Psychological time estimation and depression

The effect of mild depression on time estimation and production was investigated. Participants made both magnitudeestimation and magnitude production judgments for five time intervals (specified in seconds) from 3 sec to 65 sec. Theparameters of the best fitting psychophysical function (power law exponent, intercept, and threshold) were determinedindividually for each participant in every condition. There were no significant effects of mood (high BDI, low BDI) orjudgment (estimation, production) on the mean exponent, n=.98, 95% confidence interval (.96–1.04) or on the threshold.However, the intercept showed a ‘depressive realism’ effect, where high BDI participants had a smaller deviation fromaccuracy and a smaller difference between estimation and judgment than low BDI participants. Accuracy bias was assessedusing three measures of accuracy: difference, defined as psychological time minus physical time, ratio, defined aspsychological time divided by physical time, and a new logarithmic accuracy measure defined as ln (ratio). The ln (ratio)measure was shown to have approximately normal residuals when subjected to a mixed ANOVA with mood as a betweengroups explanatory factor and judgment and time category as repeated measures explanatory factors. The residuals of theother two accuracy measures flagrantly violated normality. The mixed ANOVAs of accuracy also showed a strong depressiverealism effect, just like the intercepts of the psychophysical functions. There was also a strong negative correlation betweenestimation and production judgments. Taken together these findings support a clock model of time estimation, combinedwith additional cognitive mechanisms to account for the depressive realism effect. The findings also suggest strongmethodological recommendations.Citation: Kornbrot DE, Msetfi RM, Grimwood MJ (2013) Kornbrot, D. E. //Msetfi. (2013). Time Perception and Depressive Realism: Judgment Type, Psychophysical Functions and Bias. PLoS ONE, 8(8), e71585. https://doi.org/10.1371/journal.pone.0071585