320 



Information Storage and Neural Control 



3.0 



- 2.5 

 <_) 



CO 



m 



< 

 ir 



2.0 



1.5 



z) 0.5 

 O 



O— O GROUP A 

 •— • GROUP B 



I 2 3 4 5 6 7 



INPUT RATE (BITS/SEC.) 



Fig. 6. Performance curves for Groups A and B. 



8 



Group Research 



We also used the IOTA apparatus with two four-man groups. 

 The procedure was as follows: Three members of the group, A, 

 B, and D, face the screen. A calls out the number of the slot in 

 which an arrow appears, and B calls out a letter representing the 

 position. C, who is facing the buttons, but whose back is turned 

 to the screen, then pushes the button indicated by the information 

 he got from A and B. When C pushes a button a small red light 

 appears over one of the slots, indicating which button he pushed. 

 If his push is correct, D says nothing. If the push is incorrect, D 

 corrects C and C tries to push the right button. The performance 

 curves from our pretest runs with two groups have the same 

 general appearance as the performance curves of the individual 

 subjects, though at lower channel capacities — about 3 bits per 

 second (Fig. 6). 



This is, of course, a very specialized sort of small group in which 

 roles are strictly differentiated. Only some members can receive 

 sensory inputs, while others make responses or perform other 

 tasks. There are structural similarities to certain lole-diflfeientiated 

 groups in military life, like tank crews, bomber crews, or sub- 



