An analysis of categorical perception of facial emotion in schizophrenia
ABSTRACT Emotion perception deficits have been extensively documented in schizophrenia and are associated with poor social functioning. Yet fundamental questions about the nature and scope of these impairments remain unanswered from commonly used experimental tasks. An alternative categorical perception paradigm that focuses on distinguishing boundaries between emotions was used to evaluate whether schizophrenia patients demonstrate atypical patterns of categorical perception and a negativity bias in the identification of ambiguous facial expressions.
47 schizophrenia outpatients and 31 nonpsychiatric controls completed a forced-choice emotion identification task. Stimuli consisted of a series of digitized facial images that were morphed in 10% signal intensity increments along continua between pairs of emotions (happy-sad; fearful-happy; angry-fearful; angry-sad) and presented in a random order. For each emotion continuum, measures of the response slope and the location of the boundary shift point between emotions were calculated for each group.
The schizophrenia group demonstrated significantly shallower response curves than controls across all emotion continua. Despite these generally less precise demarcations between emotions, patients did not significantly differ from controls in the location of the shift point between emotions on any of the continua.
Schizophrenia patients demonstrated impaired categorical perception of facial expressions with generally less sharp categorizations of ambiguous stimuli to one emotion category or another. However, patients did not demonstrate a negativity bias in their processing of ambiguous facial expressions. The emotional continuum paradigm can help to clarify the nature and boundaries of affect perception deficits in schizophrenia.
SourceAvailable from: Olga A. Korolkova[Show abstract] [Hide abstract]
ABSTRACT: We explored the effect of categorical perception of emotional facial expressions. Using artificially generated computer “morphs” and natural expressions of a male poser, we studied the identification and discrimination of transitional expressions between images of basic human emotions. The results showed that the distance in perceptual space based on the identification of emotions is a significant predictor of expressions’ discrimination accuracy. The obtained results do not support the hypothesis of an absolute categorical effect, but are consistent with the two-stage model of facial expression categorization (Huttenlocher et al., 2000; Roberson et al., 2007), suggesting a gradual increase in the efficiency of discrimination when distance from the category center is increased.
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ABSTRACT: The aim of our study was to identify the common and separate mechanisms that might underpin emotion recognition impairment in patients with traumatic brain injury (TBI) and schizophrenia (Sz) compared with healthy controls (HCs). We recruited 21 Sz outpatients, 24 severe TBI outpatients, and 38 HCs, and we used eye-tracking to compare facial emotion processing performance. Both Sz and TBI patients were significantly poorer at recognizing facial emotions compared with HC. Sz patients showed a different way of exploring the Pictures of Facial Affects stimuli and were significantly worse in recognition of neutral expressions. Selective or sustained attention deficits in TBI may reduce efficient emotion recognition, whereas in Sz, there is a more strategic deficit underlying the observed problem. There would seem to be scope for adjustment of effective rehabilitative training focused on emotion recognition.
Conference Paper: Categorical Perception of Facial Expressions Is Not a Homogeneous Effect[Show abstract] [Hide abstract]
ABSTRACT: We studied the categorical perception on transitions between seven basic emotional facial expressions and explored the influencing factors. In Experiment 1, participants performed a multiple-choice emotion labeling task while observing basic or morphed (blended between a pair of basic emotions) facial expressions. In Experiment 2, other participants completed AB-X discrimination task. They observed pairs of images adjacent in a morphing continuum, and matched the test image to one of the pair. The results of Experiment 1 revealed influence of emotional context, formed by the presented expressions, on perception of surprise, anger, disgust, and neutral face. The " categorical field " of morphed expressions includes not only the two relevant emotions (morphing basis) but a number of additional ones. Based on the data of Experiment 1, we selected the pairs of stimuli crossing the categorical boundary, and pairs falling within the category, to predict the discriminability obtained it the Experiment 2. A generalized linear mixed model was fitted to the data. We show the main effect of within/between category pair, type of continuum and continuum/category interaction on the probability of correct discrimination. Overall, our results showed the categorical perception, but its strength depends on particular pair of emotional categories.Cognitive Science Meets Artificial Intelligence: Human and Artificial Agents in Interactive Contexts. Proceedings of the 36th Annual Meeting of the Cognitive Science Society, Quebec City, Canada; 07/2014