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Right Hand Superiority in Serial Recall of Tactile Stimuli
NOTE
RIGHT HAND SUPERIORITY IN SERIAL RECALL OF TACTILE STIMULI 1 Lucia Riggio, Anna Dellantonio and Margherita Barbato (Institute of Psychology, University of Padua, Italy)
It is well known that the performance of experimental subjects in response to uni-and bilateral stimulations depends on their presentation field. By common consent the asymmetries so found depend on the different functional specialization of the two cerebral hemispheres. Recently this specialization has been explained as the result of the different way in which each hemisphere processes information. Nevertheless there is still no good unitary model that can explain the experimental results completely (see, for a review, Bradshaw and Nettleton, 1981 ). The situation is particularly uncertain when tactile input is involved in the subject's task (Dellantonio and Riggio, 1982). In fact, while using tactile material that we can define as spatial2 the left hemibody - right hemisphere superiority is confirmed by various materials, methods and populations (of the studies available, see, for example, Corkin, 1965; Levy-Agresti and Sperry, 1968; Fontenot and Benton, 1971; Zaidel and Sperry, 1973; Boll, 1974; Witelson, 1974; Benton, Varney and DeS. Hamsher, 1978), left hemisphere specialization is more difficult to test. There are however some studies on normal subjects (Efron, 1963; Nachshon and Carmon, 1975; Bakker and van der Kleij, 1978) that appear to support left hemisphere superiority with tactile material that can presumably be processed according to a temporal order. This problem is connected to the more general question of left hemisphere superiority in temporal analysis which is still being debated (e.g., Moscovitch, 1979, pp. 413-414; Kim, Royer, Bonstelle and Boller, 1980). Our research attempts to verify left hemisphere "temporal" superiority using a similar, but more complex, experimental paradigm than that adopted by Nachshon and Carmon (1975) and Bakker and van der Kleij (1978). In fact, we wish not only to verify left hemisphere superiority in a sequential task where sophisticated temporal analyses are probably used, but also to investigate the "memory" of such a task, on the basis of previous experimental results that show much clearer hemispheric differences when time intervals between stimulus presentation and response are interposed (e.g., Egeth, 1971; Goodglass and Peck, 1972; Dee and Fontenot, 1973; Hines, Satz and Clementino, 1973; Oscar-Berman, Goodglass and Donnenfeld, 1974; in particular position, Moscovitch, Scullion and Christie, 1976). In the following experiment the task consists in the reproduction of ordered sequences of random stimulations on the five fingertips of the right and left hand; 1
This research was supported by a Grant of Consiglio Nazionale delle Ricerche, Italy.
2 This term is used in a rather vague way and often seems to be synonymous with ever thing that cannot be processed along a verbal dimension (Harris, 1978; Dellantonio and Riggio, 1982).
Cortex (1982) 18, 595-601
596
Lucia Riggio, Anna Dellantonio and Margherita Barbato
reproduction occurs after an acoustic or tactile signal given at varying time intervals. Besides, more specific hypotheses are possible about the memory problem in such a task. It is well known that when presenting a brief series of items to be recalled in the same presentation order, the first and last items are better recalled. The two effects are called respectively primacy and recency. The primacy effect seems to be due to the longer rehearsal to which the first elements of the series are submitted, whereas for the recency effect the most reliable explanation so far involves the persistence of sensory traces (which are therefore tied up to the invut sensory modality and precede the categorization process), not disturbed by the interference of subsequent items. Consequently presentation of a further redundant item (called suffix), similar to the previous items but which is not to be reproduced by subjects, should greatly reduce the recency effect (e.g., Crowder and Morton, 1969; Crowder, 1971). In our experimental results, therefore, we should expect not only better recall of the extremities of the series presented, but also differences in recency effect depending on whether the recall signal is acoustic or tactile (since the tactile signal will act as a suffix). It is also true that, as there are very few studies in this field (Watkins and Watkins, 1974; Manning, 1980), we are somewhat uncertain about the fundamental characteristic of a possible tactile suffix and so we wish this study to be considered as purely preliminary for these aspects.
