Cue competition in function learning: Blocking and highlighting

In function learning, people learn to predict a continuous outcome from continuous cues. In category learning, people learn to predict a nominal outcome. The present research demonstrates that two complementary forms of cue competition, previously found in category learning, also occur in function learning. One form of cue competition is blocking of learning about a redundant cue (Kamin, 1968). A second form of cue competition is highlighting of a diagnostic cue (a.k.a. the inverse base rate effect; Medin & Edelson, 1988). For tests with conflicting cues, the results show bimodality of responses, as opposed to averaging, which implies exclusive selectivity that cannot be discerned from category learning paradigms. It is argued that these effects are caused, in both category and function learning, by attentional shifts. No previously published model of function learning can account for these effects, but a model by Kalish, Lewandowsky, and Kruschke (2001) is promising.