Perceiving while acting: action affects perception

In two experiments we studied how motor responses affect stimulus encoding when stimuli and responses are functionally unrelated and merely overlap in time. Such R-S effects across S-R assignments have been reported by Schubö, Aschersleben, and Prinz (2001), who found that stimulus encoding was affected by concurrent response execution in the sense of a contrast (i.e., emphasizing differences). The present study aimed at elucidating the mechanisms underlying this effect. Experiment 1 studied the time course of the R-S effect. Contrast was only obtained for short intertrial intervals (ITIs). With long ITIs contrast turned into assimilation (i.e., emphasizing similarities). Experiment 2 excluded an interpretation of the assimilation effect in terms of motor repetition. Our findings support the notion of a shared representational domain for perception and action control, and suggest that contrast between stimulus and response codes emerges when two S-R assignments compete with each other in perception. When perceptual competition is over, assimilation emerges in memory.     

Perceiving motion and rigid structure from optic flow: A combined weak-perspective and polar-perspective approach

Structure-from-motion algorithms based on weak-perspective projection have many interesting properties and could serve as a basis for a model of human perception of motion and structure from motion (M&SFM). There is some psychophysical evidence, however, that points to discrepancies between what can be accomplished with these algorithms and the performance of human subjects in certain M&SFM tasks. In light of this evidence, this paper presents a mechanism that both takes advantage of all the possibilities offered by a weak-perspective approach and behaves in a manner that is in close correspondence with human performance in M&SFM tasks. It consists of a novel weak-perspective—based method operating at small visual angles and a complementary, perspective-projection—based method operating at larger visual angles.     

Perceiving action identity: how pianists recognize their own performances

Can skilled performers, such as artists or athletes, recognize the products of their own actions? We recorded 12 pianists playing 12 mostly unfamiliar musical excerpts, half of them on a silent keyboard. Several months later, we played these performances back and asked the pianists to use a 5-point scale to rate whether they thought they were the person playing each excerpt (1 = no, 5 = yes). They gave their own performances significantly higher ratings than any other pianist's performances. In two later follow-up tests, we presented edited performances from which differences in tempo, overall dynamic (i.e., intensity) level, and dynamic nuances had been removed. The pianists' ratings did not change significantly, which suggests that the remaining information (expressive timing and articulation) was sufficient for self-recognition. Absence of sound during recording had no significant effect. These results are best explained by the hypothesis that an observer's action system is most strongly activated during perception of self-produced actions.     

Knowing how they feel: Perceiving emotions felt by outgroups

Individuals can often accurately perceive others’ emotions in a purely interpersonal context. However, when people identify with an important ingroup, they experience distinctive patterns of emotion [Smith, E. R., Seger, C. R., & Mackie, D. M. (2007). Can emotions be truly group-level? Evidence regarding four conceptual criteria. Journal of Personality and Social Psychology, 93, 431-446]. Thus, in three studies using a variety of meaningful groups, we examine how a salient distinction between groups might influence people’s ability to estimate the emotions of outgroup members. Participants demonstrated substantial though imperfect accuracy in estimating the emotions reported by outgroups. Specific biases affected their estimates, especially the overlap of perceived emotions of the outgroup with the ingroup’s own emotions. Furthermore, there was a general overprediction of outgroups’ negative emotions and underprediction of their positive emotions. Because of the importance of an outgroup’s emotions as potential causes of their behavior, accuracy and biases in group emotion estimation may be consequential for intergroup relations.     

Perceiving sex directly and indirectly: meaning in motion and morphology

We employed a novel technique to explore how the body's motion and morphology affect judgments of sex and gender. Stimuli depicted animated human walkers that varied in motion (gait patterns varying shoulder swagger and hip sway) and in morphology (waist-to-hip ratio). The potency of morphology in categorical sex judgments was confirmed. Visual scanning of the walkers was concentrated in the waist and hip region of the body (Study 1a). This targeted scanning was attenuated, however, when the sex of the target had been prespecified (Study 1b). Body motion permitted categorical judgments of sex, but these judgments were mediated by perceived gender (Study 2). These studies provide converging evidence for the primacy of the body's shape in categorical judgments of sex.     