MATERIALS AND METHOD
Subjects
Two groups of 24 male students enrolled on the Psychology Course at the University of Padua were tested. All subjects (age range 20-27 years) were volunteers and right-handed according to Oldfield's test (Oldfield, 1971). Furthermore, in order to make the group as homogeneous as possible, all subjects with any left-handed relatives were rejected in spite of having reached the score criterium which permitted them to be considered as right-handed. Apparatus, stimuli and responses
The experimental apparatus (see scheme in Figure I) consists of a metal plate with seven holes in it. Just above the holes are an equal number of small pushbuttons which the subject uses for his responses. Small rounded points come up through the holes, one at a time, according to the programme pre-arranged by the experimenter. These points provide the stimulation. A screen with an opening for the arm to pass through prevents the subjects from seeing their own hands on the plate. The arm is kept still and the fingers only can move, so that homolateral kinestethic feed-back is as limited as possible. The subject passes his right or left arm through the screen and puts the tips of his fingers on the holes in the plate: the 5 fingertips are stimulated singly at random. After intervals of 0.3, 1.0, 3.0, and 6.0 seconds which are constant for each group of trials, an acoustic or tactile signal sets off the response given by the subject, who pushes the small buttons which correspond to the various holes. The acoustic signal is a tone at 400 Hz,
Right hand superiority in serial recall
597
3R
2R
G 4L
G 3L
4R
G 2L
5R
G
G
SL
1R
G
G 1L
Fig. 1-JR, 2R, 3R, 4R, 5R indicate stimulation of the thumb, 2nd, 3rd, 4th and 5th finger of the right hand; JL, 2L, 3L, 4L, 5L of the left and. ®indicate the push-button for response.
whereas the tactile signal is a further stimulation in the middle of the palm, given through an extra hole in the same plate. The experimental apparatus is also fitted with a device for programming (a) the sequences in which the points come up, (b) the type of signal emitted (acoustic or tactile) and (c) the time interval between the tactile sequences and this signal. Moreover the subjects' responses are memorized and automatically recorded on paper at each trial end. Tactile stimulations last 100 msec., the interval between stimuli in the tactile sequence is 300 msec. The start of each series of stimulations is announced by the experimenter's "Go ahead"; otherwise the strictest silence is observed till all trials are completed. After brief training, each subject performs 40 trials, 10 for each of the four time-intervals between input and response, with each hand. Obviously both trials and time-intervals for recall are randomized. Half the subjects start with their right hand, half with their left. RESULTS AND DISCUSSION
Mean errors were analyzed in a 2 (hand) X 2 (suffix type) X 4 (suffix intervals) X 5 (serial positions) analysis of variance design, with all variables except suffix type being within-subjects. Only hand (F = 5.89; d.f. = 1,46; p < 0.025) and serial positions (F = 115.26; d.f. = 4, 184; p < 0.001) were significant. 3 3 Since the design was with within-subject variables, to obviate possible effects of heterogeneity of covariance, Myers (1979, p. 227) advises using conservative F tests. Even with this type ofF test the sources presented are significant.
Lucia Riggio, Anna Del/antonio and Margherita Barbato
598
As our hypothesis predicted, the right hand is more efficient than the left (44,71% error versus 47.76% ). The left hemisphere therefore makes fewer errors in the sequential "memory" task. This result seems relevant because it is unusual. As already mentioned in the introduction, not even presentation of letters in tactile modality gets a right hand -left hemisphere superiority, as can be seen from the
60
50
40
30 0
20
10
Fig. 2 - Graph shows serial position error percentages.
l.
