Colour preferences in the pigeon: a behavioural and psychopharmacological study.

Ten London pigeons were tested in an operant apparatus, and found to have marked colour preferences, blue being preferred over green, followed by yellow and red. The effects of 2 tranquilizers, diazepam and chlorpromazine, were studied and it was found that diazepam released responding, and chlorpromazine suppressed it. Diazepam also tended to abolish colour preference, whilst chlorpromazine was effective only at the highest dose used (5.00 mg/kg). The implications of these findings, particularly in relation to the design of experiments and to the aversiveness of certain stimuli, are discussed.