PSYCHOLOGY: W. CRAIG 
685 
ments also indicate that other combinations of anions other than those 
in which citrate is used also give synergy but more work remains to be 
done to establish this point. Citrates, of all the salts tried, certainly 
give the most pronounced synergy. 
Studies concerning the causes of the effects mentioned above and a 
more complete treatment of the subject are in progress, all of which it 
is hoped may appear in the near future. 
iLipman, C. B., Bot. Gaz., Chicago, 48, 1909, (105); Centralhl. Bakt., Jena, 36, 1912, 
(390). Loeb, J., /. Biol. Chem., New York, 28, 1916, (175). 
2 Osterhout, W. J. V., Science, New York, N. S., 35, 1912, (112). 
3 Osterhout, W. J. V., Bot. Gaz., Chicago, 60, 1915, (228). 
APPETITES AND AVERSIONS AS CONSTITUENTS OF INSTINCTS 
By Wallace Craig 
UNIVERSITY OF MAINE, ORONO 
Communicated by R. Pearl, October 18, 1917 
The overt behavior of adult animals occurs largely in chains and cycles, 
and it has been held^ that these are merely chain reflexes. Many years 
of study of the behavior of animals — studies especially of the Blond 
Ring-Dove {Turtur risorius) and other pigeons — have convinced me that, 
though innate chain reflexes constitute a considerable part of the in- 
stinctive equipment of doves, few or none of their instincts are mere 
chain reflexes. On the contrary, each instinct involves an element of 
appetite, or of aversion, or both. 
An appetite, so far as externally observable, is a state of agitation 
which continues so long as a certain stimulus, the appeted stimulus, is 
absent. When the appeted stimulus is at length received it releases a 
consummatory reaction, after which the appetitive behavior ceases and 
is succeeded by a state of relative rest, a state of satisfaction. The ap- 
petitive behavior serves to bring about the appeted situation by trial 
and error. The appetitive state includes a certain readiness to act. 
When most fully predetermined this has the form of a chain reflex. 
But in the case of many supposedly innate chain reflexes, the reactions 
of the beginning or middle part of the series are not innate, or not com- 
pletely innate, but must be learned by trial. The end action of the 
series, the consummatory action, is always innate. One evidence of 
this is the fact that in the first manifestation (also, in some cases, in later 
performances) of many instincts, the animal begins with an incipient 
consummatory action, although the appeted stimulus, which is the ade- 
^ quate stimulus of the consummatory reaction, has not yet been received. 
