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本研究探讨了轻度抑郁对时间估计与时间产生的影响。被试需针对3秒至65秒共5个指定秒数的时间间隔，分别完成幅度估计（magnitude estimation）与幅度产生（magnitude production）判断。针对每种实验条件，为每名被试单独拟合得到最优心理物理函数（psychophysical function）的参数，包括幂律指数（power law exponent）、截距（intercept）与阈值（threshold）。 心境状态（贝克抑郁量表高分组、低分分组，Beck Depression Inventory, BDI）与判断类型（估计、产生）对平均幂律指数（n=0.98，95%置信区间为0.96~1.04）及阈值均无显著影响。但截距项呈现出"抑郁现实主义（depressive realism）"效应：相较于贝克抑郁量表低分被试，高分被试的准确性偏差更小，且估计与产生判断间的差异也更小。 研究采用三种准确性指标评估准确性偏差：一是差值法，定义为心理时间减去物理时间；二是比值法，定义为心理时间除以物理时间；三是一种新型对数准确性指标，定义为比值的自然对数（ln(ratio)）。以心境为被试间自变量、判断类型与时间类别为被试内自变量进行混合方差分析（mixed ANOVA）后发现，对数比值法的残差近似服从正态分布。其余两种准确性指标的残差则显著违背正态性假设。 准确性指标的混合方差分析同样呈现出显著的抑郁现实主义效应，与心理物理函数截距项的结果一致。此外，估计判断与产生判断间存在显著的负相关关系。综合上述研究结果，本研究支持时间估计的时钟模型，并需结合额外的认知机制以解释抑郁现实主义效应。本研究结果同时提出了明确的实验方法论建议。 参考文献： Kornbrot DE, Msetfi RM, Grimwood MJ (2013) Kornbrot, D. E. 与 Msetfi RM. (2013). 《时间知觉与抑郁现实主义：判断类型、心理物理函数与偏差》. *PLoS ONE*, 8(8), e71585. https://doi.org/10.1371/journal.pone.0071585