Perceptual Estimates Research Articles

Developmental trends in susceptibility to perceptual illusions: Not all illusions are created equal.

This study examined the development of the utilization of contextual information in visuospatial integration during childhood. We examined four contextual size illusions in children and adults asking whether young children's sensitivity to context is reduced or varies with the perceptual mechanisms or the levels of integration involved. We tested susceptibility to contextual illusions in four-year-olds, seven-year-olds, and adults, employing two psychophysical paradigms, perceptual estimation and a 2AFC discrimination task. We tested susceptibility to Ebbinghaus and Ponzo illusions to estimate the effect of the interaction of object size with its contextual background on the rescaling of its perceived size; we also tested susceptibility to the rectangle and 3D-cube illusions to estimate the effect of the interaction of two dimensions of the target object on the rescaling of its perceived size. While four-year-olds were affected by the Ebbinghaus and Ponzo illusions, they showed no susceptibility to the rectangle or 3D-cube illusion. The results show that, overall, sensitivity to context is not reduced in early childhood; rather, it varies with the perceptual mechanisms or the levels of integration involved. In particular, development is protracted for size illusions in which contextual effects entail the extraction of the relations of dimensions within an object.

A Standard Methodology to Characterize the Intrinsic Material Properties of Compliant Test Stimuli.

Understanding how we perceive differences in material compliance, or 'softness,' is a central topic in the field of haptics. The intrinsic elasticity of an object is the primary factor thought to influence our perceptual estimates. Therefore, most studies test and report the elasticity of their stimuli, typically as stiffness or modulus. However, many reported estimates are of very high magnitude for silicone-elastomers, which may be due to artifacts in characterization technique. This makes it very difficult to compare the perceptual results between the studies. The work herein defines a standardized and easy-to-implement way to characterize test stimuli. The procedure involves the unconstrained, uniaxial compression of a plate into cylindrical substrates 10 mm tall by 10 mm diameter. The resultant force-displacement data are straightforwardly converted into stress-strain data, from which a modulus is readily derived. This procedure was used to re-characterize stimuli from prior studies. The revised results from the validated method herein are 200-1,100 percent lower than modulus values either reported and/or approximated from stiffness. This is practically significant when differences of 10-15 percent are perceptually discriminable. The re-characterized estimates are useful in comparing prior studies and designing new studies. Furthermore, this characterization methodology may help more readily bridge studies on perception with those designing technology.

Discrimination of spectral reflectance under environmental illumination

Color constancy is the ability to recover a stable perceptual estimate of surface reflectance, regardless of the lighting environment. However, we know little about how observers make judgments of the surface color of glossy objects, particularly in complex lighting environments that introduce complex spatial patterns of chromatic variation across an object’s surface. To address this question, we measured thresholds for reflectance discrimination using computer-rendered stimuli under environmental illumination. In Experiment 1, we found that glossiness and shape had small effects on discrimination thresholds. Importantly, discrimination ellipses extended along the direction in which the chromaticities in the environmental illumination spread. In Experiment 2, we also found that the observers’ abilities to judge surface colors were worse in lighting environments with an atypical chromatic distribution.

Motion and position shifts induced by the double-drift stimulus are unaffected by attentional load.

The double-drift stimulus produces a strong shift in apparent motion direction that generates large errors of perceived position. In this study, we tested the effect of attentional load on the perceptual estimates of motion direction and position for double-drift stimuli. In each trial, four objects appeared, one in each quadrant of a large screen, and they moved upward or downward on an angled trajectory. The target object whose direction or position was to be judged was either cued with a small arrow prior to object motion (low attentional load condition) or cued after the objects stopped moving and disappeared (high attentional load condition). In Experiment 1, these objects appeared 10° from the central fixation, and participants reported the perceived direction of the target's trajectory after the stimulus disappeared by adjusting the direction of an arrow at the center of the response screen. In Experiment 2, the four double-drift objects could appear between 6 ° and 14° from the central fixation, and participants reported the location of the target object after its disappearance by moving the position of a small circle on the response screen. The errors in direction and position judgments showed little effect of the attentional manipulation-similar errors were seen in both experiments whether or not the participant knew which double-drift object would be tested. This suggests that orienting endogenous attention (i.e., by only attending to one object in the precued trials) does not interact with the strength of the motion or position shifts for the double-drift stimulus.

Neural correlates of multisensory reliability and perceptual weights emerge at early latencies during audio-visual integration.

