Stereotyped motor acts

424 etc.) a p p e a r to play an analogous role in stabilization of behavior. L e a r n e d signal systems, on t h e other lmnd, generally a c h i e v e their high degree o f regularity by the d e v e l o p m e n t of extraordinm3" sensitivity and specificity in leanaing capacities which a r e species specific. T h e p h e n o m e n o n o f imprinting is but one example of such speeificitt,., In man t h e d e v e l o p m e n t of a moral sense is a further r e i n f o r c e m e n t for learned s o c i a l reactions. This may b e unique t o man but w h a t appeal" objectively to b e analogous responses occur in animals. Cultural c h a n g e interteres with the mechanisms or ritualization, s p e c i f i c learning a n d m o r a l sense.

FRIDAY AFTERNOON,

S t e r e o t y p e d Nlotor Acts

GEnSIION BEnKSO,~, Ph.D., State Pediatric h~s.titute

Illinois

Monkeys and apes reared in isolation develop behavior patterns whicli are s i m ilar in f o r m to stere0t),ped acts seen in severely defective humans. A fihn will be s h o w n demonstrating these b e h a v iors, and experiments will be described in which their level of expression is x,arled. Concepts regarding the o r i g i n and ftmction of the stereo~'ped behaviors will be reviewed, a n d a comparison made between the abnormal acts and stereotyped movements manifested by normal animals a n d h u m a n s .

2 : 0 0 P.M., F E B R U A R Y

19, 1 9 6 5

Session II. D e v e l o p m e n t a l F a c t o r s C h a i r m a n : SEY~][OUIt S. KET~',M . D . Social Behavior and Social H i e r a r c h y in the F o r m a t i o n of Personality Profiles in Animals BENso.~- E. GINSBtmC, Ph:D., The University-of Chicago Social organization is a prominent characteristic not only of vertebrates, b u t of m o s t forms of life. Its origins are deeply rooted in p h y l o g e n y a n d i t s vat= led expressions include a b r o a d sampling of taxonomic groups. T h e evolutionart, beginnings of social behavior ma t, be found in protozoans, whose aggregations confer ,~ measurable degree of protection against toxic substances and other environmental fluctuations. Some unicellular forms engage in conjugative behavior, for w h i c h proximity to appropriate neighbors is essential. Still others form physical aggregates of various kinds and durations. It appears that a basic feat-ure of the p r o t o p l a s m is its tendency towards organization involving

aggregations of s i m i l a r u n i t s , from nucleic acick% to D N A molecules, to cells, tissues, organs, individuals and societies. These latter have sometimes been referred to analogically a s superorganisms, of which the most ob~4ous a n d dramatic examples are the social insects, w h e r e the specialization and division of labor are genetically detenrfined by means of both morphological and behavioral differential tion. S u c h differentiation i s far less marked o n the v e r t e b r a t e s i d e of t h e phylogenetie tree, w h e r e its most common expression is i n t h e s e x u a l d i m o r p h ism to be f o u n d in most species, wifla its a t t e n d a n t s p e c i a l i z a t i o n of s e x u a l b e h a v ior. Nevertheless; c o m p l i c a t e d social stnmtures also occur a m o n g v e r t e b r a t e s , where genetie selection h a s n o t followed the path of impressing non-sexnal social roles upon indi~5duals within a species through the predetermination of morphological and behavioral differences. Instead parameters of behavioral plasticity