Altered time-perception performance in individuals with high schizotypy levels

Abstract

The possibility of altered time-perception in high schizotypy scorers, as postulated through previous differences shown in performance between high and low scorers in schizotypy on schedules of reinforcement with temporal elements, was examined using a series of retrospective timing tasks. Three stimuli ratio manipulations were made across two experiments, and, using an adjusted version of the bisection-point method for data analysis, results showed that high scorers on the unusual experiences subscale of the O-LIFE(B) estimated the mid point of the stimulus range to be at a significantly longer interval than low scorers. This was true when the ratio between the "short" and "long" standard stimuli were 4:1 (Experiment 1), 3:1 and 2:1 (Experiment 2). These findings are consistent with the notion of altered time-perception for high schizotypals.

Individual differences in first- and second-order temporal judgment

“…The lack of any analogous relationship between UnEx and suprasecond timing performance might be accounted for by several explanations. First, it is of course plausible that no relationship exists between these variables in the suprasecond domain, and that the results of Experiment 1 are a product of largely independent subsecond timing mechanisms (this would be consistent with the combined findings of Reed & Randell, [ 43 ] and Sarkin et al, [ 42 ]). This explanation would suggest that individuals who show high degrees of UnEx might also be expected to manifest subtle perturbations in other domains associated with the same underlying (most notably, cerebellar [ 69 ]) networks, such as perceptual decision-making and motor co-ordination [ 76 , 77 ]…”

“…Timing performance was correlated with O-LIFE subscale scores to investigate whether distinct profiles of schizotypy are associated with different patterns of duration estimation. On the basis of previous research [ 15 , 43 ], we were particularly interested in whether the Unusual Experiences (UnEx) subscale could be used to identify distinct patterns of temporal judgement.…”

“…Such aggregate measures are problematic insofar as they may lack sensitivity to between-subject differences that systematically co-vary with a particular trait dimension. More recently, Reed and Randell [ 43 ] reported two temporal-bisection experiments in which participants’ ability to correctly categorise probe stimuli as being more similar to either a short or a long reference interval (using two reference pairs of 200/800ms or 300/900ms), was analysed in relation to scores on the Oxford Liverpool Inventory of Feelings and Experiences—Brief Version (O-LIFE(B) [ 44 ]). This study revealed significant differences in the apparent duration of these subsecond intervals as judged by high- versus low-scorers on the Unusual Experiences subscale (UnEx) with high-scorers participants tending to categorise probes more accurately than their low-scoring counterparts.…”

“…Reed and Randell’s [ 43 ] results indicate that systematic variation in interval timing might be accounted for by a susceptibility or propensity towards unusual beliefs (e.g., magical ideation) and aberrant perceptual experiences (e.g., hallucinatory phenomena). Alongside evidence that the early visual processing deficits postulated in schizophrenia also extend (albeit in an attenuated fashion) to individuals who score highly on measures of schizotypy [ 45 – 47 ]; that such visual impairments may arise due to temporal processing disturbances [ 48 ]; and, finally, that high-UnEx scores predict diminished sensitivity to visual stimuli [ 15 ], these data are suggestive of a common linkage between anomalous visual experiences and distorted temporal representations in the contexts of schizotypy and schizophrenia.…”

Future thinking is related to lower delay discounting than recent thinking, regardless of the magnitude of the reward, in individuals with schizotypy

“…Previous studies have suggested that individuals with schizotypy were impaired in time perception and processing, they tend to judge "long" for shorter durations (Randell, Ranjith-Kumar, Gupta, & Reed, 2009;Reed & Randell, 2014). Based on the aforementioned findings, we may speculate that the abnormal time perception in individuals with schizotypy may be one of the factors contributed to their devaluing of delayed rewards.…”