Relationships between exploratory behaviour and fear: a review

Two main theories of the relationship between exploratory behaviour and anxiety or fearfulness are: (a) ‘Two-factor theory’, according to which novel stimuli evoke both curiosity and fear/anxiety, with exploration as the outcome of competing tendencies to approach and avoid, and (b) the ‘Halliday-Lester theory’, where the fear aroused by novelty results in either approach (low fear) or avoidance (high fear). Relevant evidence comes from animal studies varying fear by manipulating either environmental or intrinsic factors. This evidence is largely compatible with the two-factor theory and some results which have been presented as critical support for the Halliday-Lester theory are actually equivocal.