Brighten up: Smiles facilitate perceptual judgment of facial lightness

The metaphoric expression ‘bright smile’ may reflect the actual judgment of facial lightness under varying emotional expressions. The present research examined whether people in fact judge smiling faces as perceptually brighter than frowning faces. Four studies demonstrated that participants believed smiling faces were brighter compared to frowning faces in a binary choice task and in an absolute judgment task. The results suggest that emotional expressions (i.e., smiles and frowns) can bias judgments of facial brightness in ways consistent with the metaphor. Among other implications, such results suggest that stereotypes about darker-skinned individuals may be attenuated by smiles.     

Effect-based control of facial expressions: evidence from action-effect compatibility

Facial expressions such as smiling or frowning are normally followed by, and often aim at, the observation of corresponding facial expressions in social counterparts. Given this contingency between one’s own and other persons’ facial expressions, the production of such facial actions might be the subject of so-called action–effect compatibility effects. In the present Experiment 1, we confirmed this assumption. Participants were required to smile or frown. The generation of these expressions was harder when participants produced predictable feedback from a virtual counterpart that was incompatible with their own facial expression; for example, smiling produced the presentation of a frowning face. The results of Experiment 2 revealed that this effect vanishes with inverted faces as action feedback, which shows that the phenomenon is bound to the instantaneous emotional interpretation of the feedback. These results comply with the assumption that the generation of facial expressions is controlled by an anticipation of these expressions’ effects in the social environment.     

Dogs can discriminate human smiling faces from blank expressions

Dogs have a unique ability to understand visual cues from humans. We investigated whether dogs can discriminate between human facial expressions. Photographs of human faces were used to test nine pet dogs in two-choice discrimination tasks. The training phases involved each dog learning to discriminate between a set of photographs of their owner’s smiling and blank face. Of the nine dogs, five fulfilled these criteria and were selected for test sessions. In the test phase, 10 sets of photographs of the owner’s smiling and blank face, which had previously not been seen by the dog, were presented. The dogs selected the owner’s smiling face significantly more often than expected by chance. In subsequent tests, 10 sets of smiling and blank face photographs of 20 persons unfamiliar to the dogs were presented (10 males and 10 females). There was no statistical difference between the accuracy in the case of the owners and that in the case of unfamiliar persons with the same gender as the owner. However, the accuracy was significantly lower in the case of unfamiliar persons of the opposite gender to that of the owner, than with the owners themselves. These results suggest that dogs can learn to discriminate human smiling faces from blank faces by looking at photographs. Although it remains unclear whether dogs have human-like systems for visual processing of human facial expressions, the ability to learn to discriminate human facial expressions may have helped dogs adapt to human society.     

A smile biases the recognition of eye expressions: Configural projection from a salient mouth

A smile is visually highly salient and grabs attention automatically. We investigated how extrafoveally seen smiles influence the viewers' perception of non-happy eyes in a face. A smiling mouth appeared in composite faces with incongruent non-happy (fearful, neutral, etc.) eyes, thus producing blended expressions, or it appeared in intact faces with genuine expressions. Attention to the eye region was spatially cued while foveal vision of the mouth was blocked by gaze-contingent masking. Participants judged whether the eyes were happy or not. Results indicated that the smile biased the evaluation of the eye expression: The same non-happy eyes were more likely to be judged as happy and categorized more slowly as not happy in a face with a smiling mouth than in a face with a non-smiling mouth or with no mouth. This bias occurred when the mouth and the eyes appeared simultaneously and aligned, but also to some extent when they were misaligned and when the mouth appeared after the eyes. We conclude that the highly salient smile projects to other facial regions, thus influencing the perception of the eye expression. Projection serves spatial and temporal integration of face parts and changes.     

When the smile is a cue to familiarity

The question discussed in the two following experiments concerns the effect of facial expressions on face recognition. Famous and unknown faces with neutral or smiling expression were presented for different inspection durations (15 ms vs 1000 ms). Subjects had to categorise these faces as famous or unknown (Experiment 1), or estimate their degree of familiarity on a rating scale (Experiment 2). Results showed that the smile increased ratings of familiarity for unfamiliar faces (Experiments 1 and 2) and for famous faces (Experiment 2). These data are discussed in the framework of current face-recognition models and are interpreted in terms of social value of the smile. It is proposed that the smiling bias found here acts at the level of the decision process.     

