Low-level Perceptual Processes Research Articles

Fixation-related potentials during mobile map assisted navigation in the real world: The effect of landmark visualization style.

An often-proposed enhancement for mobile maps to aid assisted navigation is the presentation of landmark information, yet understanding of the manner in which they should be displayed is limited. In this study, we investigated whether the visualization of landmarks as 3D map symbols with either an abstract or realistic style influenced the subsequent processing of those landmarks during route navigation. We utilized a real-world mobile electroencephalography approach to this question by combining several tools developed to overcome the challenges typically encountered in real-world neuroscience research. We coregistered eye-movement and EEG recordings from 45 participants as they navigated through a real-world environment using a mobile map. Analyses of fixation event-related potentials revealed that the amplitude of the parietal P200 component was enhanced when participants fixated landmarks in the real world that were visualized on the mobile map in a realistic style, and that frontal P200 latencies were prolonged for landmarks depicted in either a realistic or abstract style compared with features of the environment that were not presented on the map, but only for the male participants. In contrast, we did not observe any significant effects of landmark visualization style on visual P1-N1 peaks or the parietal late positive component. Overall, the findings indicate that the cognitive matching process between landmarks seen in the environment and those previously seen on a map is facilitated by more realistic map display, while low-level perceptual processing of landmarks and recall of associated information are unaffected by map visualization style.

Involvement of the superior colliculi in crossmodal correspondences.

There is an increasing body of evidence suggesting that there are low-level perceptual processes involved in crossmodal correspondences. In this study, we investigate the involvement of the superior colliculi in three basic crossmodal correspondences: elevation/pitch, lightness/pitch, and size/pitch. Using a psychophysical design, we modulate visual input to the superior colliculus to test whether the superior colliculus is required for behavioural crossmodal congruency effects to manifest in an unspeeded multisensory discrimination task. In the elevation/pitch task, superior colliculus involvement is required for a behavioural elevation/pitch congruency effect to manifest in the task. In the lightness/pitch and size/pitch task, we observed a behavioural elevation/pitch congruency effect regardless of superior colliculus involvement. These results suggest that the elevation/pitch correspondence may be processed differently to other low-level crossmodal correspondences. The implications of a distributed model of crossmodal correspondence processing in the brain are discussed.

Beyond the simplicity of theory of mind deficit in multiple sclerosis: from kinetic perception to socio-emotional abstraction and mentalizing.

Theory of Mind (ToM) processing in Multiple Sclerosis (MS) is still poorly understood due to the difficulty of most tasks in qualifying the mentalizing deficit net of cognitive load. In this study, we administered the New False Belief Animation Task (NFBAT) to 50 MS and 33 healthy controls (HC) to investigate spontaneous mentalizing in ToM and goal-directed interactions. The global cognitive level was assessed by the Montreal Cognitive Assessment (MoCA). NFBAT appropriateness and intentionality scores were computed to investigate the ToM accuracy and intentionality attribution difficulties. NFBAT answers were qualitatively analyzed and categorized into kinetically and socially coherent/not coherent responses to test a low-level perceptual deficit. The main result showed dysfunctional mentalizing reasoning in MS compared to HC in the NFBAT Intentionality score in ToM conditions (p=0.028, d=0.501), while the two groups were equally proficient in mentalization accuracy. The Intentionality underperformance in MS was related to social low-level perceptual processing (β =0.06, p<0.001) and visuospatial functions (β =0.05, p =0.002). A predictive role of memory and executive functions on NFBAT Intentionality scores was not observed. These results strengthen the hypothesis that ToM in MS is likely related to low-level social processing.

Instant Effects of Semantic Information on Visual Perception.

