The University of Sussex

Adding 'Foveal Vision' to Wilson's Animat

D.T. Cliff, S.G. Bullock

Different animals employ different strategies for sampling sensory data. The strategies are often closely constrained by environmental considerations, such as the animal's ecological niche. In animals that can see, differences in sampling strategy manifest themselves as differences in field of view and in spatially variant sampling (so-called ``foveal'' vision). In analysing adaptive behaviour in animals, or attempting to design autonomous robots, mechanisms for exploring variations in sensory sampling strategy will be required. This paper describes our work exploring a minimal system for investigating the effects of variations in patterns of sensory sampling. We have re-implemented Wilson's (1986} animat, and then experimented with altering its sensory sampling pattern (i.e. its sensory field). Empirical results are presented which demonstrate that alterations in the sensory field pattern can have a significant effect on the animat's observable behaviour (and hence also on the internal mechanisms which generate the behaviours). Analysis of our results involves characterising the interaction between the animat's sensory field and the environment within which the animat resides. We found that the animat's observed behaviour can, at least in part, be explained as a result of the animat cautiously moving in a manner which maximises the generation of new information from the environment over time. The paper concludes with a discussion of the generality of the results, and reflections on the prospects for further work.

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