Exploiting holistic computation : an evaluation of the sequential RAAM

In recent years it has been claimed that connectionist methods of representing compositional structures, such as lists and trees, support a new form of symbol processing known as holistic computation. In a holistic computation the constituents of an object are acted upon simultaneously, rather than on a one-by-one basis as is typical in traditional symbolic systems. This thesis presents firstly, a critical examination of the concept of holistic computation, as described in the literature, along with a revised definition of the concept that aims to clarify the issues involved. In particular it is argued that holistic representations are not necessary for holistic computation and that holistic computation is not restricted to connectionist systems. Secondly, an evaluation of the capacity of a particular connectionist representation, the Sequential RAAM, to generate representations that support holistic symbol processing is presented. It is concluded that the Sequential RAAM is not as effective a vehicle for holistic symbol processing as it initially appeared, but that there may be some scope for improving its performance.