  Connectionist networks thus compute—they transform input activation values into output activation values—but the imputation of symbolic structures within this computational process, as well as explicit rules by which a C.P.U. executes operations upon these symbols, appears unfounded. As Hatfield (1991) describes connectionist networks, they are non-cognitive, in the sense that their operation involves none of the trappings of cognition upon which computationalists insist, and yet still computational, insofar as stimulation of their input nodes creates patterns of activation that lead to particular activation values in output nodes. For more on  connectionism generally, see the entry on   connectionism.  