178 John B. Calhoun 



particular E to induce any material increase in DMA. This means that if 

 E merely represents a configuration of strange stimuli with which the 

 individual can interact in no meaningful way, the second exposure to E, 

 that is (£'1)2, will evoke no response. (£"1)2 will merely be ignored. However, 

 if some aspects of the Ei configuration permit meaningful interaction, 

 then (£'1)2 will result in an interaction having an «„„ refractory period 

 proportional to the evoked directed motor action, dAIA. This a„„ will 

 normally be of shorter duration than a„p to (£"1)1 since some components 

 of the configuration are likely to be irrelevant to dAIA. Furthermore, 

 dMA may be expected to be maintained at near its initial intensity until 

 the evoked behavior terminates. No further elevation of Th accompanies 

 (£1)1 ••• {Ei)n. Persistent recurrence of any specific E merely serves to 

 prevent the drifting downward of Th. 



Each adjustment to a new E configuration resulting in an elevation in 

 Th represents a contribution to the individual's psychological area. A" . 



2. The Seeking of New. Configurations 



Consider two groups of individuals, A and B, of which the members of 

 each for a fairly long period merely reexperience particular sets of £"s. 

 Members of group A differ from those of B in that they are exposed to a 

 larger assembly of different £"s. Two such groups have been considered in 

 Section III, A, 5 and Table I la. The fact that more of the A-type individuals 

 entered the alley when exposed to this new E configuration of stimuli in- 

 dicates that reexperience of a larger assembly of different £"s does maintain 

 Th at higher levels despite some downward drift. The A-type individuals 

 obviously have a larger psychological area. A", than the B-type ones. A" 

 essentially connotes capacity to adjust. In any environment presenting 

 frequent necessity for adjustment, a high A" will prove advantageous. So 

 we need to consider the question of maximizing A" . 



Persistence in repeated interaction with certain £"s is necessary or de- 

 sirable because of acquired reward value accompanying the directed motor 

 activity, dMA, appropriate to these £"s. Such dMA can only preserve Th 

 at a given level. Response to these £"s involved in this dMA consumes time. 

 If all w^aking time becomes relegated to dMA-evoking £"s, the individual 

 will develop a static A". Furthermore, the more waking time becomes 

 filled with repetitions of response to any given E, the more restricted will 

 be A" . It is thus obvious that the best strategy for maximizing A" will be 

 to reserve a portion of one's waking hours simply for responding to new 

 £"s. Some as yet unknown but probably fairly long time, certainly of the 

 order of several days even for rats, must elapse between one exposure to 

 such a new E and a reexposure, permitting sufficient extinction of the A 



