Quarterly Journal of Experimental Psychology
ISSN: 0033-555X (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/pqje19
The effects of intensity and interval rhythms on the perception of auditory and visual temporal patterns Stephen Handel & Delmar Yoder To cite this article: Stephen Handel & Delmar Yoder (1975) The effects of intensity and interval rhythms on the perception of auditory and visual temporal patterns, Quarterly Journal of Experimental Psychology, 27:1, 111-122, DOI: 10.1080/14640747508400467 To link to this article: http://dx.doi.org/10.1080/14640747508400467
Published online: 29 May 2007.
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Date: 06 November 2015, At: 00:58
Quarterly Journal of Experimental Psychology (1975) 27,
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THE EFFECTS OF INTENSITY AND INTERVAL RHYTHMS ON T H E PERCEPTION OF AUDITORY AND VISUAL TEMPORAL PATTERNS Downloaded by [University of Cambridge] at 00:58 06 November 2015
STEPHEN HANDEL AND DELMAR YODER
Department of Psychology, University of Tennessee, Knoxville, Tennessee 37916, U.S.A. Repeating temporal patterns were presented in the auditory and visual modalities so that: (a) all elements were of equal intensity and were equally spaced in time (uniform presentation); (b) the intensity of one element was increased (accent presentation) ; or (c) the interval between two elements was increased (pause presentation). Intensity and interval patterning serve to segment the element sequence into repeating patterns. For uniform presentation, pattern organization was by pattern structure, with auditory identification being faster. For pause presentation, organization was by the pauses; both auditory and visual identification were twice as fast as for uniform presentation. For auditory accent presentation, organization was by pattern structure and identification was slower than for uniform presentation. In contrast, the organization of visual accent presentation was by accents and identification was faster than for uniform presentation. These results suggest that complex stimuli, in which elements are patterned along more than one sensory dimension, are perceptually unique and therefore their identification rests on the nature of each modality.
Introduction Temporal patterns used in this study were sequences of dichotomous elements (e.g. x or o representing a high or low tone or a red or green light) generated by a repeating pattern of eight elements (e.g. xxoxooooxxoxoooo). Since patterns were continuously repeated, they could be started at any one of the eight pattern elements and still generate the same sequence. The subjects observed the sequence, and when ready, attempted to describe the pattern verbally. Two measures of performance were obtained :(a) the manner in which the sequence was organized into a pattern as shown by the verbalized description, (in general, for a sequence n elements in length, there are n possible descriptions); and (b) the latency for identification as shown by the number of elements presented until the pattern was correctly identified. Previous research has emphasized the role of pattern structure on pattern organization and rate of identification when the dichotomous elements were of equal intensity and the interval between each element was constant. In this case, pattern organization and rate of identification were a function of presentation rate. At fast presentation rates, (three element+ or more), patterns were organized in a I11
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manner determined by the structure of all the pattern elements (i.e. holistically). T h e subjects usually organized the pattern beginning at specific elements, although they were free to begin with any element (Royer and Garner, 1966, 1970). These elements termed preferred startpoints, either begin a run of identical elements or are chosen so that a run of identical elements ends the pattern (ooooxxoxor xxoxoooo). Patterns were organized identically for both auditory and visual presentation (Garner and Gottwald, 1968). Auditory presentation, however, produced faster pattern identification than visual presentation, with the number of elements presented until pattern identification being half as great as for visual presentation (Handel and Buffardi, 1969). T h e difference in rate of identification may be due to the perceptual characteristics of each modality. T h e auditory modality is characteristically more temporal and may allow faster identification of temporal patterns than the more spatial visual modality. At slow presentation rates (one element/s or less), pattern organization was more elemental and organization was found to be a function of start point as well as pattern structure. Patterns started at preferred start points were usually organized beginning at that element. Patterns started at other start points were organized both at the actual start point and at the preferred start point (Garner and Gottwald, 1968). Again, patterns were organized identically for auditory and visual presentation (Handel and Buffardi, 1968, 1969). However, at slow presentation rates there was no difference in the rate of identification for auditory and visual presentation (Handel and Buffardi, 1969). At slow presentation rates, identification seems to be more of a learning task in which patterns are learned as a sequence of elements with subjects actively testing hypotheses. For conditions in which subjects are learning the pattern, the modality of presentation should be of secondary importance. Present experiment
T h e purpose of the present experiment was to compare auditory with visual perception of rhythmic temporal patterns. By providing alternate organizations based on temporal rhythms in addition to organizations based on the element structure, it may be possible further to differentiate auditory and visual perception. Rhythms are temporal patterns determined by the relative intensity of elements or the relative interval between elements. Rhythms, being patterns, vary in difficulty and have preferred methods of organization (i.e. preferred start points). For example, a repeating intensity pattern can be constructed using two intensities of the identical frequency (e.g. XXXXXXXXXXXXXXXX where x and X represent elements of different intensities). Similarly, repeating interval rhythm patterns can be constructed using two intervals separating identical elements (e.g. xx x x xxxx xx x x xxxx . . .). Therefore, rhythmic temporal patterns provide for two possible organizations: (a) that provided by the element structure; and (b) that provided by the rhythmic (intensity or interval) structure. I n the present experiment, only the simplest intensity and interval rhythms were used. T h e rhythms were chosen to punctuate the continuous element sequence into the repeating units of eight elements and so were also based on a repeating unit of eight elements. T h e intensity rhythm consisted of one accented element and
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seven nonaccented elements (termed accent presentation). T h e accented element is usually the preferred start point for this rhythm (i.e. the sequence xxxxXxxxxxxx Xxxx is described as Xxxxxxxx). T h e interval rhythm consisted of one long interval between two elements and seven shorter intervals (termed pause presentation because there are eight elements, a pause and then eight more elements) and the preferred start point was the element following the pause (i.e. the sequence xxxx xxxxxxxx xxxxxxxx was described as -). T h e accents and pauses therefore segment the element sequence into repeating units. If the accented element was a preferred start point (XxxxxxoooXxxxxooo) or a pause preceded a preferred start point (xxxxxooo xxxxxooo), then accent and pause organization (i.e. starting the pattern description with the accented element or after a temporal pause) would be identical to organization based on the pattern structure. If the accented element was a nonpreferred start point (XxxoooxxXxxoooxx) or the pause preceded a nonpreferred start point (xxxoooxx xxxooxx), accent and pause organization would conflict with pattern structure organization. Although auditory and visual organization have been found to be identical for uniform patterns, by providing alternate modes of organization, intensity and interval rhythms may lead to different organization for auditory and visual presentation. Rhythms may also affect the rate of pattern identification. If the superiority of auditory presentation is due to the ease of abstracting the repeating unit, then simple rhythms by artificially segmenting the sequence should produce equally fast auditory and visual identification. However, if the superiority of auditory presentation is due to difficulty in learning the elements of a segmented unit, then simple rhythms, though producing faster pattern identification by making segmentation easier, should not affect the relative difference between auditory and visual presentation. As found previously, the rate of presentation affects the nature of pattern perception, At slow rates, patterns are learned as a string of elements; at fast rates patterns are perceived as a unified whole (Garner and Gottwald, 1968). Therefore, to determine the effect of rhythmic patterning on the two types of perception, rate of presentation was varied.