To make accurate perceptual estimates, observers must take the reliability of sensory information into account. Despite many behavioural studies showing that subjects weight individual sensory cues in proportion to their reliabilities, it is still unclear when during a trial neuronal responses are modulated by the reliability of sensory information or when they reflect the perceptual weights attributed to each sensory input. We investigated these questions using a combination of psychophysics, EEG‐based neuroimaging and single‐trial decoding. Our results show that the weighted integration of sensory information in the brain is a dynamic process; effects of sensory reliability on task‐relevant EEG components were evident 84 ms after stimulus onset, while neural correlates of perceptual weights emerged 120 ms after stimulus onset. These neural processes had different underlying sources, arising from sensory and parietal regions, respectively. Together these results reveal the temporal dynamics of perceptual and neural audio‐visual integration and support the notion of temporally early and functionally specific multisensory processes in the brain.

Acoustic simulation of cochlear implant hearing: Effect of manipulating various acoustic parameters on intelligibility of speech

Objective: Cochlear implants process the acoustic speech signal and convert it into electrical impulses. During this processing, many parameters contribute to speech perception. The available literature reviewed the effect of manipulating one or two such parameters on speech intelligibility, but multiple parameters are seldom manipulated.Method: Acoustic parameters, including pulse rate, number of channels, ‘n of m’, number of electrodes, and channel spacing, were manipulated in acoustic simulations of cochlear implant hearing and 90 different combinations were created. Speech intelligibility at sentence level was measured using subjective and objective tests.Results: Principal component analysis was employed to select only those components with maximum factor loading, thus reducing the number of components to a reasonable limit. Perceptual speech intelligibility was maximum for signal processing manipulation with respect to ‘n of m’ and rate of pulses/sec. Regression analysis revealed that lower rate (=500 pps/ch) and lesser stimulating electrodes per cycle (2–4) contributed maximally for speech intelligibility. Perceptual estimate of speech quality (PESQ) and composite measures of spectral weights and likelihood ratio correlated with subjective speech intelligibility scores.Discussion: The findings are consistent with the literature review, indicating that lesser stimulated channel per cycle reduces electrode interaction and hence improve spectral resolution of speech. Reduced rate of pulses/second enhances temporal resolution of speech. Thus, these two components contribute significantly to speech intelligibility.Conclusion: Pulse rate/channel and ‘n of m’ contribute maximally to speech intelligibility, at least in simulations of electric hearing.

What’s left of the mirror illusion when the mirror can no longer be seen? Bilateral integration of proprioceptive afferents!

Recent data suggest that manipulating the muscle afferents of one arm affects both ipsilateral and contralateral perceptual estimates. Here, we used the mirror paradigm to study the bimanual integration of kinesthetic muscle afferents. The reflection of a moving hand in a mirror positioned in the sagittal plane creates an illusion of symmetrical bimanual movement. Although vision clearly has a role in kinesthesia, its role in the mirror illusion might have been overestimated. Conversely, the role of bimanual integration of muscle afferents might have been underestimated. We hypothesized that muscle-proprioceptive afferents of the passively displaced arm (the image of which was reflected in the mirror) are involved in this illusion. We evoked in 19 healthy adult participants the mirror illusion by displacing passively their left arm, the image of which was reflected in the mirror. Once participants experienced the illusion that their hidden right arm was moving, we then either occluded their view of the mirror (using occlusive glasses) and/or prevent the passive left arm displacement. Participants’ illusion characteristics (duration and kinematic) under these conditions were compared with classical mirror illusion (without visual occlusion). We found that as long as the arm was still moving, the kinesthetic illusion decayed slowly after visual occlusion. These findings suggest that the mirror illusion results from the combination of visuo-proprioceptive signals from the two arms and is not purely visual in origin. Our findings also support the more general concept whereby proprioceptive afferents are integrated bilaterally for the purpose of kinesthesia during bimanual tasks.

Evidence of Energetic Optimization during Adaptation Differs for Metabolic, Mechanical, and Perceptual Estimates of Energetic Cost

The theory that the sensorimotor system minimizes energetic cost during locomotion has long been supported by both computational models and empirical studies. However, it has yet to be determined if the behavior to which people converge when exposed to a novel perturbation during locomotion is also energetically optimal. We address this issue in the context of adaptation to walking on a split-belt treadmill, which can impose a left-right asymmetry in step lengths. In response to this asymmetry, participants gradually adjust their foot placement to adopt steps of equal length. Here, we characterized metabolic, mechanical, and perceptual estimates of energetic cost associated with a range of asymmetries to determine whether symmetry is the energetically optimal strategy for walking on a split-belt treadmill. We found that taking steps of equal length did not minimize metabolic cost or mechanical cost. In addition, perceptual estimates of cost were not sensitive to changes in asymmetry. However, symmetry was identified as the optimal strategy when energetic cost was estimated from a composite metric that combined both metabolic and mechanical costs. These results suggest that adaptation may arise from optimization of a composite estimate of effort derived from feedback about the interaction between the body and environment.