When the smile is a cue to familiarity

The question discussed in the two following experiments concerns the effect of facial expressions on face recognition. Famous and unknown faces with neutral or smiling expression were presented for different inspection durations (15 ms vs 1000 ms). Subjects had to categorize these faces as famous or unknown (Experiment 1), or estimate their degree of familiarity on a rating scale (Experiment 2). Results showed that the smile increased ratings of familiarity for unfamiliar faces (Experiments 1 and 2) and for famous faces (Experiment 2). These data are discussed in the framework of current face-recognition models and are interpreted in terms of social value of the smile. It is proposed that the smiling bias found here acts at the level of the decision process.     

The role of perceptual load in processing distractor faces

It has been established that successful ignoring of irrelevant distractors depends on the extent to which the current task loads attention. However, the previous load studies have typically employed neutral distractor stimuli (e.g., letters). In the experiments reported here, we examined whether the perception of irrelevant distractor faces would show the same effects. We manipulated attentional load in a relevant task of name search by varying the search set size and found that whereas congruency effects from meaningful nonface distractors were eliminated by higher search load, interference from distractor faces was entirely unaffected by search load. These results support the idea that face processing may be mandatory and generalize the load theory to the processing of meaningful and more complex nonface distractors.     

How many faces can be processed during a single eye fixation?

The purpose of our study was to estimate the perceptual span for facial information: how many faces can be processed during a single eye fixation. We used a visual-search task, in which the targets and distractors were facial photographs. The task of the observer was to search for and identify a target face in an array of faces. We measured the time needed for one search--threshold search time--by using a multiple-alternative staircase method. The threshold represents the duration of stimulus presentation at which the probability of correct responses was 79%. The array size was varied from 2 x 2 to 8 x 8 faces. Simultaneously with the performance measurements we measured eye movements with a video eye tracker. We found that threshold search time increased with increasing set size nearly linearly. The number of fixations also increased linearly from unity at the smallest set size to about fifteen at the largest set size. The result of 2 x 2 faces during a single fixation gave an estimate of 4 faces for the perceptual span. If, on average, only half of the elements had to be scanned for finding the target, 15 fixations at the largest set size (8 x 8) gave another estimate of 2.13 faces. The mean fixation duration was around 200 ms. Thus, the results suggest that 2-4 faces can be processed during one fixation of about 200 ms.     

Searching for politicians: An information-processing approach to face recognition

Previous work on face recognition has concentrated on the processing of unfamiliar faces. This paper examines the recognition of already familiar faces, specifically politicians. Three experiments are described in which the subject's task was to search through a series of faces for particular target politicians. In Experiment I the function relating search time to target set size was found to be negatively accelerated. A similar function was observed when names were used as search items. In Experiment II all subjects searched for four targets, and the relationship between distractors and target items was varied. Distractors rated visually similar to the targets took longer to reject than those rated dissimilar. Distractors who were other politicians took longer to reject than actors, and this effect of semantic category was independent of visual similarity. In Experiment III, where subjects searched for a single target, semantic category appeared only to have an effect when the distractors were also visually similar to the target. Models of the rejection process are discussed, and the similarities between the effects observed here, with faces, and those reported elsewhere for words are pointed out.     

Dismissing-avoidant pattern of attachment and mimicry reactions at different levels of information processing

Individuals with a dismissing-avoidant pattern of attachment are assumed to repress anxiety-related signals, a disposition hypothesized to interfere with facial mimicry and emotional contagion. Further, they are assumed to have one internal working model associated with anxiety, operating out of awareness at early, automatic stages of information processing, and another positive model operating at later, cognitively controlled stages of processing. The main aim of the present investigation was to compare facial mimicry in dismissing-avoidant and non-dismissing subjects at different levels of information processing. Pictures of happy and angry faces were exposed to 61 subjects at three different exposure times (17, 56, and 2,350 ms) in order to elicit facial muscle reactions, first at automatic levels and then at a more controlled levels. Corrugator activity ("frowning muscles") represented negative emotions and zygomaticus activity ("smiling muscles") positive emotions. The dismissing-avoidant subjects scored significantly lower on emotional empathy than the non-dismissing subjects. At the automatic level the dismissing-avoidant subjects showed "normal" corrugator responses (negative emotions) upon exposure to angry faces. At the cognitively controlled level of processing (2,350 ms) a significant interaction effect was shown between Faces x Muscles x Attachment pattern. The dismissing-avoidant subjects showed no corrugator response and an increased zygomaticus response ("smiling reaction") to the angry face, whereas the non-dismissing subjects reacted with a significant mimicking reaction. The dismissing-avoidant subjects' tendency to "smiling" in response to the angry face at the controlled level (2,350 ms) may be interpreted as a repression of their earlier, automatically evoked (56 ms) negative emotional reaction.     