• • • • • • •
'----
Fig. 3- Results of a post-hoc analysis obtained using Tukey's (a) method for source P. indicates significant differences (p < 0.01) between serial positions.
e
Right hand superiority in serial recall
599
obtained results by Witelson ( 1974); La Breche, Manning, Goble and Markmann (1977); Klein and Rosenfield (1980); only Witelson's results (1976) are in discordance, but they probably depends on the response modality. 4 In our case, left hemisphere superiority seems to be related to the kind of sequential task proposed, which involves a temporal type elaboration, and not to verbal mediation. This explanation is suggested by the subjects' introspective reports: a verbal strategy (e.g. naming the stimulated finger) was immediately found to be of no use, as the tactile sequences were very fast, and was given up for "something else" at once. Furthermore, from the results obtained by N achshon and Carmon ( 197 5) and Bakker and van der Kleij (1978) it seems that the motor aspect of the response is negligible, when we consider the differences between the right and left hands (see also Bakker and van der Kleij, 1978, p. 363). The serial position factor also produces significant differences, as has been seen. Graph in Figure 2 shows error percentages for serial position and Figure 3 shows the results of a post-hoc analysis using Tukey's (a) method. The superiority of the first serial position over the others and of the last one over the third and fourth positions is evident. The second serial position also is significantly superior to the third and fourth serial positions which reach chance levels. Consequently the primacy effect seems to concern the first two serial positions where the difference between them probably expresses the double masking effects acting on the second serial position with respect to the first, while the recency effect concerns the last serial position only. Nevertheless, contrary to the hypotheses and to previous results (Watkins and Watkins, 1974; Manning, 1980), the two types of recall signal did not act differentially on recall of the last serial position. Various hypotheses can be formulated: is the tactile suffix too far from the preceding stimulation locus to be able to interact with the test series? And/ or must the sequential nature of the series be reproduced in the suffix in order to have interference? Or does the suffix affect item information and not position order (Watkins and Todres, 1979)? We are trying to answer these questions by means of further experiments. The only reliable conclusion that can be drawn from this research concern the laterality aspects of the task which confirm data previously mentioned in tactile sequential tasks involving memory. ABSTRACT
The fingertips of right and left hand of normal subjects (right-handed male) were stimulated at random. After intervals of 0.3, 1.0, 3.0 and 6.0 seconds, an acoustic or tactile signal set off the response of the subject. The response was the ordered reproduction of the tactile sequence given to the subject. The results show a greater efficiency of right hand, a better recall of the first serial positions and of the last one but no difference depending on whether the recall signal is acoustic or tactile. The results are discussed and new hypotheses are formulated.
4 Only two-letters words are identified by touch better with right hand in children (Cioffi and Kandel, 1979).
600
Lucia Riggio, Anna Del/antonio and Margherita Barbato
REFERENCES
BAKKER, D.J., and VANDER KLEIJ, P.C.M. (1978) Development of lateral asymmetry in the perception of sequentially touched fingers, Acta Psychologica, 42, 357-365. BENTON, A.L., VARNEY, N .R., and DES. HAMSHER, K. (1978) Lateral differences in tactile directional perception, N europsychologia, 16,,, I 09-114. BOLL, J. T. (1974) Right and left cerebral hemisphere damage and tactile perception: Performance of the ipsilateral and controlateral sides of the body, Neuropsychologia, 12, 235-238. BRADSHAW, J.L., and NETTLETON, N.C. (1981) The nature of hemispheric specialisation in man, Behav. Brain Sci., 4, 51-91. CIOFFI, 1., and