Analyzing anger: how to make people mad

Does simple displeasure cause anger without appraisals or agency attributions? The authors offer 8 observations: (a) Appraisal theory also predicts that displeasure promotes anger, (b) An emotion of frustration can be usefully distinguished from anger, (c) Aggressive reactions to norm violations among animals suggest that they too distinguish bad behavior from bad outcomes, (d) Attributions to agency are perceptual and automatic in social situations, (e) It is tenuous to argue that agency attributions are enacted in angry aggression, but absent in anger elicitation. (f) The contextualized meanings of expressive movements, rather than movements themselves, elicit emotion, (g) Expressions may be better seen as constituents than as causes of emotions, (h) Cognitive components of emotion generally come before, not after, eliciting events.     

Perceiving self-motion in depth: The role of stereoscopic motion and changing-size cues

During self-motions, different patterns of optic flow are presented to the left and right eyes. Previous research has, however, focused mainly on the self-motion information contained in a single pattern of optic flow. The present experiments investigated the role that binocular disparity plays in the visual perception of self-motion, showing that the addition of stereoscopic cues to optic flow significantly improves forward linear vection in central vision. Improvements were also achieved by adding changingsize cues to sparse (but not dense) flow patterns. These findings showed that assumptions in the heading literature that stereoscopic cues facilitate self-motion only when the optic flow has ambiguous depth ordering do not apply to vection. Rather, it was concluded that both stereoscopic and changingsize cues provide additional motion-in-depth information that is used in perceiving self-motion.     

Relative contributions of face and body configurations: Perceiving emotional state and motion intention

This study addressed the relative reliance on face and body configurations for different types of emotion-related judgements: emotional state and motion intention. Participants viewed images of people with either emotionally congruent (both angry or fearful) or incongruent (angry/fearful; fearful/angry) faces and bodies. Congruent conditions provided baseline responses. Incongruent conditions revealed relative reliance on face and body information for different judgements. Body configurations influenced motion-intention judgements more than facial configurations: incongruent pairs with angry bodies were more frequently perceived as moving forward than those with fearful bodies; pairs with fearful bodies were more frequently perceived as moving away. In contrast, faces influenced emotional-state judgements more, but bodies moderated ratings of face emotion. Thus, both face and body configurations influence emotion perception, but the type of evaluation required influences their relative contributions. These findings highlight the importance of considering both the face and body as important sources of emotion information.     

Seeing while moving: measuring the online influence of action on perception

The online influence of movement production on motion perception was investigated. Participants were asked to move one of their hands in a certain direction while monitoring an independent stimulus motion. The stimulus motion unpredictably deviated in a direction that was either compatible or incompatible with the concurrent movement. Participants' task was to make a speeded response as soon as they detected the deviation. A reversed compatibility effect was obtained: Reaction times were slower under compatible conditions—that is, when motion deviations and movements went in the same direction. This reversal of a commonly observed facilitatory effect can be attributed to the concurrent nature of the perception-action task and to the fact that what was produced was functionally unrelated to what was perceived. Moreover, by employing an online measure, it was possible to minimize the contribution of short-term memory processes, which has potentially confounded the interpretation of related effects.     

Seeing while moving: Measuring the online influence of action on perception

The online influence of movement production on motion perception was investigated. Participants were asked to move one of their hands in a certain direction while monitoring an independent stimulus motion. The stimulus motion unpredictably deviated in a direction that was either compatible or incompatible with the concurrent movement. Participants' task was to make a speeded response as soon as they detected the deviation. A reversed compatibility effect was obtained: Reaction times were slower under compatible conditions—that is, when motion deviations and movements went in the same direction. This reversal of a commonly observed facilitatory effect can be attributed to the concurrent nature of the perception–action task and to the fact that what was produced was functionally unrelated to what was perceived. Moreover, by employing an online measure, it was possible to minimize the contribution of short-term memory processes, which has potentially confounded the interpretation of related effects.     

Role of optical flow field asymmetry in the perception of heading during linear motion

During linear translation through a stationary environment, the pattern of optical flow generated on each retina is symmetrical when the head is aligned with the heading, but during lateral gaze the optical flow is asymmetric. We assessed whether human subjects could use the magnitude of this asymmetry to determine the direction of heading during passive translation through a 3-D environment. When allowed to move their heads in order to look in the direction of self-motion, subjects indicated their heading precisely and accurately. When the head was locked in alignment with the misaligned body, and gaze adjustments were not allowed, responses were quite precise, but showed a large bias which increased with increasing heading angle.     

