Figure 2.

Sample psychometric functions from a single naive, representative observer (LEW) derived from duration discrimination judgements as to ‘which was longer, test or reference stimulus?’ (figure 1). These functions correspond to judgements made in the absence of adaptation (‘no adapt’, red data) or following adaptation to 160 or 640 ms (a) visual and (b) auditory duration stimuli (blue and green data, respectively). The effects of adaptation are quantified by differences in the point of subjective equality (PSE): the physical test duration corresponding to 50 per cent ‘test longer’ responses.