Nature reversed: Diminishing intensity of the maternal call affects approach behaviour of chicks

Skinner (1974) suggested that ducklings could be taught to move away from an imprinting object provided the natural consequences of approach behaviour was reversed. We constructed an apparatus in which approach behaviour toward an audio-visual stimulus caused reduced amplitude of a maternal call, whereas movement away caused an increase in amplitude. Chicks (Experiment 1) trained in this apparatus approached the training stimulus, but to a lesser degree than chicks exposed to calls of constant amplitude. Highly active experimental chicks kept a larger distance to the stimulus than passive chicks. Thus the reversal of the natural consequences of approaching influenced filial behaviour. However, a training period of three hours did not influence approach behaviour in the direction predicted by Skinner (1974). A second group of chicks (Experiment 2) which could increase the call amplitude by moving in one direction without being able to localize the sound source was more influenced by the amplitude gradient than Experiment I-chicks.     

The serial position effect and different error types in anticipation learning

Abstract.— Minor modifications of the usual serial anticipation procedure did not affect the well-known Serial Position Effect (SPE), while the errors, i.e. Intra-list-Intrusions (ILI) and Failure-TeRespond (FTR), showed deviations from the usual distributions. It was therefore concluded that the SPE should not be analysed in terms of different error types, ILI and FTR. Transfer-to-position measured by means of a number-syllable paired association (PA) task, and a free-recall test of the original serial anticipation list measured after the termination of the PA-task showed a skewed and a symmetrical trend respectively. It was suggested that response-learning accounted for the symmetrical component of the SPE while association-to-position, contrary to prevailing views, was responsible for the skewed component.