This article was downloaded by: [New York University] On: 09 June 2015, At: 06:40 Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Quarterly Journal of Experimental Psychology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/pqje19
Location and distance estimates by blind and sighted children a
B. Hermelin & N. O'Connor
a
a
MRC Developmental Psychology Unit, Drayton House, Gordon Street , London, WCI Published online: 29 May 2007.
To cite this article: B. Hermelin & N. O'Connor (1975) Location and distance estimates by blind and sighted children, Quarterly Journal of Experimental Psychology, 27:2, 295-301, DOI: 10.1080/14640747508400488 To link to this article: http://dx.doi.org/10.1080/14640747508400488
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/ page/terms-and-conditions
Quarterly Journal of Experimental Psychology (1975)27, 295-301
LOCATION AND DISTANCE ESTIMATES BY BLIND AND SIGHTED CHILDREN B. HERMELIN AND N. O’CONNOR
Downloaded by [New York University] at 06:40 09 June 2015
MRC Developmental Psychology Unit, Drayton House, Gordon Street, London WCI Blindfold normal, blindfold autistic and congenitally blind children made reproduction location and distance estimates of an arm movement. For each task they first experienced a standard vertical movement of a predetermined extent. In the test tasks which followed, they either reproduced the movement exactly, reproduced the end point although commencing from a different starting position, or reproduced the same distance from a different starting point. Sighted normal children and blind children performed very similarly on both the reproduction and the location task. However on distance reproduction, the blind children underestimated the longer distances more markedly than did the normals. Autistic children resembled the blind in their attempts to reproduce the longer distances. In addition they had a tendency to overshoot over short distances in all tasks. The results are discussed in terms of the role of a visual reference system for different aspects of motor movements.
Introduction
Is kinaesthetic data sufficient for the derivation and storage of movement components in the absence of kinaesthetic invariants? Skogland (1956) discussing specific components of movement, found kinaesthetic receptors signalling location, direction, speed and acceleration though not movement per se. It appears (Marteniuk and Roy, 1972) that distance information for example is not very precise or, perhaps, uncodable when it is the only information available regarding limb movement. Held (1961) has expressed the view however that movements of the body and the limbs are accompanied by a copy of the normally achieved visual results. The visual information resulting from movement is fed back, and compared with the visual schema which was expected on the basis of previous movements. Attneave and Benson (1969) go so far as to suggest that the specific input modality of the stimuli might be ignored, and the data transferred to that modality system best able to process and store it. They concluded that information about spatial co-ordinates was primarily represented in visual terms, regardless of whether the data was derived through vision or through one or more of the other senses. If a visual reference system is essential for coding aspects of limb movement, those who do not have such a reference system may be impaired in this respect. To investigate this we compared normally sighted but blindfold children with congenitally blind children for their ability to reproduce limb movements. Autistic children were also included, because it had been found in previous studies (Frith
295
296
B. HERMELIN AND N. O’CONNOR
and Hermelin, 1969) that they often failed to process visual information even when it was available, and relied predominantly on kinaesthetic cues. When blindfolded, their motor performance deteriorated less than that of normal children. If movement reproduction were primarily kinaesthetic it could be based on direct feedback to a modality-specific memory store. Such motor memories could be specific to the arm used or might be more general. T o investigate this, we tested movement reproduction by the practised and also by the unpractised hand.
Downloaded by [New York University] at 06:40 09 June 2015
Method Subjects Seventy-two children, 24 of them blind, 24 normal, sighted but blindfolded, and 24 blindfolded autistic children acted as subjects. The groups were matched for chronological age, which varied from 10to 15 years, with a mean C.A. of 13 years 6 months. The mental ages of the blind and sighted normal children matched their chronological ages. The blind children lacked sight either from birth or after the first few months of life, and attended schools for the totally blind. The autistic subjects were selected as suffering from childhood autism as defined by Rutter (1g71), and attended special schools. Their mean mental age, as measured by the WISC performance scale, was 10years 4 months, varying from 7 years to I 3 years. The relatively high intelligence level of this group, which is not representative of the majority of autistic children, is accounted for by selecting only those subjects who could understand the requirements of the experimental tasks. The onset of the condition of autism in all cases was reported as having occurred either at birth or during the first 18 months of life. All autistic children showed some degree of lack of social contact, severe language impairments, and repetitive, stereotyped rigid behaviour patterns.
