Electrophysiological correlates of the composite face illusion: Disentangling perceptual and decisional components of holistic face processing in the human brain

When the bottom halves of two faces differ, people’s behavioral judgment of the identical top halves of those faces is impaired: they report that the top halves are different, and/or take more time than usual to provide a response. This behavioral measure is known as the composite face effect (CFE) and has traditionally been taken as evidence that faces are perceived holistically. Recently, however, it has been claimed that this effect is driven almost entirely by decisional, rather than perceptual, factors ( Richler, Gauthier, Wenger, & Palmeri, 2008). To disentangle the contribution of perceptual and decisional brain processes, we aimed to obtain an event-related potential (ERP) measure of the CFE at a stage of face encoding ( Jacques & Rossion, 2009) in the absence of a behavioral CFE effect. Sixteen participants performed a go/no-go task in an oddball paradigm, lifting a finger of their right or left hand when the top half of a face changed identity. This change of identity of the top of the face was associated with an increased ERP signal on occipito-temporal electrode sites at the N170 face-sensitive component (∼160 ms), the later decisional P3b component, and the lateralized readiness potential (LRP) starting at ∼350 ms. The N170 effect was observed equally early when only the unattended bottom part of the face changed, indicating that an identity change was perceived across the whole face in this condition. Importantly, there was no behavioral response bias for the bottom change trials, and no evidence of decisional biases from electrophysiological data (no P3b and LRP deflection in no-go trials). These data show that an early CFE can be measured in ERPs in the absence of any decisional response bias, indicating that the CFE reflects primarily the visual perception of the whole face.     

Semantic interference in a delayed naming task: evidence for the response exclusion hypothesis

In 2 experiments participants named pictures of common objects with superimposed distractor words. In one naming condition, the pictures and words were presented simultaneously on every trial, and participants produced the target response immediately. In the other naming condition, the presentation of the picture preceded the presentation of the distractor by 1,000 ms, and participants delayed production of their naming response until distractor word presentation. Within each naming condition, the distractor words were either semantic category coordinates of the target pictures or unrelated. Orthogonal to this manipulation of semantic relatedness, the frequency of the pictures' names was manipulated. The authors observed semantic interference effects in both the immediate and delayed naming conditions but a frequency effect only in the immediate naming condition. These data indicate that semantic interference can be observed when target picture naming latencies do not reflect the bottleneck at the level of lexical selection. In the context of other findings from the picture-word interference paradigm, the authors interpret these data as supporting the view that the semantic interference effect arises at a postlexical level of processing.     

Influence of experience on postural control: effect of expertise in gymnastics

The authors investigated how expertise in motor skills that require fine postural control, such as gymnastics, influences postural regulation. Gymnasts and nongymnasts performed a postural stabilization task after anterior-posterior destabilization while looking at a target in front of them. The authors recorded and analyzed the center of pressure and the ankle, knee, and hip displacements. Gymnasts were able to react rapidly after destabilization to decrease their center of pressure and the angular movements. Moreover, they used their knees to stabilize posture, whereas the nongymnasts used their hips. These findings suggest that specific postural experience modifies the ability to coordinate and regulate posture. The authors discuss these results from an ecological perspective.     

Links between casino proximity and gambling participation, expenditure, and pathology.

Two studies investigated the relationship between casino proximity and gambling participation, expenditure, and pathology. In Study 1, 8,842 participants were categorized into 1 of 4 driving distances from their home to the nearest casino in the province of Quebec: 0-100 km, 100.01-200 km, 200.01-300 km, or 300.01-981 km. In Study 2, 5,158 participants, who lived within a 100-km driving distance from the Montreal casino, were classified into 1 of 5 equidistant, 20-km driving distances. A survey company interviewed participants regarding their gambling habits. Results indicated a positive link between casino proximity and gambling participation (at the provincial and Montreal levels) and expenditure (at the provincial level only) but no link with the current prevalence rate of probable pathological gambling or of problem gambling. In a setting in which many types of gambling activities are available, casino proximity in itself does not appear to explain the rate of gambling-related problems. It is necessary to continue prospective research on exposure and adaptation theories as potential explanations for the development of pathological gambling.     

