The quick are the dead: pheasants that are slow to reverse a learned association survive for longer in the wild

Abstract

Cognitive abilities probably evolve through natural selection if they provide individuals with fitness benefits. A growing number of studies demonstrate a positive relationship between performance in psychometric tasks and (proxy) measures of fitness. We assayed the performance of 154 common pheasant (Phasianus colchicus) chicks on tests of acquisition and reversal learning, using a different set of chicks and different set of cue types (spatial location and colour) in each of two years and then followed their fates after release into the wild. Across all birds, individuals that were slow to reverse previously learned associations were more likely to survive to four months old. For heavy birds, individuals that rapidly acquired an association had improved survival to four months, whereas for light birds, slow acquirers were more likely to be alive. Slow reversers also exhibited less exploratory behaviour in assays when five weeks old. Fast acquirers visited more artificial feeders after release. In contrast to most other studies, we showed that apparently 'poor' cognitive performance (slow reversal speed suggesting low behavioural flexibility) correlates with fitness benefits in at least some circumstances. This correlation suggests a novel mechanism by which continued exaggeration of cognitive abilities may be constrained.This article is part of the theme issue 'Causes and consequences of individual differences in cognitive abilities'.

Keywords: Phasianus colchicus; associative learning; fitness; pheasant; reversal learning; survival.

Figure 1.

The: (a) mean cognitive performance (improvement at a reversal task) when tested at 4–5 weeks old; and (b) sex (females = white, males = black); of 154 pheasants that were classed as either alive (N = 76) or dead (N = 78) 60 days after having been released into the wild. Error bars indicate ±1 s.e.

Figure 2.

The mean improvement in an acquisition task administered at 4–5 weeks by 154 pheasants that were either heavier or lighter than the population mean when released into the wild at 10 weeks and were classified as either alive (white bars) or dead (black bars) at 60 days after being released into the wild. Error bars indicate ±1 s.e.