A Study of Social Transmission in Juvenile Dicentrarchus Labrax (Pisces, Serranidae), in an Operant Conditioning Situation

Abstractjuvenile Dicentrarchus labrax having achieved good or poor performance in a task involving pushing a lever to obtain food served as demonstrators for conspecifics naive to the task. The results show that fish exposed to good demonstrators were subsequently more likely to engage in the same operant act than same-aged fish that observed poor demonstrators. Thus the development of traditions is shown to be possible in small groups of fish of the same age, originating in the appearance of a novel, adaptive behaviour by certain innovative individuals.

A Test of the Small-Trials Partial Reinforcement Extinction Effect in an Operant Conditioning Situation

Following familiarization and magazine training, three groups of rats received either: (1) four food pellets for each of four lever-presses, (2) food for only the first and third lever-presses, or (3) food for only the second and fourth lever-presses. Responding was then extinguished. There were no significant differences between the groups in number of lever presses during extinction or time to extinguish and no significant correlations between these two measures and the number of pellets received during magazine training or the elapsed time to emit the four lever-presses. These data contradict the small-trials partial reinforcement extinction effect commonly reported with the straight alley. However, these data are consistent with those recently reported by Nevin (1985) and with his concept of behavioral momentum, which may apply to the operant chamber but not to the runway.

Dominance among Captive Red-Winged Blackbirds (Agelaius Phoeniceus) in a Competitive/Cooperative Situation

8 pairs of male red-winged blackbirds were tested in an operant conditioning situation wherein both the response perch and food hopper were freely available to both members of a pair. It was observed that familiarization with a territory and epaulet visibility are not critical to maintenance of dominance in reproductively inactive birds. The potential usefulness of competitive/cooperative tasks for the study of dominance behavior is discussed.