Computational Complexity and Cognitive Science: How the Body and the World Help the Mind be Efficient

Abstract

Computational complexity has been developed under the assumption that thinking can be modelled by a Turing machine. This view of cognition has more recently been complemented with situated and embodied cognition where the key idea is that cognition consists of an interaction between the brain, the body and the surrounding world. This chapter deals with the meaning of complexity from a situated and embodied perspective. The main claim is that if the structure of the world is taken into account in problem solving, the complexity of certain problems will be reduced in relation to Turing machine complexity. For example, search algorithms can be simplified if the visual structure of the world is exploited. Another case is the logical problem of language acquisition, claiming that children cannot learn language simply by considering the input. It is argued that this problem will not arise if it is taken into account that children’s learning of grammatical features often exploits world knowledge.