SCIENCE 



Friday, May 20, 1910 



The Group as a Stimulus to Mental Activity: 

 Pbofessob William H. Btienham 761 



The Principle of Relativity: Db. D. F. CJom- 

 STOCK 767 



Some Coimderations as to the 'Nature of 

 Comets and their Probable Relation to the 

 Sun: Pbofessob Elihu Thomson 772 



Robert Parr Whitfield: L. P. G 774 



Conference on Agricultural Nature Study . . 775 



Report of an Investigation of the Phenomena 

 connected with Eusapia Palladino 776 



The Carnegie Foundation 780 



Scientific Notes amd News 781 



University and Educational News 784 



Discussion and Correspondence: — 



The Length of Service Pensions of the 

 Carnegie Foundation: Z 784 



Scientific Books: — 



The Gulick Hygiene Series: Pbofessob 

 Thomas A. Stobet. Conn's Agricultural 

 Bacteriology: Pbofessob H. L. Kussell .. 785 



Special Articles : — 



Note on the Chromosomes of Nezara: Pbo- 

 fessob JiDMUND B. Wilson. The Struc- 

 tural Characteristics and Relations of the 

 Apodal Fishes: De. Theo. Gill. The 

 Proper Restriction of Eucynopotamus : 



•• Henby W. Fowler 788 



The American Phytopatlwlogical Society: Db. 

 C. L. Sheae 790 



Societies and Academies: — 



The Chemical Society of Washington: J. A. 

 LeClebc. The American Mathematical So- 

 ciety: Pbofessob F. N. Cole. The Amer- 

 ican Chemical Society, Rhode Island Sec- 

 tion: Albebt W. Claflin 799 



MSS. intended for publication and books, etc., intended for 

 review should be sent to the Editor of Science, Garriaon-on- 

 Hudson, N. Y. 



THE GROUP AS A STIMULUS TO MENTAL 

 ACTIVITY 1 



The purpose of this paper is not to 

 present the results of an original investiga- 

 tion, but merely to suggest a problem. 

 Efficiency in brain activity and in corre- 

 lated mental activity depends upon many 

 conditions. Among these are physiological 

 age, race, sex, the blood supply to the brain, 

 as determined by general nutrition, exer- 

 cise, posture, and the size of the cerebral 

 arteries ; the quality of the blood as deter- 

 mined by food, drugs, the supply of oxy- 

 gen, nasal respiration, etc. ; again by a 

 group of conditions which make up the en- 

 vironment, the temperature, humidity, bar- 

 ometric pressure, light, peripheral stimula- 

 tion, etc. Again as the social instincts in 

 man are fundamental, one of the most 

 important factors in his environment is 

 the presence or absence of other human 

 beings. This can not be ignored. The 

 problem I wish to present is this: What 

 is the effect on mental activity of the pres- 

 ence of a group of other persons, if studied 

 objectively like the effects of temperature, 

 barometric pressure, or the like ? Perhaps 

 the best way to present this problem is to 

 recount briefly the meager but important 

 results of investigations already made.- 



Studies in social psychology have shown 

 that an individual alone and the same indi- 

 vidual in a group are two different psycho- 

 logical beings. Recent investigations show 

 that the same is true of children. The 



' Read before Section L^ American Association 

 for the Advancement of Science, Boston, Decem- 

 ber, 1909. 



- For reference to the studies mentioned below 

 see Ped. Sem., Vol. XII., June, 1905, pp. 229-230. 



