Previous studies have shown that the perceptual metric for walkable distances is bioenergetic. People perceive hills to be steeper and distances to be greater when encumbered or fatigued, and supplementation of bioenergetic resources causes the reverse: participants who complete a task to deplete blood glucose levels and then drink an artificially sweetened placebo beverage estimate hills to be steeper and distances to be greater than participants who instead drink a beverage containing glucose (glucose is the primary fuel for short-term physical activity). In exercise physiology, it is very well established that glucose supplementation enhances athletic performance. Interestingly, introducing carbohydrate solutions to the mouth but prohibiting any ingestion (i.e., rinsing and spitting) can also enhance performance. These findings suggest that the relationship between glucose levels and physical performance is not entirely reactionary with regards to momentary blood glucose levels. It seems that signals that would normally indicate an upcoming increase in blood glucose may trigger either physiological or cognitive processes (or both) that result in the same increase in performance as an actual glucose increase. Because a bioenergetic perceptual scale reflects the perceiver's ability to act, any factor that affects physical or athletic performance should also affect perception of spatial layout. To test whether oral exposure to glucose without ingestion would affect perception of walkable distances, the following experiments had participants chew and spit out gelatin sweetened either with artificial sweetener or glucose and then judge the slant of a hill (Experiment 1) or a series of distances to makers in a flat field (Experiment 2). In line with the effects of oral glucose exposure on physical performance, participants in the glucose conditions perceived hills to be shallower and distances to be shorter, respectively.

Given that observing one’s body is ubiquitous in experience, it is natural to assume that people accurately perceive the relative sizes of their body parts. This assumption is mistaken. In a series of studies, we show that there are dramatic systematic distortions in the perception of bodily proportions, as assessed by visual estimation tasks, where participants were asked to compare the lengths of two body parts. These distortions are not evident when participants estimate the extent of a body part relative to a noncorporeal object or when asked to estimate noncorporal objects that are the same length as their body parts. Our results reveal a radical asymmetry in the perception of corporeal and noncorporeal relative size estimates. Our findings also suggest that people visually perceive the relative size of their body parts as a function of each part’s relative tactile sensitivity and physical size.

We examined how observers use one aspect of their own morphology, height, when judging the physical characteristics of other people. To address this, participants judged the heights of people as they walked past. We tested the hypothesis that differences between participant and target height account for systematic patterns of variability and bias in height estimation. Height estimate error and error variability increased as the difference between participant height and target height increased, suggesting that estimates are scaled to observers’ heights. Furthermore, participants’ height estimates were biased toward two standards, demonstrating classic category effects. First, estimates were biased toward participants’ own heights. Second, participants biased height estimates toward the average height of the target distribution. These results support past research on using both the body and categorical information to estimate target properties but extend to real-world situations involving interactions with moving people, such as height judgments provided during eyewitness testimony.

A graphical user interface in which object thumbnails are rendered in a three-dimensional environment and which exploits spatial memory. The objects may be moved, continuously, with a two-dimensional input device. Pop-up title bars may be rendered over active objects. Intelligent help may be provided to the user, as visual indicators, based on proximity clustering or based on matching algorithms. The simulated location of the object thumbnails in a direction orthogonal to the surface is based on function, such as a linear, polynomial, or exponential function for example, of one or more object properties, such as number of mouse clicks since selected, age, size, etc.

Our conscious visual experience of the environment is derived from optical information consisting of an ever-changing distribution of light specified in angular units. To transform these units into linear spatial units appropriate for the specification of spatial extents, the visual system needs geometry and a ruler to scale the information. We review the evidence that perceptual rulers derive from the body’s phenotype, which is comprised of our morphology, physiology, and behavioral repertoire. We then propose that perception is also scaled relative to the socio-ecological environment. In this account, social resources affect perception by extending or contracting the relevant physiological ruler. Additionally, we suggest the human ecology functions to select the relevant perceptual ruler. Finally, we highlight research on individual differences as a useful method to further investigate these issues. In moving forward, a complete account of visual perception must necessarily include the socio-ecological environment.

The hand is a reliable and ecologically useful perceptual ruler that can be used to scale the sizes of close, manipulatable objects in the world in a manner similar to the way in which eye height is used to scale the heights of objects on the ground plane. Certain objects are perceived proportionally to the size of the hand, and as a result, changes in the relationship between the sizes of objects in the world and the size of the hand are attributed to changes in object size rather than hand size. To illustrate this notion, we provide evidence from several experiments showing that people perceive their dominant hand as less magnified than other body parts or objects when these items are subjected to the same degree of magnification. These findings suggest that the hand is perceived as having a more constant size and, consequently, can serve as a reliable metric with which to measure objects of commensurate size.

The current study shows that people's ability to inhibit implicit associations that run counter to their explicit views varies in a circadian pattern. The presence of this rhythmic variation suggests the involvement of a biological process in regulating automatic associations—specifically, with the current data, associations that form undesirable social biases. In 1998, Greenwald, McGhee, and Schwartz introduced the Implicit Association Test as a means of measuring individual differences in implicit cognition. The IAT is a powerful tool that has become widely used. Perhaps most visibly, studies employing the IAT demonstrate that people generally hold implicit biases against social groups, which often conflict with their explicitly held views. The IAT engages inhibitory processes similar to those inherent in self-control tasks. Because the latter processes are known to be resource-limited, we considered whether IAT scores might likewise be resource dependent. Analyzing IAT performance from over a million participants across all times of day, we found a clear circadian pattern in scores. This finding suggests that the IAT measures not only the strength of implicit associations, but also the effect of variations in the physiological resources available to inhibit their undesirable influences on explicit behavior.

In action teaching, assignments are created that simultaneously benefit students and society by directly connecting classroom material to a community intervention. We designed an entire course rooted in the principles of action teaching in which students facilitated the positive effects of art, nature, and music on the well-being of individuals diagnosed with dementia. Groups of three students worked with a local elderly couple, one member of whom had dementia, to create multimedia digital projects (e.g., online scrapbooks, interactive DVDs) involving experiences with art or nature tailored to the needs of their specific community partners. Students met weekly with their assigned couple to discuss their families’ interests, goals for the project, and to obtain feedback on the impact of their project on their families’ well-being. Through these weekly meetings, students took an iterative approach to designing and improving their final projects, applying material learned through classroom lectures to their projects. In this field experience, students went beyond traditional lecture learning by developing a customized project that promoted the well-being of someone experiencing dementia. This course fostered values of citizenship, developed students’ research skills, and highlighted the reciprocal nature between knowledge learned in the classroom and knowledge acquired through real-world experiences.

This chapter describes empirical evidence for an approach aimed at examining visual perception. It proposes that visual perception is comprehended by the perceiver’s physical and biological characteristics in an effort to promote appropriate actions in the environment. Investigations also reveal that visual experience associates the visually perceived environment with continually changing purposes and the processes through which these purposes are achieved. The findings reveal that people adopt different skills and improve related expertise to perform specific tasks and achieve specific purposes. People also transform respective physical and biological characteristics to achieve certain objectives and associate perceptions with relevant physical and biological characteristics to perform specific actions.