Does our perception of an object change once we discover what function it serves? We showed human participants (n = 48, 31 females and 17 males) pictures of unfamiliar objects either together with keywords matching their function, leading to semantically informed perception, or together with nonmatching keywords, resulting in uninformed perception. We measured event-related potentials to investigate at which stages in the visual processing hierarchy these two types of object perception differed from one another. We found that semantically informed compared with uninformed perception was associated with larger amplitudes in the N170 component (150-200 ms), reduced amplitudes in the N400 component (400-700 ms), and a late decrease in alpha/beta band power. When the same objects were presented once more without any information, the N400 and event-related power effects persisted, and we also observed enlarged amplitudes in the P1 component (100-150 ms) in response to objects for which semantically informed perception had taken place. Consistent with previous work, this suggests that obtaining semantic information about previously unfamiliar objects alters aspects of their lower-level visual perception (P1 component), higher-level visual perception (N170 component), and semantic processing (N400 component, event-related power). Our study is the first to show that such effects occur instantly after semantic information has been provided for the first time, without requiring extensive learning.SIGNIFICANCE STATEMENT There has been a long-standing debate about whether or not higher-level cognitive capacities, such as semantic knowledge, can influence lower-level perceptual processing in a top-down fashion. Here we could show, for the first time, that information about the function of previously unfamiliar objects immediately influences cortical processing within less than 200 ms. Of note, this influence does not require training or experience with the objects and related semantic information. Therefore, our study is the first to show effects of cognition on perception while ruling out the possibility that prior knowledge merely acts by preactivating or altering stored visual representations. Instead, this knowledge seems to alter perception online, thus providing a compelling case against the impenetrability of perception by cognition.

Unmet expectations about material properties delay perceptual decisions

Based on our expectations about material properties, we can implicitly predict an object’s future states, e.g., a wine glass falling down will break when it hits the ground. How these expectations affect relatively low-level perceptual decisions, however, has not been systematically studied previously. To seek an answer to this question, we conducted a behavioral experiment using animations of various familiar objects (e.g., key, wine glass, etc.) freely falling and hitting the ground. During a training session, participants first built expectations about the dynamic properties of those objects. Half of the participants (N = 28) built expectations consistent with their daily lives (e.g., a key bounces rigidly), whereas the other half learned an atypical behavior (e.g., a key wobbles). This was followed by experimental sessions, in which expectations were unmet in 20% of the trials. In both training and experimental sessions, the participant’s task was to report whether the objects broke or not upon hitting the ground. Critically, a specific object always remained intact or broke - only the manner in which it did so differed. For example, a key could wobble or remain rigid but never break. We found that participants’ reaction times were longer when expectations were unmet, not only for typical material behavior but also when those expectations were atypical and learned during the training session. Furthermore, we found an interplay between long-term and newly learned expectations. Overall, our results show that expectations about material properties can impact relatively low-level perceptual decision-making processes.

Subjective time is predicted by local and early visual processing

Time is as pervasive as it is elusive to study, and how the brain keeps track of millisecond time is still unclear. Here we addressed the mechanisms underlying duration perception by looking for a neural signature of subjective time distortion induced by motion adaptation. We recorded electroencephalographic signals in human participants while they were asked to discriminate the duration of visual stimuli after different types of translational motion adaptation. Our results show that perceived duration can be predicted by the amplitude of the N200 event-related potential evoked by the adapted stimulus. Moreover, we show that the distortion of subjective time can be predicted by the activity in the Beta band frequency spectrum, at the offset of the adaptor and during the presentation of the subsequent adapted stimulus. Both effects were observed from posterior electrodes contralateral to the adapted stimulus. Overall, our findings suggest that local and low-level perceptual processes are involved in generating a subjective sense of time.

