American groups (p \ .001). Further analyses of individual tasks were then conducted to more closely examine main effects and interactions for each task (see Table 3). Male Favoring Tasks On the MRT, there was no significant difference between the native Japanese group and the Japanese American group (d = .27). However, the North American group performed more poorly than the native Japanese (p = .002, d = .71) and Japanese American groups (p = .04, d = .49). As expected, males performed better than females (p\.001, d = 1.23). On the RCFT Immediate Recall (IR), the Japanese group performed significantly better than the Japanese American (p \ .001, d = .88) and North American groups (p \ .001, d = 1.03), but there was no significant difference between the Japanese American and North American groups (d = .29). Males performed significantly better than females (p = .002, d = .73). Follow up testing of our specific hypothesis related to smaller sex differences in native Japanese Kanji educated participants gave some support to the hypothesis that the Japanese group did not show significant sex differences on IR, F(1, 18)\1, d = .29, whereas the other two groups did
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Table 2 Test performance on visuospatial tasks Native Japanese (n = 20)
Japanese Americans (n = 20)
North Americans (n = 40)
Males (n = 10) M (SD)
Females (n = 10) M (SD)
Males (n = 10) M (SD)
Females (n = 10) M (SD)
Males (n = 20) M (SD)
Females (n = 20) M (SD)
15.1 (3.81)
9.9 (2.69)
14.3 (4.30)
8.4 (2.17)
10.9 (4.35)
7.7 (3.18)
IR
28.4 (3.54)
27.1 (2.14)
25 (2.79)
21.5 (2.54)
24.7 (5.04)
21.8 (3.39)
DR
27.9 (4.10)
26.8 (2.26)
23.5 (2.98)
21.8 (2.99)
23.3 (5.69)
20.2 (3.13)
Strategy
27.3 (3.77)
28.8 (2.04)
25.3 (4.62)
21.5 (3.14)
24.5 (3.76)
20.4 (5.53)
2D Location memory 20 Familiar objects
14.7 (3.33)
17.7 (1.95)
12.1 (4.12)
15.6 (1.9)
11.1 (3.55)
13.2 (2.40)
12 Non-familiar objects
7.6 (2.46)
10.4 (1.35)
8.3 (2.63)
9.6 (2.46)
8.2 (2.74)
8.9 (2.90)
Accuracy
12.9 (1.2)
14.4 (1.51)
11.3 (2.11)
13.6 (1.51)
11.3 (2.27)
13.4 (1.73)
Efficiency
12.2 (2.74)
10.2 (2.48)
15.3 (3.30)
13.2 (2.15)
14.9 (3.97)
12.4 (3.19)
Completion time (s)
258.6 (39.15)
312.7 (39.15)
251.0 (48.92)
311.6 (57.09)
255.1 (65.64)
306.4 (76.68)
MRT RCFT
VRSOLT
show sex differences, Japanese Americans: F(1, 18) = 5.84, p = .004, d = 1.38, North Americans: F(1, 38) = 4.33, p = .04, d = .67. However, this conclusion must be tentative as the overall sex by group interaction for IR did not reach significance, F(2, 74)\1, η2 = .06. On the DR portion of the RCFT, the Japanese group recalled the figure significantly better than the Japanese American group (p\.001, d = 1.08) and the North American group (p \ .001, d = 1.05), but there was no significant difference between the Japanese American and North American groups (d = .20). A significant sex difference was found in the expected direction with males performing better than females (p = .02, d = .58). On post hoc tests, the Japanese group did not show significant sex differences on DR, F(1, 18) \ 1, d = .24, while the other two groups did: Japanese Americans: F(1, 18) = 5.96, p = .03, d = .62; North Americans: F(1, 38) = 4.63, p = .04, d = .70. However, again this hypothesis is tentative as the sex by group interaction did not reach significance, F(2, 74)\1, η2 = .06. Regarding the copying strategy or approach to the RCFT, the native Japanese group used a more holistic or spatial approach to copy the figure than the Japanese American group (p = .001, d = 1.08) and the North American group (p\.001, d = 1.10). There was no significant difference between the Japanese American and North American groups (d = .38). There was a significant sex difference whereas males earned more holistic strategy points than females (p = .036, d = .49). On this task, a significant interaction between sex and cultural groups was found, F(2, 74) = 3.18, p = .04, η2 = .10. There was no sex difference in the native Japanese group, F(1, 18) = 1.22, p = .28, d = .52, while a sex difference was found in the Japanese American, F(1, 18) = 4.54, p = .047, d = 1.00, and the North American groups, F(1, 38) = 7.30, p = .01, d = 0.88.
