Observer's Face Research Articles

Observing an expert's action swapped with an observer's face increases corticospinal excitability during combined action observation and motor imagery.

This study aimed to examine whether observing an expert's action swapped with an observer's face increases corticospinal excitability during combined action observation and motor imagery (AOMI). Twelve young males performed motor imagery of motor tasks with different difficulties while observing the actions of an expert performer and an expert performer with a swapped face. Motor tasks included bilateral wrist dorsiflexion (EASY) and unilateral two-ball rotating motions (DIFF). During the AOMI of EASY and DIFF, single-pulse transcranial magnetic stimulation was delivered to the left primary motor cortex, and motor-evoked potentials (MEPs) were obtained from the extensor carpi ulnaris and first dorsal interosseous muscles of the right upper limb, respectively. Visual analogue scale (VAS) assessed the subjective similarity of the expert performer with the swapped face in the EASY and DIFF to the participants themselves. The MEP amplitude in DIFF was larger in the observation of the expert performer with the swapped face than that of the expert performer (P = 0.012); however, the corresponding difference was not observed in EASY (P = 1.000). The relative change in the MEP amplitude from observing the action of the expert performer to that of the expert performer with the swapped face was positively correlated with VAS only in DIFF (r = 0.644, P = 0.024). These results indicate that observing the action of an expert performer with the observer's face enhances corticospinal excitability during AOMI, depending on the task difficulty and subjective similarity between the expert performer being observed and the observer.

Evidence for Unintentional Emotional Contagion Beyond Dyads

Little is known about the spread of emotions beyond dyads. Yet, it is of importance for explaining the emergence of crowd behaviors. Here, we experimentally addressed whether emotional homogeneity within a crowd might result from a cascade of local emotional transmissions where the perception of another’s emotional expression produces, in the observer's face and body, sufficient information to allow for the transmission of the emotion to a third party. We reproduced a minimal element of a crowd situation and recorded the facial electromyographic activity and the skin conductance response of an individual C observing the face of an individual B watching an individual A displaying either joy or fear full body expressions. Critically, individual B did not know that she was being watched. We show that emotions of joy and fear displayed by A were spontaneously transmitted to C through B, even when the emotional information available in B’s faces could not be explicitly recognized. These findings demonstrate that one is tuned to react to others’ emotional signals and to unintentionally produce subtle but sufficient emotional cues to induce emotional states in others. This phenomenon could be the mark of a spontaneous cooperative behavior whose function is to communicate survival-value information to conspecifics.

基于头部追踪的宽视角裸眼3D显示系统

Normal naked 3D display have some defects,such as fixed viewing point,narrow viewing angle.In order to enhance the 3D performance,a 3D display system base on head tracking is introduced.In this system,a camera detects the position of observer's face,and a LC barrier moves the 3D viewing point toward the face simultaneously by changing its transmissive area.Thus the observer can receive good 3D images freely within the visual field of the camera.Because there is no meteyard for this wide viewing angle 3D display,this paper puts forward a test method.The experiment result proved the method is viable.

Measuring Internal Representations from Behavioral and Brain Data

The study of internal knowledge representations is a cornerstone of the research agenda in the interdisciplinary study of cognition. An influential proposal assumes that the brain uses its internal knowledge of the external world to constrain, in a top-down manner, high-dimensional sensory data into a lower-dimensional representation that enables perceptual decisions and other higher-level cognitive functions [1-9]. This proposal relies on a precise formulation of the observer-specific internal knowledge (i.e., the internal representations, or models) that guides reduction of the high-dimensional retinal input onto a low-dimensional code. Here, we directly revealed the content of subjective internal representations by instructing five observers to detect a face in the presence of only white noise, to force a pure top-down, knowledge-based task. We used reverse correlation methods to visualize each observer's internal representation that supports detection of an illusory face. Using reverse correlation again, this time applied to observers' electroencephalogram activity, we established where and when in the brain specific internal knowledge conceptually interprets the input white noise as a face. We show that internal representations can be reconstructed experimentally from behavioral and brain data, and that their content drives neural activity first over frontal and then over occipitotemporal cortex.

Emerging sensitivity to standards in toddlers: a necessary but insufficient condition for visual self-recognition in the rouge-task procedure?

Different explanations are put forward for the late acquisition of the(or rouge task) in comparison to other mirror tasks. A particularly interesting hypothesis about factors that mask success in MSR task concerns the growth of the appreciation of standards of proper behaviour, noticing deviations from normality in objects and in their own action (Mitchell, 1993, 1994). Standard sensitivity is proposed as a core factor in determining the self recognition capability. To test this hypothesis, we observed 40 infants, aged between 15 and 24 months, confronted with a spot on a doll's face, on the infant's hand, on the observer's face, and on the infant's face. Our data suggest that sensitivity to standards can be seen as a necessary but not sufficient requirement for success in thetask: other capacities, namely the development of representation, may play a decisive role in the successful performance on thetask.

