Recognition of facial expressions of different emotional intensities in patients with frontotemporal lobar degeneration

Behavioural problems are a key feature of frontotemporal lobar degeneration (FTLD). Also, FTLD patients show impairments in emotion processing. Specifically, the perception of negative emotional facial expressions is affected. Generally, however, negative emotional expressions are regarded as more difficult to recognize than positive ones, which thus may have been a confounding factor in previous studies. Also, ceiling effects are often present on emotion recognition tasks using full-blown emotional facial expressions. In the present study with FTLD patients, we examined the perception of sadness, anger, fear, happiness, surprise and disgust at different emotional intensities on morphed facial expressions to take task difficulty into account. Results showed that our FTLD patients were specifically impaired at the recognition of the emotion anger. Also, the patients performed worse than the controls on recognition of surprise, but performed at control levels on disgust, happiness, sadness and fear. These findings corroborate and extend previous results showing deficits in emotion perception in FTLD.     

Categorical and dimensional perceptions in decoding emotional facial expressions

We investigated whether categorical perception and dimensional perception can co-occur while decoding emotional facial expressions. In Experiment 1, facial continua with endpoints consisting of four basic emotions (i.e., happiness–fear and anger–disgust) were created by a morphing technique. Participants rated each facial stimulus using a categorical strategy and a dimensional strategy. The results show that the happiness–fear continuum was divided into two clusters based on valence, even when using the dimensional strategy. Moreover, the faces were arrayed in order of the physical changes within each cluster. In Experiment 2, we found a category boundary within other continua (i.e., surprise–sadness and excitement–disgust) with regard to the arousal and valence dimensions. These findings indicate that categorical perception and dimensional perception co-occurred when emotional facial expressions were rated using a dimensional strategy, suggesting a hybrid theory of categorical and dimensional accounts.     

Facial age cues and emotional expression interact asymmetrically: age cues moderate emotion categorisation

Facial attributes such as race, sex, and age can interact with emotional expressions; however, only a couple of studies have investigated the nature of the interaction between facial age cues and emotional expressions and these have produced inconsistent results. Additionally, these studies have not addressed the mechanism/s driving the influence of facial age cues on emotional expression or vice versa. In the current study, participants categorised young and older adult faces expressing happiness and anger (Experiment 1) or sadness (Experiment 2) by their age and their emotional expression. Age cues moderated categorisation of happiness vs. anger and sadness in the absence of an influence of emotional expression on age categorisation times. This asymmetrical interaction suggests that facial age cues are obligatorily processed prior to emotional expressions. Finding a categorisation advantage for happiness expressed on young faces relative to both anger and sadness which are negative in valence but different in their congruence with old age stereotypes or structural overlap with age cues suggests that the observed influence of facial age cues on emotion perception is due to the congruence between relatively positive evaluations of young faces and happy expressions.     

Recognising facial expression from spatially and temporally modified movements

We examined how the recognition of facial emotion was influenced by manipulation of both spatial and temporal properties of 3-D point-light displays of facial motion. We started with the measurement of 3-D position of multiple locations on the face during posed expressions of anger, happiness, sadness, and surprise, and then manipulated the spatial and temporal properties of the measurements to obtain new versions of the movements. In two experiments, we examined recognition of these original and modified facial expressions: in experiment 1, we manipulated the spatial properties of the facial movement, and in experiment 2 we manipulated the temporal properties. The results of experiment 1 showed that exaggeration of facial expressions relative to a fixed neutral expression resulted in enhanced ratings of the intensity of that emotion. The results of experiment 2 showed that changing the duration of an expression had a small effect on ratings of emotional intensity, with a trend for expressions with shorter durations to have lower ratings of intensity. The results are discussed within the context of theories of encoding as related to caricature and emotion.     

The Emotion Recognition Task: a paradigm to measure the perception of facial emotional expressions at different intensities

The Emotion Recognition Task is a computer-generated paradigm for measuring the recognition of six basic facial emotional expressions: anger, disgust, fear, happiness, sadness, and surprise. Video clips of increasing length were presented, starting with a neutral face that changes into a facial expression of different intensities (20%-100%). The present study describes methodological aspects of the paradigm and its applicability in healthy participants (N=58; 34 men; ages between 22 and 75), specifically focusing on differences in recognition performance between the six emotion types and age-related change. The results showed that happiness was the easiest emotion to recognize, while fear was the most difficult. Moreover, older adults performed worse than young adults on anger, sadness, fear, and happiness, but not on disgust and surprise. These findings indicate that this paradigm is probably more sensitive than emotion perception tasks using static images, suggesting it is a useful tool in the assessment of subtle impairments in emotion perception.     

