The role of fear in one-trial passive avoidance learning in Japanese quail chicks genetically selected for long or short duration of the tonic immobility reaction

Abstract

Emotional arousal has been shown to affect learning in mammals, but little is known about the relationship between fear and learning in birds. In order to investigate this relationship, the learning abilities of Japanese quail chicks from lines that have been divergently selected for high or low levels of underlying fearfulness, as measured by the duration of tonic immobility behaviour, were compared. Day-old chicks from both lines were trained in a one-trial passive avoidance task. In this task, young chicks spontaneously peck at a small, visually conspicuous bead. If the bead has been coated with a gustatory aversant, the chicks learn in a single trial not to peck a similar, uncoated bead upon subsequent presentation. Significantly more chicks of the low fear line pecked the training bead compared to those of the high fear line. However, 2 h later, chicks of both lines trained on a methyl anthranilate-coated bead showed similar avoidance of the test bead. Therefore, although fear affected performance during training, it did not appear to directly affect memory formation in this task.