Perceived Direction of Gaze from Eyes with Dark vs. Light Irises

Much of the previous research on the perceived direction of gaze has not specified eye color or pupil visibility. This study tests whether the lightness or darkness of a gazer's irises (typically brown vs. blue) affects their perceived direction of gaze. Twenty-five observers judged the direction of horizontal gaze from a model whose LCD-imaged head gazed toward points on the plane of the observer's face. The model's head was displayed with its natural brown irises and also with its irises digitally altered to look blue without pupils, blue with centered pupils, and blue with nasally decentered pupils. True gaze location was compared with the judged gaze location for each type of iris. For all iris types, observers judged that monocular gaze was biased outward from its true direction for all gaze locations, including central, whereas binocular gaze was close to centered and had a greater slope. Blue eyes with no pupil and blue eyes with a centered pupil exaggerated this perceived outward deviation for monocular gaze but binocular gaze remained the same. When the pupils were nasally decentered by a typical amount, straight monocular as well as binocular gaze appeared to be centered. The direction of monocular gaze from eyes that differ in the darkness of their irises is perceived differently, and, within the blue irises, small differences in pupil centration made surprisingly large differences in the perceived directions of gaze.

Strange-Face-in-the-Mirror Illusion

I describe a visual illusion which occurs when an observer sees his/her image reflected in a mirror in a dimly lit room. This illusion can be easily experienced and replicated as the details of the setting (in particular the room illumination) are not critical. These observations were made in a quiet room dimly lit by a 25 W incandescent light. The lamp was placed on the floor behind the observer so that it was not visible either directly or in the mirror. A relatively large mirror (0.5 mT0.5 m) was placed about 0.4 m in front of the observer. Luminance of the reflected face image within the mirror was about 0.2 cd m(-2) and this level allowed detailed perception of fine face traits but attenuated colour perception. The illusion occurred even at higher levels of illumination of observer's face (from 0.2 to 1.6 cd m(-2)). The task of the observer was to gaze at his/her reflected face within the mirror. Usually, after less than a minute, the observer began to perceive the strange-face illusion. Phenomenological descriptions were made by fifty naive individuals (age range 21 ^ 29 years; mean 23 years; SD 2.1 years). At the end of a 10 min session of mirror gazing, the participant was asked to write what he or she saw in the mirror. The descriptions differed greatly across individuals and included: (a) huge deformations of one's own face (reported by 66% of the fifty participants); (b) a parent's face with traits changed (18%), of whom 8% were still alive and 10% were deceased; (c) an unknown person (28%); (d) an archetypal face, such as that of an old woman, a child, or a portrait of an ancestor (28%); (e) an animal face such as that of a cat, pig, or lion (18%); (f) fantastical and monstrous beings (48%). Language: en

I Feel what You Feel if You Are Similar to Me

Social interactions are influenced by the perception of others as similar or dissimilar to the self. Such judgements could depend on physical and semantic characteristics, such as membership in an ethnic or political group. In the present study we tested whether social representations of the self and of others could affect the perception of touch. To this aim, we assessed tactile perception on the face when subjects observed a face being touched by fingers. In different conditions we manipulated the identity of the shown face. In a first experiment, Caucasian and Maghrebian participants viewed a face belonging either to their own or to a different ethnic group; in a second experiment, Liberal and Conservative politically active participants viewed faces of politicians belonging to their own or to the opposite political party. The results showed that viewing a touched face most strongly enhanced the perception of touch on the observer's face when the observed face belonged to his/her own ethnic or political group.

Spatial Coding of the Predicted Impact Location of a Looming Object

Avoiding or intercepting looming objects implies a precise estimate of both time until contact and impact location [1–4]. In natural situations, extrapolating a movement trajectory relative to some egocentric landmark requires taking into account variations in retinal input associated with moment-to-moment changes in body posture [5-7]. Here, human observers predicted the impact location on their face of an approaching stimulus mounted on a robotic arm, while we systematically manipulated the relation between eye, head, and trunk orientation. The projected impact point on the observer's face was estimated most accurately when the target originated from a location aligned with both the head and eye axes. Eccentric targets with respect to either axis resulted in a systematic perceptual bias ipsilateral to the trajectory's origin. We conclude that (1) predicting the impact point of a looming target requires combining retinal information with eye position information, (2) that this computation is accomplished accurately for some, but not all, possible combinations of these cues, (3) that the representation of looming trajectories is not formed in a single, canonical reference frame, and (4) that the observed perceptual biases could reflect an automatic adaptation for interceptive/defensive actions within near peripersonal space.

The late Meteoric Shower

WHILE going to the Naval Observatory on the, evening of November 27, I noticed many shooting-stars, and made the following observations:—From 6h. 25m. to 6h. 43m., Washington mean time, I counted one hundred meteors; and from 7h. 40m. to 8h. om. I counted fifty meteors. The observer's face was north-west. The sky was clear to within ten or fifteen degrees of the horizon. The meteors were generally very small, and I noticed only four or five near the zenith that left trails behind that endured a few seconds. In one respect the meteors were remarkable: they all appeared to radiate from a point between the great square in Pegasus and the chair in Cassiopeia, so that during my two watches I saw but a single meteor that could properly be called sporadic. By laying down some of the tracks on a globe, I found the following rough, position of the radiant point:—