Assessment of perception of morphed facial expressions using the Emotion Recognition Task: Normative data from healthy participants aged 8–75

The ability to recognize and label emotional facial expressions is an important aspect of social cognition. However, existing paradigms to examine this ability present only static facial expressions, suffer from ceiling effects or have limited or no norms. A computerized test, the Emotion Recognition Task (ERT), was developed to overcome these difficulties. In this study, we examined the effects of age, sex, and intellectual ability on emotion perception using the ERT. In this test, emotional facial expressions are presented as morphs gradually expressing one of the six basic emotions from neutral to four levels of intensity (40%, 60%, 80%, and 100%). The task was administered in 373 healthy participants aged 8–75. In children aged 8–17, only small developmental effects were found for the emotions anger and happiness, in contrast to adults who showed age‐related decline on anger, fear, happiness, and sadness. Sex differences were present predominantly in the adult participants. IQ only minimally affected the perception of disgust in the children, while years of education were correlated with all emotions but surprise and disgust in the adult participants. A regression‐based approach was adopted to present age‐ and education‐ or IQ‐adjusted normative data for use in clinical practice. Previous studies using the ERT have demonstrated selective impairments on specific emotions in a variety of psychiatric, neurologic, or neurodegenerative patient groups, making the ERT a valuable addition to existing paradigms for the assessment of emotion perception.     

Detection of emotional facial expressions and anti-expressions

Detection of emotional facial expressions has been shown to be more efficient than detection of neutral expressions. However, it remains unclear whether this effect is attributable to visual or emotional factors. To investigate this issue, we conducted two experiments using the visual search paradigm with photographic stimuli. We included a single target facial expression of anger or happiness in presentations of crowds of neutral facial expressions. The anti-expressions of anger and happiness were also presented. Although anti-expressions produced changes in visual features comparable to those of the emotional facial expressions, they expressed relatively neutral emotions. The results consistently showed that reaction times (RTs) for detecting emotional facial expressions (both anger and happiness) were shorter than those for detecting anti-expressions. The RTs for detecting the expressions were negatively related to experienced emotional arousal. These results suggest that efficient detection of emotional facial expressions is not attributable to their visual characteristics but rather to their emotional significance.     

Liberal bias mediates emotion recognition deficits in frontal traumatic brain injury

It is well-known that patients having sustained frontal-lobe traumatic brain injury (TBI) are severely impaired on tests of emotion recognition. Indeed, these patients have significant difficulty recognizing facial expressions of emotion, and such deficits are often associated with decreased social functioning and poor quality of life. As of yet, no studies have examined the response patterns which underlie facial emotion recognition impairment in TBI and which may lend clarity to the interpretation of deficits. Therefore, the present study aimed to characterize response patterns in facial emotion recognition in 14 patients with frontal TBI compared to 22 matched control subjects, using a task which required participants to rate the intensity of each emotion (happiness, sadness, anger, disgust, surprise and fear) of a series of photographs of emotional and neutral faces. Results first confirmed the presence of facial emotion recognition impairment in TBI, and further revealed that patients displayed a liberal bias when rating facial expressions, leading them to associate intense ratings of incorrect emotional labels to sad, disgusted, surprised and fearful facial expressions. These findings are generally in line with prior studies which also report important facial affect recognition deficits in TBI patients, particularly for negative emotions.     

Effects of emotion concepts on perceptual memory for emotional expressions

Three experiments tested the hypothesis that explaining emotional expressions using specific emotion concepts at encoding biases perceptual memory for those expressions. In Experiment 1, participants viewed faces expressing blends of happiness and anger and created explanations of why the target people were expressing one of the two emotions, according to concepts provided by the experimenter. Later, participants attempted to identify the facial expressions in computer movies, in which the previously seen faces changed continuously from anger to happiness. Faces conceptualized in terms of anger were remembered as angrier than the same faces conceptualized in terms of happiness, regardless of whether the explanations were told aloud or imagined. Experiments 2 and 3 showed that explanation is necessary for the conceptual biases to emerge fully and extended the finding to anger-sad expressions, an emotion blend more common in real life.     

Dynamic facial expressions of emotion induce representational momentum

Two experiments were conducted to explore whether representational momentum (RM) emerges in the perception of dynamic facial expression and whether the velocity of change affects the size of the effect. Participants observed short morphing animations of facial expressions from neutral to one of the six basic emotions. Immediately afterward, they were asked to select the last images perceived. The results of the experiments revealed that the RM effect emerged for dynamic facial expressions of emotion: The last images of dynamic stimuli that an observer perceived were of a facial configuration showing stronger emotional intensity than the image actually presented. The more the velocity increased, the more the perceptual image of facial expression intensified. This perceptual enhancement suggests that dynamic information facilitates shape processing in facial expression, which leads to the efficient detection of other people's emotional changes from their faces.     