KANDEL, G.L. (1979) Laterality of stereognostic Accuracy of Children for Words, Shapes, and Bigrams: A Sex Difference for Bigrams, Science, 204, 14321434. CORKIN, S. ( 1965) Tactually-guided maze learning in man: effects of unilateral excisions and bilateral hippocampal lesions, Neuropsychologia, 3, 339-351. CROWDER, R.G. ( 1971) Waiting for the stimulus suffix: decay, delay, rhythm, and readout in immediate memory, Quart. J. Exper. Psychol., 23, 324-340. - , and MORTON, J. (1969) Precategorical acoustic storage (PAS), Percept. Psychophys., 5, 365-373. DEE, H.L., and FONTENOT, D.J. (1973) Cerebral dominance and lateral differences in perception and memory, Neuropsychologia 11, 167-173. DELLANTONIO, A., and RIGGIO, L. ( 1982) Lateralizzazione emisferica e modalita tattile, In Neuropsicologia Sperimentale, ed. by C.A. Umilta, Franco Angeli, Milano. EFRON, R. (1963) The effect of handedness on the perception of simultaneity and temporal order, Brain, 86, 261-284. EGETH, H. (1971) Laterality effects in perceptual matching, Percept. Psychophys., 9, 375376. FONTENOT, D.J., and BENTON, A.L. (1971) Tactile perception of direction in relation to hemispheric locus of lesion, Neuropsychologia, 9, 83-88. GOODGLASS, H., and PECK, E.A. (1972) Dichotic ear order effects in Korsakoff and normal subjects, NeuropsychoJogia, 10, 211-217. HARRIS, L.J. (1978) Sex differences in spatial ability: Possible environmental, genetic and neurological factors, in Asymmetrical Function of the Brain, ed. by M. Kinsbourne, Cambridge University Press, London. HINES, D., SATZ, P., and CLEMENTINO, T. (1973) Perceptual and memory components of the superior recall of letters from the right visual half-fields, Neuropsychologia, 2, 175180. KIM, Y., ROYER, F., BONSTELLE, C., and BOLLER, F. (1980) Temporal sequencing of verbal and nonverbal materials: the effect of laterality of lesion, Cortex, 16, 135-143. KLEIN, S.P., and ROSENFIELD, W.D. (19SO) The hemispheric specialization for linguistic and non-linguistic tactile stimuli in third grade children, Cortex, 16, 205-212. LA BRECHE, T.M., MANNING, A.A., GoBLE, W., and MARKMAN, R. (1977) Hemispheric specialization for linguistic and non-linguistic tactual perception in a congenitally deaf population, Cortex, 13, 184-194. LEVY-AGRESTI, J., and SPERRY, R.W. (1968) Differential perceptual capacities in major and minor hemispheres, Proceed. Nat. Acad. Sci. U.S.A., 61, 1151. MANNING, S.K. (1980) Tactual and visual alphanumeric suffix effects, Quart. J. Exper. Psychol., 32, 257-267. MOSCOVITCH, M. (1979) Information processing and cerebral hemispheres, in Handbook of Behavioral Neurology, 2, Neuropsychology, ed. by M.S. Gazzaniga, Plenum Press, New York. - , SCULLION, D., and CHRISTIE, D. (1976) Early vs. late stages of processing and their relation to functional hemispheric asymmetries in face recognition, J. Exper. Psychol.: Hum. Percept. Perform., 2, 401-416. MYERS, J.L. (1979) Fundamentals of Experimental Design, Third Edition, Allyn and Bacon, Boston.
Right hand superiority in serial recall
601
NACHSHON, 1., and CARMON, A. (1975) Hand preference in sequential and spatial discrimination tasks, Cortex, 11, 123-131. OLDFIELD, R.C. (1971) Edinburgh Handedness Inventory of Medical Research Council. Speech and Communication Unit, Neuropsycho1ogia, 9, 15-20. OSCAR-BERMAN, M., GoODGLASS, H., and DONNENFELD, H. (1974) Dichotic ear order effects with nonverbal stimuli, Cortex, 10, 270-277. WATKINS, M.J., and WATKINS, O.C. (1974) A tactile suffix effect, Mem. Cognit., 2, 176-180. - , and TODRES, A.K. (1979) Stimulus suffix effect and the item-position distinction, J. Exper. Psycho!.: Hum. Learn. Mem., 5, 322-325. WITELSON, S.F. (1974) Hemispheric specialization for linguistic and non-linguistic tactual perception using a dichotomous stimulation technique, Cortex, 10, 3-17. - (1976) Abnormal right hemisphere specialization in developmental dyslexia, The neuropsychology of learning disorders. Theoretical Approaches, Academic Press, London. ZAJDEL, D., and SPERRY, R.W. (1973) Performance on the Raven's Colored Progressive Matrices Test by subjects with cerebral commissurotomy, Cortex, 9, 34-39.