Method Subjects T h e subjects were I 20 Kansas State University undergraduates.
Experimental variables Three rates of presentation were used: I , 3 and 5 elements per s . At each presentation rate, the element was presented for 50% of the interval. For example, at the rate of 5 elements/s, the duration of each element was IOO ms with a blank stimulus interval of IOO ms. Two start points, preferred and nonpreferred, determined from Royer and Garner (1966) were used with each pattern. The preferred start point, an element often used by subjects to begin the pattern description, was chosen so that a run of identical elements ended the pattern description. As stated previously, alternate preferred start points would begin the
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description with the run of identical elements. The nonpreferred start point was an element rarely used by subjects to begin the description.
Patterns Eight different eight-element patterns were used. The eight patterns listed starting at the preferred start point, and with the non-preferred start point italicized were: xxxxxooo; xoxoxxoo;xxoxxoxo;xoxoxooo;xxoxoooo;xxooxoooo;xooxoooo;xxxoxooo.
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Stimuli, apparatus and procedure Auditory and visual presentation were used. The two stimuli for each modality were perceptually different, one placed on the subject's left and one placed on the subject's right. The auditory stimuli were a 800 and a 1300 Hz tone. The intensity of each tone was 65 d b sound pressure level. If one auditory element was accented, the intensity of that element was 75 d b while the intensity of the other seven elements remained at 65 db. The visual stimuli consisted of a red and green panel light mounted 10cm apart on a masonite board 1.5 m in front of the subject. The luminance of each light was 15 mlm. If one element was accented, the luminance of that element was 60 mlm while the luminance of the other seven elements remained at 1 5 mlm. The perceptual increment for the auditory and visual accents was nearly identical. Stevens (1966) states that the power law exponent is about 0.33 (in terms of sound energy) for the intensity of a pure 1000Hz tone and about 0.30 for the luminance of a red light. Thus, the increment in magnitude for the auditory stimulus (65-75 db) was roughly equal to the increment in magnitude for the visual stimulus ( I 5-60 mlm). An optical tape reader and electronic timers controlled stimulus presentation. Subjects sat in a soundproof room. The experimenter observed the subject through a one-way mirror and communicated by means of an intercom. The subject observed the pattern without making any overt response until he thought he could identify the pattern. The subject then stopped the presentation and attempted to describe the pattern by verbally stating the left-right sequence. If the description was correct, the next pattern was presented. If the description was incorrect, the pattern was restarted. If the pattern had not been correctly identified before 400 elements, the pattern was terminated and the next pattern was presented.
Methods of presentation Uniform presentation Each pattern element was of equal intensity and the interval between all elements was equal.
Accent presentation One pattern element was accented by increasing its intensity. elements was equal.
The interval between all
Pause presentation Each temporal pause was the time required to present one element so that at one element/s, there was a 1.5-s blank interval preceding one element in contrast to the 500 ms blank interval preceding the remaining elements. The intensity of all elements was equal.
Experimental design For each modality and method of presentation, there are 48 experimenta1 conditions (8
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patterns x 3 presentation rates x z start points). Each subject was presented with one-half of these conditions for one modality and method of presentation. The conditions presented were chosen in the following way. Each of the eight patterns was presented three times, once at each rate of presentation. Four of the patterns were started twice at preferred start points and once at nonpreferred start points. The other four patterns were started once at preferred start points and twice at nonpreferred start points. T h e patterns presented to each subject were varied so that across 20 subjects each condition was presented to 10different subjects. Furthermore, the order of presentation was counter-balanced. Subjects were pretrained on three patterns not used in the experiment. All presentation rates were demonstrated. During the experimental session, subjects were told the rate of presentation before each pattern was presented. The experimental session lasted about 40 min. Each pattern and its complement (achieved by reversing the pattern elements, the complement of oxxoxxxx is xooxoooo) were presented equally often at every condition. For auditory presentation, the patterns h(high) l(10w) lhllll and lhhlhhhh would occur equally often. Therefore, for accent presentation the high and low pitch tone would be accented equally often and for pause presentation, the pause would proceed the high and low pitch tone equally often. The identical procedure was used for visual presentation. Furthermore, the spatial position of the sensory elements was alternated (e.g. the low pitch tone was presented to the left and right of each subject equally).
Results" Pattern Organization T h e measure of organization used was the percentage of times the pattern description started at a specific pattern element. Three types of organizations will be discussed: (a) organizations beginning at the preferred start point; (b) organizations beginning at the nonpreferred start point ; (c) organizations beginning at the element following an accented element. T h e percentages of organizations beginning at these elements did not differ among patterns so that the percentages were averaged across patterns. T h e organization of patterns started at preferred start points is shown in Fig. I and the organization of patterns started at nonpreferred start points is shown in Fig. 2.
Uniform presentation
For uniform presentation, auditory and visual organization was quite similar. For patterns started at preferred start points, the percentages of organizations beginning at the preferred start point averaged over auditory and visual presentation decreased from 87% at the 11s presentation rate to 63% at the 51s rate. For patterns started at nonpreferred start points, at the slow rate the percentage of nonpreferred and preferred start point organizations was about equal (34 and 27%). At the fastest rate, preferred start point organizations increased to 47% while nonpreferred start point organizations decreased to 9%.
* Differences in percentages of organizations were tested by z-tests. Differences in rate of identification were tested by analysis of variance, and individual differences were tested using t-tests. All differences reDorted were significant at least at the 0.05 level.
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.;
Rate of presentation
FIG.I . The organization of patterns started at preferred start points (PSP). (a) Organizations beginning at PSP. (b) Organizations beginning at element following accented PSP. Pausevision, @. Uniform-audition, 0; vision, 0. audition, A;vision A. Accent-audition,
Rate of presentation
FIG.2. The organization of patterns started at nonpreferred start points (NPSP). (a) Organizations beginning at NPSP. (b) Organizations beginning at PSP. (c) Organizations beginning at A; vision, A. Accent-audition, I; element following accented NPSP. Pause-audition, vision, @. Uniform-audition, 0; vision, 0.
