5 Comparative cognition: reasoning and problem-solving

In humans, reasoning and problem-solving are aspects of what is known as ‘executive function’. Executive function is a term that encompasses a broad set of cognitive processes involved in deliberative, goal-oriented action. Although there is no single part of the brain responsible for executive function, there is strong evidence that the neocortex (the ‘new’ part of the brain, in evolutionary terms), and the frontal lobes in particular, play important roles (Alvarez and Emory, 2006).

As with the limbic system and emotion, which you learned about in Section 3.1 of this course, it is reasonable to infer that:

• species with a neocortex may have some degree of executive function, and
• species without a neocortex are unlikely to have developed executive function.

Now have a go at Activity 7. You'll see it asks the same question as Activity 3, but this time for executive function, rather than emotions.

Activity 7 Which animals might have executive function?

Timing: Allow 10 minutes for this activity

Look at the list of animals below. Which, if any, do you think might have the capability for executive function? For example, do you think any or all of them might be able to plan ahead and solve a problem?

• chimpanzees
• cats
• crows
• lizards

Discussion

Chimpanzees and cats are both mammals, and all mammals have a neocortex. It is therefore possible that both chimpanzees and cats have a degree of executive function, and some ability to plan ahead and solve problems. The chimpanzee neocortex is larger and more developed than that of the cat (see Figure 7), so it is likely to have a greater capability for executive function.

Non-mammalian species do not have a neocortex, although there is some evidence that a part of the bird brain called the dorsal ventricular ridge may perform the same function as the neocortex in mammals (Dugas-Ford et al., 2012). Crows may therefore have some degree of executive function.

Reptiles also have a dorsal ventricular ridge, although it is not as well developed as it is in birds, and (not being mammals) they lack a neocortex. It is therefore less likely that lizards would have executive function.

Figure 7 Differences in the brains of various species. The large, wrinkled neocortex is apparent in the human, chimpanzee and cat brains, and absent in the bird and lizard brains.

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This scaled-illustration shows the differences in size of the brains of different species. The human brain is largest, followed by the chimpanzee’s, which is between one-third and one-half the size of the human brain. The cat’s brain is about half the size of the chimpanzee’s. The bird and lizard have the smallest brains.

Figure 7 Differences in the brains of various species. The large, wrinkled neocortex is apparent in the human, chimpanzee and cat brains,...

The anatomy of the brains of different species provides some information about their likely cognitive abilities, and can provide useful information about how, and when, different abilities evolved in the ancestors of modern species. But there still remains a need to test the actual abilities of animals to see how they perform on cognitive tasks.

A large number and variety of behavioural tests have been conducted, on a wide range of species. The next section of this course gives a brief outline of just a few of these.