1. The Social Use of Space 181 



a social group. Just as with /x aud n', so it is apparent here that the magni- 

 tude of v" and A" will normally change by comparable degrees in the same 

 direction and that d" will approximately vary inversely with v". 



4. The Effect of Interval between E's, on Velocity 



Further examination of the data in Table lib, in the light of the formu- 

 lations relating to exploratory behavior and configurations of stimuli, pro- 

 vides additional insight into the origin of reductions in velocity, both v 

 and v". Refer to Section III, A, 3 for other comments. Presentation of the 

 experiment in terms of the present formulations is as follows : 



The subjects consisted of male albino Osborne-Mendel strain rats iso- 

 lated at weaning. At this time each rat was placed in a 6 X 6 X 8 inch 

 cage from which it could not see out. Water and food were introduced 

 through channels from the outside which prevented the rats from seeing 

 the experimenters or being handled by them. AH rats remained in such 

 isolation for approximately three months before further treatment. These 

 isolation cages may be termed an Ei configuration of stimuh. Due to the 

 long absence of opportunity for adjustment to new configurations of 

 stimuli, the Th of all rats probably drifted toward b. 



At the end of the three months of isolation the subjects were divided 

 into four groups: A (20 rats), B (24 rats), C (16 rats), and D (16 rats). On 

 each of 10 days during the next two weeks each member of Group C was 

 exposed for two hours to a new configuration of stimuli, E2, which was a 

 Wahman activity wheel; all rats so exposed entered the wheel and ran 

 during each of the 10 days. Similarly, members of Group C were exposed 

 to an E3 configuration of stimuh. This exposure consisted of placing the 

 rats in a 2 X o-foot pen where they had the opportunity to climb onto a 

 central platform where a lever could be pressed to receive a drop of water. 

 Each day of this 10-day training period half the members of Group D 

 were exposed for two hours to E2 and then, immediately following, for 

 two hours to Ez. The other half of Group D were similarly treated but were 

 exposed to E3 just prior to E2. Group A remained in their isolation cages 

 during these two weeks. 



During the third experimental week every rat in all four groups was given 

 a two-hour exposure to the NIH Emotional Activity Alley on each of 

 four successive days. This alley represented an E4 configuration of stimuli. 

 For half the rats in each group Ei had a stationary floor, a condition we 

 may designate as Ei^. For the remaining rats Ei had a tilting floor which 

 clanged as the rats ran across it. This modification is designated as Eis, 

 which represents a much more intense or strange configuration than EiA. 

 Many rats avoided entering the alley. 