One difference between auditory and visual organization occurred for patterns started at preferred start points at the fastest presentation rate ; auditory presentation produced a much higher percentage of preferred start point organizations than visual presentation (78-47%). The dominant basis for organization for both modalities was a run of identical elements. However, for auditory presentation, subjects used the initial pattern elements as the basis for organization, as the percentage of preferred start point organizations was greater for patterns actually
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started at the preferred start point than at the nonpreferred start point (78-47%). Preusser, Garner and Gottwald (1970) have found equivalent results. For visual presentation, subjects were unable to use the initial elements as a basis; the percentage of preferred start point organizations at the 51s rate was identical for patterns started at preferred and nonpreferred start points (47-4774). A second difference between auditory and visual organization at the fastest presentation rates was that for visual presentation, subjects sometimes started the pattern with predictable elements, not preferred start points. A run of identical elements is the important perceptual component but the first or last element of the run can not be easily predicted. Nevertheless, the run can be used in organization by building the pattern around it. T h e first element following the run can indicate the end of the run and the next element can be used to begin the pattern description. For example, for auditory presentation the pattern xxxxxooo was nearly always described beginning with the run of five identical elements (90%). However, for visual presentation 40% of the descriptions were xxxxooox-the first element following a run “signalled” the start of a repetition and the second element following the run then began the description (another example would be the description ooxoooox). Overall, for patterns started at nonpreferred start points, 47% of auditory and visual organizations began at the preferred start points. Of the remaining descriptions, for auditory presentation, 28% began at alternate preferred start points (e.g. xxxoxoxo, oooxxxx, ooooxoox) and 5% began at the second element following the longest run (e.g. xoxoxxxo, xxxxooox, ooxoooox). For visual presentation, 7% of the descriptions began at alternate preferred start points and 22% began at the second element following the run. Pause presentation
For pause presentation, auditory and visual organization was identical. Pattern descriptions began at the element following the pause regardless of whether that element was a preferred or nonpreferred start point (94%). Accent presentation
For accent presentation, auditory and visual presentation differed as a function of presentation rate for both start points.
For patterns started at preferred start points, the percentage of auditory preferred start point organizations decreased at the faster presentation rates (95-80%). With respect to uniform presentation, the percentage of preferred start point organization increased at all presentation rates (an average of 6%). I n contrast, the percentage of visual preferred start point organizations was V-shaped as a function of presentation rate ; preferred start point organizations decreased at the medium rate but increased at the fastest rate until it roughly equalled the level at the slow rate. With respect to uniform presentation, the percentage of preferred start point organizations increased only at the 51s rate (78-47%). For patterns started at nonpreferred start points, with respect to uniform presentation, for both modalities the percentage of organizations beginning at the
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accented nonpreferred start point increased and the percentage of organizations beginning at the preferred start point decreased. However, organization interacted with presentation rate. For the auditory modality, at faster presentation rates, the percentage of nonpreferred start point organizations decreased (73-4774,) and the percentage of preferred start point organizations increase (16-30%). T h e reverse was true for visual presentation; at faster rates nonpreferred start point organizations increased (5 1-60%) and preferred start point organizations decreased (I2-7%)-
Finally, the percentage of organization following the accented element (e.g.
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XXXXOOOX) was much greater for visual presentation than auditory presentation for both start points (13-3%). Pattern identification
T h e average number of elements presented until pattern identification was used as the measure of the rate of identification. T h e median was found for each pattern at every experimental condition and then averaged across patterns (shown in Table I) ; geometric means were used to minimize skew. TABLE I The average number of elements presented until patterns were correctly identified ~
~~~
_____~_______
~~~
I
Modality
Start point NonPreferred preferred
~~
Rate of presentation (elements per s) 5 3 Start point Start point NonNonPreferred preferred Preferred preferred Average
A
21
Uniform presentation 32 46 78
V
24
35
A
23 24
31
83
I02
42
1 I7
108
A
I3
V
1.5
Pause presentation 45 21 28 71 32 33
68
146
174 343
376
92 165
198 290
292
I22
320
150
80 116
117 208
51
200
Accent presentation
V
79
For uniform presentation, auditory and visual presentation produced approximately equal rates of identification at the slow presentation rate. At the faster rates, auditory identification was far superior to visual identification; the number of elements presented until pattern identification was nearly twice as great for visual as for auditory presentation. These results, therefore, replicate previous work comparing the auditory and visual presentation (Garner and Gottwald, 1968; Handel and Buffardi, 1968, 1969). For pause presentation, auditory identification was superior at all conditions. Auditory identification was just slightly faster at the I / S rate but twice as fast at the s/s rate. With respect to uniform presentation, both auditory and visual pause
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presentation were 50% faster. On this basis, pause presentation aided each modality equally. For accent presentation, auditory identification was again faster. Here, the difference between auditory and visual identification did not increase at fast presentation rates, but remained comparable at all rates. With respect to uniform presentation, auditory and visual identification differed. Auditory accent identification was 25% slower than auditory uniform identification. For five of the six start point x presentation rate conditions, accent presentation was slower than uniform presentation. I n contrast, visual accent presentation produced 20% faster identification than visual uniform presentation at the three hardest start point x presentation rate conditions (241-292 elements), but 30% slower identification at the three easiest start point x presentation rate conditions (61-42elements).
Discussion For uniform presentation, auditory and visual organization was similar: patterns were mainly organized at preferred start points with runs of identical elements at the end of the pattern. At the fast presentation rates, alternate organizations for auditory presentation began with runs of identical elements. However, alternate organizations for visual presentation used the run in a different way, as a “pivot” for organization. These results, taken with the slower visual identification at the fast presentation rates suggest that visual perception was less phenomenally unified and immediate than auditory perception. For pause presentation, pattern organizations invariably began at the element following the pause. In comparison to uniform presentation, pause presentation produced faster pattern identification foi both modalities. The same superiority of the auditory modality found for uniform presentation was found for pause presentation. These results suggest that the superiority of the auditory modality was not mainly due to the faster segmentation of pattern repetitions. When the repetitions were segmented by pauses, and nearly all patterns were organized by these pauses, auditory identification was still nearly twice as fast as visual identification. The relation between organization and identification for accent presentation can best be considered by modality. For the visual modality, as the presentation rate increased, more and more of the subjects began the pattern description with the accented light. In addition, subjects used the accent as a cue to identify the start of the next pattern repetition as they organized patterns beginning with the element immediately following the accent. For patterns started at nonpreferred start points (i.e. the accented element was a nonpreferred start point), subjects were less apt to reorganize the pattern so that the description began at the non-accented preferred start point ; the percentage of preferred start point organizations actually decreased at the fast presentation rate. Therefore, for the difficult conditions at fast presentation rates where patterns are typically perceived holistically, subjects make direct use of the accented element to begin the pattern description or to cue pattern repetitions. In doing so, subjects make identifications more of a learning task using the accent rhythm to segment the element sequence into repeating units.
