Perception最新文献

The ability to differentiate between self-motion and motion in the environment is important for maintaining upright balance control. Visual motion can elicit the sensation of a fall by cueing false position sense. This study explores the relationship between thresholds for visual motion detection (VMDTs) and visual sensitivity to balance disturbances while walking. Thirty young adults (18-35 years) and 30 older adults (55-79 years) participated in a counter-balanced study where they: (1) walked on a self-paced treadmill within a virtual environment that delivered frontal plane multi-sine visual disturbances at three amplitudes (6°, 10°, and 15°), and (2) performed 100 trials of a two-alternative forced choice (2AFC) task, discriminating between a counterclockwise ("left") and clockwise ("right") rotation of a visual scene under three conditions (standing, standing with optic flow, and walking). Visual sensitivity was measured using frequency response functions of the center of mass displacement relative to the screen tilt (cm/deg). VMDTs were measured by fitting a psychometric curve to the 2AFC task responses. Significant positive correlations between measures of visual sensitivity and VMDTs were found for seven of nine conditions in young adults, with nonsignificant positive correlations in older adults. VMDTs were higher in older adults, though not significantly in the standing condition, indicating more motion in the environment is required for older adults to consciously perceive it. The positive correlations suggest that individuals with lower motion detection thresholds more accurately differentiate between self-motion and motion in the environment, resulting in lower responses to visual disturbances.

Technologies aiming to imitate human faces are becoming increasingly realistic. This study investigates a facial imitation technology that is becoming widespread - digital characters of people for presentation in virtual reality. Avatar faces were created from high-resolution 3D scans of real people. Across a series of four experiments, the photo-realism of these avatar faces was compared with passport-style face photographs of the same persons. In Experiments 1 and 2, these stimuli could be distinguished with high accuracy when a direct comparison of avatars and photographs was possible. In contrast, discrimination accuracy decreased when avatars and photographs were encountered in isolation, while awareness that avatar faces had been encountered was also low. Experiments 3 and 4 showed that avatars and face photographs generate similar trait inferences of attractiveness, dominance and trustworthiness. In cases where differences between avatars and photographs emerge, analysis of viewing patterns indicates that these originate from the eye region of these stimuli, which receive more fixations in avatars than face photographs. These findings demonstrate that the visual realism of avatars can closely resemble that of face photographs, particularly in contexts in which realism is not explicitly evaluated. Differences between avatars and photographs become more apparent when participants are cognizant and able to make direct comparisons.

Sensory signals from multiple modalities presented close in time are often integrated, building a coherent and meaningful multisensory perceptual world. A better understanding of our perception requires characterization of how the nervous system detects and encodes unisensory cues in time. There are very few studies that have focused on the development and individual variabilities in temporal aspects of unisensory signal processing in neurotypical populations across modalities. Using a temporal order judgment (TOJ) task, this study explored individual differences in the temporal processing of unisensory (auditory, tactile, and visual) stimuli in neurotypical children and young adults. We examined whether the precision of unisensory temporal processing and perceptual synchrony for unisensory stimuli can be influenced by participants' age, cognition, and sensory responsiveness profiles. Performance in each of the unisensory TOJ tasks, measured in temporal order judgment threshold (JND) and reaction time (RT), showed significant improvement with age. On the other hand, perceptual synchrony, measured in Point of Subjective Simultaneity (PSS), remained stable with age across modalities. Although cognitive abilities and sensory responsiveness patterns could not predict the individual variability in unisensory temporal precision or perceptual synchrony for this group of subjects, results from this study show a developmental trajectory of unisensory temporal sensitivity from childhood to young adulthood.

Investigating sensory processes in active human observers is critical for a holistic understanding of perception. Recent research shows that locomotion can rhythmically alter visual detection performance, illustrating how natural behaviours influence sensory processing. Here, we tested whether the speed and phase of locomotion also modulate temporal perception, focusing on the perceived synchrony of supra-threshold audio-visual stimuli. Participants made synchrony judgements over a range of stimulus onset asynchronies (SOAs) while walking at either slow or natural walking speeds. Slow walking decreased temporal sensitivity and increased reaction times compared to when walking at a natural pace. Further analysis of the shortest SOAs revealed that perceived synchrony was also biased by the relative phase of the step-cycle: with an increased bias to perceive synchrony during the swing phase, and decreased bias at the start and end of each step. Together, these results extend recent evidence that walking dynamically modulates near-threshold visual detection to include the modulation of supra-threshold audio-visual timing judgements.

Understanding speech in noisy environments is challenging, even for normal-hearing individuals, due to the complex interactions between auditory sensory processing and cognitive functions. The auditory system transforms acoustic signals into perceptual representations that are actively maintained and manipulated by working memory (WM). WM enables the retention and integration of incoming auditory information, supporting speech perception. While age-related speech perception decline is well documented in older adults, early signs of cognitive decline remain less explored in younger adults. This may be explained by the fact that conventional assessments conducted in quiet settings may not be sufficiently sensitive to detect such early signs of decline. The current study aims to explore early changes in WM abilities among adults aged 20-40 years by introducing background noise in the assessment task. Eighty normal-hearing participants were divided into four age-based groups (5-year intervals) and tested using forward digit span, backward digit span, and operation span tasks. Additionally, SNR-50 (signal-to-noise ratio at which 50% of the stimuli are correctly identified) was measured to assess speech perception in noise. Results showed a gradual age-related decline in WM performance, with significant reductions in backward and operation span performance appearing in the 35-40 age group, especially under noisy conditions. Moreover, significant negative correlations were observed between SNR-50 and WM across both quiet and noisy conditions. The findings suggest that WM decline may begin earlier than traditionally assumed in challenging auditory environments. This highlights the importance of assessing auditory cognition under ecologically valid conditions and supports cognitive load theory by demonstrating how noise increases cognitive demand, impairing performance.

This study examines the perceptual expertise basis of the own-age bias (OAB)-better recognition of faces from one's own age group-in young (n = 64; 19-30 years) and older adults (n = 64; 69-80 years). Participants engaged in an old/new recognition task involving upright and inverted young and older faces. The results revealed a robust OAB in the younger group, characterized by a reduced face inversion effect ("FIE")-more accurate recognition for upright versus inverted faces-when processing older/other-age faces compared to the pronounced FIE for own/younger-age faces. This difference was primarily driven by disrupted performance for upright older faces vs. upright young faces. In contrast, no OAB was observed in the older group, which exhibited a strong FIE for both own/older- and other/younger-age faces, with upright older faces being recognized more accurately than in the younger group. These findings underscore the importance of perceptual expertise in explaining the OAB.