Female Favoring Tasks On the 20-familiar object location task, the native Japanese group was able to reproduce the highest number of 20 locations among three groups, performing better than the Japanese American (p = .02, d = 1.25), and North American (p\.001, d = 1.33) groups, while the Japanese American and the North American groups performed similarly (p = .06, d = .54). A significant sex difference was found in the expected direction with females performing better than males (p \ .001, d = .62). While no cultural group difference was found for the 12 object location task, there was a sex difference (p = .01, d = .56). As we expected, females remembered more objects than males did. On accuracy of item placement recall of 16 items of the grocery shopping VRSOLT, the native Japanese participants outperformed the Japanese American (p = .04, d = .68) and the North American participants (p = .01, d = .66). There was no significant difference between the Japanese American and North American groups (d = .06). Similarly, in terms of efficiency, the Japanese entered aisles significantly fewer times than the Japanese Americans (p = .003, d = 1.15) or the North Americans (p = .005, d = .74) to collect all items. There was no difference in efficiency between the Japanese American and North American groups (d = .16). There were no differences in completion time, which indicated that all three groups spent a similar length of time in the virtual grocery store (d = .04). In terms of sex differences on the VRSOLT, the female participants recalled more item locations than the male participants (accuracy: p\.001, d = .85), and females found and selected items significantly more efficiently in the virtual grocery store than males (p = .004, d = .71). When comparing the completion time, female participants across all groups
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Arch Sex Behav (2014) 43:483–491
Table 3 Results of ANOVA and post hoc tests on cultural and sex differences on spatial tests F
p
Group comparison
MRT Cultural
5.84
.004
J = JA[NA
Sex
31.65
\.001
M[F
Cultural
12.75
\.001
J[JA = NA
Sex DR
10.81
.002
M[F
Cultural
14.45
\.001
J[JA = NA
Sex
6.09
.02
M[F
Cultural
12.30
\.001
J[JA = NA
Sex
4.57
.036
M[F
RCFT IR
Strategy
20 Familiar object location memory test Cultural
12.38
\.001
J[JA = NA
Sex
16.59
\.001
F[M
12 Unfamiliar object location memory test Cultural
\1
ns
Sex
7.11
.01
F[M
3.71 20.38
.03 \.001
J[JA = NA F[M
VRSOLT Accuracy Cultural Sex Efficiency Cultural
5.63
.005
J[JA = NA
Sex
8.96
.004
F[M
Completion time Cultural
\1
ns
Sex
14.98
\.001
F[M
J native Japanese, JA Japanese Americans, NA North Americans, M males, F females
spent significantly more time collecting the grocery items than male participants in the virtual grocery store (p\.001, d = .42).