Anna Dellantonio, Istituto di Psicologia, Piazza Capitaniato, 5, 35100 Padova, Italy.
RIGHT HAND SUPERIORITY IN SERIAL RECALL OF TACTILE STIMULI 1 Lucia Riggio, Anna Dellantonio and Margherita Barbato (Institute of Psychology, University of Padua, Italy)
It is well known that the performance of experimental subjects in response to uni-and bilateral stimulations depends on their presentation field. By common consent the asymmetries so found depend on the different functional specialization of the two cerebral hemispheres. Recently this specialization has been explained as the result of the different way in which each hemisphere processes information. Nevertheless there is still no good unitary model that can explain the experimental results completely (see, for a review, Bradshaw and Nettleton, 1981 ). The situation is particularly uncertain when tactile input is involved in the subject's task (Dellantonio and Riggio, 1982). In fact, while using tactile material that we can define as spatial2 the left hemibody - right hemisphere superiority is confirmed by various materials, methods and populations (of the studies available, see, for example, Corkin, 1965; Levy-Agresti and Sperry, 1968; Fontenot and Benton, 1971; Zaidel and Sperry, 1973; Boll, 1974; Witelson, 1974; Benton, Varney and DeS. Hamsher, 1978), left hemisphere specialization is more difficult to test. There are however some studies on normal subjects (Efron, 1963; Nachshon and Carmon, 1975; Bakker and van der Kleij, 1978) that appear to support left hemisphere superiority with tactile material that can presumably be processed according to a temporal order. This problem is connected to the more general question of left hemisphere superiority in temporal analysis which is still being debated (e.g., Moscovitch, 1979, pp. 413-414; Kim, Royer, Bonstelle and Boller, 1980). Our research attempts to verify left hemisphere "temporal" superiority using a similar, but more complex, experimental paradigm than that adopted by Nachshon and Carmon (1975) and Bakker and van der Kleij (1978). In fact, we wish not only to verify left hemisphere superiority in a sequential task where sophisticated temporal analyses are probably used, but also to investigate the "memory" of such a task, on the basis of previous experimental results that show much clearer hemispheric differences when time intervals between stimulus presentation and response are interposed (e.g., Egeth, 1971; Goodglass and Peck, 1972; Dee and Fontenot, 1973; Hines, Satz and Clementino, 1973; Oscar-Berman, Goodglass and Donnenfeld, 1974; in particular position, Moscovitch, Scullion and Christie, 1976). In the following experiment the task consists in the reproduction of ordered sequences of random stimulations on the five fingertips of the right and left hand; 1
This research was supported by a Grant of Consiglio Nazionale delle Ricerche, Italy.
2 This term is used in a rather vague way and often seems to be synonymous with ever thing that cannot be processed along a verbal dimension (Harris, 1978; Dellantonio and Riggio, 1982).