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T h e accent, by segmenting the element sequence produced faster pattern identification, similar to results found for pause segmentation. On the other hand, the auditory accent was used less at fast rates. If the pattern was not organized beginning at the accented element, the accent was disregarded and pattern descriptions began at a preferred start point. T h e subjects attempted to perceive the element structure, disregarding the accent. Nevertheless, the accent is phenomenally intrusive breaking up the pattern structure. I n fact, some subjects complained that the accented element seemed like a third element. Since subjects still attempted to perceive the pattern structure, the interference due to the accent brought about slower identification. T h e differential effect of the accent rhythm on auditory and visual presentation corresponds to differences found for uniform presentation. At the fast presentation rates, visual uniform presentation was difficult and the pattern descriptions suggested that the subjects actively attempted to find a predictable element to segment the element sequence. T h e perception was not of a unified pattern. T h e accented visual element could serve as a predictable element, and being easily discriminated would produce rapid segmentation. It appears therefore that the visual accent rhythm “fits” the more serial learning nature of visual identification and thereby leads to faster identification. I n contrast, at the fast presentation rates auditory uniform presentation leads to pattern descriptions based on the structure of all the pattern elements. T h e subjects did not use predictable elements to segment the sequence. It appears therefore that auditory accent rhythms, by segmenting the sequence, go counter to the holistic nature of auditory identification and thereby lead to slower identification. T h e interrelationships revealed by these results have some implications for the strategy usually used to compare auditory and visual presentations, or more generally to compare hearing and seeing. T h e rationale underlying these cornparisons suggests that these modalities are of different sorts : the (temporal) auditory modality has been described as sequential, analyzing, and mechanical, while the (spatial) visual modality has been described as simultaneous, synthesizing, and chemical. By appropriate choice of stimuli, the hope has been that careful experimentation would tease apart these differences in perceptual process. What actually seems to be the case, however, is that it is extremely difficult to compare auditory and visual perception solely on the basis of performance (either speed, accuracy, or organization) using simple stimuli. At the very least, stimuli which are equally discriminable must be found. Even for the simplest reaction time experiments-where auditory stimulation was thought to be 40 ms faster than visual stimulation (Woodworth and Schlosberg, 196q)-recent work (Kohfeld, 1971) has suggested that if discriminability is equated, auditory and visual reaction times are equal. For more complex morse-code type stimuli the particular characteristics of the stimuli determine modality superiority (Buffardi, 1972 ; Nazzaro and Nazzaro, 1970). Finally, for temporal patterns such as used here, although auditory presentation has been found to be consistently superior, this finding may also be due to the stimulus conditions (two different tones versus two different coloured lights separated by several cm). Informal observation suggests that a visual stimulus generated by making a dot on an oscilloscope expand into a
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vertical or horizontal line produces performance equal to that for auditory presentation. As it now stands, performance comparisons between auditory and visual modalities seem to be comparisons of stimulus presentation parameters, and therefore seem unlikely to lead to any basic conclusions regarding modality nerception. I n a similar vein, comparisons using simple perceptual phenomena have not led to clear distinctions among modalities. For example, Geldard (1970)has summarized research suggesting that simple phenomena involving time and space discrimination are identical for auditory, tactual, and visual modalities. Furthermore, Von BCkCsy (1967) has shown that the principles of lateral inhibition are identical for each sense and using these principles has been able to demonstrate identical illusions in each sense. What all of these data suggest is that the modalities can be made equivalent. Although hearing and seeing are different phenomenally, reducing these processes so that they are based on sensory magnitudes or so that they become cognitive acts eliminates these differences. We perceive stimulus patterns, but each modality also structures the environment. The results of the present experiments suggest that only by comparing organization and identification data for complex stimuli will qualitative (i.e. structuring) differences between modalities be found. This is not to argue that any one aspect of a complex stimulus is differentially perceived, but that the stimulus as a whole has a different meaning and that this meaning is a reflection of the perceptual mode of each modality. This is also not to argue that any complex stimulus will differentiate modalities. Only complex stimuli which allow structuring will differentiate the modalities. This research was supported in part by National Institute of Mental Health Research Grant MH 15969. We are grateful to Howard Pollio and William Calhoun for their helpful comments on the manuscript.
References BSKBSY,G. VON(1967). Sensory Inhibition. Princeton : Princeton University Press. BUFFARDI, L. (1972). Factors affecting memory span in binary and octal responding. American Journal of Psychology, 85, 377-91. GARNER, W.R. and GOTTWALD, R. L. (1968). The perception and learning of temporal patterns. Quarterly Journal of Experimental Psychotogy, 20, 97-109. GELDARD, F. A. (1970). Vision, audition, and beyond. In NEFF,W.D. (Ed.), Contributions to Sensory Physiofogy, Vol. 4 , pp. 1-17. New York: Academic Press. HANDEL, S. and BUFFARDI,L. (1969). Using several modalities to perceive one temporal pattern. Quarterly yournal of Experimental Psychology, 21,256-66. HANDEL, S. and BUFFARDI, L.(1968). Pattern perception : integrating information presented in two modalities. Science, 162,1026-8. KOHFELD, D.L.(1971). Simple reaction time as a function of stimulus intensity in decibels of light and sound. Journal of Experimental Psychology, 88,251-7. NAZZARO, J. R. and NAZZARO, J. N. (1970). Auditory versus visual learning of temporal patterns. Journal of Experimental Psychology, 84, 477-8. PREUSSER, D.,GARNER, W. R. and GOTTWALD, R. L. (1970). The effect of starting pattern on descriptions of perceived temporal patterns. Psychonomic Science, 21, 219-20. F. L. and GARNER, W. R. (1970). Perceptual organization of nine-element auditory ROYER, temporal patterns. Perception and Psychophysics, 7 , I 15-20.
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ROYER, F. L. and GARNER, W. R. (1966). Response uncertainty and perceptual difficulty of auditory temporal patterns. Perception and Psychophysics, I, 4 1 7 . STEVENS, S. S. (1966). Matching functions between loudness and ten other continua. Perception and Psychophysics, I , 5-8. WOODWORTH, R. S. and SCHLOSBERG, H. (1954). Experimental Psychology. New York: Holt, Rinehart, and Winston. Revised manuscript received 18 February 1974
ISSN: 0033-555X (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/pqje19
The effects of intensity and interval rhythms on the perception of auditory and visual temporal patterns Stephen Handel & Delmar Yoder To cite this article: Stephen Handel & Delmar Yoder (1975) The effects of intensity and interval rhythms on the perception of auditory and visual temporal patterns, Quarterly Journal of Experimental Psychology, 27:1, 111-122, DOI: 10.1080/14640747508400467 To link to this article: http://dx.doi.org/10.1080/14640747508400467
Published online: 29 May 2007.
