Success, but not failure feedback guides learning during neurofeedback: An ERP study.

Neurofeedback is a promising self-regulation technique used to modify specific targeted brain patterns. During neurofeedback, target brain activity is monitored in real time and fed back to the subject in a chosen format (e.g. visual stimulus). To date, we do not know how success and failure feedback are processed during neurofeedback learning. Here we analysed the event-related potentials (ERPs) in response to success and failure feedback during a single neurofeedback session in two experiments. Participants in experiment 1 (n = 127) took part in one of the three neurofeedback conditions: RLA: trained to increase alpha power on the right frontal in relation to the left; LRA: the reverse of the RLA; FPA: trained to increase alpha power on the mid-frontal in relation to the mid-parietal region. In experiment 2 (n = 45), participants took part in a similar session but one group received random feedback whereas the other received valid feedback to increase right frontal alpha power. We analysed the feedback related negativity (FRN), correct positivity (CP), and P3a and P3b in response to success and failure feedback. We observed stronger FRN and CP in response to success compared to failure feedback. Additionally, the P3a in response to success feedback was higher in epochs preceding subsequent good adjustments. Our findings indicate that people respond more strongly to success than failure feedback and that the P3a might mediate the encoding of the reinforced patterns in the brain.

Attention scales according to inferred real-world object size.

Natural scenes consist of objects of varying shapes and sizes. The impact of object size on visual perception has been well-demonstrated, from classic mental imagery experiments1, to recent studies of object representations reporting topographic organization of object size in the occipito-temporal cortex2. While the role of real-world physical size in perception is clear, the effect of inferred size on attentional selection is ill-defined. Here, we investigate whether inferred real-world object size influences attentional allocation. Across five experiments, attentional allocation was measured in objects of equal retinal size, but varied in inferred real-world size (for example, domino, bulldozer). Following each experiment, participants rated the real-world size of each object. We hypothesized that, if inferred real-world size influences attention, selection in retinal size-matched objects should be less efficient in larger objects. This effect should increase with greater attentional demand. Predictions were supported by faster identified targets in objects inferred to be small than large, with costlier attentional shifting in large than small objects when attentional demand was high. Critically, there was a direct correlation between the rated size of individual objects and response times (and shifting costs). Finally, systematic degradation of size inference proportionally reduced object size effect. It is concluded that, along with retinal size, inferred real-world object size parametrically modulates attention. These findings have important implications for models of attentional control and invite sensitivity to object size for future studies that use real-world images in psychological research.

Evidence for a perceptual mechanism relating body size misperception and eating disorder symptoms.

PURPOSE: There are known and serious health risks associated with extreme body weights, including the development of eating disorders. Body size misperceptions are particularly evident in individuals with eating disorders, compared to healthy controls. The present research investigated whether serial dependence, a recently discovered bias in body size judgement, is associated with eating disorder symptomatology. We additionally examined whether this bias operates on holistic body representations or whether it works by distorting specific visual features. METHODS: A correlational analysis was used to examine the association between serial dependence and eating disorder symptomatology. We used a within-subjects experimental design to investigate the holistic nature of this misperception. Participants were 63 young women, who judged the size of upright and inverted female body images using a visual analogue scale and then completed the Eating Disorder Examination-Questionnaire (EDE-Q) to assess eating disorder symptoms. RESULTS: Our findings provide the first evidence of an association between serial dependence and eating disorder symptoms, with significant and positive correlations between body size misperception owing to serial dependence and EDE-Q scores, when controlling for Body Mass Index. Furthermore, we reveal that serial dependence is consistent with distortion of local visual features. CONCLUSIONS: Findings are discussed in relation to the broader theories of central coherence, cognitive inflexibility, and multisensory integration difficulties, and as providing a candidate mechanism for body size misperception in an eating disorder population. LEVEL OF EVIDENCE: Level 1, experimental study.

Perceived duration increases not only with physical, but also with implicit size.

