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Barry, R.J. & James, A.L. (1978). Handedness in autistics, retardates, and normals of a wide age range. Journal of Autism and Childhood Schizophrenia, 8, 315-323. Barry, R.J. & James, A.L. (1988). Coding of stimulus parameters in autistic, retarded, and normal children: Evidence for a two-factor theory of autism. Internatio- nal Journal of Psychophysiology, in press. James, A.L. & Barry, R.J. (1980). Respiratory and vascular responses to simple visual stimuli in autistics, retardates, and normals. Psychophysiology, 17, 541- 547. James, A.L. & Barry, R.J. (1984). Cardiovascular and electrodetmal responses to simple stimuli in autistic, retarded, and normal children. International Journal of Psychophysiology, 1, 179-193.

COULD SYMMETRY HELP IN PATTERN RE- COGNITION?

E. BartuseviEius, 0. Gurciniene, V. Vanagas Laboratory of biophysics-neurocybemetics, Vilnius State University, Lithuanian SSR, USSR

According to the Gestalt theory, symmetry of patterns is one of the important determinants in visual percep- tion. The majority of the authors are inclined to think that in the process of recognition symmetrical patterns are preferred to asymmetrical ones. Attneave (1955) has shown that symmetrical patterns are better remem- bered than non-symmetrical ones. This data are in agreement with results of Zinchenko et al. (198 1) where there was shown that symmetrical patterns were better stored in short-term memory what ensures a greater accuracy for their recognition. Deregowski (1971) and Fisher et al. (1982) have proved that symmetrical stimuli were reproduced more accurately and that the reaction time to those is faster than to asymmetrical ones. All the above results therefore the Gestalt interpretation on the figural goodness of pat- terns symmetrical with respect to the vertical axis. The opposite results were described only in some papers. Fudin et al. (1975) and Lecher et al. (1978) have found that asymmetrical letters are perceived with greater facility than symmetrical items and that subjects spent more time for examining symmetrical shapes than at

asymmetrical ones. Bearing in mind some theoretical considerations on recognition process (Vanagas, 1987) the contradiction between the above mentioned results could be partly explained by other characteristics of patterns (e.g. by effectiveness of pattern features) but not degree of symmetry, The present paper is devoted to a verification of this premise.

Symmetrical and asymmetrical patterns recognition accuracy of human subjects and computer were meas- ured in our present study. Three experiments were performed: two psychophysical (1,2) and a computer one (3). Four symmetrical (A) and asymmetrical (B) non-verbal test-patterns were used in all our experi- ments (see the upper part of Fig). The test-patterns, so constructed, we believe, are to be of the same geometri- cal complexity which is of great importance in stu- dying the effect of symmetry on the patterns recogni- tion accuracy. As mask patterns were used: a rectangu- lar frame, whose lines coincided with the lines of test-patterns (Exp. 1) and a light flash (Exp. 2). A test-pattern subtended a visual angle of approximately 1.25 deg x 1.25 deg. Ten male and female university students, aged 19-24, with normal visual acuity, served as subjects (five in each department). The task set to the subjects was to reproduce test-patterns by drawing them. The test-patterns were presented by tachisto- scope for 10 ms, followed, after an interstimulus interval, by the 500 ms masking pattern. The length of the interstimulus interval was established for each subject individually before the experiment as a shortest interval permitting 50-80% recognition accuracy. Al- together 480 test-patterns A and B were presented to the subjects in random order in each psychophysical experiment. In the computer experiment were used the algorithm (Vanagas, 1987) that represented the pattern recognition process as a process of putting forward, verification and correction of hypotheses. During the computer experiment the patterns A and B were also presented in random order, to total number of test- patterns being 1000.

Five sessions were held with each subject in psy- chophysical experiments.

