Con-fusing contours & pieces of glass

We present a new illusory display in which illusory contours are misaligned with physical contours. In these displays, illusory Kanizsa squares, induced by the so-called pacmen, are positioned on top of a background grid of bars. The misalignment of the illusory contours with respect to physical contours of the grid of bars induces an overall 'restless' appearance and evokes the impression that parts of the grid within the illusory square are shifted. To test this impression, we created stimuli in which illusory squares were superimposed on a grid at different positions, where the grid could consist of either straight bars or indented bars. After briefly flashing these stimuli, observers reported indentations of the background grid for those cases in which physical and illusory contours were misaligned. In a control condition, the pacmen were replaced by crosses (not inducing an illusory square) at the same positions; as expected much less illusory shifts were reported in this condition. In a second experiment, we further tested the direction of the perceived shifts, revealing similar trends as in the first experiment and a consistent result with respect to the reported direction of the shifts. We explore and discuss possible underlying mechanisms with regard to our illusory display.     

Introduction to Michotte's heritage in perception and cognition research

Several decades after Michotte's work was published, it continues to inspire current research in perception, cognition, and beyond. In this special issue we pay tribute to this heritage with a collection of empirical and theoretical papers on amodal completion and the perception of causality, two areas of research within which Michotte's work and ideas have had a lasting influence. As a background to better understand the remaining papers, we briefly sketch Michotte's life and work and the scope (in breadth and in depth) of his impact. We then review Michotte's seminal contributions to the areas covered in this special issue, some of the major research discoveries and themes in the intervening decades, and the major open questions and challenges we are still facing. We also include a sneak preview of the papers in this special issue, noting how they relate to Michotte's work and to each other. This review shows both how much influence Michotte has had on contemporary perception and cognition research, and how much important work remains to be done. We hope that the papers in this special issue will serve both to celebrate Michotte's heritage in this respect, and to inspire other investigators to continue the projects he began.     

Fear and pain: investigating the interaction between aversive states

Pain and fear often co-occur and appear to interact, although the nature and direction of their relation is not clearly delineated. The present study investigates how exposure to the experience of one of these states subsequently affects responding to the other. Pressure stimulation and carbon dioxide-enriched air (CO2) were used to induce pain and fear, respectively, in 48 healthy individuals. The order in which the stimuli were introduced was manipulated, as was the CO2 level. Measures of overt behavior, physiological responding, and self-report were obtained; analyses of stimuli effects generally supported their ability to produce pain or fear. Results indicate that the stimulus rated as the most aversive, the higher level of CO2, led to the highest levels of distressed responding across dependent measures. This pattern was replicated for the stimuli found to be less aversive (i.e., pressure stimulation and low-level CO2, respectively). The authors conclude that fear and pain, in and of themselves, do not dictate the nature of their interaction; the most important factor is how aversive they are perceived to be in relation to one another.     

Associations between the developmental trajectories of visual scanning and disengagement of attention in infants

The relation between the developmental trajectories of visual scanning and disengagement of attention and gaze were examined throughout early infancy. A sample of 10 infants carried out a scanning and a disengagement task with the same visual stimuli six times between 6 and 26 weeks of age. Frequency and latency measures were analyzed using multivariate multilevel models and Monte Carlo analyses. The results suggest that the ability to scan a face or an abstract stimulus evolves slightly earlier than the ability to shift gaze to a newly appeared target in the periphery. This is consistent with the account that the parvocellular stream becomes functional slightly before the magnocellular stream. The study revealed no indications of a positive association between the development of scanning and disengagement on the level of the individual infant. Scanning and disengagement change scores contrasted more with one another than could be expected on the basis of chance. This implies that the magnocellular and the parvocellular stream develop rather independently up to the age of 26 weeks.     

Is belief reasoning automatic?

Understanding the operating characteristics of theory of mind is essential for understanding how beliefs, desires, and other mental states are inferred, and for understanding the role such inferences could play in other cognitive processes. We present the first investigation of the automaticity of belief reasoning. In an incidental false-belief task, adult subjects responded more slowly to unexpected questions concerning another person's belief about an object's location than to questions concerning the object's real location. Results in other conditions showed that responses to belief questions were not necessarily slower than responses to reality questions, as subjects showed no difference in response times to belief and reality questions when they were instructed to track the person's beliefs about the object's location. The results suggest that adults do not ascribe beliefs to agents automatically.     

New reflections on visual search: Interitem symmetry matters!

A 90 degrees rotation of a display can turn a relatively easy visual search into a more difficult one. A series of experiments examined the possible causes of this effect, including differences in overall item shape and response mapping (Experiment 1), the interpretation of scene lighting (Experiment 2), the axis of internal symmetry of the search items (Experiment 3), and the axes of interitem symmetry between target and distractor items (Experiment 4). Only the elimination of differences in interitem mirror symmetry resulted in equal search efficiency in the upright and rotated displays. This finding is strong support for the view that visual search is guided by an analysis that considers interitem relations.     

Does group efficacy increase group identification? Resolving their paradoxical relationship

Although group identification and group efficacy are both important predictors of collective action against collective disadvantage, there is mixed evidence for their (causal) relationship. Meta-analytic and correlational evidence suggests an overall positive relationship that has been interpreted as consistent with the idea that group identification leads to group efficacy. However, experimental evidence has not supported this causal relationship. To resolve this paradox, we show in an experiment that it is group efficacy that leads to increased group identification because group efficacy puts individuals' identity into action. We discuss the theoretical and practical implications of these findings.     

Social status as a cue for tacit coordination

The present paper investigates how and when social status may serve as a cue for tacit coordination. In three experimental studies, we demonstrate that low status individuals are inclined to defer to the preferences of high status individuals, thereby facilitating coordination success. Furthermore, we investigate the boundary conditions of this effect. More specifically, we show that social status only facilitates coordination success when the people involved have asymmetric (or conflicting) preferences (Study 2), and when there is a clear social hierarchy (Study 3). In the general discussion, we relate these findings to earlier research on dominance hierarchies, social power, deference and perspective-taking and we provide suggestions for future research.