International Journal of Comparative Psychology

Pigmented dark agouti and albino Wistar rats were compared for the effect of differentially reinforced pre-exposure to peppermint as a positive and vanilla as a negative odour cue. Both types of rat showed significantly enhanced performance on the simultaneous odour discrimination task with the same cues, when compared to control groups not pre-exposed to the odour cues. However, the pigmented rats had steeper learning curves than the albinos, with the albino controls performing significantly worse than the other groups. The results are discussed in terms of task components of cue significance and response regulation. It appeared that the response component was more difficult for the albino rats compared to the pigmented rats.