Social exclusion influences attentional bias to social information

Using three experiments, the present study investigates the impact of social exclusion on attention. Specifically, we investigate whether social exclusion promotes attentional bias to social acceptance cues (smiling faces) or social exclusion cues (angry faces) among an Asian population. The Cyberball game was adopted to manipulate social inclusion or exclusion, and a dot‐probe task was used to measure individuals' responses to smiling or angry faces. In Experiments 1 and 2, each trial consisted of either a smiling or angry face that was paired with a neutral face. In Experiment 1, when the stimulus onset‐asynchronies (SOA) were 500 ms, the inhibition of return emerged, indirectly indicating that social exclusion promotes sensitivity to social acceptance cues. In Experiment 2, after setting the SOA to 200 ms, we found that social exclusion promotes attentional bias to smiling faces compared to neutral faces. In Experiment 3, both smiling and angry faces were shown during each trial, and we found that social exclusion promotes attentional bias to smiling faces compared to angry faces. Therefore, the present study extends our understanding of the relationship between social exclusion and attention. Overall, it appears that after social exclusion, the desire for social reconnection trumps the desire to avoid social exclusion.     

The effects of smiling on perceived age defy belief

It is a common belief that smiling makes people appear younger. Empirical findings, however, suggest that smiling faces are actually perceived as older than neutral faces. Here we show that these two apparently contradictory phenomena can co-exist in the same person. In the first experiment, participants were first asked to estimate the ages of a series of smiling or neutral faces. After that, they were asked to estimate the average age of the set of neutral and smiling faces they had just evaluated. Finally, they were asked what effect smiling has on one’s perceived age. In the experimental session, smiling faces were perceived as older than neutral faces. Nevertheless, after the experiment, consistent with their retrospective evaluations, participants recalled smiling faces as being younger than the neutral faces. Experiment 2 replicated and extended these results to a set of emotional expressions that also included surprised faces. Smiling faces were again perceived as older than neutral faces, which were in turn perceived as older than surprised faces. Again, retrospective evaluations were consistent with the belief that smiling makes people look younger. The findings show that this belief, well-rooted in popular media, is a complete misconception.     

Unconscious Familiarity and Local Context Effects on Low-Level Face Processing: A Reconstruction Hypothesis

A common view in face recognition research holds that there is a stored representation specific to each known face. It is also posited that semantic or memory-based information cannot influence low-level face processing. The two experiments reported in this article investigate the nature of this representation and the flow of face information processing. Participants had to search for a particular primed face among other faces. In Experiment 1, the search was done in a context where distractors had either a different degree of fame or the same degree of fame. In Experiment 2, the target face was primed either with semantic information or without any information. Both experiments demonstrated that increasing the display set size lengthened face detection time. However, the lengthening was a function of face fame. The search context also had an effect on the slope of the famous face detection. The results are explained in terms of the idea that face representations are reconstructed and that high- and low-level information are integrated into the processing. The integration process is not a conscious one.     

Error monitoring in the hemispheres: the effect of lateralized feedback on lexical decision.

Does each hemisphere have its own system for monitoring and responding to errors? Three experiments investigate the effect of presenting lateralized accuracy feedback in a bilateral lexical decision task. We presented feedback after each trial in either the left visual field (LVF) or right visual field (RVF). In Experiment 1 the feedback stimuli were faces smiling or frowning, in Experiment 2 we used colored squares, and Experiment 3 tested the effect of verbal feedback. Negative feedback presented in the LVF tended to improve performance on the following trial, while the same negative feedback in the RVF tended to disrupt performance on the following trial. This result was strongest with the faces as feedback, was less pronounced with colored squares, and disappeared with verbal feedback. The results are interpreted as suggesting a right hemisphere superiority for error monitoring that depends on the mode of feedback.     

