The Jackdaw sat in the Cardinal's chair! Bishop and Abbot and Prior were there, Many a monk and many a friar, Many a knight and many a squire, With a great many more of lesser degree-- In sooth a goodly company
—Richard Harris Barham

Adaptation Value


Complex Cognition May Allow Animals to More Optimally Handle the Trade-offs Faced in the Vagaries of Everyday Life

It's better to be smart than to be dumb, right? Informed instead of uninformed? Well, no, evolutionarily speaking. Complex cognition is inefficient from a fitness standpoint and it is metabolically exorbitant. This is to say, if much of an animal's behavior is innate or acquired quickly through simple associative learning, the animal will be able to find a mate and reproduce relatively quickly. On the other hand, complex cognition requires that an animal spend more time learning (defined as a "relatively permanent change in behavior as a result of experience" by Dugatkin 2004) about the world and developing its adult behaviors. There is also a very high cost associated with maintaining the brain tissue that makes cognition possible (see phylogeny). The benefits of intelligence, therefore, must be substantial.

Many scientists agree that the adaptive function of intelligence is to produce flexible behavior in the face of variable and complex environments, and that these environments can be both physical and social in nature (Seed et al. 2009; see table in phylogeny). The ability to learn is under strong selectional pressure and individuals who learn appropriate cues that are useful in their particular environment are strongly favored. The issue of how such a costly strategy could have evolved is explored in more detail on the phylogeny page, but here it is enough to note that an unpredictable environment seems to be a necessary precondition, because under these circumstances passively hard-wired behaviors are less adaptive than actively flexible ones.

Crows have become highly skilled at making a living in new urban environments; photo credit: David Monniaux, wikimedia commons

Some of the best evidence for bird brains being adapted for cognition comes by way of comparative analysis between the size of certain brain anatomy and observed behavioral complexity. The ability to innovate and behavioral flexibility have obvious fitness benefits, allowing their possessors to take advantage of novel situations when they arise. Lefevbre and colleagues have collected around 2000 anecdotes about a wide variety of birds that have been observed using new methods of obtaining food or eating novel foods (feeding innovation). They grouped them by family and correlated the frequency of anecdotes across families with either relative forebrain size or various brain components, such as nidopallium or mesopallium. Consistently, there was a significant relationship between high innovation rate and large relative brain size for corvids, parrots, and to a lesser extent, non-corvid songbirds, woodpeckers, hornbills, owls, and falcons (Lefebvre et al. 1997, 2004; Timmermans et al. 2000; Lefebvre & Bolhuis 2003).

The advantages that complex cognition confers on its bearers are so obvious and numerous that relatively few studies have set out with the goal of elucidating its adaptation value. Rather, this point follows directly from behavioral flexibility, innovation, and insight; the ability to keep track of what you cache and where; tracking the relative rates of decay of different cached items; damage control for when you are observed caching by a potential thief, etc. Thus, a full appreciation of adaptation value comes from a thoughtful reading of all the webpages herein.

 

This website was created by Nathaniel Raley for Suzy Renn's Animal Behavior course (BIO 342) at Reed College, Fall 2010