Encoding speech rate in challenging listening conditions: White noise and reverberation

Temporal contrasts in speech are perceived relative to the speech rate of the surrounding context. That is, following a fast context sentence, listeners interpret a given target sound as longer than following a slow context, and vice versa. This rate effect, often referred to as “rate-dependent speech perception,” has been suggested to be the result of a robust, low-level perceptual process, typically examined in quiet laboratory settings. However, speech perception often occurs in more challenging listening conditions. Therefore, we asked whether rate-dependent perception would be (partially) compromised by signal degradation relative to a clear listening condition. Specifically, we tested effects of white noise and reverberation, with the latter specifically distorting temporal information. We hypothesized that signal degradation would reduce the precision of encoding the speech rate in the context and thereby reduce the rate effect relative to a clear context. This prediction was borne out for both types of degradation in Experiment 1, where the context sentences but not the subsequent target words were degraded. However, in Experiment 2, which compared rate effects when contexts and targets were coherent in terms of signal quality, no reduction of the rate effect was found. This suggests that, when confronted with coherently degraded signals, listeners adapt to challenging listening situations, eliminating the difference between rate-dependent perception in clear and degraded conditions. Overall, the present study contributes towards understanding the consequences of different types of listening environments on the functioning of low-level perceptual processes that listeners use during speech perception.

Inversion Reduces Sensitivity to Complex Emotions in Eye Regions

Inferring humans’ complex emotions is challenging but can be done with surprisingly limited emotion signals, including merely the eyes alone. Here, we test for a role of lower-level perceptual processes involved in such sensitivity using the well-validated Reading the Mind in the Eyes task. Over three experiments, we manipulated configural processing to show that it contributes to sensitivity to complex emotion from human eye regions. Specifically, inversion, a well-established manipulation affecting configural processing, undermined sensitivity to complex emotions in eye regions (Experiments 1-3). Inversion extended to undermine sensitivity to nonmentalistic information from human eye regions (gender; Experiment 2) but did not extend to affect sensitivity to attributes of nonhuman animals (Experiment 3). Taken together, the current findings provide evidence for the novel hypothesis that configural processing facilitates sensitivity to complex emotions conveyed by the eyes via the broader extraction of socially relevant information.

Decoding complex emotions and humanization show related face processing effects.

Inferring others' complex emotions is central to ascribing humanness to others. However, little past research has investigated the perceptual processes linking the inference of complex emotions to judging others' humanness. To this end, we disrupted the low-level perceptual processes typically employed in face processing via face inversion. Of interest was whether the inversion-driven deficits in complex emotion judgments and in humanness judgments were related. In three experiments, we find that disrupting efficient face processing via face inversion undermined the accurate decoding of complex emotions from the eyes (Experiments 1a, 1b, and 2) and triggered more dehumanized evaluations of target eye regions (Experiments 1a and 1b) and faces (Experiment 2). Critically, these inversion effects on emotion decoding and dehumanization were positively correlated. People who demonstrated stronger inversion effects on the accuracy of decoding complex emotions also demonstrated stronger inversion effects on dehumanizing evaluations. Taken together, these findings provide novel evidence that sensitivity to complex emotions and (de)humanization are related through a shared perceptual basis in efficient face processing. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Color Modulates Feature Integration.

Bayesian models of object recognition propose the resolution of ambiguity through probabilistic integration of prior experience with available sensory information. Color, even when task-irrelevant, has been shown to modulate high-level cognitive control tasks. However, it remains unclear how color modulations affect lower-level perceptual processing. We investigated whether color affects feature integration using the flash-jump illusion. This illusion occurs when an apparent motion stimulus, a rectangular bar appearing at different locations along a motion trajectory, changes color at a single position. Observers misperceive this color change as occurring farther along the trajectory of motion. This mislocalization error is proposed to be produced by a Bayesian perceptual framework dependent on responses in area V4. Our results demonstrated that the color of the flash modulated the magnitude of the flash-jump illusion such that participants reported less of a shift, i.e., a more veridical flash location, for both red and blue flashes, as compared to green and yellow. Our findings extend color-dependent modulation effects found in higher-order executive functions into lower-level Bayesian perceptual processes. Our results also support the theory that feature integration is a Bayesian process. In this framework, color modulations play an inherent and automatic role as different colors have different weights in Bayesian perceptual processing.

