Integration of disparity and velocity information for haptic and perceptual judgments of object depth

Do reach-to-grasp (prehension) movements require a metric representation of three-dimensional (3D) layouts and objects? We propose a model relying only on direct sensory information to account for the planning and execution of prehension movements in the absence of haptic feedback and when the hand is not visible. In the present investigation, we isolate relative motion and binocular disparity information from other depth cues and we study their efficacy for reach-to-grasp movements and visual judgments. We show that (i) the amplitude of the grasp increases when relative motion is added to binocular disparity information, even if depth from disparity information is already veridical, and (ii) similar distortions of derived depth are found for haptic tasks and perceptual judgments. With a quantitative test, we demonstrate that our results are consistent with the Intrinsic Constraint model and do not require 3D metric inferences (Domini, Caudek, & Tassinari, 2006). By contrast, the linear cue integration model (Landy, Maloney, Johnston, & Young, 1995) cannot explain the present results, even if the flatness cues are taken into account.     

Matching perceived depth from disparity and from velocity: Modeling and psychophysics

We asked observers to match in depth a disparity-only stimulus with a velocity-only stimulus. The observers’ responses revealed systematic biases: the two stimuli appeared to be matched in depth when they were produced by the projection of different distal depth extents. We discuss two alternative models of depth recovery that could account for these results. (1) Depth matches could be obtained by scaling the image signals by constants not specified by optical information, and (2) depth matches could be obtained by equating the stimuli in terms of their signal-to-noise ratios (see Domini & Caudek, 2009). We show that the systematic failures of shape constancy revealed by observers’ judgments are well accounted for by the hypothesis that the apparent depth of a stimulus is determined by the magnitude of the retinal signals relative to the uncertainty (i.e., internal noise) arising from the measurement of those signals.     

Are irrational reactions to unfairness truly emotionally-driven? Dissociated behavioural and emotional responses in the Ultimatum Game task

The “irrational” rejections of unfair offers by people playing the Ultimatum Game (UG), a widely used laboratory model of economical decision-making, have traditionally been associated with negative emotions, such as frustration, elicited by unfairness (Sanfey et al., 2003, van’t Wout et al., 2006). We recorded skin conductance responses as a measure of emotional activation while participants performed a modified version of the UG, in which they were asked to play both for themselves and on behalf of a third-party. Our findings show that even unfair offers are rejected when participants’ payoff is not affected (third-party condition); however, they show an increase in the emotional activation specifically when they are rejecting offers directed towards themselves (myself condition). These results suggest that theories emphasizing negative emotions as the critical factor of “irrational” rejections (Pillutla & Murninghan, 1996) should be re-discussed. Psychological mechanisms other than emotions might be better candidates for explaining this behaviour.     

Criminal Quarantine and the Burden of Proof

In the recent literature a number of free will skeptics, skeptics who believe (as I do) that punishment is justified only if deserved, have argued for these two points: first, that the free will realist who would justify punishment has the burden of establishing to a high level of certainty - perhaps beyond a reasonable doubt, but certainly at least by clear and convincing evidence - that any person to be punished acted freely in breaking the law; and, second, that that level of evidence is simply not there. In this paper I make two parallel points against a quarantine theory of criminal justice. First, the free will skeptic who would justify universal criminal quarantine is also faced with a burden of proof, the burden to establish to a similarly high level that no human being ever acts freely. Second, there is not sufficient evidence for that conclusion either. I believe that the quandary that this creates for criminal justice can be resolved by distinguishing the methods associated with a particular approach from the approach itself: if our choice is between the methods of punishment and the methods of quarantine, the methods that constitute punishment are, I would argue, morally preferable to those that constitute quarantine.

     

Temporal integration in structure from motion

A temporal integration model is proposed that predicts the results reported in 4 psychophysical experiments. The main findings were (a) the initial part of a structure-from-motion (SFM) sequence influences the orientation evoked by the final part of that sequence (an effect lasting for more than 1 s), and (b) for oscillating SFM sequences, perceived slant is affected by the oscillation frequency and by the sign of the final gradient. For contracting optic flows (i.e., rotations away from the image plane), the sequence with the lowest oscillation frequency appeared more slanted; for expanding optic flows (i.e., rotations toward the image plane), the sequence with the highest oscillation frequency appeared more slanted.     

The validity of the Antisocial Process Screening Device as a self-report measure of psychopathy in adolescent offenders

There is a growing interest in the assessment of adolescent psychopathy to enable early treatment and intervention. Recently, a self-report measure has been developed to assess psychopathic traits in adolescents. The Antisocial Process Screening Device (APSD), a self-report measure of psychopathic traits, and the Psychopathy Checklist: Youth Version (PCL:YV), a clinical rating scale, were administered to a sample of 100 incarcerated male adolescent offenders to assess the concurrent validity of the APSD. Results indicated that the APSD had limited concurrent validity with respect to the PCL:YV and that there appears to be a method effect in the measurement of psychopathy. Thus, it appears the APSD did not assess psychopathy in a manner parallel to that of the PCL:YV.     

Emotions in action through the looking glass1

Abstract: The paper aims at highlighting how our primary understanding of others’ actions is rooted in the mirror mechanism. To this end, the anatomical architecture of the mirror neuron system for action will be outlined as well as its role in grasping goals and intentions in others’ motor behaviour. One further step through the looking glass of social cognition will be referring to the ubiquitous emotional colouring of actions and considering its links with the motor domain. This will allow a clearer perspective on the mechanism underlying our abilities for emotional understanding and on cases in which these abilities are amiss, as in autistic spectrum disorders.     

The Right to Belong: Individual Motives and Youth Gang Initiation Rites

The current study uses a mixed-methods approach to describe the nature and context of the initiations undergone by 54 participants among a sample of 73 incarcerated gang members. The study describes and compares types of initiation and how they vary based on individual characteristics of the individuals being initiated. Three general types of initiation are found: (1) the ego violent event, (2) the crime commission, and (3) the expressive violence toward others. An ego violent initiation was more frequent among younger prospective members and those who were coerced into joining. Individuals who were looking for respect were more likely to be required to perpetrate an act of violence toward someone in order to get in. No individual characteristics were associated with crime commission type. The policy implications of such findings are discussed in conclusion.