Basic mechanisms of interval timing and associative learning are shared by many animal species, and develop quickly in early life, particularly across infancy, and childhood. Indeed, John Wearden in his book “The Psychology of Time Perception”, which is based on decades of his own research with colleagues, and which our commentary serves to primarily review, has been instrumental in implementing animal models and methods in children and adults, and has revealed important similarities (and differences) between human timing (and that of animals) when considered within the context of scalar timing theory. These seminal studies provide a firm foundation upon which the contemporary multifaceted field of timing and time perception has since advanced. The contents of the book are arguably one piece of a larger puzzle, and as Wearden cautions, “The reader is warned that my own contribution to the field has been exaggerated here, but if you are not interested in your own work, why would anyone else be?” Surely there will be many interested readers, however the book is noticeably lacking in it neurobiological perspective. The mind (however it is conceived) needs a brain (even if behaviorists tend to say “the brain behaves”, and most neuroscientists currently have a tenuous grasp on the neural mechanisms of temporal cognition), and to truly understand the psychology of time, brain and behavior must go hand in hand regardless of the twists, turns, and detours along the way.
The present study explored the effect of vocally expressed emotions on duration perception. Recordings of the syllable ‘ah’ spoken in a disgusted (negative), surprised (positive), and neutral voice were subjected to a compression/stretching algorithm producing seven durations ranging from 300 to 1200 ms. The resulting stimuli served in a duration bisection procedure in which participants indicated whether a stimulus was more similar in duration to a previously studied 300 ms (short) or 1200 ms (long) 440 Hz tone. Behavioural results indicate that disgusted expressions were perceived as shorter than surprised expressions in both men and women and this effect was related to perceived valence. Additionally, both emotional expressions were perceived as shorter than neutral expressions in women only and this effect was related to perceived arousal. Event-related potentials showed an influence of emotion and rate of acoustic change (fast for compressed/short and slow for stretched/long stimuli) on stimulus encoding in women only. Based on these findings, we suggest that emotions interfere with temporal processes and facilitate the influence of contextual information (e.g., rate of acoustic change, attention) on duration judgements. Because women are more sensitive than men to unattended vocal emotions, their temporal judgements are more strongly distorted.
The influence of non-temporal distractor stimuli on interval timing under conditions expected to elicit covert shifts of attention was examined using seconds range stimuli and the duration bisection task. Distractor stimuli appeared in positions peripheral to the timing signal on half of the trials, but participants were instructed to maintain fixation on the timing stimulus while their eye positions were monitored using an eye-tracker. In Experiment 1, participants ignored the distractors, whereas in Experiment 2 participants counted the distractors. In both experiments, trials with distractors were judged as longer than equivalent duration trials without distractors. Presenting a cue that indicated whether or not the subsequent trial would include distractors (Experiment 3) eliminated this lengthening effect. Taken together, these results suggest that when the presence of distractor stimuli during a trial is uncertain, distractor expectation captures attention that would otherwise be allocated to timing, with the result that perceived duration is shorter on trials in which distractors are absent.
A transient suppression of visual perception during saccades ensures perceptual stability. In two experiments, we examined whether saccades affect time perception of visual and auditory stimuli in the seconds range. Specifically, participants completed a duration reproduction task in which they memorized the duration of a 6 s timing signal during the training phase and later reproduced that duration during the test phase. Four experimental conditions differed in saccade requirements and the presence or absence of a secondary discrimination task during the test phase. For both visual and auditory timing signals, participants reproduced longer durations when the secondary discrimination task required saccades to be made (i.e., overt attention shift) during reproduction as compared to when the discrimination task merely required fixation at screen center. Moreover, greater total saccade duration in a trial resulted in greater time distortion. However, in the visual modality, requiring participants to covertly shift attention (i.e., no saccade) to complete the discrimination task increased reproduced duration as much as making a saccade, whereas in the auditory modality making a saccade increased reproduced duration more than making a covert attention shift. In addition, we examined microsaccades in the conditions that did not require full saccades for both the visual and auditory experiments. Greater total microsaccade duration in a trial resulted in greater time distortion in both modalities. Taken together, the experiments suggest that saccades and microsaccades affect seconds range visual and auditory interval timing via attention and saccadic suppression mechanisms.