Kinematic cues for person identification from biological motion

We examined the role of kinematic information for person identification. Observers learned to name seven walkers shown as point-light displays that were normalized by their size, shape, and gait frequency under a frontal, half-profile, or profile view. In two experiments, we analyzed the impact of individual harmonics as created by a Fourier analysis of a walking pattern, as well as the relative importance of the amplitude and the phase spectra in walkers shown from different viewpoints. The first harmonic contained most of the individual information, but performance was also above chance level when only the second harmonic was available. Normalization of the amplitude of a walking pattern resulted in a severe deterioration of performance, whereas the relative phase of the point lights was only used from a frontal viewpoint. No overall advantage for a single learning viewpoint was found, and there is considerable generalization to novel testing viewpoints.     

Implicit and explicit false belief development in preschool children

The ability to represent the mental states of other agents is referred to as Theory of Mind (ToM). A developmental breakthrough in ToM consists of understanding that others can have false beliefs about the world. Recently, infants younger than 2 years of age have been shown to pass novel implicit false belief tasks. However, the processes underlying these tasks and their relation to later‐developing explicit false belief understanding, as well as to other cognitive abilities, are not yet understood. Here, we study a battery of implicit and explicit false belief tasks in 3‐ and 4‐year‐old children, relating their performance to linguistic abilities and executive functions. The present data show a significant developmental change from failing explicit false belief tasks at 3 years of age to passing them at the age of 4, while both age groups pass implicit false belief tasks. This differential developmental trajectory is reflected by the finding that explicit and implicit false belief tasks do not correlate. Further, we demonstrate that explicit false belief tasks correlate with syntactic and executive functions, whereas implicit false belief tasks do not. The study thus indicates that the processes underlying implicit false belief tasks are different from later‐developing explicit false belief understanding. Moreover, our results speak for a critical role of syntactic and executive functions for passing standard explicit false belief tasks in contrast to implicit tasks.     

Self recognition versus recognition of others by biological motion: viewpoint-dependent effects

We investigated the influence of viewing angle on performance in recognising the identity of one's own person and familiar individuals such as friends or colleagues from walking patterns. Viewpoint-dependent recognition performance was tested in two groups of twelve persons who knew each other very well. Participants' motion data were acquired by recording their walking patterns in three-dimensional space with the use of a motion capture system. Size-normalised point-light displays of biological motion of these walking patterns, including one's own, were presented to the same group members on a computer screen in frontal view, half-profile view, and profile view. Observers were requested to assign the person's name to the individual gait pattern. No feedback was given. Whereas recognition performance of one's own walking patterns was viewpoint independent, recognition rate for other familiar individuals was better for frontal and half-profile view than for profile view. These findings are discussed in the context of the theory of common coding of motor and visual body representations.     

Taxing behavioral control diminishes sharing and costly punishment in childhood

Instances of altruism in children are well documented. However, the underlying mechanisms of such altruistic behavior are still under considerable debate. While some claim that altruistic acts occur automatically and spontaneously, others argue that they require behavioral control. This study focuses on the mechanisms that give rise to prosocial decisions such as sharing and costly punishment. In two studies it is shown in 124 children aged 6–9 years that behavioral control plays a critical role for both prosocial decisions and costly punishment. Specifically, the studies assess the influence of taxing aspects of self‐regulation, such as behavioral control (Study 1) and emotion regulation (Study 2) on subsequent decisions in a Dictator and an Ultimatum Game. Further, children's perception of fairness norms and emotional experience were measured. Taxing children's behavioral control prior to making their decisions reduced sharing and costly punishment of unfair offers, without changing perception of fairness norms or the emotional experience. Conversely, taxing children's emotion regulation prior to making their decisions only led to increased experience of anger at seeing unfair offers, but left sharing, costly punishment and the perception of fairness norms unchanged. These findings stress the critical role of behavioral control in prosocial giving and costly punishment in childhood.