Discussion Native Japanese participants with a high level of Kanji education outperformed both Japanese Americans with no Kanji education and North American English speakers on all spatial tasks except for the MRT (where both Japanese groups outperformed North Americans). Given that the native Japanese outperformed Japanese Americans on the majority of tasks, and both Japanese groups had similar ancestry, an argument
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can be made that experiential cultural differences between the groups may account for many of the performance differences on the spatial tasks employed here. In addition, the diminishment of sex differences on the RCFT in the native Japanese Kanji educated group suggests an influence of intensive pictorial language experience for this task. First, experiential cultural differences may relate to the intensive practice over years by native Japanese Kanji educated people. Ninth grade education requires a high level of Kanji training. Some complicated characters comprise 30 or more strokes. As previous studies have suggested (Bond, 1980; Gitterman & Sies, 1992), the vigorous visual training, such as the visual processing skills, formation of images, and attention to details involved in constant learning and use of complex symbolic characters on a daily basis may lead to the native Japanese superiority on most of the visuospatial tasks in this study and may partly explain the difference in findings between this study and previous work in which there was no significant difference in spatial object location memory between cultures for lower levels of Kanji education despite apparent differences in strategy (Flaherty & Connolly, 1995). In addition to the influence of Kanji itself, other general educational systems must be considered. Japanese children’s better performance than Westerners in mathematics has been well reported (Iben, 1991; Stevenson, Lee, & Stigler, 1996; Witman et al., 1997). Researchers found that, when comparing educational achievement in North American and Japanese youth of the same age, Japanese students were two grade levels ahead of North American students. Considering the Japanese children’s higher performance in mathematics, it may be that the Japanese raised in this system, as our native Japanese group was, would outperform the Japanese Americans and North Americans on most spatial measures, as well as many measures related to math. On one measure, the MRT, which is strongly associated with geometry, Japanese Americans performed similarly to native Japanese and Japanese Americans outperformed North Americans. Sociological and anthropological studies have reported that East Asian parents’ beliefs in academic achievement, especially mathematics, are stronger than those of North American parents (Chen & Stevenson, 1995; Ginsberg, Choi, Lopez, Netley, & Chi, 1997; Stevenson, Chen, & Lee, 1993). East Asian children, including Japanese children, are encouraged to devote more time to do math homework and are challenged to do more difficult math problems by their teachers and parents (Chen & Stevenson, 1989; Stigler & Hiebert, 1999). Therefore, even though the Japanese American participants in this study did not participate in the Japanese educational system, they might have attained a higher level of spatial achievement related to their parent’s encouragement of educational achievement (Chen & Stevenson, 1995; d’Ailly, 1992). It is also possible that the Japanese Americans had high achievement motivation on the math-like
Arch Sex Behav (2014) 43:483–491
task, the MRT (Heil & Jansen-Osmann, 2008; Voyer et al., 2006). Finally, the native Japanese in this study were international students who were studying overseas and therefore they might have been academically superior and have higher motivation than participants in other cultural groups. While all participants across three cultural groups were college students whose IQ generally falls in the above average range, and there were no group differences in years of age and education, participants’ global intelligence was not systematically compared. However, since intelligence tests are highly culturally specific (i.e., generally North American in origin) and are strongly correlated with educational attainment, cognitive equivalence across cultural groups using IQ tests is difficult to determine. Future research is needed to tease out the effects of general educational attainment and rigor, motivation to achieve, and a focus on intensive spatial practice on spatial task performance. Regarding the hypothesis of smaller sex differences in Asians, we found significant sex differences across all cultural groups; therefore, this hypothesis was not supported across most tasks, except with the task that could be considered most like Kanji, the RCFT. Thus, the hypothesized interaction that native Japanese with Kanji education would show smaller sex differences on spatial tasks than Japanese Americans or North Americans without Kanji education was suggested only in the case of the RCFT. These findings were partially consistent with Isomura’s (2002) study