Emotional memory and perception of emotional faces in patients suffering from depersonalization disorder

Previous work has shown that patients with depersonalization disorder (DPD) have reduced physiological responses to emotional stimuli, which may be related to subjective emotional numbing. This study investigated two aspects of affective processing in 13 patients with DPD according to the DSM‐IV criteria and healthy controls: the perception of emotional facial expressions (anger, disgust, fear, happiness, sadness, and surprise) and memory for emotional stimuli. Results revealed a specific lack of sensitivity to facial expression of anger in patients, but normal enhancement of memory for peripheral aspects of arousing emotional material. The results are consistent with altered processing of threat‐related stimuli but intact consolidation processes, at least when the stimuli involved are potently arousing.     

Categorical perception of emotional facial expressions does not require lexical categories

Does our perception of others' emotional signals depend on the language we speak or is our perception the same regardless of language and culture? It is well established that human emotional facial expressions are perceived categorically by viewers, but whether this is driven by perceptual or linguistic mechanisms is debated. We report an investigation into the perception of emotional facial expressions, comparing German speakers to native speakers of Yucatec Maya, a language with no lexical labels that distinguish disgust from anger. In a free naming task, speakers of German, but not Yucatec Maya, made lexical distinctions between disgust and anger. However, in a delayed match-to-sample task, both groups perceived emotional facial expressions of these and other emotions categorically. The magnitude of this effect was equivalent across the language groups, as well as across emotion continua with and without lexical distinctions. Our results show that the perception of affective signals is not driven by lexical labels, instead lending support to accounts of emotions as a set of biologically evolved mechanisms.     

Effects of direct and averted gaze on the perception of facially communicated emotion

Research has largely neglected the effects of gaze direction cues on the perception of facial expressions of emotion. It was hypothesized that when gaze direction matches the underlying behavioral intent (approach-avoidance) communicated by an emotional expression, the perception of that emotion would be enhanced (i.e., shared signal hypothesis). Specifically, the authors expected that (a) direct gaze would enhance the perception of approach-oriented emotions (anger and joy) and (b) averted eye gaze would enhance the perception of avoidance-oriented emotions (fear and sadness). Three studies supported this hypothesis. Study 1 examined emotional trait attributions made to neutral faces. Study 2 examined ratings of ambiguous facial blends of anger and fear. Study 3 examined the influence of gaze on the perception of highly prototypical expressions.     

Caricaturing facial expressions

The physical differences between facial expressions (e.g. fear) and a reference norm (e.g. a neutral expression) were altered to produce photographic-quality caricatures. In Experiment 1, participants rated caricatures of fear, happiness and sadness for their intensity of these three emotions; a second group of participants rated how 'face-like' the caricatures appeared. With increasing levels of exaggeration the caricatures were rated as more emotionally intense, but less 'face-like'. Experiment 2 demonstrated a similar relationship between emotional intensity and level of caricature for six different facial expressions. Experiments 3 and 4 compared intensity ratings of facial expression caricatures prepared relative to a selection of reference norms - a neutral expression, an average expression, or a different facial expression (e.g. anger caricatured relative to fear). Each norm produced a linear relationship between caricature and rated intensity of emotion; this finding is inconsistent with two-dimensional models of the perceptual representation of facial expression. An exemplar-based multidimensional model is proposed as an alternative account.     

Overt congruent facial reaction to dynamic emotional expressions in 9–10-month-old infants

The current study aimed to extend the understanding of the early development of spontaneous facial reactions toward observed facial expressions. Forty-six 9- to 10-month-old infants observed video clips of dynamic human facial expressions that were artificially created with morphing technology. The infants’ facial responses were recorded, and the movements of the facial action unit 12 (e.g., lip-corner raising, associated with happiness) and facial action unit 4 (e.g., brow-lowering, associated with anger) were visually evaluated by multiple naïve raters. Results showed that (1) infants make congruent, observable facial responses to facial expressions, and (2) these specific facial responses are enhanced during repeated observation of the same emotional expressions. These results suggest the presence of observable congruent facial responses in the first year of life, and that they appear to be influenced by contextual information, such as the repetition of presentation of the target emotional expressions.     

