Visual perception of force: comment on White (2012)

White (2012) proposed that kinematic features in a visual percept are matched to stored representations containing information regarding forces (based on prior haptic experience) and that information in the matched, stored representations regarding forces is then incorporated into visual perception. Although some elements of White's (2012) account appear consistent with previous findings and theories, other elements do not appear consistent with previous findings and theories or are in need of clarification. Some of the latter elements include the (a) differences between perception and impression (representation of force; relationship of force and resistance; role and necessity of stored representations and of concurrent simulation; roles of rules, cues, and heuristics), (b) characteristics of object motion and human movement (whether motion is internally generated or externally generated and whether motion is biological or nonbiological; generalization of human action and the extent to which perceived force depends upon similarity of object movement to human patterns of movement), (c) related perceptual and cognitive phenomena (representational momentum, imagery, psychophysics of force perception, perception of causality), and (d) scope and limitations of White's account (attributions of intentionality, falsifiability).     

Phenomenal Causality II: Integration and Implication

The empirical literature on phenomenal causality (the notion that causality can be perceived) is reviewed. Different potential types of phenomenal causality and variables that influence phenomenal causality were considered in Part I (Hubbard 2012b) of this two-part series. In Part II, broader questions regarding properties of phenomenal causality and connections of phenomenal causality to other perceptual or cognitive phenomena (different types of phenomenal causality, effects of spatial and temporal variance, phenomenal causality in infancy, effects of object properties, naïve physics, spatial localization, other illusions, amodal completion, Gestalt principles of perceptual grouping, effects of context, differences between physical and social causality, effects of learning and experience, individual differences, effects of predictability, asymmetry in phenomenal causality, differences between perceived causality and perceived force, phenomenal causality in nonhuman animals) are considered. Potential mechanisms of phenomenal causality (inference from contiguity, a priori understanding, ampliation, perceptual learning, stimulus activity, beliefs regarding kinematics, haptic experience, beliefs regarding impetus, postdiction, innateness, modularity, specific neural structures) are also considered.     

Phenomenal Causality I: Varieties and Variables

The empirical literature on phenomenal causality (i.e., the notion that causality can be perceived) is reviewed. In Part I of this two-part series, different potential types of phenomenal causality (launching, triggering, reaction, tool, entraining, traction, braking, enforced disintegration and bursting, coordinated movement, penetration, expulsion) are described. Stimulus variables (temporal gap, spatial gap, spatial overlap, direction, absolute velocity, velocity ratio, trajectory length, radius of action, size, motion type, modality, animacy) and observer variables (attention, eye movements and fixation, prior experience, intelligence, age, culture, psychopathology) that influence phenomenal causality are reviewed. This provides the necessary background for consideration in Part II (Hubbard, in press) of broader questions regarding properties of phenomenal causality, empirical and theoretical connections of phenomenal causality to other perceptual or cognitive phenomena or processes, and potential mechanisms and models of phenomenal causality.     

A possible role of naïve impetus in Michotte's "launching effect": Evidence from representational momentum

In Michotte's (1946/1963) launching effect paradigm, a moving launcher contacts a stationary target, and then the launcher becomes stationary and the target begins to move. In the experiments reported here, observers were presented with modifications of a launching effect display, and displacement in memory for targets was measured. Faster launcher velocities resulted in larger displacements for moving targets, and the effect of launcher velocity was larger with faster target velocities. Launcher velocity did not influence displacement of targets that remained stationary after contact. Increases in the distance travelled by moving targets after contact from the launcher resulted in smaller displacements. Displacement appeared to result from an expectation that impetus would be imparted from the launcher rather than from contact between the launcher and the target. Displacement patterns were consistent with naïve impetus theory and with the hypothesis that observers believed impetus from the launcher was imparted to the target and dissipated with subsequent target motion.     

Role of arms in somersaulting from compliant surfaces: a simulation study of springboard standing dives

The role of arms in compliant-surface jumping for maximizing backward somersault rotations is studied using multi-segment models and is applied to springboard diving. The surface (springboard) is modeled by a rigid bar with a rotational spring with a hinged end and point mass at the tip. Planar four- and five-segment human models are used (with the fifth segment representing the arms) and are driven by torque actuators at the ankle, knee, hip, and shoulder. Each joint torque is the product of maximum isometric torque and three variable functions depending on instantaneous joint angle, angular velocity, and activation level, respectively. Movement simulation starts from a balanced initial posture and ends at jump takeoff. The objective is to find joint torque activation patterns during board contact so that the number of backward rotations in flight is maximized. Kinematic differences in jumps with and without arms are mainly in smaller takeoff vertical velocity and more flexed knee and hip in the former. In both jumps, joint torque/activations are similar in their minor flexion-full extension patterns. Maximum hip torque is larger with arms but maximum knee torque is larger without arms. Except at the knee, more joint work can be done with arm swing. Total angular momentum is increased considerably by arm motion because of its remote contribution. Consequently segment remote contributions to total angular momentum are much larger in jumping with arms. Shoulder strength helps generate angular momentum only to a certain limit. If more work is used to generate horizontal velocity away from the board, the amount of total angular momentum is reduced.     

Memory psychophysics

Summary The relationship between perceptual and cognitive processes has been a topic of increasing interest. This review focuses on the use of techniques and theory drawn from classical psychophysics and applied to the study of mental representation. Several issues including examination of the functions that relate remembered and perceived magnitude to physical intensity, the relationship of memorial to perceptual functions, the effect of time on the memorial function, considerations in the methodology of memory psychophysics experiments, the level of functional equivalence between memorial and perceptual representation, and the use of psychophysical techniques and theory in the study of visual imagery are addressed. While the data suggest that the relationship between remembered magnitude and physical intensity and between perceived magnitude and physical intensity can be described by power functions, a model capable of accounting for the behavior of the memory magnitude for all stimulus dimensions and at all time intervals has not yet been found. Several unresolved issues and typical difficulties with research in memory psychophysics are also discussed.     

Perseverance in self-perception and social perception: biased attributional processes in the debriefing paradigm.

Two experiments demonstrated that self-perceptions and social perceptions may persevere after the initial basis for such perceptions has been completely discredited. In both studies subjects first received false feedback, indicating that they had either succeeded or failed on a novel discrimination task and then were thoroughly debriefed concerning the predetermined and random nature of this outcome manipulation. In experiment 2, both the initial outcome manipulation and subsequent debriefing were watched and overheard by observers. Both actors and observers showed substantial perseverance of initial impressions concerning the actors' performance and abilities following a standard "outcome" debriefing. "Process" debriefing, in which explicit discussion of the perseverance process was provided, generally proved sufficient to eliminate erroneous self-perceptions. Biased attribution processes that might underlie perserverance phenomena and the implications of the present data for the ethical conduct of deception research are discussed.