Apparatus and design The apparatus used is shown in Fig.
I.
It consisted of a so-cm long vertical rod with a
7
\
I
1
FIG.I. Apparatus.
LOCATION AND DISTANCE ESTIMATION
297
sliding pointer and two centimeter scales. There were three experimental conditions, and in each the initial standard task was to move the pointer vertically from the base up the rod until it encountered a stopper. The test movement, differed for each of the three experimental tasks, so that the first task asked for simple reproduction, the second required retention of end position but began from a different starting point, while the third required reproduction of a distance independent of previous starting position and end location.
Downloaded by [New York University] at 06:40 09 June 2015
Reproduction The stopper was set by the experimenter in a predetermined random order at a height of either 10,15, 2 0 , ~ sor 30 cm. The child was asked to move the pointer from the bottom up to the stopper three times. After this the stopper was removed and the task was to move the pointer again from the bottom and stop at the same point as on the standard trials. Location Following the three standard trials the stopper was removed and the pointer was put at a new starting position half way between the bottom and the end location, so that for a movement terminating at a height of 1 0 cm the starting point was 5 cm up, for one terminating at 20 cm 10cm up, etc. The task was to start from the new point and stop at the original end point. Distance After the standard trials the pointer was set half way between the base and the stopper. The task was to attempt a movement of the same extent as before, which should terminate in a position above the previous stopping point. All subjects were individually tested under all conditions. Order of conditions was randomized and balanced between subjects. The standard movements were 10,15, 20, 25 and 30 cm and two trials were given for each. This resulted in 10trials for each subject on each of the three tasks. Tasks were presented in blocks, and distances were randomized. Half the children carried out the standard movements with the non-preferred hand, and the reproduction movements with the preferred hand. The other children moved the pointer with the preferred hand in both standard and test trials. Every effort was made to make the instructions clear to the children. When verbal explanations seemed insufficient, as with many of the autistic children, demonstrations and examples were given until the child seemed to understand the tasks. No reinforcement was given in the test trials, except for praising the child at intervals, regardless of his performance.
Results Two analyses of variance were carried out, one on absolute and one on algebraic error scores. For both, the main terms were Groups, Tasks, Height settings and the use of the same or different hands for standard and test trials. Absolzite errors T h e data were the mean for each subject of the two trials under each condition. They are summarized in Table I. T h e main effects of groups, (F=19.05,df = 2, 66, P 0.05). When the same hand was used for standard and practice trials the overall mean error score was 5-36 and when different hands were used it was 6-1I . A groups by height interaction (F=2-07,df = 8,792, P < 0.05)reflects the fact
B. HERMELIN AND N. O'CONNOR
298
TABLE I Mean absolute error (cm): means of combined hand scores Height (cm) Groups Sighted
Downloaded by [New York University] at 06:40 09 June 2015
Blind
Autistic
Tasks
I0
I5
20
25
30
2.6
3 '4 3 '4
3 '9 4'5 7'6 5'3
4'9 5 TJ 8.9 6-3 4'1 4.8 13.1 7 '3 7'2 6 '2 13.1
Reproduction Location Distance Mean
3 '7 3 '0
3 '5 3'5 3 '7 36
Reproduction Location Distance Mean
2'7 3 '0 3'3 3' 0
3'3 3.6 5 '3 4'1
4'3 6.0 4.8
4'4 4'5 10.3 6.4
Reproduction Location Distance Mean
6.2
7'0 7'2 7.8 7'3
7'2 6.7 8.0 7'3
6.7 6.0 9'7 7'5
2.6
6.5 7'9 6-8
5.6 4'1
4'2
8.8