A permutation algorithm based on dynamic time warping in speech frequency-domain blind source separation

Frequency-Domain Blind Source Separation (FD-BSS) is an efficient way to analyze convolutive mixed speech. To improve the quality of the separated speech, a permutation algorithm based on Dynamic Time Warping (DTW) is proposed in this paper. Because signals in adjacent frequency bins have high similarity, DTW technology is used to compare them and generate adjustment matrices to solve the permutation ambiguity. Our approach is evaluated through simulated and practical experiments. Using Signal to Distortion Ratio (SDR), Signal to Interference Ratio (SIR), Signal to Artifacts Ratio (SAR), and Perceptual Estimation of the Speech Quality (PESQ) for measurements. To examine the quality of the separated speech in a practical acoustic environment, we adopt the accuracy ratio of Automatic Speech Recognition (ASR). In the experiments, we compare our approach with other classical permutation criteria such as K-L divergence distance, envelope correlation and higher-order statistics. The experimental results show that the proposed algorithm performs permutation alignment more accurately and improves the acoustic quality of separation.

Correlates of Perceptual Orientation Biases in Human Primary Visual Cortex.

Vision can be considered as a process of probabilistic inference. In a Bayesian framework, perceptual estimates from sensory information are combined with prior knowledge, with a stronger influence of the prior when the sensory evidence is less certain. Here, we explored the behavioral and neural consequences of manipulating stimulus certainty in the context of orientation processing. First, we asked participants to judge whether a stimulus was oriented closer to vertical or the clockwise primary oblique (45°) for two stimulus types (spatially filtered noise textures and sinusoidal gratings) and three manipulations of certainty (orientation bandwidth, contrast, and duration). We found that participants consistently had a bias toward reporting orientation as closer to 45° during conditions of high certainty and that this bias was reduced when sensory evidence was less certain. Second, we measured event-related fMRI BOLD responses in human primary visual cortex (V1) and manipulated certainty via stimulus contrast (100% vs 3%). We then trained a multivariate classifier on the pattern of responses in V1 to cardinal and primary oblique orientations. We found that the classifier showed a bias toward classifying orientation as oblique at high contrast but categorized a wider range of orientations as cardinal for low-contrast stimuli. Orientation classification based on data from V1 thus paralleled the perceptual biases revealed through the behavioral experiments. This pattern of bias cannot be explained simply by a prior for cardinal orientations.SIGNIFICANCE STATEMENT Our perception of the world around us is biased through prior expectations rather than necessarily reflecting the true state of our environment. Here, we investigate biases in the visual processing of spatial orientation to understand how prior expectations and current sensory information interact to generate a percept. By degrading visual input in various ways, we are able to quantify the extent to which prior experience affects both perceptual judgments and neural responses in the human visual system. We observe systematic biases in the perception of orientation that correlate with the pattern of activity in the primary visual cortex of the human brain. These results indicate that prior expectations influence neural processing right from the earliest stage of the cortical hierarchy.

Multisensory cue combination after sensory loss: Audio-visual localization in patients with progressive retinal disease.

Human adults can combine perceptual estimates from different senses to minimize uncertainty, by taking a reliability-weighted average (the maximum likelihood estimate, MLE). Although research has shown that healthy human adults reweight estimates as their reliability changes from one trial to the next, less is known about how humans adapt to gradual long-term changes in sensory reliability. This study assessed whether individuals diagnosed with progressive visual deterioration, due to retinal disease, combined auditory and visual cues to location according to optimal (MLE) predictions. Twelve patients with central visual loss, 10 patients with peripheral visual loss, and 12 normally sighted adults were asked to localize visual and/or auditory targets in central (1°-18°) and peripheral (36°-53°) locations. Normally sighted adults and patients with peripheral visual loss showed multisensory uncertainty reduction and cue weighting in line with MLE predictions. In contrast, patients with central visual loss did not weight estimates appropriately in either the center or the periphery, and failed to meet MLE predictions in the periphery. Our results show that one visual loss patient group succeeded at optimal cue combination, whereas the other patient group (patients with central vision loss) did not. We propose that sensory remapping due to changes in fixation behavior may contribute to apparent failures in the latter group. (PsycINFO Database Record

