The Intelligent Brain

In this chapter I address the question as to why brain size and its variation is interesting. Because for many the answer is that a bigger brain endows greater intelligence, in this chapter I first provide a definition of intelligence, or cognition. I then describe a variety of factors that need to be considered in order to attempt to make comparisons, within or among species, of cognitive abilities. These include motivation, environmental factors, and methodologies used to train and test animals (typically) in the laboratory. For the remainder of the chapter I use the demonstration of the relationships between food storing, spatial cognition, and the hippocampus to illustrate these issues.

Highly social pinyon jays, but not less social Clark’s nutcrackers, modify their food-storing behaviour when observed by a heterospecific

Behavioural flexibility can be described as the ability to use information and generalise it across contexts. Social living is thought to favour behavioural flexibility. We used a food-storing (caching) paradigm, during which individuals either ate or cached food under different conditions, to investigate whether they could flexibly adjust their caching behaviour when observed by conspecifics and heterospecifics. We examined the location and number of caches made by two corvid species differing in sociality, highly social pinyon jays (Gymnorhinus cyanocephalus) and less social Clark’s nutcrackers (Nucifraga columbiana). Although pinyon jays cached a similar amount of food across conditions, they allocated more caches to areas less accessible to the observer when the observer spent more time close to the caching locations. Nutcrackers, however, reduced the number of seeds cached when observed by another nutcracker in comparison to when they cached alone, but did not significantly change their caching behaviour when observed by a pinyon jay. The differences in cache protection strategies, and the social cues (e.g., presence and behaviour of an observing bird) that elicit them, may be explained by the species’ social organisation. Overall, our results provide insight into understanding how pressures associated with the social environment may influence foraging behaviours.