Filip Germeys

Transsaccadic perception of saccade target and flanker objects.

To account for location-dependent and location-independent preview benefits in transsaccadic object perception, J. M. Henderson (1994) and J. M. Henderson and M. D. Anes (1994) proposed a dual-route model in which both episodic object representations and long-term memory representations store information across a saccade. Four experiments are reported in which the dual-route model was assessed. Preview benefits for saccade target objects were found to be location independent, whereas preview benefits for flanker objects were location dependent. These results support a single-route, 2-stage model of transsaccadic object perception. First, preattentive object files are set up to parse a set of attentional and/or saccade targets from peripheral vision, causing location-dependent preview benefits. Second, 1 object is attentionally selected for further processing, activating long-term memory representations and resulting in location-independent preview benefits.

Holistic processing of human body postures: evidence from the composite effect.

The perception of socially relevant stimuli (e.g., faces and bodies) has received considerable attention in the vision science community. It is now widely accepted that human faces are processed holistically and not only analytically. One observation that has been taken as evidence for holistic face processing is the face composite effect: two identical top halves of a face tend to be perceived as being different when combined with different bottom halves. This supports the hypothesis that face processing proceeds holistically. Indeed, the interference effect disappears when the two face parts are misaligned (blocking holistic perception). In the present study, we investigated whether there is also a composite effect for the perception of body postures: are two identical body halves perceived as being in different poses when the irrelevant body halves differ from each other? Both a horizontal (i.e., top-bottom body halves; Experiment 1) and a vertical composite effect (i.e., left-right body halves; Experiment 2) were examined by means of a delayed matching-to-sample task. Results of both experiments indicate the existence of a body posture composite effect. This provides evidence for the hypothesis that body postures, as faces, are processed holistically.

The visual analog: Evidence for a preattentive representation across saccades

Earlier research supports the idea that transsaccadic memory involves a relatively sparse and abstract representation with little detail, much like visual short-term memory (VSTM) within a fixation. We examined whether transsaccadic memory is restricted to VSTM representations or whether it also includes a maskable, short-lived, and more detailed representation, referred to as the visual analog. First, a within-fixation change detection experiment is reported, aimed at clarifying the distinction between VSTM and the visual analog, and also the relationship between the two components. We then report 4 transsaccadic change detection experiments that make use of a modified version of the blanking paradigm originally introduced by H. Deubel, W. X. Schneider, and B. Bridgeman (1996). The results support the idea that transsaccadic memory includes a VSTM representation for attended objects (i.e., the saccade target) and a visual analog component for both attended and non-attended objects.

Transsaccadic integration of bystander locations

The present study investigated whether and how the location of bystander objects is encoded, maintained, and integrated across an eye movement. Bystander objects are objects that remain unfixated directly before and after the saccade for which transsaccadic integration is being examined. Three experiments are reported that examine location coding of bystander objects relative to the future saccade target object, relative to the saccade source object, and relative to other bystander objects. Participants were presented with a random‐dot pattern and made a saccade from a central source to a designated saccade target. During this saccade the position of a single bystander was changed on half of the trials and participants had to detect the displacement. Postsaccadically the presence of the target, source, and other bystanders was manipulated. Results indicated that the location of bystander objects could be integrated across a saccade, and that this relied on configurational coding. Furthermore the present data provide evidence for the view that transsaccadic perception of spatial layout is not inevitably tied to the saccade target or the saccade source, that it makes use of objects and object configurations in a flexible manner that is partly governed by the task relevance of the various display items, and that it exploits the incidental configurational structure in the displays layout in order to increase its capacity limits.

Endogenous cueing attenuates object substitution masking.

Object substitution masking (OSM) is a form of visual masking in which a briefly presented target surrounded by four small dots is masked by the continuing presence of the four dots after target offset. A major parameter in the prediction of OSM is the time required for attention to be directed to the target following its onset. Object substitution theory (Di Lollo et al. in J Exp Psychol Gen 129:481–507, 2000) predicts that the sooner attention can be focused at the target’s location, the less masking will ensue. However, recently Luiga and Bachmann (Psychol Res 71:634–640, 2007) presented evidence that precueing of attention to the target location prior to target-plus-mask onset by means of a central (endogenous) arrow cue does not reduce OSM. When attention was cued exogenously, OSM was attenuated. Based on these results, Luiga and Bachmann argued that object substitution theory should be adapted by differentiating the ways of directing attention to the target location. The goal of the present study was to further examine the dissociation between the effects of endogenous and exogenous precueing on OSM. Contrary to Luiga and Bachmann, our results show that prior shifts of attention to the target location initiated by both exogenous and endogenous cues reduce OSM as predicted by object substitution theory and its computational model CMOS.