Validity of auditory perceptual assessment of velopharyngeal function and dysfunction – the VPC-Sum and the VPC-Rate

ABSTRACTOverall weighted or composite variables for perceptual auditory estimation of velopharyngeal closure or competence have been used in several studies for evaluation of velopharyngeal function during speech. The aim of the present study was to investigate the validity of a composite score (VPC-Sum) and of auditory perceptual ratings of velopharyngeal competence (VPC-Rate). Available VPC-Sum scores and judgments of associated variables (hypernasality, audible nasal air leakage, weak pressure consonants, and non-oral articulation) from 391 5-year olds with repaired cleft palate (the Scandcleft project) were used to investigate content validity, and 339 of these were compared with an overall judgment of velopharyngeal competence (VPC-Rate) on the same patients by the same listeners. Significant positive correlations were found between the VPC-Sum and each of the associated variables (Cronbachs alpha 0.55–0.87, P < 0.001), and a moderately significant positive correlation between VPC-Sum and VPC-Rate (Rho 0.698, P < 0.01). The latter classified cases well when VPC-Sum was dichotomized with 67% predicted velopharyngeal competence and 90% velopharyngeal incompetence. The validity of the VPC-Sum was good and the VPC-Rate a good predictor, suggesting possible use of both measures depending on the objective.

Orientation Probability and Spatial Exogenous Cuing Improve Perceptual Precision and Response Speed by Different Mechanisms.

We are faster and more accurate at detecting frequently occurring objects than infrequent ones, just as we are faster and more accurate at detecting objects that have been spatially cued. Does this behavioral similarity reflect similar processes? To evaluate this question we manipulated orientation probability and exogenous spatial cuing within a single perceptual estimation task. Both increased target probability and spatial cuing led to shorter response initiation times and more precise perceptual reports, but these effects were additive. Further, target probability changed the shape of the distribution of errors while spatial cuing did not. Different routes and independent mechanisms could lead to changes in behavioral measures that look similar to each other and to ‘attentional’ effects.

制御対象の幾何学寸法の知覚原理の視触覚的要因に着目した考察

This paper examined and discussed an examinations of the estimation skill of a controlled objects based on the multi modal information such as a tactile or a visual information. By the way to do the description to the indicate way to accomplish the task, it will be able to detect the phenomena to recognize the surround of the optical inflation. In the research, perceptual estimation of the dynamics of the controlled objects based on the tactile and visual information were discussed. Some experimental assumptions were investigate the validity of the proposed estimation methods.

Separating Predicted and Perceived Sensory Consequences of Motor Learning.

During motor adaptation the discrepancy between predicted and actually perceived sensory feedback is thought to be minimized, but it can be difficult to measure predictions of the sensory consequences of actions. Studies attempting to do so have found that self-directed, unseen hand position is mislocalized in the direction of altered visual feedback. However, our lab has shown that motor adaptation also leads to changes in perceptual estimates of hand position, even when the target hand is passively displaced. We attribute these changes to a recalibration of hand proprioception, since in the absence of a volitional movement, efferent or predictive signals are likely not involved. The goal here is to quantify the extent to which changes in hand localization reflect a change in the predicted sensory (visual) consequences or a change in the perceived (proprioceptive) consequences. We did this by comparing changes in localization produced when the hand movement was self-generated (‘active localization’) versus robot-generated (‘passive localization’) to the same locations following visuomotor adaptation to a rotated cursor. In this passive version, there should be no predicted consequences of these robot-generated hand movements. We found that although changes in localization were somewhat larger in active localization, the passive localization task also elicited substantial changes. Our results suggest that the change in hand localization following visuomotor adaptation may not be based entirely on updating predicted sensory consequences, but may largely reflect changes in our proprioceptive state estimate.

Separate process for perceptual and numerical estimation of temporal average

Separate process for perceptual and numerical estimation of temporal average

Temporally stable adaptation is robust, incomplete and specific.

