Reprinted from The Journal of Comparative Neurc logy 

 Vol. 57, No. 1, February, 1933 



DEPARTMENT ( 



UNIVERSITY OF 13*OtJT& 



STUDIES OF CEREBRAL FUNCTION IN LEARNING 1 



IX. MASS ACTION IN" RELATION TO THE NUMBER OF ELEMENTS IN 

 THE PROBLEM TO BE LEARNED 



K. S. LASHLEY AND L. E. WILEY 

 Department of Psychology, The University of Chicago 



THREE TEXT FIGURES AND FIVE PLATES 



INTRODUCTION 



Measurements of the influence of extent of cerebral lesion 

 upon efficiency in various functions have given quite different 

 results, according to the functions studied. In some cases 

 there is clearly an all-or-nothing relation between some func- 

 tional area and the capacity for performance; in others, a 

 close relationship between surface extent of injury and degree 

 of lowering of efficiency. The data thus far accumulated in 

 quantitative studies are summarized in table 1. The constants 

 given are based on error scores, where these are available, 

 otherwise on trials for learning or relearning. The table 

 shows a definite bimodal distribution of the constants. Six 

 fall below 0.10, thirteen are above 0.50, and only three fall 

 between these limits. Of these three (double platform box, 

 difference threshold for two lights, and learning of a 1 cul de 

 sac maze) the first reduces to zero when corrected for motor 

 disorders, the second is approximately 0.50, and the third is 

 based on a maze which is known on other grounds to be an 

 unreliable measure of performance. 



1 This work was supported by a grant from the Otho S. A. Sprague Memorial 

 Institute. We are indebted to Prof. L. L. Thurstone and to Mrs. Annette M. 

 Wiley for advice and assistance in the statistical treatment of the data and to 

 Dr. Margaret Frank for assistance in the training of animals and the preparation 

 of material for histological study. 



