Homing tasks and distance matching tasks reveal different types of perceptual variables associated with perceiving self-motion during over-ground locomotion.

Self-motion perception refers to the ability to perceive how the body is moving through the environment. Perception of self-motion has been shown to depend upon the locomotor action patterns used to move the body through the environment. Two separate lines of enquiry have led to the establishment of two distinct theories regarding this effect. One theory has proposed that distances travelled during locomotion are perceived via higher order perceptual variables detected by the haptic perceptual system. This theory proposes that two higher order haptic perceptual variables exist, and that the implication of one of these variables depends upon the type of gait pattern that is used. A second theory proposes that self-motion is perceived via a higher order perceptual variable termed multimodally specified energy expenditure (MSEE). This theory proposes that the effect of locomotor actions patterns upon self-motion perception is related to changes in the metabolic cost of locomotion per unit of perceptually specified traversed distance. Here, we test the hypothesis that the development of these distinct theories is the result of different choices in methodology. The theory of gait type has been developed based largely on the results of homing tasks, whereas the effect of MSEE has been developed based on the results of distance matching tasks. Here we test the hypothesis that the seemly innocuous change in experimental design from using a homing task to using a distance matching task changes the type of perceptual variables implicated in self-motion perception. To test this hypothesis, we closely replicated a recent study of the effect of gait type in all details bar one-we investigated a distance matching task rather than a homing task. As hypothesized, this change yielded results consistent with the predictions of MSEE, and distinct from gait type. We further show that, unlike the effect of gait type, the effect of MSEE is unaffected by the availability of vision. In sum, our findings support the existence of two distinct types of higher order perceptual variables in self-motion perception. We discuss the roles of these two types of perceptual variables in supporting effective human wayfinding.

The problem of obesity and dietary nudges.

From a psychological perspective, Cass R. Sunstein's 2016 book The Ethics of Influence is an insightful examination of the ethics of using social and cognitive psychological principles to influence behavior and decision-making. The United States has been experiencing what can only be described as an obesity epidemic. Scientists know that this epidemic has been brought about in part by the prevailing choice architecture, which influences what we eat, how much we eat, and how little we exercise. From a public health perspective, the policy issue centers on how a democracy can employ a combination of bans, mandates, and nudges to reshape our dietary habits to combat obesity. In this article, I will address how policymakers must nudge and change the existing psychological and physical choice architecture to combat obesity. The obesity epidemic cannot be won solely by increasing taxes, mandates, and bans on certain food items as that infringes on the personal liberty, welfare, autonomy, and dignity of citizens.

Heavy objects and small children: Developmental data extend the passive frame theory.

Passive frame theory is compatible with modern complexity theory and the idea that conflict drives the emergence of a novel structural organization. After describing new developmental data, we suggest that this conflict needs to be expanded to include not only conflict between action options, but also between action and perception.

Multimodally specified energy expenditure and action-based distance judgments.

Previous research has demonstrated that perceived self-motion can be manipulated by the relation between optic flow rate and walking rate. Other studies have revealed that verbal reports of perceived distance are influenced by the energy that would be expended to traverse the distance in question. In an effort to integrate these findings, we investigated how action-based distance judgments are influenced by multimodally specified energy expenditure (MSEE)--the metabolic cost associated with traversing an optically specified distance--using a virtual-reality treadmill environment. The energy expenditure associated with walking, measured as the volume of oxygen consumed, was manipulated by changing treadmill speed or grade. Optically specified distance was manipulated by changing the virtual optic flow rate. All three manipulations of MSEE (walking rate, grade, and optic flow rate) influenced distance reports in the predicted directions and to equivalent degrees.