CHAPTER XXX. 



THE PLASTIC BEHAVIOR OF ANTS. 



" Die Ameisen sind weder intelligente Miniaturmenschen noch blosse Rerlex- 

 maschinen. Sie sind mit dem Vermogen der sinnlichen Empfindung und \\ill- 

 kurlichen Bewegting ausgestattete Wesen, deren sinnliche Triebe (Instinkte) 

 durch sinnliche Wahrnehmung und Empfindung in ihrer Ausfuhrung geleitet 

 werden und je nach der Verschiedenheit der augenblicklichen Wahrnehmungen 

 und Empfindungszustaride, sowie zum Theile auch durch den Einfluss friiher 

 gemachter Erfahrungen in mannigfaltiger Weise modificirt werden kunnen. Das 

 ist eine Auffassung des Ameisenlebens, die mit den Thatsachen iibereinstimmt 

 und den Thieren weder zu viel noch zu wenig zuerkennt." E. Wasmann, " Die 

 psychischen Fahigkeiten der Ameisen," 1899. 



While there has long been unanimity of opinion in regard to the 

 predominant role of instincts in the lives of ants, there is still consid- 

 erable diversity of opinion in regard to the plasticity or modifiability 

 of behavior in these insects. This plasticity is what Hobhouse calls 

 " the power of an organism to adapt action to requirement without the 

 guidance of a hereditary method of adjustment." It may also be 

 defined as action on the basis of individual, /. c., ontogenetic experience 

 (" historische Reaktionsbasis " of Driesch), and as such is commonly 

 designated as " intelligence." Scholastic writers, like the Jesuit Was- 

 mann, and a few modern psychologists, like Wundt, however, restrict 

 this term to reasoning, or ratiocination, the highest type of plastic 

 behavior. Though not in conformity with general usage, Wasmann's 

 preference for using the term in this sense is not a serious matter, but 

 when he persists in comprising under instinct also the modifiable activi- 

 ties of organisms, he clearly reveals his zeal to minimize the difference 

 between automatic and plastic behavior on the one hand, and to increase 

 the gap between the latter and ratiocination on the other, in order to 

 save one of the old Thomistic dogmas concerning the nature of the 

 human soul. While I am quite as unable as all his other non-scholastic 

 critics (Forel, Emery, Escherich, Bethe, von Buttel-Reepen, Driesch, 

 etc.) to accept Wasmann's terminology, I nevertheless find myself in 

 rather close agreement with his interpretation of the facts of ant 

 behavior. This interpretation, however, is not original with Wasmann, 

 but is essentially that of Forel, as outlined in his earliest myrmeco- 

 logical work (1874) and since developed in a number of his publica- 

 tions. 



In addition to instinct, two types of plastic behavior may be distin- 



