In three experiments the location of pigeons was monitored during 20-second illuminations of a right or left key presented in various temporal relationships with food delivery. In general, subjects approached a signal positively correlated with food and withdrew from a signal negatively correlated with food. (Editor)

The main finding of these four experiments was that the strong conditioning produced by a brief exposure to a truly random control weakened with prolonged exposure. (Author/RK)

A general hypothesis of associative learning should be based on the broadest possible foundation of empirical evidence, including confirmation in both aversive and appetitive situations. For this reason the present experiment was designed to test the surprise hypothesis using a procedure in which the unconditioned stimulus was the presentation of…

Recent data indicate that the form of the conditioned response (CR) may often be substantially influenced by the characteristics of the conditioned stimulus (CS) as well as by those of the unconditioned stimulus (US). Here five experiments examine the influence of CS characteristics on the form of the Pavlovian CR anticipatory to a food US in…

An analysis of two paradigms suggests that predictions in regard to the effects of stimulus preexposure must take into account not only the novelty of the stimulus, but the relationship of that novelty to that of the environment at the time of testing. (Editor/RK)