1 Introduction
R e u v e n D u k a s & J o h n M. R at c l i f f eI have endeavoured in this chapter briefly to show that the mental qualities of
our domestic animals vary, and that the variations are inherited.
c h a r l e s d a r w i n, The Origin of Species (1859)Cognitive ecology focuses on the ecology and evolution of “cognition,” de-
fined as the neuronal processes concerned with the acquisition, retention,
and use of information. That is, animals rely on a wide variety of information
to interact with physical and biotic elements in their surrounding environ-
ment, and these interactions determine individual “fitness,” defined as lifetime
reproductive success. Individuals within a species exhibit large variation in
fitness, which is determined in part by heritable variation in their cognitive
traits. Consequently, cognitive traits are subjected to evolution by natural se-
lection. Hence, we ought to rely on ecological and evolutionary knowledge for
studying cognition. Likewise, because the ways in which animals use available
information influence their fitness, we must consider cognitive traits when we
examine animal ecology and evolution (Dukas 1998d, 2004a).
An evolutionary approach to understanding cognition is as old as evolu-
tionary biology itself. It received considerable attention by Darwin, first in
The Origin of Species (1859), especially in chapter 8 (see above quotation), and
later in his analyses of emotion and sexual selection (1871, 1872). Darwin’s fol-
lowers also integrated evolution into their writings on psychology (Romanes
1883; Baldwin 1893; James 1890; L. Morgan 1890). For much of the twentieth
century, however, evolutionary ecology and psychology were quite detached.
The emergence of ethology (Tinbergen 1963; Lorenz 1970) and, later, behav-
ioral ecology (Krebs and Davies 1978) helped bring together biologists and
experimental psychologists (Kamil and Sargent 1981) and gradually led to
greater integration of cognition, ecology, and evolution. For illuminating his-
torical perspectives, see R. Richards 1987, Houck and Drickamer 1996, Kruuk
2003, and Burkhardt and Richard 2005. Evidence for the growing interest in
integrative research on the ecology and evolution of cognition was explicitly