Cognition, personality, and stress in budgerigars, Melopsittacus undulatus

Abstract

To study the fitness effects of individual variation in cognitive traits, it is paramount to understand whether traits such as personality and physiological stress influence cognitive performance. We first tested whether budgerigars showed both consistent personalities and cognitive performance across time and tasks. We tested object and food neophobia, and exploratory behavior. We measured cognitive performance in habituation, ability to solve foraging problems, spatial memory, and seed discrimination tasks. Budgerigars showed consistency in their neophobic tendencies and these tendencies were associated with their exploratory behavior. Birds were also consistent in how they performed in most of the cognitive tasks (temporal consistency), but were not consistent in their performance across tasks (context consistency). Neither corticosterone levels (baseline and stress-induced) showed a significant relationship with either cognitive or personality measures. Neophobic and exploratory tendencies determined the willingness of birds to engage only in the seed discrimination task. Such tendencies also had a significant effect on problem-solving ability. Our results suggest that consistent individual differences in cognitive performance along with consistent differences in personality could determine response to environmental change and therefore have important fitness consequences.

Keywords: Budgerigar; cognition; cognitive performance; neophobia; personality; stress.

Figure 1

Timeline of personality, cognition, and stress response tests.

Figure 2

Heat maps indicating strength of Spearman rank correlations (effect sizes) between all measures of personality (arranged by order taken). Blue indicates positive associations and red indicates negative associations. Top and bottom lines of the boxes indicate upper and lower 95% confidence intervals respectively. N for pairwise comparisons was either 41 or 42, except for comparisons including Sociability 1 (N = 32).

Figure 3

Heat maps indicating strength of Spearman rank correlations (effect sizes) between daily cognitive performance in 3 tasks. The cognitive measures compared here were problem-solving score, maximum seed discrimination efficiency, detour-reaching score, and average number of errors in the spatial memory task. Blue indicates positive associations and red indicates negative associations. Top and bottom lines of the boxes indicate upper and lower 95% confidence intervals respectively. Number of pairwise comparisons: problem-solving task (N = 36), seed discrimination task (between N = 21 and N = 23), spatial memory task (between N = 9 and N = 18).

Figure 4

Heat maps indicating strength of Spearman rank correlations (effect sizes) between performance in 3 cognitive tasks. The cognitive measures compared here were problem-solving score, maximum seed discrimination efficiency, detour-reaching score, and average number of errors in the spatial memory task. Blue indicates positive associations and red indicates negative associations. Top and bottom lines of the boxes indicate upper and lower 95% confidence intervals respectively. Number of pairwise comparisons ranged between 17 and 24.