Cortex (1982) 18, 595-601
596
Lucia Riggio, Anna Dellantonio and Margherita Barbato
reproduction occurs after an acoustic or tactile signal given at varying time intervals. Besides, more specific hypotheses are possible about the memory problem in such a task. It is well known that when presenting a brief series of items to be recalled in the same presentation order, the first and last items are better recalled. The two effects are called respectively primacy and recency. The primacy effect seems to be due to the longer rehearsal to which the first elements of the series are submitted, whereas for the recency effect the most reliable explanation so far involves the persistence of sensory traces (which are therefore tied up to the invut sensory modality and precede the categorization process), not disturbed by the interference of subsequent items. Consequently presentation of a further redundant item (called suffix), similar to the previous items but which is not to be reproduced by subjects, should greatly reduce the recency effect (e.g., Crowder and Morton, 1969; Crowder, 1971). In our experimental results, therefore, we should expect not only better recall of the extremities of the series presented, but also differences in recency effect depending on whether the recall signal is acoustic or tactile (since the tactile signal will act as a suffix). It is also true that, as there are very few studies in this field (Watkins and Watkins, 1974; Manning, 1980), we are somewhat uncertain about the fundamental characteristic of a possible tactile suffix and so we wish this study to be considered as purely preliminary for these aspects.
MATERIALS AND METHOD
Subjects
Two groups of 24 male students enrolled on the Psychology Course at the University of Padua were tested. All subjects (age range 20-27 years) were volunteers and right-handed according to Oldfield's test (Oldfield, 1971). Furthermore, in order to make the group as homogeneous as possible, all subjects with any left-handed relatives were rejected in spite of having reached the score criterium which permitted them to be considered as right-handed. Apparatus, stimuli and responses
The experimental apparatus (see scheme in Figure I) consists of a metal plate with seven holes in it. Just above the holes are an equal number of small pushbuttons which the subject uses for his responses. Small rounded points come up through the holes, one at a time, according to the programme pre-arranged by the experimenter. These points provide the stimulation. A screen with an opening for the arm to pass through prevents the subjects from seeing their own hands on the plate. The arm is kept still and the fingers only can move, so that homolateral kinestethic feed-back is as limited as possible. The subject passes his right or left arm through the screen and puts the tips of his fingers on the holes in the plate: the 5 fingertips are stimulated singly at random. After intervals of 0.3, 1.0, 3.0, and 6.0 seconds which are constant for each group of trials, an acoustic or tactile signal sets off the response given by the subject, who pushes the small buttons which correspond to the various holes. The acoustic signal is a tone at 400 Hz,
Right hand superiority in serial recall
597
3R
2R
G 4L
G 3L
4R
G 2L
5R
G
G
SL
1R
G
G 1L
Fig. 1-JR, 2R, 3R, 4R, 5R indicate stimulation of the thumb, 2nd, 3rd, 4th and 5th finger of the right hand; JL, 2L, 3L, 4L, 5L of the left and. ®indicate the push-button for response.
whereas the tactile signal is a further stimulation in the middle of the palm, given through an extra hole in the same plate. The experimental apparatus is also fitted with a device for programming (a) the sequences in which the points come up, (b) the type of signal emitted (acoustic or tactile) and (c) the time interval between the tactile sequences and this signal. Moreover the subjects' responses are memorized and automatically recorded on paper at each trial end. Tactile stimulations last 100 msec., the interval between stimuli in the tactile sequence is 300 msec. The start of each series of stimulations is announced by the experimenter's "Go ahead"; otherwise the strictest silence is observed till all trials are completed. After brief training, each subject performs 40 trials, 10 for each of the four time-intervals between input and response, with each hand. Obviously both trials and time-intervals for recall are randomized. Half the subjects start with their right hand, half with their left. RESULTS AND DISCUSSION
Mean errors were analyzed in a 2 (hand) X 2 (suffix type) X 4 (suffix intervals) X 5 (serial positions) analysis of variance design, with all variables except suffix type being within-subjects. Only hand (F = 5.89; d.f. = 1,46; p < 0.025) and serial positions (F = 115.26; d.f. = 4, 184; p < 0.001) were significant. 3 3 Since the design was with within-subject variables, to obviate possible effects of heterogeneity of covariance, Myers (1979, p. 227) advises using conservative F tests. Even with this type ofF test the sources presented are significant.
