The Impact of Viewing Distance and Proprioceptive Manipulations on a Virtual Reality Based Balance Test.

Our ability to maintain our balance plays a pivotal role in day-to-day activities. This ability is believed to be the result of interactions between several sensory modalities including vision and proprioception. Past research has revealed that different aspects of vision including relative visual motion (i.

Stubby versus stabby: A preliminary analysis of canine microwear in primates: Implication for inferring ingestive behaviors.

Molar and incisor microwear reflect aspects of food choice and ingestive behaviors in living primates and have both been used to infer the same for fossil samples. Canine microwear, however, has received less attention, perhaps because of the prominent role canines play in social display and because they are used as weapons-while outside of a few specialized cases, their involvement in diet related behaviors has not been obvious. Here, we posit that microwear can also provide glimpses into canine tooth use in ingestion.

Joint Contributions of Auditory, Proprioceptive and Visual Cues on Human Balance.

One's ability to maintain their center of mass within their base of support (i.e., balance) is believed to be the result of multisensory integration.

Changing perspectives on early hominin diets.

It is axiomatic that knowledge of the diets of extinct hominin species is central to any understanding of their ecology and our evolution. The importance of diet in the paleontological realm has led to the employment of multiple approaches in its elucidation. Some of these have deep historical roots, while others are dependent upon more recent technical and methodological advances.

The contribution of interoceptive signals to spatial orientation: A mini-review.

Humans' sensory systems work synergistically to allow us to determine where our head and body are relative to the environment. To date, most research on this topic has focused on the visual and vestibular systems. There has been much less research on the contributions of interoceptive signals to spatial orientation, so the overall picture of how spatial orientation works is incomplete.

Comparing the impact of the method of adjustment and forced-choice methodologies on subjective visual vertical bias and variability.

Background: Previous research suggested that the method of adjustment and forced choice variants of the subjective visual vertical (SVV) produce comparable estimates of both bias and variability. However, variants of the SVV that utilize a method of adjustment procedure are known to be heavily influenced by task parameters, including the stimulus rotation speed, which was not accounted for in previous SVV research comparing the method of adjustment to forced-choice.

Objective: The aim of the present study was to determine if (1) the SVV with a forced-choice procedure produces both bias and variability estimates that are comparable to those obtained using a method of adjustment procedure, (2) to see if rotation speed impacts the comparability of estimates and (3) quantify correlations between the estimates produced by different procedures.

Muscle activity prior to experiencing the rubber hand illusion is associated with alterations in perceived hand location.

The rubber hand illusion (RHI) is a perceptual illusion in which one is made to feel that a hand-shaped object is part of their body. This illusion is believed to be the result of the integration of afferent information. However, there has been an increasing amount of evidence that suggests efferent information plays a role in this illusion as well.

Using Nonlinear Kinematic Parameters as a Means of Predicting Motion Sickness in Real-Time in Virtual Environments.

Objective: This article presents two studies (one simulation and one pilot) that assess a custom computer algorithm designed to predict motion sickness in real-time.

Background: Virtual reality has a wide range of applications; however, many users experience visually induced motion sickness. Previous research has demonstrated that changes in kinematic (behavioral) parameters are predictive of motion sickness.

Preliminary Evaluation of the Moving Rubber Foot Illusion in a Sample of Female University Students.

The Rubber Foot Illusion (RFI) is an illusion in which one is made to feel that a model foot is their own through synchronous visuo-tactile stimulation. Previous research suggests that the conditions the RFI can be elicited under are similar to those of the Rubber Hand Illusion (RHI). However, it was unknown if the RFI could be elicited by synchronous movement of a participant's foot and a model foot.

Grit your teeth and chew your food: Implications of food material properties and abrasives for rates of dental microwear formation in laboratory (Primates).

Dental microwear analysis has been employed in studies of a wide range of modern and fossil animals, yielding insights into the biology/ecology of those taxa. Some researchers have suggested that dental microwear patterns ultimately relate back to the material properties of the foods being consumed, whereas others have suggested that, because exogenous grit is harder than organic materials in food, grit should have an overwhelming impact on dental microwear patterns. To shed light on this issue, laboratory-based feeding experiments were conducted on tufted capuchin monkeys [] with dental impressions taken before and after consumption of different artificial foods.

The Impact of Experimentally Induced Limb Ischemia on the Rubber Hand Illusion.

The rubber hand illusion (RHI) is a perceptual illusion in which one experiences an object as part of their body when synchronous visuo-tactile stimulation is applied to one's hand and the object. There are a variety of factors that can impact the occurrence of the RHI. In the present study, we demonstrate that experimentally induced peripheral ischemia can impact the RHI, namely it can result in larger alterations to the perceived position of one's hand.

Perceptual Validation of Nonlinear Postural Predictors of Visually Induced Motion Sickness.

