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Modulation of Emotional Category Induced by Temporal Factors in Emotion Recognition.

Maeshima H, Yamashita Y, Fujimura T, Okada M, Okanoya K - PLoS ONE (2015)

Bottom Line: CP is considered as the result of the integration of the top-down processing including background knowledge and verbal labeling and the bottom-up processing such as physical characteristics of the sensory signal.The results demonstrated that the emotionally ambiguous stimuli are categorized more distinctively with the extension of delay length, not of stimulus duration.These findings suggest that paying more attention to temporal factors in CP could be useful for further study of the mechanisms underlying CP.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan; JST, ERATO, Okanoya Emotional Information Project, Wako, Saitama, Japan.

ABSTRACT
Categorical perception (CP), the perceptual experience whereby continuous sensory phenomena are perceived as distinct and separate percepts, is one of the most characteristic features of information processing in human cognition. CP is considered as the result of the integration of the top-down processing including background knowledge and verbal labeling and the bottom-up processing such as physical characteristics of the sensory signal. However, the underlying mechanisms governing the integration remain unclear. To address this issue, we focused on the temporal characteristics of CP of facial expression. In the current study, we investigated the contributions of temporal factors in CP processes, using facial expression recognition tasks as an example of CP. Participants completed an identification task and a discrimination task, well-established tasks for evaluating CP of facial expressions, with variable temporal parameters, that is, duration of stimulus presentation and delay time (interval between stimulus and response). The results demonstrated that the emotionally ambiguous stimuli are categorized more distinctively with the extension of delay length, not of stimulus duration. In contrast, the category boundary for facial expressions shifted toward "happy" with extention in stimulus duration, not in delay length. This dissociation between the impact of stimulus duration and delay suggests that there are two processes contributing to CP of facial emotion; one process may reflect the internal processing associated with the length of the delay period including verbal labeling of the stimuli, and the other process may reflect the temporal summation of stimulus inputs, associated with stimulus duration. These findings suggest that paying more attention to temporal factors in CP could be useful for further study of the mechanisms underlying CP.

No MeSH data available.


Related in: MedlinePlus

Changes in the category boundary in the identification task.The y-axis represents the mean of the morphing intensity of the category boundary. The differences between durations of 50 and 200 ms and between 50 and 750 ms are significant. Error bars indicate the standard error.
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pone.0131636.g004: Changes in the category boundary in the identification task.The y-axis represents the mean of the morphing intensity of the category boundary. The differences between durations of 50 and 200 ms and between 50 and 750 ms are significant. Error bars indicate the standard error.

Mentions: Fig 4 shows the average category boundary from all participants for each experimental condition. A two-factor within-subject ANOVA (duration × delay) revealed a significant main effect of duration (F(2, 40) = 9.02, p < .001, η2 = .110). There was no significant main effect of delay, nor a significant interaction. Multiple comparisons (Tukey’s HSD) revealed that the category boundary (i.e., inflexion point of the logistic curve) was larger at 50 ms than at 200 and 750 ms (HSD = 0.265, α = .05), meaning that the estimated category boundary shifted toward “happier” facial expressions at longer durations.


Modulation of Emotional Category Induced by Temporal Factors in Emotion Recognition.

Maeshima H, Yamashita Y, Fujimura T, Okada M, Okanoya K - PLoS ONE (2015)

Changes in the category boundary in the identification task.The y-axis represents the mean of the morphing intensity of the category boundary. The differences between durations of 50 and 200 ms and between 50 and 750 ms are significant. Error bars indicate the standard error.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4521787&req=5

pone.0131636.g004: Changes in the category boundary in the identification task.The y-axis represents the mean of the morphing intensity of the category boundary. The differences between durations of 50 and 200 ms and between 50 and 750 ms are significant. Error bars indicate the standard error.
Mentions: Fig 4 shows the average category boundary from all participants for each experimental condition. A two-factor within-subject ANOVA (duration × delay) revealed a significant main effect of duration (F(2, 40) = 9.02, p < .001, η2 = .110). There was no significant main effect of delay, nor a significant interaction. Multiple comparisons (Tukey’s HSD) revealed that the category boundary (i.e., inflexion point of the logistic curve) was larger at 50 ms than at 200 and 750 ms (HSD = 0.265, α = .05), meaning that the estimated category boundary shifted toward “happier” facial expressions at longer durations.

Bottom Line: CP is considered as the result of the integration of the top-down processing including background knowledge and verbal labeling and the bottom-up processing such as physical characteristics of the sensory signal.The results demonstrated that the emotionally ambiguous stimuli are categorized more distinctively with the extension of delay length, not of stimulus duration.These findings suggest that paying more attention to temporal factors in CP could be useful for further study of the mechanisms underlying CP.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan; JST, ERATO, Okanoya Emotional Information Project, Wako, Saitama, Japan.

ABSTRACT
Categorical perception (CP), the perceptual experience whereby continuous sensory phenomena are perceived as distinct and separate percepts, is one of the most characteristic features of information processing in human cognition. CP is considered as the result of the integration of the top-down processing including background knowledge and verbal labeling and the bottom-up processing such as physical characteristics of the sensory signal. However, the underlying mechanisms governing the integration remain unclear. To address this issue, we focused on the temporal characteristics of CP of facial expression. In the current study, we investigated the contributions of temporal factors in CP processes, using facial expression recognition tasks as an example of CP. Participants completed an identification task and a discrimination task, well-established tasks for evaluating CP of facial expressions, with variable temporal parameters, that is, duration of stimulus presentation and delay time (interval between stimulus and response). The results demonstrated that the emotionally ambiguous stimuli are categorized more distinctively with the extension of delay length, not of stimulus duration. In contrast, the category boundary for facial expressions shifted toward "happy" with extention in stimulus duration, not in delay length. This dissociation between the impact of stimulus duration and delay suggests that there are two processes contributing to CP of facial emotion; one process may reflect the internal processing associated with the length of the delay period including verbal labeling of the stimuli, and the other process may reflect the temporal summation of stimulus inputs, associated with stimulus duration. These findings suggest that paying more attention to temporal factors in CP could be useful for further study of the mechanisms underlying CP.

No MeSH data available.


Related in: MedlinePlus