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Article views: 11
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Citing articles: 6 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=pqje19 Download by: [University of Cambridge]
Date: 06 November 2015, At: 00:58
Quarterly Journal of Experimental Psychology (1975) 27,
I I 1-122
THE EFFECTS OF INTENSITY AND INTERVAL RHYTHMS ON T H E PERCEPTION OF AUDITORY AND VISUAL TEMPORAL PATTERNS Downloaded by [University of Cambridge] at 00:58 06 November 2015
STEPHEN HANDEL AND DELMAR YODER
Department of Psychology, University of Tennessee, Knoxville, Tennessee 37916, U.S.A. Repeating temporal patterns were presented in the auditory and visual modalities so that: (a) all elements were of equal intensity and were equally spaced in time (uniform presentation); (b) the intensity of one element was increased (accent presentation) ; or (c) the interval between two elements was increased (pause presentation). Intensity and interval patterning serve to segment the element sequence into repeating patterns. For uniform presentation, pattern organization was by pattern structure, with auditory identification being faster. For pause presentation, organization was by the pauses; both auditory and visual identification were twice as fast as for uniform presentation. For auditory accent presentation, organization was by pattern structure and identification was slower than for uniform presentation. In contrast, the organization of visual accent presentation was by accents and identification was faster than for uniform presentation. These results suggest that complex stimuli, in which elements are patterned along more than one sensory dimension, are perceptually unique and therefore their identification rests on the nature of each modality.
Introduction Temporal patterns used in this study were sequences of dichotomous elements (e.g. x or o representing a high or low tone or a red or green light) generated by a repeating pattern of eight elements (e.g. xxoxooooxxoxoooo). Since patterns were continuously repeated, they could be started at any one of the eight pattern elements and still generate the same sequence. The subjects observed the sequence, and when ready, attempted to describe the pattern verbally. Two measures of performance were obtained :(a) the manner in which the sequence was organized into a pattern as shown by the verbalized description, (in general, for a sequence n elements in length, there are n possible descriptions); and (b) the latency for identification as shown by the number of elements presented until the pattern was correctly identified. Previous research has emphasized the role of pattern structure on pattern organization and rate of identification when the dichotomous elements were of equal intensity and the interval between each element was constant. In this case, pattern organization and rate of identification were a function of presentation rate. At fast presentation rates, (three element+ or more), patterns were organized in a I11
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manner determined by the structure of all the pattern elements (i.e. holistically). T h e subjects usually organized the pattern beginning at specific elements, although they were free to begin with any element (Royer and Garner, 1966, 1970). These elements termed preferred startpoints, either begin a run of identical elements or are chosen so that a run of identical elements ends the pattern (ooooxxoxor xxoxoooo). Patterns were organized identically for both auditory and visual presentation (Garner and Gottwald, 1968). Auditory presentation, however, produced faster pattern identification than visual presentation, with the number of elements presented until pattern identification being half as great as for visual presentation (Handel and Buffardi, 1969). T h e difference in rate of identification may be due to the perceptual characteristics of each modality. T h e auditory modality is characteristically more temporal and may allow faster identification of temporal patterns than the more spatial visual modality. At slow presentation rates (one element/s or less), pattern organization was more elemental and organization was found to be a function of start point as well as pattern structure. Patterns started at preferred start points were usually organized beginning at that element. Patterns started at other start points were organized both at the actual start point and at the preferred start point (Garner and Gottwald, 1968). Again, patterns were organized identically for auditory and visual presentation (Handel and Buffardi, 1968, 1969). However, at slow presentation rates there was no difference in the rate of identification for auditory and visual presentation (Handel and Buffardi, 1969). At slow presentation rates, identification seems to be more of a learning task in which patterns are learned as a sequence of elements with subjects actively testing hypotheses. For conditions in which subjects are learning the pattern, the modality of presentation should be of secondary importance. Present experiment
T h e purpose of the present experiment was to compare auditory with visual perception of rhythmic temporal patterns. By providing alternate organizations based on temporal rhythms in addition to organizations based on the element structure, it may be possible further to differentiate auditory and visual perception. Rhythms are temporal patterns determined by the relative intensity of elements or the relative interval between elements. Rhythms, being patterns, vary in difficulty and have preferred methods of organization (i.e. preferred start points). For example, a repeating intensity pattern can be constructed using two intensities of the identical frequency (e.g. XXXXXXXXXXXXXXXX where x and X represent elements of different intensities). Similarly, repeating interval rhythm patterns can be constructed using two intervals separating identical elements (e.g. xx x x xxxx xx x x xxxx . . .). Therefore, rhythmic temporal patterns provide for two possible organizations: (a) that provided by the element structure; and (b) that provided by the rhythmic (intensity or interval) structure. I n the present experiment, only the simplest intensity and interval rhythms were used. T h e rhythms were chosen to punctuate the continuous element sequence into the repeating units of eight elements and so were also based on a repeating unit of eight elements. T h e intensity rhythm consisted of one accented element and
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seven nonaccented elements (termed accent presentation). T h e accented element is usually the preferred start point for this rhythm (i.e. the sequence xxxxXxxxxxxx Xxxx is described as Xxxxxxxx). T h e interval rhythm consisted of one long interval between two elements and seven shorter intervals (termed pause presentation because there are eight elements, a pause and then eight more elements) and the preferred start point was the element following the pause (i.e. the sequence xxxx xxxxxxxx xxxxxxxx was described as -). T h e accents and pauses therefore segment the element sequence into repeating units. If the accented element was a preferred start point (XxxxxxoooXxxxxooo) or a pause preceded a preferred start point (xxxxxooo xxxxxooo), then accent and pause organization (i.e. starting the pattern description with the accented element or after a temporal pause) would be identical to organization based on the pattern structure. If the accented element was a nonpreferred start point (XxxoooxxXxxoooxx) or the pause preceded a nonpreferred start point (xxxoooxx xxxooxx), accent and pause organization would conflict with pattern structure organization. Although auditory and visual organization have been found to be identical for uniform patterns, by providing alternate modes of organization, intensity and interval rhythms may lead to different organization for auditory and visual presentation. Rhythms may also affect the rate of pattern identification. If the superiority of auditory presentation is due to the ease of abstracting the repeating unit, then simple rhythms by artificially segmenting the sequence should produce equally fast auditory and visual identification. However, if the superiority of auditory presentation is due to difficulty in learning the elements of a segmented unit, then simple rhythms, though producing faster pattern identification by making segmentation easier, should not affect the relative difference between auditory and visual presentation. As found previously, the rate of presentation affects the nature of pattern perception, At slow rates, patterns are learned as a string of elements; at fast rates patterns are perceived as a unified whole (Garner and Gottwald, 1968). Therefore, to determine the effect of rhythmic patterning on the two types of perception, rate of presentation was varied.
