An investigation of inattentional blindness using gaze and frequency tagging.

Inattentional blindness (IB) occurs when a salient object presented in plain sight goes unnoticed when its appearance is unexpected. Across two experiments, participants completed a classic dynamic IB task while eye movements and steady-state visual evoked potential (SSVEP) responses were continually recorded. This allowed us to measure the modulation of gaze and brain-based indices of attention during IB. While an SSVEP response to all stimuli including the unexpected object was attained, only gaze measures were able to discriminate noticers from nonnoticers. Experiment 1 used a prototypical sustained IB task and found that gaze toward the unexpected object was largely unrelated to noticing that object. Experiment 2 manipulated the contrast of the target and distractor stimuli, and instead observed a tight concordance between gazing at the unexpected object and reporting its presence. This task-based variability in gaze deployment is consistent with the broader literature and cumulatively delineates the challenges faced in translating lab-based IB research from the bench to the bedside. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The role of social context in own body size estimations: An investigation of the body schema.

Women tend to overestimate their body size, including space needed to pass through gaps/apertures. These results were generated using static apertures resembling doorways. However, body image is influenced by other bodies around us, and how estimations of passability may be influenced by social context is unknown. To investigate, a series of apertures were created comprising two women facing each other, with the space between creating the 'doorway'. The apertures were created using either two larger-bodied or two smaller-bodied women. Non-social versions were generated using the social aperture silhouettes. Thirty-four undergraduate women viewed a series of apertures - varying in width relative to their own size - and judged whether they believed they could pass through them. State and trait body dissatisfaction measurements were also taken. Point of subjective equality (PSE) data suggested that participants did not overestimate the space needed to pass through apertures overall, but showed an overestimation of space for the larger-bodied social doorways. Correlations suggested higher levels of state body dissatisfaction associated with higher PSEs, but only in the social conditions. Results showed that participants may have been engaging in different mechanisms regarding social versus non-social doorways, and the importance of social context when investigating own body size estimations.

The effect of cognitive load on horizontal and vertical spatial asymmetries.

Healthy individuals typically show a leftward attentional bias in the allocation of spatial attention along the horizontal plane, a phenomenon known as pseudoneglect, which relies on a right hemispheric dominance for visuospatial processing. Also, healthy individuals tend to overestimate the upper hemispace when orienting attention along the vertical plane, a phenomenon that may depend on asymmetric ventral and dorsal visual streams activation. Previous research has demonstrated that when attentional resources are reduced due to increased cognitive load, pseudoneglect is attenuated (or even reversed), due to decreased right-hemispheric activations. Critically, whether and how the reduction of attentional resources under load modulates vertical spatial asymmetries has not been addressed before. We asked participants to perform a line bisection task both with and without the addition of a concurrent auditory working memory task with lines oriented either horizontally or vertically. Results showed that increasing cognitive load reduced the typical leftward/upward bias with no difference between orientations. Our data suggest that the degree of cognitive load affects spatial attention not only in the horizontal but also in the vertical plane. Lastly, the similar effect of load on horizontal and vertical judgements suggests these biases may be related to only partially independent mechanisms.

The dissociable influence of social context on judgements of facial attractiveness and trustworthiness.

The cheerleader effect occurs when the same face is rated to be more attractive when it is seen in a group compared to when seen alone. We investigated whether this phenomenon also occurs for trustworthiness judgements, and examined how these effects are influenced by the characteristics of the individual being evaluated and those of the group they are seen in. Across three experiments, we reliably replicated the cheerleader effect. Most faces became more attractive in a group. Yet, the size of the cheerleader effect that each face experienced was not related to its own attractiveness, nor to the attractiveness of the group or the group's digitally averaged face. We discuss the implications of our findings for the hierarchical encoding and contrast mechanisms that have previously been used to explain the cheerleader effect. Surprisingly, judgements of facial trustworthiness did not experience a 'cheerleader effect'. Instead, we found that untrustworthy faces became significantly more trustworthy in all groups, while there was no change for faces that were already trustworthy alone. Taken together, our results demonstrate that social context can have a dissociable influence on our first impressions, depending on the trait being evaluated.

