The Role of Action in Affordance Perception Using Virtual Reality

Space perception in virtual reality (VR) is distorted. Does action in conjunction with an avatar\u27s presence improve perception in VR? Participants judged whether a virtual ball was within reach. Condition 1 was perception-only, where the participant was not allowed to move nor could see their arms. Condition 2 was perception with nonvisible action, where the participant could move their real arm to reach but could not see an avatar representation of the arm. Condition 3 was perception with visible action, where the participant could move and see a virtual hand that corresponded to the actual arm movement. Participants overestimated their own reach by about 15% in the avatar condition and the proprioceptive condition. The perception-only condition was the most accurate (only 5% overestimation). Response times were comparable for distances within reach but got longer in Conditions 2 and 3 when the ball was out of reach. The affordance responses (‘yes’ or ‘no’) did not correlate with response time, postural instability, nor with the head leaning forward. Instead, affordance responses mapped onto the mean magnitude of head movements. Specifically, complexity measured by effort-to-compress (ETC), which was lowest at the action boundary in the avatar condition, may helped to differentiate between experimental conditions. Our results point to the lack of expected haptic feedback as a critical variable, and the utility of complex exploration that may have contributed to the difference between the avatar and the perception-only condition

Reality Hackers: The Next Wave of Media Revolutionaries

Just as the printing press gave rise to the nation-state, emerging technologies are reshaping collective identities and challenging our understanding of what it means to be human. Should citizens have the right to be truly anonymous on-line? Should we be concerned about the fact that so many people are choosing to migrate to virtual worlds? Are injectible microscopic radio-frequency ID chips a blessing or a curse? Is the use of cognitive enhancing nootropics a human right or an unforgivable transgression? Should genomic data about human beings be hidden away with commercial patents or open-sourced like software? Should hobbyists known as biohackers be allowed to experiment with genetic engineering in their home laboratories? The time-frame for acting on such questions is relatively short, and these decisions are too important to be left up to a small handful of scientists and policymakers. If democracy is to continue as a viable alternative to technocracy, the average citizen must become more involved in these debates. To borrow a line from the computer visionary Ted Nelson, all of us can -- and must -- understand technology now. Challenging the popular stereotype of hackers as ciminal sociopaths, reality hackers uphold the basic tenets of what Steven Levy (1984) terms the hacker ethic. These core principles include a commitment to: sharing, openness, decentralization, public access to information, and the use of new technologies to make the world a better place.https://digitalcommons.trinity.edu/mono/1000/thumbnail.jp

Correction: Molecular Subtypes in Head and Neck Cancer Exhibit Distinct Patterns of Chromosomal Gain and Loss of Canonical Cancer Genes

Head and neck squamous cell carcinoma (HNSCC) is a frequently fatal heterogeneous disease. Beyond the role of human papilloma virus (HPV), no validated molecular characterization of the disease has been established. Using an integrated genomic analysis and validation methodology we confirm four molecular classes of HNSCC (basal, mesenchymal, atypical, and classical) consistent with signatures established for squamous carcinoma of the lung, including deregulation of the KEAP1/NFE2L2 oxidative stress pathway, differential utilization of the lineage markers SOX2 and TP63, and preference for the oncogenes PIK3CA and EGFR. For potential clinical use the signatures are complimentary to classification by HPV infection status as well as the putative high risk marker CCND1 copy number gain. A molecular etiology for the subtypes is suggested by statistically significant chromosomal gains and losses and differential cell of origin expression patterns. Model systems representative of each of the four subtypes are also presented

Complex Postural Sway is Related to Perception of Stand-on-Ability

Body movements during perceptual tasks can be considered as exploratory activity that facilitate perception. In the present study we tested whether the complexity of postural sway is related to perception of affordances. Effort-to-compress (ETC), a novel measure of complexity, was shown to be related to perception as compared to gross measures of body sway (mean magnitude and variability). Specifically, complexity was related to perceptual responses in a behavioral task (judge standonableness of sloped terrain), but not when numerical angle judgments of slope were solicited. Furthermore, ETC was extreme at the action boundary of standonableness whereas magnitude and variability of body sway were not. This provides further evidence that the purpose of perception is to guide meaningful behavior (perceive affordances) via active exploration, and not to estimate abstract numerical quantities such as slope angles of ramps. We concluded that moving the body in ways that produces complex exploratory activity is necessary to perceive affordances. [ABSTRACT FROM AUTHOR

Complexity of Postural Sway Affects Affordance Perception of Reachability In Virtual Reality

Visual perception of whether an object is within reach while standing in different postures was investigated. Participants viewed a three-dimensional (3D) virtual reality (VR) environment with a stimulus object (red ball) placed at different egocentric distances. Participants reported whether the object was reachable while in a standard pose as well as in two separate active balance poses (yoga tree pose and toe-to-heel pose). Feedback on accuracy was not provided, and participants were not allowed to attempt to reach. Response time, affordance judgements (reachable and not reachable), and head movements were recorded on each trial. Consistent with recent research on perception of reaching ability, the perceived boundary occurred at approximately 120% of arm length, indicating overestimation of perceived reaching ability. Response times increased with distance, and were shortest for the most difficult pose—the yoga tree pose. Head movement amplitude increased with increases in balance demands. Unexpectedly, the coefficient of variation was comparable in the two active balance poses, and was more extreme in the standard control pose for the shortest and longest distances. More complex descriptors of postural sway (i.e., effort-to-compress) were predictive of perception while in the tree pose and the toe-to-heel pose, as compared with control stance. This demonstrates that standard measures of central tendency are not sufficient for describing multiscale interactions of postural dynamics in functional tasks

Molecular Subtypes in Head and Neck Cancer Exhibit Distinct Patterns of Chromosomal Gain and Loss of Canonical Cancer Genes

10.1371/journal.pone.0056823PLoS ONE82e5682