The results show that in both psychophysical experi- ments symmetrical patterns are recognized with sig- nificantly worse accuracy than asymmetrical ones. In’ recognizing the same symmetrical patterns at computer experiments, it is necessary to verify more hypotheses (2.27) than recognizing asymmetrical ones (1.96). The

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computer results will correlate with the psychophysical results. So the larger number of hypotheses required in recognizing symmetrical patterns under the condition of visual masking reduces the probability of recogni- tion accuracy. Basing on the results obtained and on the principle of the algorithm we can conclude that sym- metrical patterns contain a smaller number “effective” features (location of lines, line crossing knots, number of angles, etc.) and that does not permit to fast decreasing the number of hypotheses when in the process of comparison, the presented pattern does not coincide with the hypothetical one. Therefore, we can assume that the human visual system is based on the “effective” feature of patterns in the process of visual recognition. This assumption will agree with our psy- chophysical results showing that pattern symmetry does not always correspond to “Figural goodness” as it was suggested by Gestalt interpretation.

References

Atmeave, F. (1955) Symmetry, information and me- mory for patterns. America1 Journal of Psychology. 68: 209-23 1 Deregowski, J. (197) Symmetry, gestalt and informa- tion theory. Quarterly Journal of Experimental Psy- chology. 23:381-385 Fisher, C. and Bomstein M. (1982) Identification of symmetry: Effects of stimulus orientation and head position. 32:443:448 Fudin, R., Garcia, M. and Solomon, N. (1975) Identifi- cation of tachistoscopically exposed symmetrical and asymmetrical letter arrays. Perceptual and Motor skills. 41:103-106 Lecher, P. and Simmons, R. (1978) Influence of stimulus symmetry and complexity upon haptic scan- ning strategies during detection, learning, and recogni- tion tasks. Perception and Psychophysics. 23:110- 116 Royer, F. (1981) Detection of Symmetry. Journal of Experimental Psychology: Human Perception and Per- formance. 7: 1186-1210 Vanagas, V. (1987) Princip aktivnogo mnogou - rovnevogo uznavania zritelnich izobrazhenij. Zritelny- je sistemi. Vilnius: 46-74 Zinczenko, T. (198 1) Opoznanie i kodirovanie Izda- telstwo Leningradskogo Universiteta.

PSYCHOPHYSIOLOGICAL ASPECTS OF BIOBE- HAVIORAL RESEARCH OF NEOPLASTIC DIS- EASES

J. BaStecky

Dept. of Psychiatry, Postgraduate Medical and Phar- maceutical Inst., Prague, Czechoslovakia

Biobehavioral (psychooncological) approach to neo- plastic diseases is a complex approach which tries to prove and objectivize a share of biological, psychologi- cal and social factors in their etiology and the share of neurovegetative, neuroendocrine and neuroimmune mechanisms in their pathogenesis. It is based on bio - psycho - social model of disease according to G.L. Engel and considers neoplastic diseases as having neither mere organic nor mere psychogenic etiology but being characterized by multifactorial etiology in which psychosocial factors may play an important role. Biobehavioral research of neoplastic diseases searches also for biological, psychological and social markers and aims at more effective and more complex thera- peutic intervention including psychotherapy, psycho- pharmacotherapy and sociotherapy. It aims at preven- tive measures as well. In an agreement with Lipowski’s concept of psychosomatic diseases (1986) biobehav- ioral research of cancer stresses psychophysiological approach in all investigated areas. Verification of psychooncologic hypotheses will need prospective studies.

Main research and clinical topics of the biobehav- ioral cancer research are the following.

1. Evidence from animal trials. Kavetsky (1958), Balitski (1958, 1983) and other

authors proved that certain strains supported an origin and development of induced and transplanted tumors and their metastases predominantly in animals with a weak type of the higher nervous activity. The develop- ment of experimental tumors is followed by an inade- quate action of neuroendocrine system on malignant cells; plasmatic concentrations of corticosteroids in- crease. These changes lead to a weakness of natural antitumor resistance. On the other hand some stresses in some animal species can act as protective, e.g. restraint experiment or electroconvulsive treatment in rats with DMBA induced tumors (Madden et al. 1985). Some antidepressants of the 2nd generation (pyrazidol,