Fooling the size\u2013weight illusion\u2014Using augmented reality to eliminate the effect of size on perceptions of heaviness and sensorimotor prediction

Augmented reality, whereby computer-generated images are overlaid onto the physical environment, is becoming significant part of the world of education and training. Little is known, however, about how these external images are treated by the sensorimotor system of the user – are they fully integrated into the external environmental cues, or largely ignored by low-level perceptual and motor processes? Here, we examined this question in the context of the size–weight illusion (SWI). Thirty-two participants repeatedly lifted and reported the heaviness of two cubes of unequal volume but equal mass in alternation. Half of the participants saw semi-transparent equally sized holographic cubes superimposed onto the physical cubes through a head-mounted display. Fingertip force rates were measured prior to lift-off to determine how the holograms influenced sensorimotor prediction, while verbal reports of heaviness after each lift indicated how the holographic size cues influenced the SWI. As expected, participants who lifted without augmented visual cues lifted the large object at a higher rate of force than the small object on early lifts and experienced a robust SWI across all trials. In contrast, participants who lifted the (apparently equal-sized) augmented cubes used similar force rates for each object. Furthermore, they experienced no SWI during the first lifts of the objects, with a SWI developing over repeated trials. These results indicate that holographic cues initially dominate physical cues and cognitive knowledge, but are dismissed when conflicting with cues from other senses.

A neurocognitive model of ideological thinking.

Ideological behavior has traditionally been viewed as a product of social forces. Nonetheless, an emerging science suggests that ideological worldviews can also be understood in terms of neural and cognitive principles. The article proposes a neurocognitive model of ideological thinking, arguing that ideological worldviews may be manifestations of individuals' perceptual and cognitive systems. This model makes two claims. First, there are neurocognitive antecedents to ideological thinking: the brain's low-level neurocognitive dispositions influence its receptivity to ideological doctrines. Second, there are neurocognitive consequences to ideological engagement: strong exposure and adherence to ideological doctrines can shape perceptual and cognitive systems. This article details the neurocognitive model of ideological thinking and synthesizes the empirical evidence in support of its claims. The model postulates that there are bidirectional processes between the brain and the ideological environment, and so it can address the roles of situational and motivational factors in ideologically motivated action. This endeavor highlights that an interdisciplinary neurocognitive approach to ideologies can facilitate biologically informed accounts of the ideological brain and thus reveal who is most susceptible to extreme and authoritarian ideologies. By investigating the relationships between low-level perceptual processes and high-level ideological attitudes, we can develop a better grasp of our collective history as well as the mechanisms that may structure our political futures.

Atypical context-dependent speech processing in autism

AbstractThe ability to take contextual information into account is essential for successful speech processing. This study examines individuals with high-functioning autism and those without in terms of how they adjust their perceptual expectation while discriminating speech sounds in different phonological contexts. Listeners were asked to discriminate pairs of sibilant-vowel monosyllables. Typically, discriminability of sibilants increases when the sibilants are embedded in perceptually enhancing contexts (if the appropriate context-specific perceptual adjustment were performed) and decreases in perceptually diminishing contexts. This study found a reduction in the differences in perceptual response across enhancing and diminishing contexts among high-functioning autistic individuals relative to the neurotypical controls. The reduction in perceptual expectation adjustment is consistent with an increase in autonomy in low-level perceptual processing in autism and a reduction in the influence of top-down information from surrounding information.

Angry, old, male - and trustworthy? How expressive and person voice characteristics shape listener trust.

