CHAPTER V 
Toe MENTAL LIFE OF THE MONKEYS; AN EXPERIMENTAL 
Stupy! 
THE literary form of this monograph is not at all satis- 
factory to its author. Compelled by practical considera- 
tions to present the facts in a limited space, he has found it 
necessary to omit explanation, illustration and many rhetor- 
ical aids to clearness and emphasis. For the same reason 
detailed accounts of the administration of the experiments 
have not always been given. In many places theoretical 
matters are discussed with a curtness that savors of dog- 
matism. In general when a theoretical point has appeared 
justified by the evidence given, I have, to economize space, 
withheld further evidence. 
There is, however, to some extent a real fitness in the lack 
of clearness, completeness and finish in the monograph. For 
the behavior of the monkeys, by virtue of their inconstant 
attention, decided variability of performance, and generally 
aimless, unforetellable conduct would be falsely represented 
in any clean-cut, unambiguous, emphatic exposition. The 
most striking testimony to the mental advance of the mon- 
keys over the dogs and cats is given by the difficulty of mak- 
ing clear emphatic statements about them. | 
‘This chapter appeared originally as Monograph Supplement No. 15 to 
the Psychological Review. 
172 