that errors of the autistic children were greater than those of blind and normal children at the lower heights. Testing the interaction for simple effects at the 10 cm distance resulted in t = 5-12, P 0.05). T h e slope coefficients for the autistic group and therefore for other groups differed significantly from zero (t = 10.46, P< 0.001). Discussion T h e experiment investigated the adequacy of kinaesthetic data for making reproduction, location and distance estimates of arm movements. Both Absolute and Algebraic error scores showed that when subjects had to reproduce invariant locations, (start or end points) all groups behaved similarly, except that autistic children showed a tendency to overestimate. For the blind and normal children kinaesthetic data seems to have been sufficient for accurate estimation of reproduction and location tasks. As same-hand judgements in blind as well as sighted groups were not significantly better than other-hand judgements it must be assumed that this kinaesthetic information was centrally represented. I n distance judgements however, there were no invariant spatial points, and hence no kinaesthetic invariants. Though all subjects showed a progressive increase in absolute error with increasing heights in this task, due to increasing undershooting, this was more marked with the blind and autistic than with the normal group. For the blind, it may be that visual as well as kinaesthetic representations are necessary for accurate derivations of distance. T h e autistic did not lack the visual reference data, but may have failed to make the necessary cognitive inferences from it. However, the present experiment was designed in such a way that in the distance task the target point was always higher than that for the corresponding distance in each of the other conditions. Therefore, the direction as well as the size of errors may have been dependent on the extent to which the child had to reach upwards in order to complete a movement ending near the top of the scale. Blind children seemed to have a non-linear metric for vertical space, perhaps because they were reluctant to extend their arms above head height. Though the autistic children seem to have a poor concept of vertical distance, the slopes of the regression lines show that they were responsive to target heights. T h e results may be interpreted as showing that the absence of sight may have a similar effect to the failure to make cognitive inferences from a visual reference system. It seems, that when tasks can be solved by the use of directly available kinaesthetic data, visually as well as cognitively impaired children can perform adequately. However, when it is necessary to make inferential judgements in terms of perceptual reference systems, those lacking such systems, or lacking the ability to use them, are at a disadvantage. Such an interpretation would conform with findings from a previous study of spatial judgements by blind and sighted children (O’Connor and Hermelin, 1975). We would like to thank M. J. R. Healy of the MRC Clinical Research Centre, Division of Computing and Statistics, for his statistical advice and help, and the staff and children of the schools, who helped us with this experiment.
References ATTNEAVE, F. and BENSON,L. (1969). Spatial coding and tactual stimulation. Journal of Experimental Psychology, 81, 216-22.
LOCATION AND DISTANCE ESTIMATION
30'
FRITH, U. and HERMELIN, B. (1969). The role of visual and motor cues for normal, subnormal and autistic children. Journal of Child Psychology and Psychiatry,
10,153-63.
HELD, R. (1961). Exposure history as a factor in maintaining stability of perception and coordination. Journal of Nervous and Mental Diseases, 132,26-32. MARTENIUK, R. G. and ROY, E. A. (1972). The codability of kinaesthetic location and distance information. Acta Psychologica, 36,47 1-79. O'CONNOR,N. and HERMELIN, B. (1975). Modality specific spatial co-ordinates. Perception and Psychophysics (in press). RUTTER, M. (1971). The description and classification of infantile autism. CHURCHILL, D. W., ALPERN,G. D. and DEMYER, M. K. (Eds). Springfield, Illinois: Charles C.