The perception of changing emotion expressions

The utility of recognising emotion expressions for coordinating social interactions is well documented, but less is known about how continuously changing emotion displays are perceived. The nonlinear dynamic systems view of emotions suggests that mixed emotion expressions in the middle of displays of changing expressions may be decoded differently depending on the expression origin. Hysteresis is when an impression (e.g., disgust) persists well after changes in facial expressions that favour an alternative impression (e.g., anger). In expression changes based on photographs (Study 1) and avatar images (Studies 2a-c, 3), we found hystereses particularly in changes between emotions that are perceptually similar (e.g., anger-disgust). We also consistently found uncertainty (neither emotion contributing to the mixed expression was perceived), which was more prevalent in expression sequences than in static images. Uncertainty occurred particularly in changes between emotions that are perceptually dissimilar, such as changes between happiness and negative emotions. This suggests that the perceptual similarity of emotion expressions may determine the extent to which hysteresis and uncertainty occur. Both hysteresis and uncertainty effects support our premise that emotion decoding is state dependent, a characteristic of dynamic systems. We propose avenues to test possible underlying mechanisms.     

Recognition of emotional facial expressions: the role of facial and contextual information in the accuracy of recognition

Recognition of emotional facial expressions is a central area in the psychology of emotion. This study presents two experiments. The first experiment analyzed recognition accuracy for basic emotions including happiness, anger, fear, sadness, surprise, and disgust. 30 pictures (5 for each emotion) were displayed to 96 participants to assess recognition accuracy. The results showed that recognition accuracy varied significantly across emotions. The second experiment analyzed the effects of contextual information on recognition accuracy. Information congruent and not congruent with a facial expression was displayed before presenting pictures of facial expressions. The results of the second experiment showed that congruent information improved facial expression recognition, whereas incongruent information impaired such recognition.     

Categorical perception of facial expressions.

People universally recognize facial expressions of happiness, sadness, fear, anger, disgust, and perhaps, surprise, suggesting a perceptual mechanism tuned to the facial configuration displaying each emotion. Sets of drawings were generated by computer, each consisting of a series of faces differing by constant physical amounts, running from one emotional expression to another (or from one emotional expression to a neutral face). Subjects discriminated pairs of faces, then, in a separate task, categorized the emotion displayed by each. Faces within a category were discriminated more poorly than faces in different categories that differed by an equal physical amount. Thus emotional expressions, like colors and speech sounds, are perceived categorically, not as a direct reflection of their continuous physical properties.     

High Hostility Among Smokers Predicts Slower Recognition of Positive Facial Emotion

High levels of trait hostility are associated with wide-ranging interpersonal deficits and heightened physiological response to social stressors. These deficits may be attributable in part to individual differences in the perception of social cues. The present study evaluated the ability to recognize facial emotion among 48 high hostile (HH) and 48 low hostile (LH) smokers and whether experimentally-manipulated acute nicotine deprivation moderated relations between hostility and facial emotion recognition. A computer program presented series of pictures of faces that morphed from a neutral emotion into increasing intensities of happiness, sadness, fear, or anger, and participants were asked to identify the emotion displayed as quickly as possible. Results indicated that HH smokers, relative to LH smokers, required a significantly greater intensity of emotion expression to recognize happiness. No differences were found for other emotions across HH and LH individuals, nor did nicotine deprivation moderate relations between hostility and emotion recognition. This is the first study to show that HH individuals are slower to recognize happy facial expressions and that this occurs regardless of recent tobacco abstinence. Difficulty recognizing happiness in others may impact the degree to which HH individuals are able to identify social approach signals and to receive social reinforcement.     

Facial-expression affective attributes and their configural correlates: components and categories

The present study investigates the perception of facial expressions of emotion, and explores the relation between the configural properties of expressions and their subjective attribution. Stimuli were a male and a female series of morphed facial expressions, interpolated between prototypes of seven emotions (happiness, sadness, fear, anger, surprise and disgust, and neutral) from Ekman and Friesen (1976). Topographical properties of the stimuli were quantified using the Facial Expression Measurement (FACEM) scheme. Perceived dissimilarities between the emotional expressions were elicited using a sorting procedure and processed with multidimensional scaling. Four dimensions were retained in the reconstructed facial-expression space, with positive and negative expressions opposed along D1, while the other three dimensions were interpreted as affective attributes distinguishing clusters of expressions categorized as "Surprise-Fear," "Anger," and "Disgust." Significant relationships were found between these affective attributes and objective facial measures of the stimuli. The findings support a componential explanatory scheme for expression processing, wherein each component of a facial stimulus conveys an affective value separable from its context, rather than a categorical-gestalt scheme. The findings further suggest that configural information is closely involved in the decoding of affective attributes of facial expressions. Configural measures are also suggested as a common ground for dimensional as well as categorical perception of emotional faces.