Lucia Riggio, Anna Del/antonio and Margherita Barbato
598
As our hypothesis predicted, the right hand is more efficient than the left (44,71% error versus 47.76% ). The left hemisphere therefore makes fewer errors in the sequential "memory" task. This result seems relevant because it is unusual. As already mentioned in the introduction, not even presentation of letters in tactile modality gets a right hand -left hemisphere superiority, as can be seen from the
60
50
40
30 0
20
10
Fig. 2 - Graph shows serial position error percentages.
l.
• • • • • • •
'----
Fig. 3- Results of a post-hoc analysis obtained using Tukey's (a) method for source P. indicates significant differences (p < 0.01) between serial positions.
e
Right hand superiority in serial recall
599
obtained results by Witelson ( 1974); La Breche, Manning, Goble and Markmann (1977); Klein and Rosenfield (1980); only Witelson's results (1976) are in discordance, but they probably depends on the response modality. 4 In our case, left hemisphere superiority seems to be related to the kind of sequential task proposed, which involves a temporal type elaboration, and not to verbal mediation. This explanation is suggested by the subjects' introspective reports: a verbal strategy (e.g. naming the stimulated finger) was immediately found to be of no use, as the tactile sequences were very fast, and was given up for "something else" at once. Furthermore, from the results obtained by N achshon and Carmon ( 197 5) and Bakker and van der Kleij (1978) it seems that the motor aspect of the response is negligible, when we consider the differences between the right and left hands (see also Bakker and van der Kleij, 1978, p. 363). The serial position factor also produces significant differences, as has been seen. Graph in Figure 2 shows error percentages for serial position and Figure 3 shows the results of a post-hoc analysis using Tukey's (a) method. The superiority of the first serial position over the others and of the last one over the third and fourth positions is evident. The second serial position also is significantly superior to the third and fourth serial positions which reach chance levels. Consequently the primacy effect seems to concern the first two serial positions where the difference between them probably expresses the double masking effects acting on the second serial position with respect to the first, while the recency effect concerns the last serial position only. Nevertheless, contrary to the hypotheses and to previous results (Watkins and Watkins, 1974; Manning, 1980), the two types of recall signal did not act differentially on recall of the last serial position. Various hypotheses can be formulated: is the tactile suffix too far from the preceding stimulation locus to be able to interact with the test series? And/ or must the sequential nature of the series be reproduced in the suffix in order to have interference? Or does the suffix affect item information and not position order (Watkins and Todres, 1979)? We are trying to answer these questions by means of further experiments. The only reliable conclusion that can be drawn from this research concern the laterality aspects of the task which confirm data previously mentioned in tactile sequential tasks involving memory. ABSTRACT
The fingertips of right and left hand of normal subjects (right-handed male) were stimulated at random. After intervals of 0.3, 1.0, 3.0 and 6.0 seconds, an acoustic or tactile signal set off the response of the subject. The response was the ordered reproduction of the tactile sequence given to the subject. The results show a greater efficiency of right hand, a better recall of the first serial positions and of the last one but no difference depending on whether the recall signal is acoustic or tactile. The results are discussed and new hypotheses are formulated.
