Higher Order Autoshaping*

A series of experiments is reported on appetitive higher order conditioning in the pigeon. Experiment I showed that second order autoshaping can be produced by pairing a neutral keylight with a keylight of another colour, previously paired with food. Experiment II employed an omission procedure to show that second order autoshaping is a consequence of the contingency between first and second order stimuli. In Experiment III, extinction of responding to the first order stimulus was shown to reduce responding to the second order stimulus. Experiments IV and V showed firstly that this reduction is not due to generalization of extinction, and secondly that second order key pecks may be produced in the absence of any pecking to the first order stimulus. The results suggest that second order autoshaping is based largely on a direct association between the first and second order stimuli.