When people judge the duration of stimuli, judgments are influenced by the physical size of these stimuli. Specifically, people tend to judge the duration of large stimuli longer than the duration of small stimuli. However, some authors (Bottini & Casasanto, 2010; Ma, Yang, & Zhang, 2012) have reported that even implicit size can affect duration estimates. The present study extends the results of these studies. Specifically, we examined whether the imagined size of objects would also influence duration estimates. In each trial, participants reproduced the duration of an animal word. During the presentation of the word, they were asked to imagine the word's referent. The animals employed in all experiments varied in size. In Experiment 1, participants were instructed to imagine the animals in a fixed context. Reproduced duration increased not only with the numbers of letters of the animal word (i.e., physical size) but also with the size of the word's referent (i.e., implicit size of the animal). Experiments 2 and 3 examined whether the effect of size would increase when the size of the animals was made more salient. The results of all experiments showed that reproduced duration increases with implicit stimulus size. In addition, Experiments 2 and 3 provide some evidence that the imagined size effect becomes more pronounced when the participant's attention is drawn to the size differences among the imagined animals. It is argued that the implicit size effect is mediated by mental imagery that operates on pre-existing space-time associations. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Perceived Weight Is Affected by Auditory Pitch Not Loudness.

This study examined whether auditory pitch and loudness affect the perception of object's weight. Two series experiments showed that the object with High-Pitch sound was perceived as being lighter than the object with Low-Pitch sound and that the perceived weight was not affected by loudness. Because auditory pitch has a relationship to the weight of an object while loudness has a relationship to the distance of a placed object, the perceived weight was affected by auditory pitch not loudness. Given these results, perhaps sound effects may make it easier to carry heavy luggage?

Visual illusions modify object size estimates for prospective action judgements.

How does the eye guide the hand in an ever-changing world? The perception-action model posits that visually-guided actions rely on object size estimates that are computed from an egocentric perspective independently of the visual context. Accordingly, adjusting grip aperture to object size should be resistant to illusions emerging from the contrast between a target and surrounding elements. However, experimental studies gave discrepant results that have remained difficult to explain so far. Visual and proprioceptive information of the acting hand are potential sources of ambiguity in previous studies because the on-line corrections they allow may contribute to masking the illusory effect. To overcome this problem, we investigated the effect on prospective action judgements of the Ebbinghaus illusion, a visual illusion in which the perceived size of a central circle varies according to the size of surrounding circles. Participants had to decide whether they thought they would be able to grasp the central circle of an Ebbinghaus display between their index finger and thumb, without moving their hands. A control group had to judge the size of the central circle relative to a standard. Experiment 1 showed that the illusion affected perceptual and grasping judgements similarly. We further investigated the interaction between visual illusions and grip aperture representation by examining the effect of concurrent motor tasks on grasping judgements. We showed that participants underestimated their ability to grasp the circle when they were squeezing a ball between their index finger and thumb (Experiment 2), whereas they overestimated their ability when their fingers were spread apart (Experiment 3). The illusion also affected the grasping judgement task and modulated the interference of the squeezing movement, with the illusion of largeness enhancing the underestimation of one's grasping ability observed in Experiment 2. We conclude that visual context and body posture both influence action anticipation, and that perception and action support each other.

Aperture Synthesis Shows Perceptual Integration of Geometrical Form Across Saccades.

We investigated the perceptual bias in perceived relative lengths in the Brentano version of the Müller-Lyer arrowheads figure. The magnitude of the bias was measured both under normal whole-figure viewing condition and under an aperture viewing condition, where participants moved their gaze around the figure but could see only one arrowhead at a time through a Gaussian-weighted contrast window. The extent of the perceptual bias was similar under the two conditions. The stimuli were presented on a CRT in a light-proof room with room-lights off, but visual context was provided by a rectangular frame surrounding the figure. The frame was either stationary with respect to the figure or moved in such a manner that the bias would be counteracted if the observer were locating features with respect to the frame. Biases were reduced in the latter condition. We conclude that integration occurs over saccades, but largely in an external visual framework, rather than in a body-centered frame using an extraretinal signal.