Downloaded by [New York University] at 06:40 09 June 2015
Thomas. SKOGLUND, S. (1956). Anatomical and physiological studies of knee joint innervation in the cat. Acta Physiologica, Scandinavia, 36, I 24-6. Revised manuscript received 7 June I 974
Quarterly Journal of Experimental Psychology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/pqje19
Location and distance estimates by blind and sighted children a
B. Hermelin & N. O'Connor
a
a
MRC Developmental Psychology Unit, Drayton House, Gordon Street , London, WCI Published online: 29 May 2007.
To cite this article: B. Hermelin & N. O'Connor (1975) Location and distance estimates by blind and sighted children, Quarterly Journal of Experimental Psychology, 27:2, 295-301, DOI: 10.1080/14640747508400488 To link to this article: http://dx.doi.org/10.1080/14640747508400488
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/ page/terms-and-conditions
Quarterly Journal of Experimental Psychology (1975)27, 295-301
LOCATION AND DISTANCE ESTIMATES BY BLIND AND SIGHTED CHILDREN B. HERMELIN AND N. O’CONNOR
Downloaded by [New York University] at 06:40 09 June 2015
MRC Developmental Psychology Unit, Drayton House, Gordon Street, London WCI Blindfold normal, blindfold autistic and congenitally blind children made reproduction location and distance estimates of an arm movement. For each task they first experienced a standard vertical movement of a predetermined extent. In the test tasks which followed, they either reproduced the movement exactly, reproduced the end point although commencing from a different starting position, or reproduced the same distance from a different starting point. Sighted normal children and blind children performed very similarly on both the reproduction and the location task. However on distance reproduction, the blind children underestimated the longer distances more markedly than did the normals. Autistic children resembled the blind in their attempts to reproduce the longer distances. In addition they had a tendency to overshoot over short distances in all tasks. The results are discussed in terms of the role of a visual reference system for different aspects of motor movements.
Introduction
Is kinaesthetic data sufficient for the derivation and storage of movement components in the absence of kinaesthetic invariants? Skogland (1956) discussing specific components of movement, found kinaesthetic receptors signalling location, direction, speed and acceleration though not movement per se. It appears (Marteniuk and Roy, 1972) that distance information for example is not very precise or, perhaps, uncodable when it is the only information available regarding limb movement. Held (1961) has expressed the view however that movements of the body and the limbs are accompanied by a copy of the normally achieved visual results. The visual information resulting from movement is fed back, and compared with the visual schema which was expected on the basis of previous movements. Attneave and Benson (1969) go so far as to suggest that the specific input modality of the stimuli might be ignored, and the data transferred to that modality system best able to process and store it. They concluded that information about spatial co-ordinates was primarily represented in visual terms, regardless of whether the data was derived through vision or through one or more of the other senses. If a visual reference system is essential for coding aspects of limb movement, those who do not have such a reference system may be impaired in this respect. To investigate this we compared normally sighted but blindfold children with congenitally blind children for their ability to reproduce limb movements. Autistic children were also included, because it had been found in previous studies (Frith
295
296
B. HERMELIN AND N. O’CONNOR
and Hermelin, 1969) that they often failed to process visual information even when it was available, and relied predominantly on kinaesthetic cues. When blindfolded, their motor performance deteriorated less than that of normal children. If movement reproduction were primarily kinaesthetic it could be based on direct feedback to a modality-specific memory store. Such motor memories could be specific to the arm used or might be more general. T o investigate this, we tested movement reproduction by the practised and also by the unpractised hand.
Downloaded by [New York University] at 06:40 09 June 2015
Method Subjects Seventy-two children, 24 of them blind, 24 normal, sighted but blindfolded, and 24 blindfolded autistic children acted as subjects. The groups were matched for chronological age, which varied from 10to 15 years, with a mean C.A. of 13 years 6 months. The mental ages of the blind and sighted normal children matched their chronological ages. The blind children lacked sight either from birth or after the first few months of life, and attended schools for the totally blind. The autistic subjects were selected as suffering from childhood autism as defined by Rutter (1g71), and attended special schools. Their mean mental age, as measured by the WISC performance scale, was 10years 4 months, varying from 7 years to I 3 years. The relatively high intelligence level of this group, which is not representative of the majority of autistic children, is accounted for by selecting only those subjects who could understand the requirements of the experimental tasks. The onset of the condition of autism in all cases was reported as having occurred either at birth or during the first 18 months of life. All autistic children showed some degree of lack of social contact, severe language impairments, and repetitive, stereotyped rigid behaviour patterns.