Sensorimotor adaptation, the process that reduces movement errors by learning from sensory feedback, is often studied within a session of about half an hour. Within such a single session, adaptation generally reaches plateau before errors are completely removed. However, adaptation may complete on longer timescales: the slow components of error‐based adaptation are associated with good retention. In this study, we tested how adaptation evolves over time by asking participants to perform six adaptation sessions on different days. In these sessions, participants performed a three‐dimensional reaching task while visual feedback about endpoint errors was rotated around the cyclopean eye. In addition, context specificity of the adaptation was addressed by measuring inter‐limb transfer and transfer to visual and proprioceptive perceptual tasks. We show that from the second session on, the adaptation was retained almost completely across sessions. However, after six learning sessions, adaptation still reached plateau before errors were completely removed. The adaptation was specific: the adaptation did neither transfer to the other hand, nor to the visual, and only marginally to the proprioceptive perceptual estimates. We conclude that motor adaptation is robust, specific and incomplete.

Fear Similarly Alters Perceptual Estimates of and Actions over Gaps.

Previous research has demonstrated an influence of one’s emotional state on estimates of spatial layout. For example, estimates of heights are larger when the viewer is someone typically afraid of heights (trait fear) or someone who, in the moment, is experiencing elevated levels of fear (state fear). Embodied perception theories have suggested that such a change in perception occurs in order to alter future actions in a manner that reduces the likelihood of injury. However, other work has argued that when acting, it is important to have access to an accurate perception of space and that a change in conscious perception does not necessitate a change in action. No one has yet investigated emotional state, perceptual estimates, and action performance in a single paradigm. The goal of the current paper was to investigate whether fear influences perceptual estimates and action measures similarly or in a dissociable manner. In the current work, participants either estimated gap widths (Experiment 1) or were asked to step over gaps (Experiment 2) in a virtual environment. To induce fear, the gaps were placed at various heights up to 15 meters. Results showed an increase in gap width estimates as participants indicated experiencing more fear. The increase in gap estimates was mirrored in participants’ stepping behavior in Experiment 2; participants stepped over fewer gaps when experiencing higher state and trait fear and, when participants actually stepped, they stepped farther over gap widths when experiencing more fear. The magnitude of the influence of fear on both perception and action were also remarkably similar (5.3 and 3.9 cm, respectively). These results lend support to embodied perception claims by demonstrating an influence on action of a similar magnitude as seen on estimates of gap widths.

Aging Effect on Korean Female Voice: Acoustic and Perceptual Examinations of Breathiness

Objective: This paper sought to examine perceptual and acoustic characteristics in Korean female voices, focusing on the ‘breathy' quality as a function of aging. In addition, we aimed to investigate if the three selected measures, H1-H2, H1-A1, and H1-A3, demonstrated any changes along a sustained vowel production. Participants and Methods: A total of 42 participants were assigned to two age groups, young women and elderly women. All participants were asked to sustain /a/ as long and as steadily as possible. Perceptual judgments of breathiness were made on the GRBAS scale and by a direct magnitude estimation technique, while three acoustic parameters, H1-H2, H1-A1, and H1-A3, were measured at five measurement time points during the sustained vowel test. Results: Results indicated that the H1-H2 and H1-A1 values were significantly lower for elderly women compared to young women, although no difference in the perceptual estimation of breathiness was found between the age groups. Among the acoustic measures, only H1-A1 was significantly regressed against the perceptual estimate of breathiness. In addition, no significant acoustic difference in the measures was found across the five measurement points. Conclusion: Our findings suggest that the aging voice might not be universally characterized by the breathy quality, which hints at the need for further research on ethnic diversity in vocal quality.

Микродинамика перцептивного доверия при восприятии выражений лица

&lt;p&gt;The article discusses the phenomenon of &amp;laquo;perceptual trust&amp;raquo; and its formation in micro intervals of time. The results of two empirical studies of trust&amp;rsquo;s perceptual estimates by human faces in various aspects of time exposure was revealed. In the first study, the following values of the time exposure used: 100,250 and 1000 ms. It is shown that the value for adequacy of perceptual trust are the highest exposure at 250 ms, and the least at 1000 ms. It is suggested that the evaluation of perceptual trust depends not only on the time of the demonstration of human facial expressions, sex, but also on the expression of human face. Wider range of exposure time values was used in the second study, 100, 300, 500, 1000 and 3000 to 1000 ms. As of stimulus images were made by representatives of persons Caucasoid, Mongoloid and Negroid racial groups. As the subjects were made by representatives of the Mongoloid racial group. The relationship between the adequacy of the perceptual trust evaluations and race of subjects and models are tested and evaluated models was revealed. The main result of the research can be considered a lack of empirical fixation unambiguous relationship between the level of trust in the person being evaluated and the duration of the perception of his face.&lt;/p&gt;