To the next decade and beyond.

Sebastian Ocklenburg and colleagues have written an important and exciting summary of where laterality research might go. Perhaps reiterating some of their points, it seems important to understand the nuances of laterality. Laterality research can fall into the trap of "dichotomania" - where all laterality is seen in terms of left versus right. However, important insights can also be gained by examining the strength of laterality as well as the cooperation and competition between the hemispheres. Care also needs to be taken when examining individual differences between left- and right-handers. Studies, which may suffer from type 1 errors, often stigmatise left-handers with a host of negative traits. Pre-registration and the reporting of effect size may eliminate this bias.

Reinforcement history shapes primary visual cortical responses: An SSVEP study.

Efficient learning requires allocating limited attentional resources to meaningful stimuli and away from irrelevant stimuli. This prioritization may occur via covert attention, evident in the activity of the visual cortex. We used steady-state visual evoked potentials (SSVEPs) to assess whether associability-driven changes in stimulus processing were evident in visuocortical responses. Participants were trained on a learned-predictiveness protocol, whereby one stimulus on each trial accurately predicted the correct response for that trial, and the other was irrelevant. In a second phase the task was arranged so that all cues were objectively predictive. Participants' overt attention (eye gaze) was affected by each cue's reinforcement history, as was their covert attention (SSVEP responses). These biases persisted into Phase 2 when all stimuli were objectively predictive, thereby demonstrating that learned attentional processes are evident in basic sensory processing, and exert an effect on covert attention above and beyond the effects of overt gaze bias.

One-handed motor activity does not interfere with naming lateralized pictures of tools.

The motor interference hypothesis posits that performing a secondary motor task with a task relevant effector (e.g., the hand) impairs performance on a primary object-naming task wherein objects are used by the same effector. However, evidence in favor of this hypothesis has been mixed. We sought to replicate findings from a lateralized object-naming paradigm, which supports the motor interference hypothesis, and to expand upon this previous research by also examining handedness. Across four experiments, we examined whether performance on a primary object-naming task is impaired by a secondary motor task where participants either squeezed a ball or continually moved their fingers in and out of a fist posture. We failed to observe any significant effects on either response times or error rates on the primary task. Furthermore, handedness did not influence performance on the primary task. Overall, our findings do not provide strong support for a functional role for motor neural resources in object naming. This could suggest that the motor activation that accompanies object recognition is a byproduct of this process. We also argue for a contextual rather than invariant activation of motor information in object processing tasks and discuss the implications of this view on theories of object conceptual representation. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Flowers in the Attic: Lateralization of the detection of meaning in visual noise.

The brain is a slave to sense; we see and hear things that are not there and engage in ongoing correction of these illusory experiences, commonly termed pareidolia. The current study investigates whether the predisposition to see meaning in noise is lateralized to one hemisphere or the other and how this predisposition to visual false-alarms is related to personality. Stimuli consisted of images of faces or flowers embedded in pink (1/f) noise generated through a novel process and presented in a divided-field paradigm. Right-handed undergraduates participated in a forced-choice signal-detection task where they determined whether a face or flower signal was present in a single-interval trial. Experiment 1 involved an equal ratio of signal-to-noise trials; experiment 2 provided more potential for illusionary perception with 25% signal and 75% noise trials. There was no asymmetry in the ability to discriminate signal from noise trials (measured using d') for either faces and flowers, although the response criterion (c) suggested a stronger predisposition to visual false alarms in the right visual field, and this was negatively correlated to the unusual experiences dimension of schizotypy. Counter to expectations, changing the signal-image to noise-image proportion in Experiment 2 did not change the number of false alarms for either faces and flowers, although a stronger bias was seen to the right visual field; sensitivity remained the same in both hemifields but there was a moderate positive correlation between cognitive disorganization and the bias (c) for "flower" judgements. Overall, these results were consistent with a rapid evidence-accumulation process of the kind described by a diffusion decision model mediating the task lateralized to the left-hemisphere.

Through Doorways and Down Corridors: Investigating Asymmetries During Computer Maze Navigation.