Method Subjects T h e subjects were I 20 Kansas State University undergraduates.
Experimental variables Three rates of presentation were used: I , 3 and 5 elements per s . At each presentation rate, the element was presented for 50% of the interval. For example, at the rate of 5 elements/s, the duration of each element was IOO ms with a blank stimulus interval of IOO ms. Two start points, preferred and nonpreferred, determined from Royer and Garner (1966) were used with each pattern. The preferred start point, an element often used by subjects to begin the pattern description, was chosen so that a run of identical elements ended the pattern description. As stated previously, alternate preferred start points would begin the
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description with the run of identical elements. The nonpreferred start point was an element rarely used by subjects to begin the description.
Patterns Eight different eight-element patterns were used. The eight patterns listed starting at the preferred start point, and with the non-preferred start point italicized were: xxxxxooo; xoxoxxoo;xxoxxoxo;xoxoxooo;xxoxoooo;xxooxoooo;xooxoooo;xxxoxooo.
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Stimuli, apparatus and procedure Auditory and visual presentation were used. The two stimuli for each modality were perceptually different, one placed on the subject's left and one placed on the subject's right. The auditory stimuli were a 800 and a 1300 Hz tone. The intensity of each tone was 65 d b sound pressure level. If one auditory element was accented, the intensity of that element was 75 d b while the intensity of the other seven elements remained at 65 db. The visual stimuli consisted of a red and green panel light mounted 10cm apart on a masonite board 1.5 m in front of the subject. The luminance of each light was 15 mlm. If one element was accented, the luminance of that element was 60 mlm while the luminance of the other seven elements remained at 1 5 mlm. The perceptual increment for the auditory and visual accents was nearly identical. Stevens (1966) states that the power law exponent is about 0.33 (in terms of sound energy) for the intensity of a pure 1000Hz tone and about 0.30 for the luminance of a red light. Thus, the increment in magnitude for the auditory stimulus (65-75 db) was roughly equal to the increment in magnitude for the visual stimulus ( I 5-60 mlm). An optical tape reader and electronic timers controlled stimulus presentation. Subjects sat in a soundproof room. The experimenter observed the subject through a one-way mirror and communicated by means of an intercom. The subject observed the pattern without making any overt response until he thought he could identify the pattern. The subject then stopped the presentation and attempted to describe the pattern by verbally stating the left-right sequence. If the description was correct, the next pattern was presented. If the description was incorrect, the pattern was restarted. If the pattern had not been correctly identified before 400 elements, the pattern was terminated and the next pattern was presented.
Methods of presentation Uniform presentation Each pattern element was of equal intensity and the interval between all elements was equal.
Accent presentation One pattern element was accented by increasing its intensity. elements was equal.
The interval between all
Pause presentation Each temporal pause was the time required to present one element so that at one element/s, there was a 1.5-s blank interval preceding one element in contrast to the 500 ms blank interval preceding the remaining elements. The intensity of all elements was equal.
Experimental design For each modality and method of presentation, there are 48 experimenta1 conditions (8
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patterns x 3 presentation rates x z start points). Each subject was presented with one-half of these conditions for one modality and method of presentation. The conditions presented were chosen in the following way. Each of the eight patterns was presented three times, once at each rate of presentation. Four of the patterns were started twice at preferred start points and once at nonpreferred start points. The other four patterns were started once at preferred start points and twice at nonpreferred start points. T h e patterns presented to each subject were varied so that across 20 subjects each condition was presented to 10different subjects. Furthermore, the order of presentation was counter-balanced. Subjects were pretrained on three patterns not used in the experiment. All presentation rates were demonstrated. During the experimental session, subjects were told the rate of presentation before each pattern was presented. The experimental session lasted about 40 min. Each pattern and its complement (achieved by reversing the pattern elements, the complement of oxxoxxxx is xooxoooo) were presented equally often at every condition. For auditory presentation, the patterns h(high) l(10w) lhllll and lhhlhhhh would occur equally often. Therefore, for accent presentation the high and low pitch tone would be accented equally often and for pause presentation, the pause would proceed the high and low pitch tone equally often. The identical procedure was used for visual presentation. Furthermore, the spatial position of the sensory elements was alternated (e.g. the low pitch tone was presented to the left and right of each subject equally).
Results" Pattern Organization T h e measure of organization used was the percentage of times the pattern description started at a specific pattern element. Three types of organizations will be discussed: (a) organizations beginning at the preferred start point; (b) organizations beginning at the nonpreferred start point ; (c) organizations beginning at the element following an accented element. T h e percentages of organizations beginning at these elements did not differ among patterns so that the percentages were averaged across patterns. T h e organization of patterns started at preferred start points is shown in Fig. I and the organization of patterns started at nonpreferred start points is shown in Fig. 2.
Uniform presentation
For uniform presentation, auditory and visual organization was quite similar. For patterns started at preferred start points, the percentages of organizations beginning at the preferred start point averaged over auditory and visual presentation decreased from 87% at the 11s presentation rate to 63% at the 51s rate. For patterns started at nonpreferred start points, at the slow rate the percentage of nonpreferred and preferred start point organizations was about equal (34 and 27%). At the fastest rate, preferred start point organizations increased to 47% while nonpreferred start point organizations decreased to 9%.
* Differences in percentages of organizations were tested by z-tests. Differences in rate of identification were tested by analysis of variance, and individual differences were tested using t-tests. All differences reDorted were significant at least at the 0.05 level.
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.;
Rate of presentation
FIG.I . The organization of patterns started at preferred start points (PSP). (a) Organizations beginning at PSP. (b) Organizations beginning at element following accented PSP. Pausevision, @. Uniform-audition, 0; vision, 0. audition, A;vision A. Accent-audition,
Rate of presentation
FIG.2. The organization of patterns started at nonpreferred start points (NPSP). (a) Organizations beginning at NPSP. (b) Organizations beginning at PSP. (c) Organizations beginning at A; vision, A. Accent-audition, I; element following accented NPSP. Pause-audition, vision, @. Uniform-audition, 0; vision, 0.