Apparatus and design The apparatus used is shown in Fig.
I.
It consisted of a so-cm long vertical rod with a
7
\
I
1
FIG.I. Apparatus.
LOCATION AND DISTANCE ESTIMATION
297
sliding pointer and two centimeter scales. There were three experimental conditions, and in each the initial standard task was to move the pointer vertically from the base up the rod until it encountered a stopper. The test movement, differed for each of the three experimental tasks, so that the first task asked for simple reproduction, the second required retention of end position but began from a different starting point, while the third required reproduction of a distance independent of previous starting position and end location.
Downloaded by [New York University] at 06:40 09 June 2015
Reproduction The stopper was set by the experimenter in a predetermined random order at a height of either 10,15, 2 0 , ~ sor 30 cm. The child was asked to move the pointer from the bottom up to the stopper three times. After this the stopper was removed and the task was to move the pointer again from the bottom and stop at the same point as on the standard trials. Location Following the three standard trials the stopper was removed and the pointer was put at a new starting position half way between the bottom and the end location, so that for a movement terminating at a height of 1 0 cm the starting point was 5 cm up, for one terminating at 20 cm 10cm up, etc. The task was to start from the new point and stop at the original end point. Distance After the standard trials the pointer was set half way between the base and the stopper. The task was to attempt a movement of the same extent as before, which should terminate in a position above the previous stopping point. All subjects were individually tested under all conditions. Order of conditions was randomized and balanced between subjects. The standard movements were 10,15, 20, 25 and 30 cm and two trials were given for each. This resulted in 10trials for each subject on each of the three tasks. Tasks were presented in blocks, and distances were randomized. Half the children carried out the standard movements with the non-preferred hand, and the reproduction movements with the preferred hand. The other children moved the pointer with the preferred hand in both standard and test trials. Every effort was made to make the instructions clear to the children. When verbal explanations seemed insufficient, as with many of the autistic children, demonstrations and examples were given until the child seemed to understand the tasks. No reinforcement was given in the test trials, except for praising the child at intervals, regardless of his performance.
Results Two analyses of variance were carried out, one on absolute and one on algebraic error scores. For both, the main terms were Groups, Tasks, Height settings and the use of the same or different hands for standard and test trials. Absolzite errors T h e data were the mean for each subject of the two trials under each condition. They are summarized in Table I. T h e main effects of groups, (F=19.05,df = 2, 66, P 0.05). When the same hand was used for standard and practice trials the overall mean error score was 5-36 and when different hands were used it was 6-1I . A groups by height interaction (F=2-07,df = 8,792, P < 0.05)reflects the fact
B. HERMELIN AND N. O'CONNOR
298
TABLE I Mean absolute error (cm): means of combined hand scores Height (cm) Groups Sighted
Downloaded by [New York University] at 06:40 09 June 2015
Blind
Autistic
Tasks
I0
I5
20
25
30
2.6
3 '4 3 '4
3 '9 4'5 7'6 5'3
4'9 5 TJ 8.9 6-3 4'1 4.8 13.1 7 '3 7'2 6 '2 13.1
Reproduction Location Distance Mean
3 '7 3 '0
3 '5 3'5 3 '7 36
Reproduction Location Distance Mean
2'7 3 '0 3'3 3' 0
3'3 3.6 5 '3 4'1
4'3 6.0 4.8
4'4 4'5 10.3 6.4
Reproduction Location Distance Mean
6.2
7'0 7'2 7.8 7'3
7'2 6.7 8.0 7'3
6.7 6.0 9'7 7'5
2.6
6.5 7'9 6-8
5.6 4'1
4'2
8.8
