Ambiguous Stimuli Research Articles

A - 63 Neuropsychiatric and Cognitive Correlates of Pareidolias in Dementia with Lewy Bodies.

Pareidolias represent visual illusions of meaningful objects in ambiguous stimuli. Prior research has demonstrated phenomenological similarities between pareidolias and visual hallucinations (VH) and the potential clinical utility of pareidolias in discriminating dementia with Lewy bodies (DLB) from Alzheimer's dementia (ad). Though pareidolias have been linked with VH severity in DLB, the relationships between pareidolias and other neuropsychiatric symptoms have not been explored in large DLB samples. Individuals meeting 2017 McKeith criteria for probable DLB (n = 114) were enrolled in a multi-site systematic longitudinal study of the US DLB Consortium. Study assessments included an informant-rated psychiatric inventory (NPI), Montreal Cognitive Assessment (MoCA), and Noise Pareidolia Task (NPT). Ninety-five participants completed all clinical assessments. To examine baseline relationships between pareidolias responses (NPT) and the presence of 12 neuropsychiatric symptom dimensions (NPI), we used Poisson regression models with robust standard error estimates adjusted for age, education, disease duration, cognition (MoCA), and cholinesterase inhibitor use. Contrary to expectation, the presence of VH was not associated with pareidolias in DLB (Incidence Rate Ratio = 1.37, p = 0.275). The presence of both delusions (IRR = 2.11, p = 0.01) and depression (IRR = 1.79, p = 0.015) was associated with greater pareidolias. Additionally, overall cognitive dysfunction was associated with pareidolias (IRR = 0.90, p < 0.001). Our findings indicate that pareidolias are associated with poorer cognition and neuropsychiatric dimensions beyond VH, including depression and delusions. As pareidolias have been put forth as a surrogate marker of VH in DLB, future studies examining pareidolias in conjunction with comprehensive psychiatric/cognitive assessment and neuroimaging will further elucidate the clinical utility of pareidolia testing.

Serial Dependence in Perception.

Much evidence has shown that perception is biased towards previously presented similar stimuli, an effect recently termed serial dependence. Serial dependence affects nearly every aspect of perception, often causing gross perceptual distortions, especially for weak and ambiguous stimuli. Despite unwanted side-effects, empirical evidence and Bayesian modeling show that serial dependence acts to improve efficiency and is generally beneficial to the system. Consistent with models of predictive coding, the Bayesian priors of serial dependence are generated at high levels of cortical analysis, incorporating much perceptual experience, but feed back to lower sensory areas. These feedback loops may drive oscillations in the alpha range, linked strongly with serial dependence. The discovery of top-down predictive perceptual processes is not new, but the new, more quantitative approach characterizing serial dependence promises to lead to a deeper understanding of predictive perceptual processes and their underlying neural mechanisms.

More than just ambivalence: the perception of emotionally ambiguous words on the spaces of origin and activation indexed by behavioural and webcam-based eye-tracking correlates

AbstractWhen we think about emotional ambiguity, we usually think about the feeling of ambivalence. However, in a recently proposed model, ambiguity might also be present in different emotional spaces, such as origin (dimensions of automaticity and reflectiveness) and activation (arousal and subjective significance) as proposed in the basics of dual-process theories. In two experiments, we checked for behavioural and psychophysical differences in processing words of origin and activation ambiguities while completing an emotionality rating task. In Experiment 1, we assessed emotionality ratings and reaction times; in Experiment 2, we used a webcam-based eye-tracking measurement to assess the number and mean duration of fixations. We found significant effects for words differing in origin and activation: the emotionality ratings increased within the intensity of origin ambiguity but decreased within the intensity of activation ambiguity; more and longer fixations were registered for words of higher origin ambiguity; and gradually fewer and shorter fixations were registered within increases in activation ambiguity. We found that the ambiguities on spaces of origin and activation produced their own main effects, but they also factored significantly into the interaction, modifying each other’s results. Our study is the first to show specifics of the perception of ambiguous stimuli on spaces other than valence.

Studying perceptual bias in favor of the from-above Necker cube perspective in a goal-directed behavior.