Low is large: spatial location and pitch interact in voice-based body size estimation.

The binding of incongruent cues poses a challenge for multimodal perception. Indeed, although taller objects emit sounds from higher elevations, low-pitched sounds are perceptually mapped both to large size and to low elevation. In the present study, we examined how these incongruent vertical spatial cues (up is more) and pitch cues (low is large) to size interact, and whether similar biases influence size perception along the horizontal axis. In Experiment 1, we measured listeners' voice-based judgments of human body size using pitch-manipulated voices projected from a high versus a low, and a right versus a left, spatial location. Listeners associated low spatial locations with largeness for lowered-pitch but not for raised-pitch voices, demonstrating that pitch overrode vertical-elevation cues. Listeners associated rightward spatial locations with largeness, regardless of voice pitch. In Experiment 2, listeners performed the task while sitting or standing, allowing us to examine self-referential cues to elevation in size estimation. Listeners associated vertically low and rightward spatial cues with largeness more for lowered- than for raised-pitch voices. These correspondences were robust to sex (of both the voice and the listener) and head elevation (standing or sitting); however, horizontal correspondences were amplified when participants stood. Moreover, when participants were standing, their judgments of how much larger men's voices sounded than women's increased when the voices were projected from the low speaker. Our results provide novel evidence for a multidimensional spatial mapping of pitch that is generalizable to human voices and that affects performance in an indirect, ecologically relevant spatial task (body size estimation). These findings suggest that crossmodal pitch correspondences evoke both low-level and higher-level cognitive processes.

Evaluating the basis of the between-group production effect in recognition.

Reading a list of words aloud can improve recognition over silently reading them. This between-groups production effect (PE) cannot be due to relative distinctiveness because each group studies only 1 type of item. We tested 2 other possibilities. By a strategy account, a pure-aloud group might benefit from use of a production-based distinctiveness strategy at test (e.g., "Did I say this word aloud?"). By a strength account, aloud items may simply be more strongly encoded than silent items. To evaluate these accounts, we tested whether a between-group PE occurs when participants experience a salient within-group manipulation of font size, generation, or imagery at study. The answer was yes, except when imagery was the within-group task. This pattern, and aspects of participants' strategy reports, fit well with a strategy account if it is assumed that the imagery task led participants to abandon a production-based strategy. However, many of our findings were also compatible with an evaluated strength account if it is assumed that the imagery task led participants to abandon evaluating memory strength. In conjunction with recent findings, we suggest that multiple processes may contribute to the PE, and the relevant subset in play will differ as a function of study design, study task, and memory test. (PsycINFO Database Record

In the eye of the beholder: Visual biases in package and portion size perceptions.

As the sizes of food packages and portions have changed rapidly over the past decades, it has become crucial to understand how consumers perceive and respond to changes in size. Existing evidence suggests that consumers make errors when visually estimating package and portion sizes, and these errors significantly influence subsequent food choices and intake. We outline four visual biases (arising from the underestimation of increasing portion sizes, the dimensionality of the portion size change, labeling effects, and consumer affect) that shape consumers' perceptions of package and portion sizes. We discuss the causes of these biases, review their impact on food consumption decisions, and suggest concrete strategies to reduce them and to promote healthier eating. We conclude with a discussion of important theoretical and practical issues that should be addressed in the future.

Evaluating the accuracy of size perception on screen-based displays: Displayed objects appear smaller than real objects.

Accurate perception of the size of objects in computer-generated imagery is important for a growing number of applications that rely on absolute scale, such as medical visualization and architecture. Addressing this problem requires both the development of effective evaluation methods and an understanding of what visual information might contribute to differences between virtual displays and the real world. In the current study, we use 2 affordance judgments--perceived graspability of an object or reaching through an aperture--to compare size perception in high-fidelity graphical models presented on a large screen display to the real world. Our goals were to establish the use of perceived affordances within spaces near to the observer for evaluating computer graphics and to assess whether the graphical displays were perceived similarly to the real world. We varied the nature of the affordance task and whether or not the display enabled stereo presentation. We found that judgments of grasping and reaching through can be made effectively with screen-based displays. The affordance judgments revealed that sizes were perceived as smaller than in the real world. However, this difference was reduced when stereo viewing was enabled or when the virtual display was viewed before the real world.

