An analysis of categorical perception of facial emotion in schizophrenia
California State University Channel Islands, United States. Schizophrenia Research
(Impact Factor: 3.92).
11/2006; 87(1-3):228-37. DOI: 10.1016/j.schres.2006.06.001
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.
Available from: Fabien D'Hondt
- "The higher the value of the slope, the more abruptly the change in the responses happens. A high value for the slope can be considered as an index of a typical pattern of categorical perception while a low value for the slope is representative of a more continuous perception (Kee et al., 2006; Pollak and Kistler, 2002 "
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Emotional deficits have been widely described in alcohol-dependence, but several subtle and critical emotional decoding abilities remain to be investigated. In particular, the ability of alcohol-dependent individuals to process emotionally ambiguous facial stimuli, which are more frequent in everyday life than full emotional facial expressions, remains poorly understood. The present study used a categorical perception paradigm to evaluate the identification of mixed emotional facial expressions among alcohol-dependent participants.
Nineteen recently detoxified participants with alcohol-dependence and 19 healthy controls were presented with facial stimuli depicting four emotional facial expressions (happy, angry, sad, and neutral), morphed along continua between each possible pair of emotions. Participants had to indicate the predominant emotion within the randomly presented facial stimuli. For each emotional category, a logistic function that estimated the percentage of identification according to the morph steps was adjusted for each participant's data.
While there was no significant group difference regarding the response slope (p=0.502, ηp(2)=0.014), the identification threshold was significantly increased in alcohol-dependent participants compared to controls (p=0.007, ηp(2)=0.204), independently of the emotional category.
The categorical perception of emotional facial expression per se appeared preserved in alcohol-dependence, but alcohol-dependent participants exhibited a bias in emotional facial expression decoding characterized by a global under-identification. This study is the first to evidence a deficit of alcohol-dependent individuals in the processing of ambiguous emotional facial expressions by using this emotional continuum paradigm measuring the categorical perception effect.
Available from: Delphine Pins
- "We therefore hypothesized that SZP would demonstrate a shift in the familiarity threshold compared to HS. On the other hand, the slope of the logistic function allows us to estimate the abruptness of the response change (Kee et al., 2006). "
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ABSTRACT: Familiarity is a crucial aspect of recognition that may be perturbed in schizophrenia patients (SZP) and may lead to delusional disorders. However, there are no existing guidelines on how to assess and treat familiarity disorders in schizophrenia. Some experimental studies have investigated familiarity processing in SZP but have produced inconsistent results, which are likely a result of methodological issues. Moreover, these studies only assessed whether familiarity processing is preserved or impaired in SZP, but not the tendency of SZP to consider unfamiliar stimuli to be familiar. By using a familiarity continuum task based on the existence of the categorical perception effect, the objective of this study was to determine whether SZP present hyper- or hypo-familiarity. To this purpose, 15 SZP and 15 healthy subjects (HS) were presented with facial stimuli, which consisted of picture morphs of unfamiliar faces and faces that were personally familiar to the participants. The percentage of the familiar face contained in the morph ranged from 5 to 95%. The participants were asked to press a button when they felt familiar with the face that was presented. The main results revealed a higher percentage of familiarity responses for SZP compared with HS from the stimuli with low levels of familiarity in the morph and a lower familiarity threshold, suggesting a hyper-familiarity disorder in SZP. Moreover, the intensity of this "hyper-familiarity" was correlated with positive symptoms. This finding clearly suggests the need for a more systematic integration of an assessment of familiarity processing in schizophrenia symptoms assessments.
Available from: Yu-Tao Xiang
- "Thus, it appears that the similarity of negative emotions is in part responsible for deficits in recognition accuracy in patients with schizophrenia. The errors in the attribution and categorization of emotions, found in the current study and previously reported elsewhere (Kee et al., 2006; Kohler et al., 2003), may contribute to some of the deficits in socialization observed in schizophrenia, in that intended meanings behind subtle or ambiguous emotional cues may be misinterpreted. This tendency towards misinterpretation might be one reason why patients with paranoid schizophrenia frequently misjudge the language or behavior of others as persecutory, potentially contributing to the development of delusions. "
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ABSTRACT: Facial emotion recognition has been found to be impaired in schizophrenia, although overall results have been inconclusive. A new set of facial emotion stimuli with Chinese faces was developed, using static and dynamic avatars, the identification of which were subsequently validated in 562 healthy control subjects. This test was then used to identify facial emotion recognition accuracy in 44 patients with schizophrenia and 41 healthy controls. Overall, patients identified facial emotions significantly worse than healthy controls (p = 0.018) with a significant main effect for type of emotion (p = 0.016). Patients performed significantly worse in fear (p = 0.029) and sadness (p = 0.037), and marginally worse in anger (p = 0.052). No significant differences were evident in contempt (p = 0.254) or happiness (p = 0.943). Regarding error rates of misattribution, patients overidentified contempt (p = 0.035) and sadness (p = 0.01), but not anger, fear, or happiness. Conclusion, patients of Chinese ethnicity with schizophrenia may have significantly greater difficulties identifying negative, but not positive emotions.
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