APPETITES AND AVERSIONS. IOI 



doves free in one pen, the mated male will try the mettle of the 

 intruder and conquer him if he can; if he fails, he will turn all his 

 energies into an effort to drive his mate away from the intruder. 

 Or if in former experiences he has learned to gage this individual 

 intruder, if he conquered him before he will promptly attack him 

 now, but if defeated by him before he will now choose the alter- 

 native of driving his mate away. In sum, the instinctive aver- 

 sion impels the dove to thoroughly intelligent efforts to get rid 

 of the disturbing situation. 



8. In some cases the seeking of a certain situation involves 

 both appetences and aversions in considerable number. Thus, 

 when the day draws to a close, each dove seeks as its roosting- 

 place a perch that is high up, with free space both below it and 

 above it, with no enemies near, with friendly companions by its 

 side, but these companions not too close, not touching (except in 

 certain cases of mate, nest-mate, or parent). The endeavor to 

 achieve this complex situation, to secure the appeted stimuli and 

 to avoid the disturbing ones, keeps the birds busy every evening, 

 often for an hour or more. 



CYCLES. 



Instinctive activity runs in cycles. The type cycle, as it were 

 a composite photograph representing all such cycles, would show 

 four phases as follows. 



Phase I. Absence of a certain 8 stimulus. Physiological state 

 of appetite for that stimulus. Restlessness, varied movements, 

 effort, search. Incipient consummatory action. 



Phase II. Reception of the appeted stimulus. Consumma- 

 tory reaction in response to that stimulus. State of satisfaction. 

 No restlessness nor search. 



Phase III. Surfeit of the said stimulus, which has now be- 

 come a disturbing stimulus. State of aversion. Restlessness, 

 trial, effort, directed toward getting rid of the stimulus. 



Phase IV. Freedom from the said stimulus. Physiological 

 state of rest. Inactivity of the tendencies which were active 

 in Phases I., II., III. 



Some forms of behavior show all four phases clearly. The 

 following are examples. 