Pseudoneglect causes neurologically intact individuals to bias their attention to the left in near space, and to the right in far space. These attentional asymmetries impact both ambulatory and non-ambulatory activities, causing individuals to deviate rightward. While most studies investigating real-world navigation have found a rightward deviation when passing through a door, some have found the opposite pattern for corridors. To explore this dissociation, the current experiment explicitly compared navigation through doorways and corridors. To allow for a direct comparison between these two environments, the navigation task was undertaken in a simulated environment. Dextral participants (n = 98) completed several trials in either the doorway or corridor condition and their mean lateral position and variance was analysed. A rightward deviation was observed for doorways, consistent with previous research. Rightward biases were also observed for corridors, irrespective of the position within the corridor. The results argue against an explanation based on near/far space for the leftward bias in corridors. An explanation based on elevation of view is proposed as an alternative. The study also demonstrates that simulated environments provide an efficient means of investigating asymmetries in navigation.

Cognitive load exacerbates rightward biases during computer maze navigation.

Neurologically healthy individuals exhibit subtle attentional asymmetries, such that attention is preferentially directed leftwards for objects in near space and rightwards for objects in far space. These attentional biases also affect navigation and cause people to deviate to the right when passing through an aperture. The current study examined whether the rightward deviations observed in real-world environments translate to simulated environments. As proof of concept and to determine whether rightward biases could be further exacerbated, the degree of cognitive load imposed on participants was manipulated. Experiment 1 asked participants to navigate through the centre of a computer-based doorway. In one block of trials, participants completed the task by itself (baseline condition), while in another block of trials they also completed a simple auditory discrimination task (load condition). While analyses revealed rightward biases for both conditions, the difference between conditions was not significant. Experiment 2 therefore increased the difficulty of the auditory task. Analyses revealed a significant difference between conditions, suggesting that the degree of cognitive load further exacerbates rightward biases, demonstrating that the rightward asymmetries in navigation observed in the real world generalises to a simulated environment and that this phenomenon behaves in a way that is consistent with pseudoneglect.

Perception of an ambiguous figure is affected by own-age social biases.

Although the perception of faces depends on low-level neuronal processes, it is also affected by high-level social processes. Faces from a social in-group, such as people of a similar age, receive more in-depth processing and are processed holistically. To explore whether own-age biases affect subconscious face perception, we presented participants with the young/old lady ambiguous figure. Mechanical Turk was used to sample participants of varying ages from the USA. Results demonstrated that younger and older participants estimated the age of the image as younger and older, respectively. This own-age effect ties in with socio-cultural practices, which are less inclusive towards the elderly. Participants were not aware the study was related to ageing and the stimulus was shown briefly. The results therefore demonstrate that high-level social group processes have a subconscious effect on the early stages of face processing. A neural feedback model is used to explain this interaction.

Asymmetries in Distractibility: Left Distractors Improve Reaction Time Performance.

Research using the irrelevant-distractor paradigm shows perceptual load influences distractibility, such that distractors are more likely to be processed and decrease reaction times during low perceptual load. In contrast, under high load, attentional resources are limited, and the likelihood of distractibility is decreased. We manipulated distractor placement to determine whether location differentially influenced distractibility. During low load, reaction times were increased equally for all distractor locations. Under high load, left distractors speeded reaction times significantly more than right distractors. We suggest two potential explanations: (1) the central focus of attention was sufficiently large to encapsulate both the distractor and the visual array during low perceptual load, leading to increased distraction-during high load, attention was split across the two visual stimuli, allowing the distractors and array to be processed independently; (2) superior executive control for stimuli in the left visual field allowed participants to 'catch and release' left distractors more efficiently, ultimately decreasing distraction and providing a performance benefit. Our findings represent an intriguing development in relation to visual asymmetries in distractibility.

Visuospatial asymmetries do not modulate the cheerleader effect.

