Cognitive Judgment Bias in Red Junglefowl (Gallus gallus) Selected for High vs. Low Fear of Humans

Abstract: The Red Junglefowl is a species of bird that was domesticated by humans around 8 000 years ago. Over time, domestication has led to changes in behavior and morphology, made possible by reduced fear of humans. Fear has been shown to affect cognitive processes, such as the way ambiguous stimuli are perceived by the individual. In this study, I observed the behavior of Red Junglefowl hens that had been selected for either high or low fear of humans to see how the early stages of domestication would affect their tendency to make pessimistic or optimistic judgements. The hens were put in a test arena where they were exposed to positive, negative, and ambiguous stimulus cues, and the time taken to approach each was measured. Hens that had been selected for low fear of humans had overall, albeit not significantly, shorter latencies to approach ambiguous cues. In other words, they were more likely to make optimistic judgements. The results were also affected by the order each stimulus cue was presented. I conclude that domestication may influence the way Red Junglefowl perceive ambiguous stimuli by reducing pessimism.