Personality predicts cognitive bias in captive psittacines, Amazona amazonica

• Temporally stable personality factors exist in Amazona amazonica.
• These factors can be reliably measured by multiple raters, and predict behaviour.
• Our results provide experimental support for a link between cognition and personality.
• We found that more neurotic parrots showed greater attention bias for environmental stimuli.
• Attention biases were negatively correlated with performance on a foraging task.

The prevalence of stable behavioural differences between individuals of a species (i.e. personality) is puzzling because it indicates that there are limits on animals' behavioural plasticity and, therefore, optimality of behaviour. Personality may result from individual state characteristics (e.g. morphology or physiology). In turn, these characteristics can lead to differential fitness outcomes for individuals. Cognitive processing of environmental information may be such a characteristic. We developed a subjective personality assessment for Amazona amazonica. We then assessed whether personality predicted a cognitive state difference in attention bias, as measured by the proportion of balks and errors when performing a spatial foraging task in the presence of a passive human observer. Attention biases occur either because individuals attend more quickly to certain environmental stimuli, or because they cannot disengage their attention from such stimuli. Two factors, ‘neuroticism’ and ‘extraversion’, accounted for 66% of the total variance in personality. There was individual variation between parrots' scores on both personality factors and both factors were temporally consistent over 1 year. There was a significant correlation between neuroticism and attention bias. Evolutionarily, attention biases are selected for because the fitness cost of failing to attend to potential threats is much greater than the cost of expending energy attending to benign stimuli. Therefore, cognitive biases such as attention bias are logical candidate cognitive states driving stable personality differences. Our findings show that differences in personality in A. amazonica are correlated with attention bias, a biologically relevant difference in cognition.