4 Only two-letters words are identified by touch better with right hand in children (Cioffi and Kandel, 1979).
600
Lucia Riggio, Anna Del/antonio and Margherita Barbato
REFERENCES
BAKKER, D.J., and VANDER KLEIJ, P.C.M. (1978) Development of lateral asymmetry in the perception of sequentially touched fingers, Acta Psychologica, 42, 357-365. BENTON, A.L., VARNEY, N .R., and DES. HAMSHER, K. (1978) Lateral differences in tactile directional perception, N europsychologia, 16,,, I 09-114. BOLL, J. T. (1974) Right and left cerebral hemisphere damage and tactile perception: Performance of the ipsilateral and controlateral sides of the body, Neuropsychologia, 12, 235-238. BRADSHAW, J.L., and NETTLETON, N.C. (1981) The nature of hemispheric specialisation in man, Behav. Brain Sci., 4, 51-91. CIOFFI, 1., and KANDEL, G.L. (1979) Laterality of stereognostic Accuracy of Children for Words, Shapes, and Bigrams: A Sex Difference for Bigrams, Science, 204, 14321434. CORKIN, S. ( 1965) Tactually-guided maze learning in man: effects of unilateral excisions and bilateral hippocampal lesions, Neuropsychologia, 3, 339-351. CROWDER, R.G. ( 1971) Waiting for the stimulus suffix: decay, delay, rhythm, and readout in immediate memory, Quart. J. Exper. Psychol., 23, 324-340. - , and MORTON, J. (1969) Precategorical acoustic storage (PAS), Percept. Psychophys., 5, 365-373. DEE, H.L., and FONTENOT, D.J. (1973) Cerebral dominance and lateral differences in perception and memory, Neuropsychologia 11, 167-173. DELLANTONIO, A., and RIGGIO, L. ( 1982) Lateralizzazione emisferica e modalita tattile, In Neuropsicologia Sperimentale, ed. by C.A. Umilta, Franco Angeli, Milano. EFRON, R. (1963) The effect of handedness on the perception of simultaneity and temporal order, Brain, 86, 261-284. EGETH, H. (1971) Laterality effects in perceptual matching, Percept. Psychophys., 9, 375376. FONTENOT, D.J., and BENTON, A.L. (1971) Tactile perception of direction in relation to hemispheric locus of lesion, Neuropsychologia, 9, 83-88. GOODGLASS, H., and PECK, E.A. (1972) Dichotic ear order effects in Korsakoff and normal subjects, NeuropsychoJogia, 10, 211-217. HARRIS, L.J. (1978) Sex differences in spatial ability: Possible environmental, genetic and neurological factors, in Asymmetrical Function of the Brain, ed. by M. Kinsbourne, Cambridge University Press, London. HINES, D., SATZ, P., and CLEMENTINO, T. (1973) Perceptual and memory components of the superior recall of letters from the right visual half-fields, Neuropsychologia, 2, 175180. KIM, Y., ROYER, F., BONSTELLE, C., and BOLLER, F. (1980) Temporal sequencing of verbal and nonverbal materials: the effect of laterality of lesion, Cortex, 16, 135-143. KLEIN, S.P., and ROSENFIELD, W.D. (19SO) The hemispheric specialization for linguistic and non-linguistic tactile stimuli in third grade children, Cortex, 16, 205-212. LA BRECHE, T.M., MANNING, A.A., GoBLE, W., and MARKMAN, R. (1977) Hemispheric specialization for linguistic and non-linguistic tactual perception in a congenitally deaf population, Cortex, 13, 184-194. LEVY-AGRESTI, J., and SPERRY, R.W. (1968) Differential perceptual capacities in major and minor hemispheres, Proceed. Nat. Acad. Sci. U.S.A., 61, 1151. MANNING, S.K. (1980) Tactual and visual alphanumeric suffix effects, Quart. J. Exper. Psychol., 32, 257-267. MOSCOVITCH, M. (1979) Information processing and cerebral hemispheres, in Handbook of Behavioral Neurology, 2, Neuropsychology, ed. by M.S. Gazzaniga, Plenum Press, New York. - , SCULLION, D., and CHRISTIE, D. (1976) Early vs. late stages of processing and their relation to functional hemispheric asymmetries in face recognition, J. Exper. Psychol.: Hum. Percept. Perform., 2, 401-416. MYERS, J.L. (1979) Fundamentals of Experimental Design, Third Edition, Allyn and Bacon, Boston.
Right hand superiority in serial recall
601
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Anna Dellantonio, Istituto di Psicologia, Piazza Capitaniato, 5, 35100 Padova, Italy.