Information Processing in the Time Domain 341 



a special purpose digital computer is employed to measure the 

 amount of coincidence between the active GSR time of the in- 

 dividual subjects in various combinations. The square wave of 

 Subject A is compared for coincidence or overlap in time with the 

 square waves from the GSR of Subject B, C, D, etc. In a four- 

 man group, the coincidence of all four GSR's at one time is a 

 relatively rare event. Such a ''four of a kind" coincidence is 

 usually the result of a rather strong stimulus which has been 

 experienced by all four members. 



Consideration of coincidence analysis has led us tentatively tc 

 formulate a model of group interaction predicated on "overlap 

 of value systems'" among the individuals of the group. The specific 

 GSR represents perception and reaction to a specific stiinulus. 

 Generally, it may be assumed that a stimulus has meaning or an 

 "aflfect investment" for the individual if it produces a GSR. The 

 GSR, as an indicator of "investment," is taken as a "yes-no" 

 index without regard for the afi'ect polarity. That is to say, the 

 occurrence of a GSR reveals that the stimulus is "invested" but 

 does not reveal whether the stimulus produces a positive aflfective 

 response or a negative affective response. We are aware of some 

 of the diflficulties implicit in this rather simplified interpretation 

 of the GSR in relation to the psychological variables of affect 

 and investment. We suspect that under certain circumstances 

 extreme high negative affect may "freeze" the GSR and wipe 

 out all response. It may be that this sort of inhibition effect is an 

 idiosyncratic response of the individual or that such a phenomenon 

 may be seen more often in the schizophrenic than in the normal 

 patient. The group interaction is seen as a continuously moving 

 field which presents a sequence of stimuli to all individuals in the 

 group. Some individuals may not perceive a given stimulus or 

 may derive no meaning from it. When two or more individuals 

 perceive and are invested in a given stimulus, it is postulated 

 that each will produce a GSR and that these GSR's will be 

 approximately coincident. Insofar as two individuals have coinci- 

 dent GSR's to a finite but large stimulus array, our hypothesis 

 would suggest that they have "overlap of value systems." 



In clinical group therapy we might ask the following question: 

 "In the course of group therapy, will two patients in the same diag- 