When viewing a completely ambiguous image, different interpretations can switch involuntarily due to internal top-down processing. In the case of the Necker cube, an entirely ambiguous stimulus, observers often display a bias in perceptual switching between two interpretations based on their perspectives: one with a from-above perspective (FA) and the other with a from-below perspective (FB). Typically, observers exhibit a priori top-down bias in favor of the FA interpretation, which may stem from a statistical tendency in everyday life where we more frequently observe objects from above. However, it remains unclear whether this perceptual bias persists when individuals voluntarily decide on the Necker cube's interpretation in goal-directed behavior, and the impact of ambiguity in this context is not well-understood. In our study, we instructed observers to voluntarily identify the orientation of a Necker cube while manipulating its ambiguity from low (LA) to high (HA). Our investigation aimed to test two hypotheses: (i) whether the perspective (FA or FB) would result in a bias in response time, and (ii) whether this bias would depend on the level of stimulus ambiguity. Additionally, we analyzed electroencephalogram (EEG) signals to identify potential biomarkers that could explain the observed perceptual bias. The behavioral results confirmed a perceptual bias in favor of the from-above perspective, as indicated by shorter response times. However, this bias diminished for stimuli with high ambiguity. For the LA stimuli, the occipital theta-band power consistently exceeded the frontal theta-band power throughout most of the decision-making time. In contrast, for the HA stimuli, the frontal theta-band power started to exceed the occipital theta-band power during the 0.3-s period preceding the decision. We propose that occipital theta-band power reflects evidence accumulation, while frontal theta-band power reflects its evaluation and decision-making processes. For the FB perspective, occipital theta-band power exhibited higher values and dominated over a longer duration, leading to an overall increase in response time. These results suggest that more information and more time are needed to encode stimuli with a FB perspective, as this template is less common for the observers compared to the template for a cube with a FA perspective.

Conspiracy beliefs are associated with a reduction in frontal beta power and biases in categorizing ambiguous stimuli

Prior beliefs, such as conspiracy beliefs, significantly influence our perception of the natural world. However, the brain activity associated with perceptual decision-making in conspiracy beliefs is not well understood. To shed light on this topic, we conducted a study examining the EEG activity of believers, and skeptics during resting state with perceptual decision-making task. Our study shows that conspiracy beliefs are related to the reduced power of beta frequency band. Furthermore, skeptics tended to misclassify ambiguous face stimuli as houses more frequently than believers. These results help to explain the differences in brain activity between believers and skeptics, especially in how conspiracy beliefs impact the categorization of ambiguous stimuli.

When feeling is for seeing: comparing the effects of motivated perception between fear and anger on ambiguous threatening stimuli.

We do not see the world as it is: distortions of visual perception can occur depending on the goals we wish to achieve ("wishful seeing"). Following functionalist theories of emotions (e.g., "feeling is for doing"), visual perception biases could also be involved in the link between emotion and specific behavior. Previous research has shown that anger can modify visual perception towards ambiguous menacing stimuli, or that fear can similarly direct our attention and perception towards threatening stimuli (e.g., weapons). The aim of our research was to replicate these effects by directly comparing the effects of these two emotions on perceptual biases and by relying on general mixed models to control Type I errors and reduce the risk related to the non-independence between observations. Our results partially replicate a perceptual bias toward threatening objects for both emotions although this effect depends on the type of stimulus and of the emotional dimension involved. These results are discussed in terms of the impact of emotions in attentional and perceptual processes and in relation to alternative theoretical explanations for motivated perception.

Fearful snake pictures make monkeys pessimistic

Judgment bias is the cognitive tendency of animals experiencing negative (or positive) affect to expect undesirable (or favorable) outcomes in ambiguous situations. The lack of examination of judgment biases induced by ecologically relevant stimuli hampers our understanding of the adaptive role of these biases. We examined whether predator-related stimuli, i.e., pictures of snakes, induce a pessimistic judgment bias in Japanese macaques (Macaca fuscata). Our subjects underwent a touchscreen-based Go/No-go judgment bias test. We found that the subjects were less likely and slower to make Go responses to ambiguous stimuli after viewing the snake pictures, indicating that pictures of snakes induce a pessimistic evaluation of ambiguous stimuli. In environments with high levels of threat, behavioral strategies that reduce risk-taking would be evolutionarily advantageous. Hence, an affective response system that lowers expectations of favorable outcomes in ambiguous situations after encountering threat-related stimuli would serve adaptive purposes, such as curbing excessive exploratory behavior.

Post-migration living difficulties and poor mental health associated with increased interpretation bias for threat.