Seeing while acting: hand movements can modulate attentional capture by motion onset

The onset of new motion has been shown to be a very robust cause of attentional capture, generating a processing advantage for the location of motion onset regardless of the observer's concurrent goal. The present study, motivated by the common-coding account of action and perception, examined whether the effect of motion onset on visual attention can be modulated by the observer's mode of action. Specifically, the common-coding account predicts that preparing an action can render the features that are used in the action plan less available for visual processes. Consistent with this hypothesis, in Experiment 1 the magnitude of attentional capture caused by a single motion onset was reduced when this motion was similar to the observer's response (i.e., along the same axis). Similarly, in Experiment 2 the onset of a response-different motion gained a processing advantage over the response-similar motion onset when the two were presented simultaneously. Since both types of motion were present in every trial, the results of Experiment 2 suggest that response similarity affected visual-attentional processes rather than motor processes. Together, these results suggest that the processes of attentional prioritization caused by motion onset can be modulated by the observer's concurrent action.     

Visuospatial perspective taking in a dynamic environment: Perceiving moving objects from a first-person-perspective induces a disposition to act

Spatial perspective taking is an everyday cognitive process that is involved in predicting the outcome of goal directed behavior. We used dynamic virtual stimuli and fMRI to investigate at the neural level whether motion perception interacts with spatial perspective taking in a life-like design. Subjects were asked to perform right-left-decisions about the position of either a motionless, hovering (STATic) or a flying ball (DYNamic), either from their own (1PP) or from the perspective of a virtual character (avatar, 3PP). Our results showed a significant interaction of STIMULUS TYPE and PERSPECTIVE with significantly increased activation in right posterior intraparietal sulcus (IPS) for 1PPDYN condition. As the IPS is critically involved in the computation of object-directed action preparation, we suppose that the simple perception of potentially action-relevant dynamic objects induces a ‘readiness for (re)action’, restricted to the 1PP. Results are discussed against the background of current theories on embodiment and enactive perception.     

Moving thoughts make for moving targets: Capturing time-sensitive effects in global/local processing

ABSTRACT

We examined the time-course of global/local processing with the goal of describing average change over time and individual differences in that change, namely, variability in level (intercept) and magnitude (slope) of change. To do so, we probed global/local processing across a broad time-course so that effects of time may be estimated from a randomly sampled set of time-points from the “true” population of time-points. Results showed that, on average, processing transitioned from global to local dominance; variation around this average, however, pointed to an ebb-and-flow in dominance rather than strict linear change.     

The fruits of irony: gaining insight into how we make meaning of the world

Many philosophers of education emphasise the impossibility to really ‘solve’ philosophical—and with that, educational—problems these days. Philosophers have been trying to give philosophy a new, constructive turn in the face of this insolvability. This paper focuses on irony-based approaches that try to exploit the very uncertainty of philosophical issues to further philosophical understanding. We will first briefly discuss a few highlights of historical uses of irony as a philosophical tool. Then we concentrate on two different interpretations of irony, formulated by Bransen and Rorty, that aim at gaining insight into how we make meaning of the world, while at the same time recognising that such an understanding would be impossible. After discussing some problematic aspects of these interpretations a third interpretation of irony is developed, based on a third view of the nature of meaning-making. Following these three interpretations, we will discuss their philosophical merits and the different kinds of insight they can produce for philosophy of education.     

Motion cues that make an impression: Predicting perceived personality by minimal motion information

The current study presents a methodology to analyze first impressions on the basis of minimal motion information. In order to test the applicability of the approach brief silent video clips of 40 speakers were presented to independent observers (i.e., did not know speakers) who rated them on measures of the Big Five personality traits. The body movements of the speakers were then captured by placing landmarks on the speakers' forehead, one shoulder and the hands. Analysis revealed that observers ascribe extraversion to variations in the speakers' overall activity, emotional stability to the movements' relative velocity, and variation in motion direction to openness. Although ratings of openness and conscientiousness were related to biographical data of the speakers (i.e., measures of career progress), measures of body motion failed to provide similar results. In conclusion, analysis of motion behavior might be done on the basis of a small set of landmarks that seem to capture important parts of relevant nonverbal information.     

Dynamic visual capture: apparent auditory motion induced by a moving visual target

Apparent motion of a sound source can be induced by a moving visual target. The direction of the perceived motion of the sound source is the same as that of the visual target, but the subjective velocity of the sound source is 25-50% of that of the visual target measured under the same conditions. Eye tracking of the light target tends to enhance the apparent motion of the sound, but is not a prerequisite for its occurrence. The findings are discussed in connection with the 'visual capture' or 'ventriloquism' effect.