Abstract
Reproductive success and its consequences for fitness are key to determining how natural selection shapes cognitive abilities, and thus how and why cognition might change over evolutionary time. However, demonstrating reproductive costs or benefits owing to variation in cognitive ability is hugely challenging, in part because traits such as body size and condition make the largest contribution to reproductive success. Our ability to discriminate a role for 'being smart' in fitness is then already limited. Additionally, most animals have many ways to solve problems, only some of which will depend on their cognitive abilities. However, specific instances in key parts of animal's life may depend heavily on their cognitive abilities, and without them the animal will not survive or reproduce. Retrieving food stores is one example and nest building might be another. For food-storing, spatial ability is key, while for nest building the pertinent ability is learning what works. The importance of animals learning from previous experience may be very common but is rarely considered explicitly in cognitive terms. Work on fitness consequences of cognition should develop from the presentation of discrete tasks testing specific abilities to encompass how learning from experience influences behavioural evolution more broadly.This article is part of the Theo Murphy meeting issue 'Selection shapes diverse animal minds'.