One difference between auditory and visual organization occurred for patterns started at preferred start points at the fastest presentation rate ; auditory presentation produced a much higher percentage of preferred start point organizations than visual presentation (78-47%). The dominant basis for organization for both modalities was a run of identical elements. However, for auditory presentation, subjects used the initial pattern elements as the basis for organization, as the percentage of preferred start point organizations was greater for patterns actually
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started at the preferred start point than at the nonpreferred start point (78-47%). Preusser, Garner and Gottwald (1970) have found equivalent results. For visual presentation, subjects were unable to use the initial elements as a basis; the percentage of preferred start point organizations at the 51s rate was identical for patterns started at preferred and nonpreferred start points (47-4774). A second difference between auditory and visual organization at the fastest presentation rates was that for visual presentation, subjects sometimes started the pattern with predictable elements, not preferred start points. A run of identical elements is the important perceptual component but the first or last element of the run can not be easily predicted. Nevertheless, the run can be used in organization by building the pattern around it. T h e first element following the run can indicate the end of the run and the next element can be used to begin the pattern description. For example, for auditory presentation the pattern xxxxxooo was nearly always described beginning with the run of five identical elements (90%). However, for visual presentation 40% of the descriptions were xxxxooox-the first element following a run “signalled” the start of a repetition and the second element following the run then began the description (another example would be the description ooxoooox). Overall, for patterns started at nonpreferred start points, 47% of auditory and visual organizations began at the preferred start points. Of the remaining descriptions, for auditory presentation, 28% began at alternate preferred start points (e.g. xxxoxoxo, oooxxxx, ooooxoox) and 5% began at the second element following the longest run (e.g. xoxoxxxo, xxxxooox, ooxoooox). For visual presentation, 7% of the descriptions began at alternate preferred start points and 22% began at the second element following the run. Pause presentation
For pause presentation, auditory and visual organization was identical. Pattern descriptions began at the element following the pause regardless of whether that element was a preferred or nonpreferred start point (94%). Accent presentation
For accent presentation, auditory and visual presentation differed as a function of presentation rate for both start points.
For patterns started at preferred start points, the percentage of auditory preferred start point organizations decreased at the faster presentation rates (95-80%). With respect to uniform presentation, the percentage of preferred start point organization increased at all presentation rates (an average of 6%). I n contrast, the percentage of visual preferred start point organizations was V-shaped as a function of presentation rate ; preferred start point organizations decreased at the medium rate but increased at the fastest rate until it roughly equalled the level at the slow rate. With respect to uniform presentation, the percentage of preferred start point organizations increased only at the 51s rate (78-47%). For patterns started at nonpreferred start points, with respect to uniform presentation, for both modalities the percentage of organizations beginning at the
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accented nonpreferred start point increased and the percentage of organizations beginning at the preferred start point decreased. However, organization interacted with presentation rate. For the auditory modality, at faster presentation rates, the percentage of nonpreferred start point organizations decreased (73-4774,) and the percentage of preferred start point organizations increase (16-30%). T h e reverse was true for visual presentation; at faster rates nonpreferred start point organizations increased (5 1-60%) and preferred start point organizations decreased (I2-7%)-
Finally, the percentage of organization following the accented element (e.g.
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XXXXOOOX) was much greater for visual presentation than auditory presentation for both start points (13-3%). Pattern identification
T h e average number of elements presented until pattern identification was used as the measure of the rate of identification. T h e median was found for each pattern at every experimental condition and then averaged across patterns (shown in Table I) ; geometric means were used to minimize skew. TABLE I The average number of elements presented until patterns were correctly identified ~
~~~
_____~_______
~~~
I
Modality
Start point NonPreferred preferred
~~
Rate of presentation (elements per s) 5 3 Start point Start point NonNonPreferred preferred Preferred preferred Average
A
21
Uniform presentation 32 46 78
V
24
35
A
23 24
31
83
I02
42
1 I7
108
A
I3
V
1.5
Pause presentation 45 21 28 71 32 33
68
146
174 343
376
92 165
198 290
292
I22
320
150
80 116
117 208
51
200
Accent presentation
V
79
For uniform presentation, auditory and visual presentation produced approximately equal rates of identification at the slow presentation rate. At the faster rates, auditory identification was far superior to visual identification; the number of elements presented until pattern identification was nearly twice as great for visual as for auditory presentation. These results, therefore, replicate previous work comparing the auditory and visual presentation (Garner and Gottwald, 1968; Handel and Buffardi, 1968, 1969). For pause presentation, auditory identification was superior at all conditions. Auditory identification was just slightly faster at the I / S rate but twice as fast at the s/s rate. With respect to uniform presentation, both auditory and visual pause
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presentation were 50% faster. On this basis, pause presentation aided each modality equally. For accent presentation, auditory identification was again faster. Here, the difference between auditory and visual identification did not increase at fast presentation rates, but remained comparable at all rates. With respect to uniform presentation, auditory and visual identification differed. Auditory accent identification was 25% slower than auditory uniform identification. For five of the six start point x presentation rate conditions, accent presentation was slower than uniform presentation. I n contrast, visual accent presentation produced 20% faster identification than visual uniform presentation at the three hardest start point x presentation rate conditions (241-292 elements), but 30% slower identification at the three easiest start point x presentation rate conditions (61-42elements).
Discussion For uniform presentation, auditory and visual organization was similar: patterns were mainly organized at preferred start points with runs of identical elements at the end of the pattern. At the fast presentation rates, alternate organizations for auditory presentation began with runs of identical elements. However, alternate organizations for visual presentation used the run in a different way, as a “pivot” for organization. These results, taken with the slower visual identification at the fast presentation rates suggest that visual perception was less phenomenally unified and immediate than auditory perception. For pause presentation, pattern organizations invariably began at the element following the pause. In comparison to uniform presentation, pause presentation produced faster pattern identification foi both modalities. The same superiority of the auditory modality found for uniform presentation was found for pause presentation. These results suggest that the superiority of the auditory modality was not mainly due to the faster segmentation of pattern repetitions. When the repetitions were segmented by pauses, and nearly all patterns were organized by these pauses, auditory identification was still nearly twice as fast as visual identification. The relation between organization and identification for accent presentation can best be considered by modality. For the visual modality, as the presentation rate increased, more and more of the subjects began the pattern description with the accented light. In addition, subjects used the accent as a cue to identify the start of the next pattern repetition as they organized patterns beginning with the element immediately following the accent. For patterns started at nonpreferred start points (i.e. the accented element was a nonpreferred start point), subjects were less apt to reorganize the pattern so that the description began at the non-accented preferred start point ; the percentage of preferred start point organizations actually decreased at the fast presentation rate. Therefore, for the difficult conditions at fast presentation rates where patterns are typically perceived holistically, subjects make direct use of the accented element to begin the pattern description or to cue pattern repetitions. In doing so, subjects make identifications more of a learning task using the accent rhythm to segment the element sequence into repeating units.