in which reduced sex differences were found in the Japanese group but only in the DR portion of the RCFT. It is important to note that, in this study, only Japanese Americans and European Americans were compared. The Japanese Americans showed significantly smaller sex differences only in DR of the RCFT as compared to European Americans, but it is unknown to what degree the Japanese American participants were exposed to Kanji education. Unlike that study, the current study included not only Japanese Americans but also the native Japanese who had intensive Kanji experience. Furthermore, we evaluated the RCFT strategy, measuring one’s approach for drawing the complex figure, and found smaller sex differences in strategy in addition to IR and DR in our native Japanese group only. Since the RCFT is the most Kanjilike test in form and execution, compared to the rest of the tests used in the present study, Kanji education may be an important factor here. In addition to recording strategy points, it was qualitatively observed that all native Japanese participants copied and reproduced the Rey figure in a very similar way-left to right, top to bottom, and bigger outlines to smaller details in the figure while the other two cultural groups (Japanese American and North American) demonstrated a variety of strategies. This particular style and specific order is taught to learn Kanji characters in the Japanese education system. Because both Japanese males and females have an equally long history
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of Kanji education, the sex difference in IR, DR, and strategy on the RCFT might be diminished. In regard to sex differences found on the RCFT, it is important to reiterate that studies of Western participants have suggested variability in performance. Some studies have shown strong sex differences, often favoring makes, while others have shown none (for review, see Mitrushina et al., 2005; Strauss et al., 2006). The results of the current study support previous suggestions that performance differences on the RCFT are not simply characterized by sex and may involve other factors, such as culture, educational experience, and handedness (D’Andrea & Spiers, 2005; Vlachos et al., 2003; Weinstein et al., 1990). The most robust sex differences in spatial performance were evident in the spatial visualization task (MRT) and spatial location memory tasks (2D and 3D object location memory tests) regardless of cultural group membership. A number of studies suggest that brain organizing hormones play an important role in sex-related spatial performance (Bibawi, Cherry, & Hellige, 1995; Janowsky, Oviatt, & Orwoll, 1994), and particularly that testosterone increases overall spatial ability; therefore, males, as a group, might outperform females on many spatial tasks (Janowsky et al., 1994). Additionally, males’ brains are reportedly more specialized and localized for spatial function (Gur et al., 2000). Neural activation studies also suggest that males and females implement different cognitive strategies (Jordan, Wu¨stenberg, Heinze, Peters, & Ja¨ncke, 2002), which may relate to the results seen in the current study. In summary, this study suggests that sex and cultural differences in spatial performance exist, and yet experiential, educational, and cultural differences may increase or decrease the magnitude of the group and sex differences in some tasks. In particular, individuals with a native Japanese Kanji educational background showed decreased sex differences on some aspects of the RCFT but not on the MRT or spatial location memory tasks. There were a few limitations to this study. Due to the stringent inclusion and exclusion criteria and the location of this study, the recruitment of participants, especially native Japanese and Japanese Americans, was challenging and resulted in a small sample size. As a result, statistical power to detect interactions may have been reduced. However, effect sizes for interaction terms were between small to medium, which suggests that meaningful significant differences at this level may not be found even if we increased the sample size. Second, as mentioned above, a question regarding the group equivalence still remains. Even though the three cultural groups were comparable in terms of age and education, they might not be entirely equivalent on cognitive, motivational or other cultural measures. Additionally, since only young and healthy participants were recruited for this study, it is important for future studies to investigate sex and cultural differences in spatial performance with clinical populations or participants in different age groups.
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To date, norms and interpretations of many spatial tests in achievement, intellectual, and neuropsychological assessments are still keyed to Western culture. The results of this study suggest that, even for spatial tests that have traditionally been characterized as less culture bound because of their non-verbal nature, the importance of culture and experience should not be minimized and warrants further exploration.
