'Blocking of the sexual conditioning of differentially effective conditioned stimulus objects' by F Koksal, M Domjan and G Weisman (Animal Learning and Behavior, 1944, pp103-111) explores the effect of conditioned stimuli on the sexual behaviour of the quail.
The standard experiment on blocking starts by conditioning rats to associate noise with an electric shock by giving the rats a shock (the unconditioned stimulus, or US) every time a bell rings (the conditioned stimulus, CS). When this is established, a bright light (CS2) is added to the noise before each shock. In this case, however, the rats do not learn to associate the light with the forthcoming shock. The effect is blocked by the already conditioned response to the noise.
Substituting quails for rats and sex for shocks, we have the basis of the current experiment. 'The opportunity to copulate with a female quail served as the US,' they explain. Eighteen three-month-old sexually naive male Japanese quail (Coturnix coturnix japonica) served as subjects. Six three-month-old female Japanese quail 'were used to provide copulatory opportunity'. So after making the necessary introductions ('During the habituation period, the subjects received access to a female quail twice for 5 min'), each male was left alone for half an hour, then a light shone, a buzzer sounded, and a female quail was dropped into the cage for five minutes. When the quail was conditioned to the light + buzzer (CS1), an additional stimulus object (CS2) was added: CS2 might be a block of wood, a terry-cloth on a cylinder, or a terry-cloth on a cylinder 'made more salient by the addition of a taxidermically prepared head (of a female quail)'. Videotapes of the quails' behaviour were analysed to see how much time each bird spent near to CS2 during the trials, and whether copulation with CS2 was attempted.
Whereas no quail ever attempted to grab and mount the wooden block, and only one jumped on the terry-cloth in a sexual frenzy, by the end of the experimental period all of the conditioned quails had attempted to copulate with the terrycloth + head.
'The results indicate that the blocking effect occurs in sexual conditioning even with stimulus objects that can support copulation. However, the addition of species- typical head cues to an object makes that object such a powerful stimulus that conditioned approach responding to it cannot be blocked by a previously conditioned audiovisual cue.'Reuse content