764 



SCIENCE 



[N. S. Vol. XXXI. No. 803 



group distinctly affects the mental activity. 

 Of course the easy explanation of the in- 

 creased ability to work often found in the 

 group is to say that it is due to ambition, 

 rivalry and the like. This is all true 

 enough, but we can analyze this a little 

 further. 



A few things are pretty obvious. First 

 of all, where activity is involved, there is 

 the stimulus to greater exertion which 

 comes from the sight of another perform- 

 ing an act. As Professor James has said, 

 the sight of action in another is the greatest 

 stimulus to action by oui-selves. This has 

 manifold illustrations from the activities of 

 primitive man to modern experiments in 

 the laboratory. In early stages, for ex- 

 ample, an institution sometimes found is 

 the prcesul. A leader stands before a 

 group who are engaged in work or a dance 

 and himself performs perhaps in panto- 

 mine the activities which they are attempt- 

 ing. This stimulates and renders easier the 

 activity of the group. Every paced race on 

 the athletic field also furnishes an excellent 

 illustration. Ag-ain in the laboratory, 

 Fere found that the amount of work 

 one could do with the ergograph was in- 

 creased by having another person simply 

 go through the action of contracting the 

 muscles of the finger in sight of the subject 

 of the experiment, the second person acting 

 as a sort of pace-maker for the first. The 

 clearer and more intense the idea of an 

 action the more efficient the action. 



There is undoubtedly also an affective 

 stimulus in the presence of the group. 

 This is the stimulus which comes from our 

 social impulses as inherited from the past, 

 and yet it should be noticed that such 

 affective stimuli, which, I take it, are what 

 is really meant by ambition and the like, 

 may act either to increase or to inhibit the 

 mental activity. A certain degree of 

 affective stimulus undoubtedly increases 



the ability to work, but if the stimulus is 

 extreme the work is checked or inhibited 

 altogether. For example, extreme anger, 

 stage fright and even extreme joy, in the 

 presence of the group, may inhibit the 

 mental activity. 



In many individuals at least the presence 

 of the group is a stimulus to greater con- 

 centration of attention. In case others are 

 doing the same thing, this helps us attend 

 better to the activity in hand ; and even in 

 case others are doing something different, 

 the distraction itself is sometimes a stim- 

 ulus to better attention, because the indi- 

 vidual tries to resist the distraction and 

 there is an over-compensation which im- 

 proves the attention. Meumann, for ex- 

 ample, has found this result in certain 

 experiments. 



Meumann emphasizes particularly this 

 compensation power of attention. Not 

 merely is it true that the performance of 

 an individual often increases when there 

 are disturbing stimuli, because the in- 

 creased concentration to overcome the dis- 

 tractions increases the work ; but more than 

 this, the compensation, which in this case 

 becomes an over-compensation, shows that 

 the disturbing stimulus has the effect of 

 increasing rather than decreasing the 

 energy, that is, it has a dynamogenic ef- 

 fect, although this effort does not occur in 

 case of all individuals. 



The measure of this is of course the 

 increase of the performance by the dis- 

 tracting stimulus. This is very well shown 

 with the distraction stimulus when one is 

 committing to memory. By Meumann 's 

 method the memory span or the number of 

 figures or letters that can be remembered 

 without error after once hearing is deter- 

 mined, and then disturbing stimuli are 

 introduced. An acoustic stimulus may be 

 introduced for distraction, e. g., a metro- 



