. - 
- 
strategies that would tax the relatively limited resources 
of short-term memory and attention. For example, with 
respect to ownership, one plausible heuristic might be that 
we know our territorial spaces, and that we use the 
rule-of-thumb that what is in personal territory is personal 
property. This obviously would result in errors, and where 
such disputes were important, reference could be made to 
more exact criteria of ownership, possibly only available to 
legal experts. 
Quite recently, dualistic semantic theories have been 
considered in the psychological literature. The common 
theoretical view in reterential semantics has been that a 
lexical item is decomposible and has an internal logic for 
pointing to its extension. Typically, the internal logic 
entails some use of feature theory (Armstrong, Gleitman & 
Gleitman, 1983). That is, features (i.e. attributes, 
characteristics, or criteria) get related, bundled or 
associated by some rule system. So a 'bird' is mentally 
represented as an ‘animal', that 'flies', has 'wings' and 
'feathers', ‘lays eggs', etc. (Locke, cited in Armstrong et 
al., 1983). Prototype theories (Rosch, 1975) and fuzzy set 
theories (Zadeh, 1975) loosen the requirements for specific 
features, but still proceed by decomposition and 
consideration of features (Fodor, Garrett, Walker & Parkes, 
1980: Armstrong et al., 1983). Entailment (Miller, 1978) is