A procedure for obtaining young children’s reports of olfactory stimuli

Young children (ages 2 to 5) have proved to be difficult subjects for obtaining valid reports of their ratings of olfactory stimuli. Thirty-six preschoolers were tested on benzaldehyde (a pleasant odor) and on dimethyl disulfide (an unpleasant odor) using a smiling or frowning face as a response format. The results showed the ability of young children to discriminate between pleasant and unpleasant odors.     

Greater visual averaging of face identity for own-gender faces

Recent evidence suggests that observers can rapidly form an average representation based on a set of simultaneously presented faces. Here, we replicate this finding and show that the tendency to process sets of faces in terms of an average representation is greater for own-gender faces. Male and female participants viewed sets of four male or female faces before deciding whether or not a subsequently presented single test face had been present in the set. Incorrect endorsement that it was one of the set members was greater when the test face was a morphed average of the four faces than when it was an actual set member, and this effect was strongest when the gender of the faces was the same as the observer’s. The finding that observers were more likely to incorrectly endorse own-gender (vs. other-gender) faces forms an exception to the often reported own-gender advantage in face recognition.     

哭泣表情面孔的注意偏向:眼动的证据

研究采用双选择Oddball范式和线索-靶子范式,并结合眼动技术,以微笑、哭泣和中性表情面孔为刺激材料,综合考察哭泣表情面孔在识别和解离过程中的注意偏向。研究发现:在识别阶段,哭泣表情面孔的识别正确率和反应速度都显著优于微笑表情面孔,进一步的兴趣区注视偏向分析发现,哭泣和微笑表情面孔的注视模式既具有一致的规律,又存在细微的差异;在解离阶段,返回抑制受线索表情类型的影响,在有效线索条件下,哭泣表情线索呈现后个体对目标刺激的平均注视时间和眼跳潜伏期都显著短于其它表情线索。表明哭泣表情面孔在识别和解离过程中具有不同的注意偏向表现,在识别阶段表现为反应输出优势和注视模式上的一致性与差异性;在解离阶段表现为有效线索条件下,对目标刺激定位和视觉加工的促进作用。     

Recognizing face identity from natural and morphed smiles

It is easier to identify a degraded familiar face when it is shown moving (smiling, talking; nonrigid motion), than when it is displayed as a static image (Knight & Johnston, 1997; Lander, Christie, & Bruce, 1999). Here we explore the theoretical underpinnings of the moving face recognition advantage. In Experiment 1 we show that the identification of personally familiar faces when shown naturally smiling is significantly better than when the person is shown artificially smiling (morphed motion), as a single static neutral image or as a single static smiling image. In Experiment 2 we demonstrate that speeding up the motion significantly impairs the recognition of identity from natural smiles, but has little effect on morphed smiles. We conclude that the recognition advantage for face motion does not reflect a general benefit for motion, but suggests that, for familiar faces, information about their characteristic motion is stored in memory.     

Recognizing face identity from natural and morphed smiles

It is easier to identify a degraded familiar face when it is shown moving (smiling, talking; nonrigid motion), than when it is displayed as a static image (Knight & Johnston, 1997; Lander, Christie, & Bruce, 1999). Here we explore the theoretical underpinnings of the moving face recognition advantage. In Experiment 1 we show that the identification of personally familiar faces when shown naturally smiling is significantly better than when the person is shown artificially smiling (morphed motion), as a single static neutral image or as a single static smiling image. In Experiment 2 we demonstrate that speeding up the motion significantly impairs the recognition of identity from natural smiles, but has little effect on morphed smiles. We conclude that the recognition advantage for face motion does not reflect a general benefit for motion, but suggests that, for familiar faces, information about their characteristic motion is stored in memory.     

Irrelevant objects of expertise compete with faces during visual search

Prior work suggests that nonface objects of expertise can interfere with the perception of faces when the two categories are alternately presented, suggesting competition for shared perceptual resources. Here, we ask whether task-irrelevant distractors from a category of expertise compete when faces are presented in a standard visual search task. Participants searched for a target (face or sofa) in an array containing both relevant and irrelevant distractors. The number of distractors from the target category (face or sofa) remained constant, whereas the number of distractors from the irrelevant category (cars) varied. Search slopes, calculated as a function of the number of irrelevant cars, were correlated with car expertise. The effect was not due to car distractors grabbing attention, because they did not compete with sofa targets. Objects of expertise interfere with face perception even when they are task irrelevant, visually distinct, and separated in space from faces.