Body size perception among African American women.

OBJECTIVE: To assess body size perception among African American women using cultural definitions of body size terms. METHODS: Sixty-nine African American women classified Body Image Scale figures as overweight, obese, and too fat, and independently selected the figure they considered closest to their current body size. RESULTS: Body size classifications of figures did not vary by participant weight status. Overweight figures were not considered too fat. For 86% of overweight (body mass index [BMI], 25-29.9) women and 40% of obese (BMI > 30) women, the self figure was not defined as overweight, obese, or too fat. Among participants with BMI ≥ 35, 65% did not classify their self figure as obese and 29% did not classify their self figure as overweight. CONCLUSIONS AND IMPLICATIONS: The difference between cultural (folk) and medical definitions of body size terms may serve as a barrier to effective communication between patients and providers about health effects of excess adiposity.

A new illusion of height and width: taller people are perceived as thinner.

It is commonly said that tall people look thinner. Here, we asked whether an illusion exists such that the taller of two equally wide stimuli looks thinner, and conversely whether the thinner of two equally tall stimuli looks taller. In five experiments, participants judged the horizontal or vertical extents of two identical bodies, rectangles, or cylinders that differed only in their vertical or horizontal extents. Our results confirmed the folk wisdom that being tall makes you look thinner. We similarly found that being thin makes you look taller, although this effect was less pronounced. The same illusion was present for filled rectangles and cylinders, but it was consistently stronger for both photographs and silhouettes of the human body, raising the question of why the human form should be more prone to this illusion.

A real-world size organization of object responses in occipitotemporal cortex.

While there are selective regions of occipitotemporal cortex that respond to faces, letters, and bodies, the large-scale neural organization of most object categories remains unknown. Here, we find that object representations can be differentiated along the ventral temporal cortex by their real-world size. In a functional neuroimaging experiment, observers were shown pictures of big and small real-world objects (e.g., table, bathtub; paperclip, cup), presented at the same retinal size. We observed a consistent medial-to-lateral organization of big and small object preferences in the ventral temporal cortex, mirrored along the lateral surface. Regions in the lateral-occipital, inferotemporal, and parahippocampal cortices showed strong peaks of differential real-world size selectivity and maintained these preferences over changes in retinal size and in mental imagery. These data demonstrate that the real-world size of objects can provide insight into the spatial topography of object representation.

Musicians outperform nonmusicians in magnitude estimation: evidence of a common processing mechanism for time, space and numbers.

It has been proposed that time, space, and numbers may be computed by a common magnitude system. Even though several behavioural and neuroanatomical studies have focused on this topic, the debate is still open. To date, nobody has used the individual differences for one of these domains to investigate the existence of a shared cognitive system. Musicians are known to outperform nonmusicians in temporal discrimination tasks. We therefore observed professional musicians and nonmusicians undertaking three different tasks: temporal (participants were required to estimate which of two tones lasted longer), spatial (which line was longer), and numerical discrimination (which group of dots was more numerous). If time, space, and numbers are processed by the same mechanism, it is expected that musicians will have a greater ability, even in nontemporal dimensions. As expected, musicians were more accurate with regard to temporal discrimination. They also gave better performances in both the spatial and the numerical tasks, but only outside the subitizing range. Our data are in accordance with the existence of a common magnitude system. We suggest, however, that this mechanism may not involve the whole numerical range.

Perceptual fading without retinal adaptation.