This study examined how trustworthiness impressions depend on vocal expressive and person characteristics and how their dependence may be explained by acoustical profiles. Sentences spoken in a range of emotional and conversational expressions by 20 speakers differing in age and sex were presented to 80 age and sex matched listeners who rated speaker trustworthiness. Positive speaker valence but not arousal consistently predicted greater perceived trustworthiness. Additionally, voices from younger as compared with older and female as compared with male speakers were judged more trustworthy. Acoustic analysis highlighted several parameters as relevant for being perceived as trustworthy (i.e., accelerated tempo, low harmonic-to-noise ratio, more shimmer, low fundamental frequency, more jitter, large intensity range) and showed that effects partially overlapped with those for perceived speaker affect, age, but not sex. Specifically, a fast speech rate and a lower harmonic-to-noise ratio differentiated trustworthy from untrustworthy, positive from negative, and younger from older voices. Male and female voices differed in other ways. Together, these results show that a speaker’s expressive as well as person characteristics shape trustworthiness impressions and that their effect likely results from a combination of low-level perceptual and higher-order conceptual processes.

Revisiting mental rotation with stereoscopic disparity: A new spin for a classic paradigm

To understand how the presence of stereoscopic disparity influences cognitive and neural processing, we recorded participants’ behavior and scalp electrical activity while they performed a mental rotation task. Participants wore active shutter 3D goggles, allowing us to present stimuli with or without stereoscopic disparity on a trial-by-trial basis. Participants were more accurate and faster when stimuli were presented with stereoscopic disparity. This improvement in performance was accompanied by changes in neural activity recorded from scalp electrodes at parietal and occipital regions; stereoscopic disparity produced earlier P2 peaks, larger N2 amplitudes, and earlier, smaller P300 peak amplitudes. The presence of stereoscopic disparity also produced greater neural entropy at occipital electrode sites, and lower entropy at frontal sites. These findings suggest that the nature of the benefit afforded by stereoscopic disparity occurs at both low-level perceptual processing and higher-level cognitive processing, and results in more accurate and rapid performance.

Endogenous fluctuations in the dopaminergic midbrain drive behavioral choice variability

Human behavior is surprisingly variable, even when facing the same problem under identical circumstances. A prominent example is risky decision making. Economic theories struggle to explain why humans are so inconsistent. Resting-state studies suggest that ongoing endogenous fluctuations in brain activity can influence low-level perceptual and motor processes, but it remains unknown whether endogenous fluctuations also influence high-level cognitive processes including decision making. Here, using real-time functional magnetic resonance imaging, we tested whether risky decision making is influenced by endogenous fluctuations in blood oxygenation level-dependent (BOLD) activity in the dopaminergic midbrain, encompassing ventral tegmental area and substantia nigra. We show that low prestimulus brain activity leads to increased risky choice in humans. Using computational modeling, we show that increased risk taking is explained by enhanced phasic responses to offers in a decision network. Our findings demonstrate that endogenous brain activity provides a physiological basis for variability in complex human behavior.

Prediction errors in surface segmentation are reflected in the visual mismatch negativity, independently of task and surface features.

The visual system quickly registers perceptual regularities in the environment and responds to violations in these patterns. Errors of perceptual prediction are associated with electrocortical modulation, including the visual mismatch negativity (vMMN) and P2 event-related potential. One relatively unexplored question is whether these prediction error signals can encode higher-level properties such as surface segmentation, or whether they are limited to lower-level perceptual features. Using a roving standard paradigm, a triangle surface appeared either behind (featuring amodal contours) or in front of (featuring real contours) a second surface with hole-like windows. A surface layout appeared for two to five repetitions before switching to the other "deviant" layout; lighting and orientation of stimuli varied across presentations while remaining isoluminant. Observers responded when they detected a rare "pinched" triangle, which occasionally appeared. Cortical activity-reflected in mismatch responses affecting the P2-N2 and P300 amplitudes-was sensitive to a change in stimulus layout, when surfaces shifted position in depth, following several repetitions. Specifically, layout deviants led to a more negative P2-N2 complex at posterior electrodes, and greater P300 positivity at central sites. Independently of these signals of a deviant surface layout, further modulations of the P2 encoded differences between layouts and detection of the rare target stimulus. Comparison of the effect of preceding layout repetitions on this prediction error signal suggests that it is all or none and not graded with respect to the number of previous repetitions. We show that within the visual domain, unnoticed and task-irrelevant changes in visual surface segmentation leads to observable electrophysiological signals of prediction error that are dissociable from stimulus-specific encoding and lower-level perceptual processing.