References Bennett-Levy, J. (1984). Determinants of performance on the ReyOsterrieth Complex Figure Test: An analysis, and a new technique for single-case assessment. British Journal of Clinical Psychology, 23, 109–119. Bibawi, D., Cherry, B., & Hellige, J. B. (1995). Fluctuations of perceptual memory asymmetry across time in women and men: Effects related to menstrual cycle. Neuropsychologia, 33, 131–138. Bond, M. H. (1980). The psychology of the Chinese people. Hong Kong: Oxford University Press. Chen, C., & Stevenson, H. W. (1989). Homework: A cross-cultural examination. Child Development, 60, 551–561. Chen, C., & Stevenson, H. W. (1995). Motivation and mathematics achievement: A comparative study of Asian-American, CaucasianAmerican, and East Asian high school students. Child Development, 66, 1215–1234. Collaer, M. L., & Nelson, J. D. (2002). Large visuospatial sex difference in line judgment: Possible role of attentional factors. Brain and Cognition, 49, 1–12. d’Ailly, H. H. (1992). Asian mathematics superiority: A search for explanation. Educational Psychologist, 27, 243–261. D’Andrea, E., & Spiers, M. V. (2005). The effect of familial sinistrality and academic experience on cognition in right-handed women. Neuropsychology, 19, 657–663. Flaherty, M., & Connolly, M. (1995). Space perception, coordination and a knowledge of Kanji in Japanese and non-Japanese. Psychologia, 38, 229–237. Ginsberg, H. C., Choi, Y. E., Lopez, L. S., Netley, R., & Chi, C. Y. (1997). Happy birthday to you: Early mathematical thinking of Asian, South American and U.S. children. In T. Nunes & P. Bryant (Eds.), Learning and teaching mathematics: An international perspective (pp. 163–207). Hove, UK: Psychology Press. Gitterman, M. R., & Sies, L. F. (1992). Nonbiological determinants of the organization of language in the brain: A comment on Hu, Qiou and Zhong. Brain and Language, 43, 162–165. Gro¨n, G., Schul, D., Bretschneider, V., Wunderlich, A. P., & Riepe, M. W. (2003). Alike performance during nonverbal episodic learning from diversely imprinted neural networks. European Journal of Neuroscience, 18, 3112–3120. Gur, R. C., Alsop, D., Glahn, D., Petty, R., Swanson, C. L., Maldjian, J. A., … Gur, R. E. (2000). An fMRI study of sex differences in regional activation to a verbal and a spatial task. Brain and Language, 74, 157–170. Hampstead, B. M., Stringer, A. Y., Stilla, R. F., Amaraneni, A., & Sathian, K. (2011). Where did I put that? Patients with amnestic mild cognitive impairment demonstrate widespread reductions in activity during the encoding of ecologically relevant object-location associations. Neuropsychologia, 49, 2349–2361. Heil, M., & Jansen-Osmann, P. (2008). Gender differences in math and mental rotation. European Journal of Developmental Science, 2, 190–196. Iben, M. F. (1991). Attitudes and mathematics. Comparative Education, 27, 135–151.
123
Arch Sex Behav (2014) 43:483–491 Isomura, A. J. (2002). Verbal and spatial explicit memory performance among Japanese Americans and European Americans: Gender and ethnic differences. Dissertation Abstracts International, 63-B(6), 3034. Janowsky, J. S., Oviatt, S. K., & Orwoll, E. S. (1994). Testosterone influences spatial cognition in older men. Behavioral Neurosciences, 108, 325–332. Jordan, K., Wu¨stenberg, T., Heinze, H.-J., Peters, M., & Ja¨ncke, L. (2002). Women and men exhibit different cortical activation patterns during mental rotation tasks. Neuropsychologia, 40, 2397–2408. Linn, M. C., & Petersen, A. C. (1985). Emergence and characterization of sex differences in spatial ability: A meta-analysis. Child Development, 56, 1479–1498. Lynn, R. (1987). The intelligence of the Japanese. Bulletin of British Psychological Society, 30, 69–72. Lynn, R., Hampton, F., & Bingham, R. (1987). Japanese, British, and American adolescents compared for Spearman’s g and for verbal, numerical, and visuospatial abilities. Psychologia, 30, 137–144. Mitrushina, M., Boone, K. B., Razani, J., & D’Elia, L. F. (2005). Handbook of normative data for neuropsychological assessment. New