Multiple-cue probabilistic learning in spider-fearful and in panic-prone individuals.

Probabilistic learning was studied in spider-fearful and in panic-prone individuals. Participants learned to predict the occurrence of aversive outcomes on the basis of relevant and irrelevant stimuli. The salience of irrelevant stimuli was manipulated by the use of threat-related objects, i.e. pictures of spiders and pictures of emergency situations. In spider-fearful individuals, the presence of irrelevant pictures of spiders interfered with the adequate acquisition of the association between neutral relevant stimuli and aversive outcomes. Salient, i.e. threat-related, irrelevant stimuli exerted competitive effects on the accruing of associative strengths between neutral stimuli and aversive outcomes in spider-fearful, but not in panic-prone, individuals.