The cheerleader effect occurs when the same individual appears to be more attractive when seen in a group, compared to alone. As observers over-attend to visual information presented in the left visual field, we investigated whether the spatial arrangement of the faces in a group would influence the magnitude of the cheerleader effect. In Experiment 1, target faces were presented twice in the centre of the display: once alone, and once in a group. Group images featured two distractor faces, which were presented in either the left or the right visual field, or on either side of the target. The location of the distractor faces did not modulate the size of the cheerleader effect, which was observed in each group configuration. In Experiment 2, we manipulated the location of the target faces, which were presented at the far left, far right, or centre of the group. Faces were again significantly more attractive in each group configuration, and the spatial location of the target face did not influence the size of the cheerleader effect. Together, our results show that the cheerleader effect is a robust phenomenon, which is not influenced by the spatial arrangement of the faces in the group.

Close interpersonal proximity modulates visuomotor processing of object affordances in shared, social space.

Research suggests that the human brain codes manipulable objects as possibilities for action, or affordances, particularly objects close to the body. Near-body space is not only a zone for body-environment interaction but also is socially relevant, as we are driven to preserve our near-body, personal space from others. The current, novel study investigated how close proximity of a stranger modulates visuomotor processing of object affordances in shared, social space. Participants performed a behavioural object recognition task both alone and with a human confederate. All object images were in participants' reachable space but appeared relatively closer to the participant or the confederate. Results revealed when participants were alone, objects in both locations produced an affordance congruency effect but when the confederate was present, only objects nearer the participant elicited the effect. Findings suggest space is divided between strangers to preserve independent near-body space boundaries, and in turn this process influences motor coding for stimuli within that social space. To demonstrate that this visuomotor modulation represents a social phenomenon, rather than a general, attentional effect, two subsequent experiments employed nonhuman joint conditions. Neither a small, Japanese, waving cat statue (Experiment 2) nor a metronome (Experiment 3) modulated the affordance effect as in Experiment 1. These findings suggest a truly social explanation of the key interaction from Experiment 1. This study represents an important step toward understanding object affordance processing in real-world, social contexts and has implications broadly across fields of social action and cognition, and body space representation.

Is trustworthiness lateralized in the face? Evidence from a trust game.

A turn of the head can be used to convey or conceal emotion, as the left side of the face is more expressive than the right. As the left cheek moves more when smiling, the present study investigated whether perceived trustworthiness is lateralized to the left cheek, using a trust game paradigm. In Experiment 1, participants were asked to share money with male and female "virtual partners." Left-left or right-right composite faces were used to represent the partners. There were no differences in the amount shared based on composite face, suggesting trustworthiness is not lateralized in the face. However, there was a robust effect whereby female partners were perceived to be significantly more trustworthy than males. In Experiment 2, the virtual partners presented either the left or the right cheek prominently. As in Experiment 1, the amount shared with the partners did not change depending on the cheek presented. Interestingly, female partners were again sent significantly more money than males. We found no support for lateralized trustworthiness in the face, suggesting that asymmetries in the face are not large enough to influence trustworthiness judgements. Instead, more stable facial features, such as sex-typical characteristics, appear to influence perceived trustworthiness.

Emotion processing in persons who respond vicariously towards others in pain: Disinhibited left-lateralized neural activity for threatening expressions.

We investigated emotional processing in vicarious pain (VP) responders. VP responders report an explicit sensory and emotional feeling of pain when they witness another in pain, which is greater in magnitude than the empathic processing of pain in the general population. In Study 1, 31 participants completed a chimeric faces task, judging whether emotional chimera in the left, or right, visual field was more intense. VP responders took longer to judge emotionality than non-responders, and fixated more on the angry hemiface in the right visual field, whereas non-responder controls had no lateralized fixation bias. In Study 2, blood-oxygen level-dependent signals were recorded during an emotional face matching task. VP intensity was correlated with increased insula activity and reduced middle frontal gyrus activity for angry faces, and with reduced activity in the inferior and middle frontal gyri for sad faces. Together, these findings suggest that VP responders are more reactive to negative emotional expressions. Specifically, emotional judgements involved altered left-hemisphere activity in VP responders, and reduced engagement of regions involved in emotion regulation.

An investigation of left/right driving rules on deviations while walking.