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T h e accent, by segmenting the element sequence produced faster pattern identification, similar to results found for pause segmentation. On the other hand, the auditory accent was used less at fast rates. If the pattern was not organized beginning at the accented element, the accent was disregarded and pattern descriptions began at a preferred start point. T h e subjects attempted to perceive the element structure, disregarding the accent. Nevertheless, the accent is phenomenally intrusive breaking up the pattern structure. I n fact, some subjects complained that the accented element seemed like a third element. Since subjects still attempted to perceive the pattern structure, the interference due to the accent brought about slower identification. T h e differential effect of the accent rhythm on auditory and visual presentation corresponds to differences found for uniform presentation. At the fast presentation rates, visual uniform presentation was difficult and the pattern descriptions suggested that the subjects actively attempted to find a predictable element to segment the element sequence. T h e perception was not of a unified pattern. T h e accented visual element could serve as a predictable element, and being easily discriminated would produce rapid segmentation. It appears therefore that the visual accent rhythm “fits” the more serial learning nature of visual identification and thereby leads to faster identification. I n contrast, at the fast presentation rates auditory uniform presentation leads to pattern descriptions based on the structure of all the pattern elements. T h e subjects did not use predictable elements to segment the sequence. It appears therefore that auditory accent rhythms, by segmenting the sequence, go counter to the holistic nature of auditory identification and thereby lead to slower identification. T h e interrelationships revealed by these results have some implications for the strategy usually used to compare auditory and visual presentations, or more generally to compare hearing and seeing. T h e rationale underlying these cornparisons suggests that these modalities are of different sorts : the (temporal) auditory modality has been described as sequential, analyzing, and mechanical, while the (spatial) visual modality has been described as simultaneous, synthesizing, and chemical. By appropriate choice of stimuli, the hope has been that careful experimentation would tease apart these differences in perceptual process. What actually seems to be the case, however, is that it is extremely difficult to compare auditory and visual perception solely on the basis of performance (either speed, accuracy, or organization) using simple stimuli. At the very least, stimuli which are equally discriminable must be found. Even for the simplest reaction time experiments-where auditory stimulation was thought to be 40 ms faster than visual stimulation (Woodworth and Schlosberg, 196q)-recent work (Kohfeld, 1971) has suggested that if discriminability is equated, auditory and visual reaction times are equal. For more complex morse-code type stimuli the particular characteristics of the stimuli determine modality superiority (Buffardi, 1972 ; Nazzaro and Nazzaro, 1970). Finally, for temporal patterns such as used here, although auditory presentation has been found to be consistently superior, this finding may also be due to the stimulus conditions (two different tones versus two different coloured lights separated by several cm). Informal observation suggests that a visual stimulus generated by making a dot on an oscilloscope expand into a
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vertical or horizontal line produces performance equal to that for auditory presentation. As it now stands, performance comparisons between auditory and visual modalities seem to be comparisons of stimulus presentation parameters, and therefore seem unlikely to lead to any basic conclusions regarding modality nerception. I n a similar vein, comparisons using simple perceptual phenomena have not led to clear distinctions among modalities. For example, Geldard (1970)has summarized research suggesting that simple phenomena involving time and space discrimination are identical for auditory, tactual, and visual modalities. Furthermore, Von BCkCsy (1967) has shown that the principles of lateral inhibition are identical for each sense and using these principles has been able to demonstrate identical illusions in each sense. What all of these data suggest is that the modalities can be made equivalent. Although hearing and seeing are different phenomenally, reducing these processes so that they are based on sensory magnitudes or so that they become cognitive acts eliminates these differences. We perceive stimulus patterns, but each modality also structures the environment. The results of the present experiments suggest that only by comparing organization and identification data for complex stimuli will qualitative (i.e. structuring) differences between modalities be found. This is not to argue that any one aspect of a complex stimulus is differentially perceived, but that the stimulus as a whole has a different meaning and that this meaning is a reflection of the perceptual mode of each modality. This is also not to argue that any complex stimulus will differentiate modalities. Only complex stimuli which allow structuring will differentiate the modalities. This research was supported in part by National Institute of Mental Health Research Grant MH 15969. We are grateful to Howard Pollio and William Calhoun for their helpful comments on the manuscript.
References BSKBSY,G. VON(1967). Sensory Inhibition. Princeton : Princeton University Press. BUFFARDI, L. (1972). Factors affecting memory span in binary and octal responding. American Journal of Psychology, 85, 377-91. GARNER, W.R. and GOTTWALD, R. L. (1968). The perception and learning of temporal patterns. Quarterly Journal of Experimental Psychotogy, 20, 97-109. GELDARD, F. A. (1970). Vision, audition, and beyond. In NEFF,W.D. (Ed.), Contributions to Sensory Physiofogy, Vol. 4 , pp. 1-17. New York: Academic Press. HANDEL, S. and BUFFARDI,L. (1969). Using several modalities to perceive one temporal pattern. Quarterly yournal of Experimental Psychology, 21,256-66. HANDEL, S. and BUFFARDI, L.(1968). Pattern perception : integrating information presented in two modalities. Science, 162,1026-8. KOHFELD, D.L.(1971). Simple reaction time as a function of stimulus intensity in decibels of light and sound. Journal of Experimental Psychology, 88,251-7. NAZZARO, J. R. and NAZZARO, J. N. (1970). Auditory versus visual learning of temporal patterns. Journal of Experimental Psychology, 84, 477-8. PREUSSER, D.,GARNER, W. R. and GOTTWALD, R. L. (1970). The effect of starting pattern on descriptions of perceived temporal patterns. Psychonomic Science, 21, 219-20. F. L. and GARNER, W. R. (1970). Perceptual organization of nine-element auditory ROYER, temporal patterns. Perception and Psychophysics, 7 , I 15-20.
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ROYER, F. L. and GARNER, W. R. (1966). Response uncertainty and perceptual difficulty of auditory temporal patterns. Perception and Psychophysics, I, 4 1 7 . STEVENS, S. S. (1966). Matching functions between loudness and ten other continua. Perception and Psychophysics, I , 5-8. WOODWORTH, R. S. and SCHLOSBERG, H. (1954). Experimental Psychology. New York: Holt, Rinehart, and Winston. Revised manuscript received 18 February 1974