Virtual reality (VR) technology has become increasingly prevalent in our society and has been used for a myriad of applications ranging from psychotherapy to training members of the military. However, one issue that arises from the use of VR is motion sickness, thus making predictors and indicators of motion sickness desirable. To date, a number of indicators of motion sickness have been derived based on nonlinear characteristics of human motion recorded using motion capture systems.

Getting Humans Off Monkeys' Backs: Using Primate Acclimation as a Guide for Habitat Management Efforts.

Wild primates face grave conservation challenges, with habitat loss and climate change projected to cause mass extinctions in the coming decades. As large-bodied Neotropical primates, mantled howling monkeys (Alouatta palliata) are predicted to fare poorly under climate change, yet are also known for their resilience in a variety of environments, including highly disturbed habitats. We utilized ecophysiology research on this species to determine the morphological, physiological, and behavioral mechanisms howlers employ to overcome ecological challenges.

The dental microwear of hard-object feeding in laboratory Sapajus apella and its implications for dental microwear formation.

Objectives: This study seeks to determine if (a) consumption of hard food items or a mixture of food items leads to the formation of premolar or molar microwear in laboratory capuchin monkeys (Sapajus apella) in one feeding session and (b) rates of microwear formation are associated with the number of food items consumed.

Materials And Methods: Five adult male capuchins were used in two experiments, one where they were fed unshelled Brazil nuts, and the other where they were fed a mixture of food items. Dental impressions were taken before and after each feeding session.

The phylogenetic signal in tooth wear: What does it mean?

A new study by Fraser et al (2018) urges the use of phylogenetic comparative methods, whenever possible, in analyses of mammalian tooth wear. We are concerned about this for two reasons. First, this recommendation may mislead the research community into thinking that phylogenetic signal is an artifact of some sort rather than a fundamental outcome of the evolutionary process.

Geriatric Complex Figure Test: A test for the assessment of planning, visual spatial ability, and memory in older adults.

The present study describes the development of a simplified complex figure for older adults. This new figure is based on theoretical organizational strategy models developed for the Rey Complex Figure Test and combines several new technologies for the enhancement of the data capture. The study shows that the accuracy and memory scores for the new measure correlate significantly with Trail Making Test, Five Point Test, and RBANS Complex Figure scores.

Microwear textures of Australopithecus africanus and Paranthropus robustus molars in relation to paleoenvironment and diet.

The importance of diet in primate ecology has motivated the use of a variety of methods to reconstruct dietary habits of extinct hominin taxa. Dental microwear is one such approach that preserves evidence from consumed food items. This study is based on 44 specimens of Australopithecus africanus from Makapansgat and Sterkfontein, and 66 specimens of Paranthropus robustus from Swartkrans, Kromdraai and Drimolen.

A molar microwear texture analysis of pitheciid primates.

Dental microwear textures have been examined for a broad range of extant primates to assess their efficacy for reconstructing diets of fossil species. To date though, no dental microwear texture data have been published for pitheciid molars, despite reported variation in degree of sclerocarpy and, by extension, the fracture properties of foods these platyrrhines eat. While all pitheciids eat hard or tough seeds, Chiropotes and Pithecia have been documented to consume more than Callicebus.

Base-rate data and norms for the Rey Auditory Verbal Learning Embedded Performance Validity Indicator.

The present study examines the Rey Auditory Verbal Learning Test (RAVLT) Embedded Performance Validity Indicator (EPVI) for detecting performance validity. This retrospective study analyzes the performance of four groups of 879 participants comprised of 464 clinically referred patients with suspected dementia, 91 forensic patients identified as not exhibiting adequate effort on other measures of response bias, 25 patients with well documented TBI, and a random sample of 198 adults collected in the Gulf State of Oman. The EPVI was also put to the test using normative data collected from the literature.

Canine and incisor microwear in pitheciids and Ateles reflects documented patterns of tooth use.

Objectives: Platyrrhine species differ in the extent to and the manner in which they use their incisors and canines during food ingestion. For example, Ateles uses its anterior teeth to process mechanically nondemanding soft fruits, while the sclerocarp-harvesting pitheciids rely extensively on these teeth to acquire and process more demanding foods. Pitheciids themselves vary in anterior tooth use, with the pitheciines (Cacajao, Chiropotes, and Pithecia) noted to use their robust canines in a variety of ways to predate seeds, while Callicebus, which rarely predates seeds, uses its incisors and exceptionally short canines to scrape tough mesocarp from fruits.

Environmental perturbations can be detected through microwear texture analysis in two platyrrhine species from Brazilian Amazonia.

Recent dental microwear studies have shown that fossil species differ from one another in texture attributes-both in terms of central tendency and dispersion. Most comparative studies used to interpret these results have relied on poorly provenienced museum samples that are not well-suited to consideration of within species variation in diet. Here we present a study of two species of platyrrhine monkeys, Alouatta belzebul (n = 60) and Sapajus apella (n = 28) from Pará State in the Brazilian Amazon in order to assess effects of habitat variation on microwear (each species was sampled from forests that differ in the degree of disturbance from highly disturbed to minimally disturbed).