When traversing through an aperture, such as a doorway, people characteristically deviate towards the right. This rightward deviation can be explained by a rightward attentional bias which leads to rightward bisections in far space. It is also possible, however, that left or right driving practices affect the deviation. To explore this possibility, Australian (left-side drivers) and Swiss (right-side drivers) participants (n = 36 & 34) walked through the middle of an aperture. To control for the sway of the body, participants started with either their left or right foot. Sway had a significant effect on participants' position in the doorway and the amount of sway was greater for Australians-perhaps due to national differences in gait. There was a significant rightward deviation for the Swiss, but not for the Australians. It is suggested that driving practices have a small additive effect on rightward attentional biases whereby the bias is increased for people who drive on the right and reduced in people who drive on the left.

Fat or fiction? Effects of body size, eating pathology, and sex upon the body schema of an undergraduate population.

Although there is a growing consensus that women with anorexia nervosa have a distorted body schema, the origins of this disturbance remain uncertain. The present investigation examined the effects of body size, eating pathology, and sex upon the body schema of an at-risk, undergraduate population. In Study 1, 98 participants mentally simulated their passage through apertures. When aperture width was manipulated, narrow and broad women over- and under-estimated their spatial requirements for passage, respectively. This relationship was exacerbated by dietary restraint. When aperture height was manipulated, short and tall men over- and under-estimated their spatial requirements for passage, respectively. Study 2 (N=32) replicated the association between women's veridical and internally-represented widths, although no significant effects of eating pathology were observed. Our findings suggest that body schema enlargement is not necessarily pathological, and may be driven by normal perceptual biases and internalised sociocultural body ideals.

Cross-modal influences on attentional asymmetries: Additive effects of attentional orienting and arousal.

Attention is asymmetrically distributed across the visual field, such that left side stimuli are more salient, which causes a spatial bias known as pseudoneglect. Although auditory cues can be used to direct visual attention to a location, the influence of auditory distractors on visuospatial asymmetries remains unknown. We examined whether attentional orienting or arousal effects occur when either left or right auditory distractors are presented during the landmark task. We also categorised participants based on the baseline direction of pseudoneglect. Experiment 1 showed a strong attentional orienting effect. A slightly weaker arousal effect was also observed. Interestingly, these effects appear to be additive, such that infrequent right ear distractors rendered leftward biases non-significant. A second experiment, using centralised auditory distractors, was conducted to isolate the role of arousal. A strong arousal effect occurred, which was mediated by baseline direction of pseudoneglect. Left- and right-responders showed parallel decreases in the strength of attentional asymmetries, as biases decreased in the presence of distractors. Importantly, these decreases were not accompanied by an increase in accuracy. We conclude that both attentional orienting and arousal mechanisms contribute to the cross-modal integration of auditory and visual information during visuospatial processing, with the role of attentional orienting being more dominant.

Perceptual biases in the horizontal and vertical dimensions are driven by separate cognitive mechanisms.

Perceptual attention in healthy participants is characterized by two biases, one operating in the horizontal plane, which draws attention leftward, and the other operating in the vertical plane, which draws attention upward. Given that these biases are reliably found in the same individual, and appear similar at a surface level, a number of researchers have investigated the relationship between horizontal and vertical attentional biases. To date, these investigations have failed to find an association, and this may be due to the fact that one-dimensional vertical and horizontal stimuli were presented separately rather than being measured from a single, two-dimensional stimulus. Across three experiments, two dimensional stimuli were presented, and participants marked the centre of the stimuli. In addition, the shapes of the stimuli were manipulated to determine whether this produced the same modulation of the two biases. Across 13 stimuli and three experiments there were no correlations between the vertical and horizontal biases. In addition, manipulations of stimulus shape, which affected biases in one dimension, did not affect biases in the other dimension. There were, however, consistent correlations between the degree of bias within each dimension across the different stimuli. This study has produced converging evidence that horizontal and vertical biases in spatial judgments rely on separate cognitive mechanisms. To account for these results we discuss a model whereby horizontal asymmetries rely more on space-based mechanisms whereas vertical asymmetries rely more on object-based mechanisms.