Perceptual contributions to racial bias in pain recognition.

The pain of Black Americans is systematically underdiagnosed and undertreated, compared to the pain of their White counterparts. Extensive research has examined the psychological factors that might account for such biases, including status judgments, racial prejudice, and stereotypes about biological differences between Blacks and Whites. Across seven experiments, we accumulated evidence that lower-level perceptual processes also uniquely contribute to downstream racial biases in pain recognition. We repeatedly observed that White participants showed more stringent thresholds for perceiving pain on Black faces, compared to White faces. A tendency to see painful expressions on Black faces less readily arose, in part, from a disruption in configural processing associated with other-race faces. Subsequent analyses revealed that this racial bias in pain perception could not be easily attributed to stimulus features (e.g., color, luminance, or contrast), subjective evaluations related to pain tolerance and experience (e.g., masculinity, dominance, etc.), or objective differences in face structure and expression intensity between Black and White faces. Finally, we observed that racial biases in perception facilitated biases in pain treatment decisions, and that this relationship existed over and above biased judgments of status and strength, explicit racial bias, and endorsement of false beliefs regarding biological differences. A meta-analysis across 9 total experiments (N = 1,289) confirmed the robustness and size of these effects. This research establishes a subtle, albeit influential, perceptual pathway to intergroup bias in pain care and treatment. Implications for racial bias, face perception, and medical treatment are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Angry, old, male - and trustworthy? How expressive and person voice characteristics shape listener trust.

This study examined how trustworthiness impressions depend on vocal expressive and person characteristics and how their dependence may be explained by acoustical profiles. Sentences spoken in a range of emotional and conversational expressions by 20 speakers differing in age and sex were presented to 80 age and sex matched listeners who rated speaker trustworthiness. Positive speaker valence but not arousal consistently predicted greater perceived trustworthiness. Additionally, voices from younger as compared with older and female as compared with male speakers were judged more trustworthy. Acoustic analysis highlighted several parameters as relevant for differentiating trustworthiness ratings and showed that effects largely overlapped with those for speaker valence and age, but not sex. Specifically, a fast speech rate, a low harmonic-to-noise ratio, and a low fundamental frequency mean and standard deviation differentiated trustworthy from untrustworthy, positive from negative, and younger from older voices. Male and female voices differed in other ways. Together, these results show that a speaker’s expressive as well as person characteristics shape trustworthiness impressions and that their effect likely results from a combination of low-level perceptual and higher-order conceptual processes.

International Organization of Psychophysiology

The conceptual properties of a conditional stimulus could contribute to human fear generalization, but how typicality influences fear generalization involving different conceptual hierarchies remains unclear. This study used event-related potential technology to investigate this in four categories of generalized stimulus (GS). We divided the GS into four categories: inferior typical members of conditioned stimulus (CS+) (TCS+), inferior atypical members of CS+ (ATCS+), inferior typical members of CS- (TCS-), and inferior atypical members of CS- (ATCS-). The CS+ groups elicited a larger P2 versus the CS- groups suggesting that aversive stimuli can automatically capture attention with timely avoidance of danger. Stimulus type (CS+; CS-) and typicality (typical; atypical) showed an interaction with N400. The elicited N400 was larger for atypical than typical members in CS- groups, but not in CS+ groups. Fear emotion elicited by CS+ may feature restrained semantic networks, dissipating typicality effects. Separate processing stages may modulate category-based fear generalization, with P2 representing first-stage low-level perceptual processing, and N400 second-stage high-level cognitive processing.