that errors of the autistic children were greater than those of blind and normal children at the lower heights. Testing the interaction for simple effects at the 10 cm distance resulted in t = 5-12, P 0.05). T h e slope coefficients for the autistic group and therefore for other groups differed significantly from zero (t = 10.46, P< 0.001). Discussion T h e experiment investigated the adequacy of kinaesthetic data for making reproduction, location and distance estimates of arm movements. Both Absolute and Algebraic error scores showed that when subjects had to reproduce invariant locations, (start or end points) all groups behaved similarly, except that autistic children showed a tendency to overestimate. For the blind and normal children kinaesthetic data seems to have been sufficient for accurate estimation of reproduction and location tasks. As same-hand judgements in blind as well as sighted groups were not significantly better than other-hand judgements it must be assumed that this kinaesthetic information was centrally represented. I n distance judgements however, there were no invariant spatial points, and hence no kinaesthetic invariants. Though all subjects showed a progressive increase in absolute error with increasing heights in this task, due to increasing undershooting, this was more marked with the blind and autistic than with the normal group. For the blind, it may be that visual as well as kinaesthetic representations are necessary for accurate derivations of distance. T h e autistic did not lack the visual reference data, but may have failed to make the necessary cognitive inferences from it. However, the present experiment was designed in such a way that in the distance task the target point was always higher than that for the corresponding distance in each of the other conditions. Therefore, the direction as well as the size of errors may have been dependent on the extent to which the child had to reach upwards in order to complete a movement ending near the top of the scale. Blind children seemed to have a non-linear metric for vertical space, perhaps because they were reluctant to extend their arms above head height. Though the autistic children seem to have a poor concept of vertical distance, the slopes of the regression lines show that they were responsive to target heights. T h e results may be interpreted as showing that the absence of sight may have a similar effect to the failure to make cognitive inferences from a visual reference system. It seems, that when tasks can be solved by the use of directly available kinaesthetic data, visually as well as cognitively impaired children can perform adequately. However, when it is necessary to make inferential judgements in terms of perceptual reference systems, those lacking such systems, or lacking the ability to use them, are at a disadvantage. Such an interpretation would conform with findings from a previous study of spatial judgements by blind and sighted children (O’Connor and Hermelin, 1975). We would like to thank M. J. R. Healy of the MRC Clinical Research Centre, Division of Computing and Statistics, for his statistical advice and help, and the staff and children of the schools, who helped us with this experiment.
References ATTNEAVE, F. and BENSON,L. (1969). Spatial coding and tactual stimulation. Journal of Experimental Psychology, 81, 216-22.
LOCATION AND DISTANCE ESTIMATION
30'
FRITH, U. and HERMELIN, B. (1969). The role of visual and motor cues for normal, subnormal and autistic children. Journal of Child Psychology and Psychiatry,
10,153-63.
HELD, R. (1961). Exposure history as a factor in maintaining stability of perception and coordination. Journal of Nervous and Mental Diseases, 132,26-32. MARTENIUK, R. G. and ROY, E. A. (1972). The codability of kinaesthetic location and distance information. Acta Psychologica, 36,47 1-79. O'CONNOR,N. and HERMELIN, B. (1975). Modality specific spatial co-ordinates. Perception and Psychophysics (in press). RUTTER, M. (1971). The description and classification of infantile autism. CHURCHILL, D. W., ALPERN,G. D. and DEMYER, M. K. (Eds). Springfield, Illinois: Charles C.
Downloaded by [New York University] at 06:40 09 June 2015
Thomas. SKOGLUND, S. (1956). Anatomical and physiological studies of knee joint innervation in the cat. Acta Physiologica, Scandinavia, 36, I 24-6. Revised manuscript received 7 June I 974