Women's eye contact and men's later interest: two field experiments

Previous studies indicated various nonverbal behaviors including eye contact of women are associated with men's approach; however, duration of the eye contact was not tested. In Exp. 1, a female confederate established eye-contact of 3 sec. or 1 sec. with a man when entering a bar. Duration of returned glance was the dependent variable. Analysis showed mean duration of the return glance was statistically shorter in the 1-sec. condition. In Exp. 2, the confederate made eye contact with a man and looked at him less than 1 sec., 2 sec., or 4 sec. The presence versus absence of smile was the dependent variable. Longer duration of eye contact was associated with an increase of smiling.     

A new methodology providing evidence of two distinct processes in the production of hand/foot simultaneous responses

To get simultaneous responses of the hand and the foot, it is mandatory to compensate for the longer peripheral motor conduction delay of the foot. According to the reactive-projective model [Paillard, J. (1948). Quelques données psychophysiologiques relatives au déclenchement de la commande motrice (Some psychophysiological data in relation to the releasing of the motor commands). Année Psychologique, 28-47; Paillard, J. (1990). Réactif et prédictif: deux modes de gestion du geste de la motricité. In V. Nougier, & J. Blanchi (Eds.), Pratiques sportives et modélisation du geste (Sport activity and gesture modeling) (pp. 13-56). Grenoble: Université Joseph-Fourier.] no compensation occurs in a reaction time situation; the hand responds before the foot, which indicates a single motor command released for both effectors. However, in a self-initiated condition, the foot tends to precede the hand suggesting that two distinct motor commands are issued, with the foot command first. Fully self-initiated movements are not usual. It is more usual to prepare a response in anticipation of the time occurrence of a stimulus (e.g., a musician following a conductor, synchronized swimmers emerging together with the music). Therefore, we developed a methodology to test whether the model holds in an anticipation coincidence task. In Experiment 1, the participants were asked to initiate a synchronized hand/foot response when the continuous visual stimulus (constant speed) reaches a target. The results fitted the model. In Experiment 2, anticipation coincidence tasks were performed in three conditions: using the foot (1) or the hand (2) alone, and using the hand and the foot simultaneously (3). Following a constant stimulus protocol, short tones were randomly produced, prior the stimulus, to indicate the participants to inhibit their response. As expected, the frequencies of correct inhibition in each preset period followed a sigmoid curve. The command release is assumed to occur at the biserial point (50% of inhibition). The results confirmed that the motor command of the foot is released sooner than the command of the hand. The hand/foot delay is lower in the simultaneous condition, because the command of the hand is released 40 ms earlier; while the foot command is 10 ms earlier. These data confirm and extend the projective-reactive model to a new category of coordination behavior.     

Gender differences in cooperation and competition: the male-warrior hypothesis

Evolutionary scientists argue that human cooperation is the product of a long history of competition among rival groups. There are various reasons to believe that this logic applies particularly to men. In three experiments, using a step-level public-goods task, we found that men contributed more to their group if their group was competing with other groups than if there was no intergroup competition. Female cooperation was relatively unaffected by intergroup competition. These findings suggest that men respond more strongly than women to intergroup threats. We speculate about the evolutionary origins of this gender difference and note some implications.     

Temporal distribution of favourite books, movies, and records: differential encoding and re-sampling

The reminiscence bump is the effect that people recall more personal events from early adulthood than from childhood or adulthood. The bump has been examined extensively. However, the question of whether the bump is caused by differential encoding or re-sampling is still unanswered. To examine this issue, participants were asked to name their three favourite books, movies, and records. Furthermore,they were asked when they first encountered them. We compared the temporal distributions and found that they all showed recency effects and reminiscence bumps. The distribution of favourite books had the largest recency effect and the distribution of favourite records had the largest reminiscence bump. We can explain these results by the difference in rehearsal. Books are read two or three times, movies are watched more frequently, whereas records are listened to numerous times. The results suggest that differential encoding initially causes the reminiscence bump and that re-sampling increases the bump further.