A retinally stabilized object readily undergoes perceptual fading and disappears from consciousness. This startling phenomenon is commonly believed to arise from local bottom-up sensory adaptation to edge information that occurs early in the visual pathway, such as in the lateral geniculate nucleus of the thalamus or retinal ganglion cells. Here we use random dot stereograms to generate perceivable contours or shapes that are not present on the retina and ask whether perceptual fading occurs for such "cortical" contours. Our results show that perceptual fading occurs for "cortical" contours and that the time a contour requires to fade increases as a function of its size, suggesting that retinal adaptation is not necessary for the phenomenon and that perceptual fading may be based in the cortex.

Perceived size change induced by audiovisual temporal delays.

The retinal image of an object does not contain information about its actual size. Size must instead be inferred from extraretinal cues for which distance information makes an essential contribution. Asynchronies in the arrival time across visual and auditory sensory components of an audiovisual event can reliably cue its distance, although this cue has been largely neglected in vision research. Here we demonstrate that audio-visual asynchronies can produce a shift in the apparent size of an object and attribute this shift to a change in perceived distance. In the present study participants were asked to match the perceived size of a test circle paired with an asynchronous sound to a variable-size probe circle paired with a simultaneous sound. The perceived size of the circle increased when the sound followed its onset with delays up to around 100 ms. For longer sound delays and sound leads, no effect was seen. We attribute this selective modulation in perceived visual size to audiovisual timing influences on the intrinsic relationship between size and distance. This previously unsuspected cue to distance reveals a surprisingly interactive system using multisensory information for size/distance perception.

Perceptual learning incepted by decoded fMRI neurofeedback without stimulus presentation.

It is controversial whether the adult primate early visual cortex is sufficiently plastic to cause visual perceptual learning (VPL). The controversy occurs partially because most VPL studies have examined correlations between behavioral and neural activity changes rather than cause-and-effect relationships. With an online-feedback method that uses decoded functional magnetic resonance imaging (fMRI) signals, we induced activity patterns only in early visual cortex corresponding to an orientation without stimulus presentation or participants' awareness of what was to be learned. The induced activation caused VPL specific to the orientation. These results suggest that early visual areas are so plastic that mere inductions of activity patterns are sufficient to cause VPL. This technique can induce plasticity in a highly selective manner, potentially leading to powerful training and rehabilitative protocols.

Healthy eating perceptions of older adults living in Canadian rural and northern communities.

Aging produces physiologic changes that can affect the nutritional health of the older adult. It is estimated that 80% of community-dwelling older adults have inadequate intakes of four or more nutrients. Socioeconomic factors, such as income and geographic location, can also play an important role in nutritional status; however, limited research is available that specifically explores this. The purpose of this qualitative study was to examine the healthy eating perceptions of older adults residing in rural and northern communities in one Canadian province. Five focus groups were conducted in three rural and two northern Manitoba communities. Thirty-nine older adults participated in audio-recorded focus groups. Five themes emerged from the discussions. All respondents stated that healthy eating was important, but knowledge deficits were observed regarding label reading, understanding and visualizing portion sizes, and vitamin D recommendations and sources. Food programs were not commonly attended by participants due to availably and resistance. Regularly delivered nutrition education programs would assist in providing current nutrition information to older adults and their families in rural settings.

Visual perceptual load induces inattentional deafness.

In this article, we establish a new phenomenon of "inattentional deafness" and highlight the level of load on visual attention as a critical determinant of this phenomenon. In three experiments, we modified an inattentional blindness paradigm to assess inattentional deafness. Participants made either a low- or high-load visual discrimination concerning a cross shape (respectively, a discrimination of line color or of line length with a subtle length difference). A brief pure tone was presented simultaneously with the visual task display on a final trial. Failures to notice the presence of this tone (i.e., inattentional deafness) reached a rate of 79% in the high-visual-load condition, significantly more than in the low-load condition. These findings establish the phenomenon of inattentional deafness under visual load, thereby extending the load theory of attention (e.g., Lavie, Journal of Experimental Psychology. Human Perception and Performance, 25, 596-616, 1995) to address the cross-modal effects of visual perceptual load.