Study of spatial learning based upon the shape of an environment

• Main Author: Hayward, Andrew James
• Published: Cardiff University 2008
• Subjects: 153.7
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.584437

In nine experiments rats were required to escape from a swimming pool of opaque water by swimming to a submerged platform. The position of the platform was determined by the shape of the pool, which was either rectangular or triangular. In Chapter 2, a spherical landmark, above the surface of the water, failed to overshadow (Experiment 1) and block (Experiments 2 & 3) learning about the position of the platform relative to these shapes. The same landmark also failed to overshadow learning to find the platform relative to a rectangle described by four identical landmarks (Experiment 4). Experiments in Chapter 3 provided equivalent results with cues situated outside the pool (Experiments 5a & 5b). Experiment 6 revealed that the presence of the triangular-shaped pool potentiated learning based on the cues which surrounded it. In Chapter 4, a landmark was attached to the platform which potentiated learning based on the rectangular pool (Experiment 7). The results of Experiment 8, however, make it unlikely that such potentiation resulted from associations developing between the shape of the pool and the landmark (Experiment 8). These findings offer little support to theories of associative learning like the Rescorla-Wagner model (1972) but are in general agreement with the proposal that animals possess a dedicated Geometric Module, impenetrable to featural information (Cheng, 1986 Gallistel, 1990). The results of Experiment 9 may bring this interpretation of the results into question. In that study, rats were trained to find a submerged platform in one corner of a rectangular, and then a kite-shaped pool. In the kite the platform was easier to find if it was located in a corner congruent with the corner it had previously occupied. Rats must have therefore found the platform with reference to local cues rather than the overall shape of the pool.