Toby Tyrrell: Computational Mechanisms for Action Selection.
Imagine a zebra in the African savannah. At each moment in time this zebra
has to weigh up alternative courses of action before deciding which will be
most beneficial to it. For instance, it may want to graze because it is
short of food, or it may want to head towards a water hole because it is
short of water, or it may want to remain motionless in order to avoid
detection by the predator it can see lurking nearby. This is an example of
the problem of action selection: how to choose, at each moment in time, the
most appropriate out of a repertoire of possible actions.
This thesis investigates action selection in a novel way and makes three
main contributions. Firstly, a description is given of a simulated
environment which is an extensive and detailed simulation of the problem of
action selection for animals. Secondly, this simulated environment is used
to investigate the adequacy of several theories of action selection such as
the drive model, Lorenz's hydraulic model and Maes' spreading activation
network. Thirdly, a new approach to action selection is developed which
determines the most appropriate action in a principled way, and which does
not suffer from the inherent shortcomings found in other methods.
Toby Tyrrell : T.Tyrrell@noc.soton.ac.uk