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Three groups of pigeons received 60, 150, or 300 continuous reinforcements (CRF) for pecking at a vertical line and then were tested in extinction with brief presentations of a variety of different line tilts. Reliable gradients, with maximal responding to the vertical line, were obtained in all groups. No significant differences were found among the groups in either gradient slope or number of responses emitted during the test. Control of behavior by certain specific features or properties of environmental stimuli apparently develops very quickly in such situations.

Subjects learned 20 CVC pairs and reported the method used in learning (rote or natural language mediator, NLM). After 1, 3, or 9 days, recall was tested and method of learning was reported. Recall was virtually unchanged over 9 days for those pairs for which the NLM reported at recall was the same as at acquisition. Retention was low for pairs learned by rote or with a NLM that was forgotten at recall, and decreased as the retention interval increased.

A transfer design was used to assess the effects of incidental training and knowledge of results (KR) on mixed schema learning in a reproduction task. The results indicated that schema learning is no faster with KR than without KR and that schemata can be learned when Ss merely attend to the stimuli. The relevance of schema theory to concept formation and other cognitive processes is discussed.

A group of domestic rats and a group of wild pack rats were exposed to food and a 20% alcohol solution continuously for 20 weeks. Subsequently, both groups were exposed to food, alcohol solution, and water for nine weeks. No major changes in alcohol consumption rates occurred in either group within either of the two periods. Alcohol consumption decreased for both groups when the choice situation (alcohol vs water) was instituted. This decrease was more pronounced for domestic rats than for wild rats. The results are discussed in terms of potential physiological or other pre-experimental factors affecting alcohol consumption rate.

Following the achievement of a bar press avoidance criterion, three marmoset monkeys were exposed to gradually increasing intensities of response shock. After response rates stabilized, a non-punished avoidance bar was introduced. No evidence of a response shift occurred through 19 sessions (1900 trials), although two Ss made occasional unpunished avoidance responses, and the third S suddenly shifted to the unpunished bar in the 20th session. Thus, punished avoidance behavior was maintained over a relatively long time despite the non-punished alternative. The final differences were explained in terms of reinforcing and aversive interactions.

Peeping was measured in 1-day-old and 4-day-old chicks in four different testing conditions. No differences were found between the two ages, but peeping increased markedly with the degree of environmental change. This latter variable may have been overlooked in past work because of the prevailing interest in changes of behavior as a function of disruption of social imprinting bonds.

An attempt was made to repeat the finding of Schneider & Sherman (1968) that apparent amnesia results from the pairing of footshock and ECS independently of passive-avoidance training. Pairing of footshock and ECS 5 h after training was not found to cause a retention deficit, whereas ECS immediately after training resulted in memory loss. This result shows that the “aftereffects” demonstrated by Schneider and Sherman are not general enough to account for all reported ECS-induced amnesia.