York: Oxford University Press. Nagoshi, C. T., & Johnson, R. C. (1987). Cognitive abilities profiles of Caucasian vs Japanese in the Hawaiian Family Study of Cognition. Personality and Individual Differences, 8, 581–583. Osterrieth, P. A. (1944). Le test de copie d’une figure complex: Contribution a l’etude de la perception et de la memoire. Archives de Psychologie, 30, 286–356. Peters, M., Laeng, B., Latham, K., Jackson, M., Zaiyouna, M., & Richardson, C. (1995). A redrawn Vandenberg and Kuse Mental Rotations test: Different versions and factors that affect performance. Brain and Cognition, 28, 39–58. Postma, A., Kessels, R. P. C., & van Asselen, M. (2008). How the brain remembers and forgets where things are: The neurocognition of object-location memory. Neuroscience and Biobehavioral Reviews, 32, 1339–1345. Rahman, Q., Wilson, G. D., & Abrahams, S. (2003). Sexual orientation related differences in spatial memory. Journal of the International Neuropsychological Society, 9, 376–383. Rey, A. (1941). L’examen psychologique dans les cas d’encephalopathie traumatique. Archives de Psychologie, 28, 286–340. Rey, A. (1964). L’examen clinique en psychologie. Paris: Presses Universitaires & France. Silverman, I., Phillips, K., & Silverman, L. K. (1996). Homogeneity of effect sizes for sex across spatial tests and cultures: Implications for hormonal theories. Brain and Cognition, 31, 90–94. Sommer, T., Rose, M., Weiller, C., & Bu¨chel, C. (2005). Contributions of occipital, parietal and parahippocampal cortex to encoding of object-location associations. Neuropsychologia, 43, 732–743. Spiers, M. V., Sakamoto, M., Elliott, R. J., & Baumann, S. (2008). Sex differences in spatial object-location memory in a virtual grocery store. CyberPsychology & Behavior, 11, 471–473. Stevenson, H. M., Chen, C., & Lee, S. (1993). Mathematics achievement of Chinese, Japanese, and American children: Ten years later. Science, 259, 53–58. Stevenson, H. M., Lee, S., & Stigler, J. M. (1996). Mathematics achievement of Chinese, Japanese, and American children. Science, 231, 693–698. Stigler, J. W., & Hiebert, J. (1999). The teaching gap: Best ideas from the world’s teachers for improving education in the classroom. New York: Free Press. Strauss, E., Sherman, E. M. S., & Spreen, O. (2006). A compendium of neuropsychological tests: Administration, norms, and commentary (3rd ed.). New York: Oxford University Press. Tottenham, L. S., Saucier, D., Elias, L., & Gutwin, C. (2003). Female advantage for spatial location memory in both static and dynamic environments. Brain and Cognition, 53, 381–383.
Arch Sex Behav (2014) 43:483–491 Vlachos, F., Andreou, G., & Andreou, E. (2003). Biological and environmental influences in visuospatial abilities. Learning and Individual Differences, 13, 339–347. Voyer, D., Butler, T., Cordero, J., Brake, B., Silbersweig, D., Stern, E., & Imperato-McGinley, J. (2006). The relation between computerized and paper-and-pencil mental rotation tasks: A validation study. Journal of Clinical and Experimental Neuropsychology, 28, 928–939. Voyer, D., Voyer, S., & Bryden, M. P. (1995). Magnitude of sex differences in spatial abilities: A meta-analysis and consideration of critical variables. Psychological Bulletin, 117, 250–270. Wang, X. (1994). Gender differences in spatial, verbal, and mathematical abilities for Chinese students: A cross-cultural comparison. Unpublished doctoral dissertation, University of Iowa.
491 Ward, C., & Kennedy, A. (1994). Acculturation strategies, psychological adjustment, and sociocultural competence during cross-cultural transitions. International Journal of Intercultural Relations, 18, 329–343. Weinstein, C. S., Kaplan, E., Casey, M. B., & Hurwitz, I. (1990). Delineation of female performance on the Rey-Osterrieth Complex Figure. Neuropsychology, 4, 117–127. Witman, N. C., Nohda, N., Lai, M. K., Hashimoto, T., Iijima, Y., Isoda, M., & Hoffer, A. (1997). Mathematics education: A cross-cultural study. Peabody Journal of Education, 72, 215–232.
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