Perceiving where another person is looking: The integration of head and body information in estimating another person’s gaze

The process through which an observer allocates his/her attention based on the attention of another person is known as joint attention. To be able to do this, the observer effectively has to compute where the other person is looking. It has been shown that observers integrate information from the head and the eyes to determine the gaze of another person. Most studies have documented that observers show a bias called the overshoot effect when eyes and head are misaligned. That is, when the head is not oriented straight to the observer, perceived gaze direction is sometimes shifted in the direction opposite to the head turn. The present study addresses whether body information is also used as a cue to compute perceived gaze direction. In Experiment 1, we observed a similar overshoot effect in both behavioral and saccadic responses when manipulating body orientation. In Experiment 2, we explored whether the overshoot effect was due to observers assuming that the eyes are oriented further than the head when head and body orientation are misaligned. We removed horizontal eye information by presenting the stimulus from a side view. Head orientation was now manipulated in a vertical direction and the overshoot effect was replicated. In summary, this study shows that body orientation is indeed used as a cue to determine where another person is looking.

Cognitive inhibitory control in children following early childhood music education

The relationship between music training and executive functions has remained inconsistent in previous studies, possibly due to methodological limitations. This study aims to investigate cognitive inhibitory control in children (9–12 years old) with and without musical training, while carefully considering confounding variables. To assess executive functions, the Simon task was used, measuring reaction times (RTs) and error rates on congruent and incongruent trials. Information on important variables such as bilingualism, socio-economic status (SES), music pedagogy and amount of musical training was collected through a parental questionnaire. Furthermore, verbal and non-verbal intelligence were assessed with validated tests to consider their effects as well. The results showed that the samples did not significantly differ in background variables. The analysis of the RT data on the Simon task revealed a significant group × congruency interaction, such that musically trained children showed a reduced magnitude of the congruency effect (RTs on incongruent trials – RTs on congruent trials) compared to non-musicians. To conclude, music training seems to be associated with enhanced cognitive inhibitory control in well-matched samples.

The Effect of Head Orientation on Perceived Gaze Direction: Revisiting Gibson and Pick (1963) and Cline (1967).

Two biases in perceived gaze direction have been observed when eye and head orientation are not aligned. An overshoot effect indicates that perceived gaze direction is shifted away from head orientation (i.e., a repulsive effect), whereas a towing effect indicates that perceived gaze direction falls in between head and eye orientation (i.e., an attraction effect). In the 60s, three influential papers have been published with respect to the effect of head orientation on perceived gaze direction (Gibson and Pick, 1963; Cline, 1967; Anstis et al., 1969). Throughout the years, the results of two of these (Gibson and Pick, 1963; Cline, 1967) have been interpreted differently by a number of authors. In this paper, we critically discuss potential sources of confusion that have led to differential interpretations of both studies. At first sight, the results of Cline (1967), despite having been a major topic of discussion, unambiguously seem to indicate a towing effect whereas Gibson and Pick’s (1963) results seem to be the most ambiguous, although they have never been questioned in the literature. To shed further light on this apparent inconsistency, we repeated the critical experiments reported in both studies. Our results indicate an overshoot effect in both studies.

Revisiting scene primes for object locations

Sanocki and Epstein (1997) provided evidence that an immediate prior experience of a scene, as a prime, can induce representations of its spatial layout, facilitating the subsequent spatial processing of objects in the target scene. In their experiments, observers responded to target scenes by indicating which of two critical objects was closer in the pictorial space. Reaction times to target scenes that were preceded by same-scene primes without the critical objects were faster than reaction times to target scenes that were preceded by different scene or control primes (geometrical figures). By manipulating the nature of the prime and the interval between prime and target, and by cueing the position of the critical objects, we obtain evidence that the facilitating effect of the same-scene primes can also be explained by the sudden appearance of the critical objects in the target scene. In same-scene conditions, the critical objects cause a local onset, whereas in different-scene and control conditions the entire target scene causes a global onset. As a result, the local onset in the same-scene condition produces a shift of attention towards the critical objects, resulting in faster processing of the critical objects.

Hemispheric Lateralization Moderates the Life Events–Distress Relationship

Past studies show that life events (LE) predict mental distress. This research tested whether hemispheric lateralization (HL) moderated the relationship between LE and mental distress. In studies 1 and 2, different instruments for assessing HL were used (questionnaire and neuropsychological test). In both studies, LE or daily hassles were positively correlated with distress (study 1) and with anxiety and depression (study 2), only in people with right but not left HL, controlling for effects of gender. In study 3, experimentally induced stress led to increased perceived stress, again only in participants with right but not left HL. These results show consistently that left HL may protect against adverse effects of LE, hassles or acute stress on well-being. We propose possible mechanisms and future research directions.