Previous research has found associations between mental health difficulties and interpretation biases, including heightened interpretation of threat from neutral or ambiguous stimuli. Building on this research, we explored associations between interpretation biases (positive and negative) and three constructs that have been linked to migrant experience: mental health symptoms (Global Severity Index [GSI]), Post-Migration Living Difficulties (PMLD), and Perceived Ethnic Discrimination Questionnaire (PEDQ). Two hundred thirty students who identified as first- (n = 94) or second-generation ethnic minority migrants (n = 68), and first-generation White migrants (n = 68) completed measures of GSI, PEDQ, and PMLD. They also performed an interpretation bias task using Point Light Walkers (PLW), dynamic stimuli with reduced visual input that are easily perceived as humans performing an action. Five categories of PLW were used: four that clearly depicted human forms undertaking positive, neutral, negative, or ambiguous actions, and a fifth that involved scrambled animations with no clear action or form. Participants were asked to imagine their interaction with the stimuli and rate their friendliness (positive interpretation bias) and aggressiveness (interpretation bias for threat). We found that the three groups differed on PEDQ and PMLD, with no significant differences in GSI, and the three measured were positively correlated. Poorer mental health and increased PMLD were associated with a heightened interpretation for threat of scrambled animations only. These findings have implications for understanding of the role of threat biases in mental health and the migrant experience.

Hemispheric functional asymmetries and sex effects in visual bistable perception

This study investigates bistable perception as a function of the presentation side of the ambiguous figures and of participants’ sex, to evaluate left–right hemispheric (LH-RH) asymmetries related to consciousness. In two experiments using the divided visual field paradigm, two Rubin's vase-faces figures were projected simultaneously and continuously 180 s long to the left (LVF) and right (RVF; Experiment 1) or to the upper (UVF) and lower (DVF; Experiment 2) visual hemifields of 48 healthy subjects monitored with eye-tracker. Experiment 1 enables stimulus segregation from the LVF to the RH and from the RVF to the LH, whereas Experiment 2 does not. Results from Experiment 1 show that males perceived the face profiles for more time in the LVF than in the RVF, with an opposite trend for the vase, whereas females show a similar pattern of perception in the two hemifields. A related result confirmed the previously reported possibility to have simultaneously two different percepts (qualia) in the two hemifields elicited by the two identic ambiguous stimuli, which was here observed to occur more frequently in males. Similar effects were not observed in Experiment 2. These findings suggest that the percepts display the processing abilities of the hemisphere currently processing the stimulus eliciting them (e.g., RH-faces), and that females and males reflect in bistable perception, a genuine manifestation of consciousness, the well-known hemispheric asymmetry differences they show in ordinary perception.

Neural representations of ambiguous affective stimuli and resilience to anxiety in emerging adults

The tendency to interpret ambiguous stimuli as threatening has been associated with a range of anxiety disorders. Responses to ambiguity may be particularly relevant to mental health during the transition from adolescence to adulthood (“emerging adulthood”), when individuals encounter unfamiliar challenges and navigate novel social situations. However, it remains unclear whether neural representations of ambiguity relate to risk for anxiety. The present study sought to examine whether multivariate representations of ambiguity — and their similarity to representations of threat — relate to appraisals of ambiguity or anxiety in a sample of emerging adults. Participants (N = 41) viewed threatening (angry), nonthreatening (happy), and ambiguous (surprised) facial stimuli while undergoing fMRI. Outside of the scanner, participants were presented with the same stimuli and categorized the ambiguous faces as positive or negative. Using representational similarity analyses (RSA), we investigated whether the degree of pattern similarity in responses to ambiguous, nonthreatening, and threatening faces within the amygdala related to appraisals of ambiguous stimuli and anxiety symptomatology. We found that individuals who evidenced greater similarity (i.e., less differentiation) in neural representations of ambiguous and nonthreatening faces within the left amygdala reported lower concurrent anxiety. Additionally, trial-level pattern similarity predicted subsequent appraisals of ambiguous stimuli. These findings provide insight into how neural representations of ambiguity relate to risk or resilience for the development of anxiety.

Flying enhances viewing from above bias on ambiguous visual stimuli.

The human spatial orientation system is well designed on the ground but is imperfect in the aeronautical three-dimensional (3D) environment. However, human perception systems perform Bayesian statistics based on encountered environments and form shortcuts to improve perceptual efficiency. It is unknown whether our perception of spatial orientation is modified by flying experience and forms perceptual biases. The current study tested pilot perceptual biases on ambiguous visual stimuli, the bistable point-light walkers, and found that flying experiences increased the pilot's tendency to perceive himself as higher than the target and the target as farther away from them. Such perceptual effects due to flight are likely to be attributed to experience of variable vestibular state in a higher position in 3D space, rather than the experience of a higher viewpoint. Our findings suggest that flying experience will modifies our visual perceptual biases, and that more attention should be paid to the enhanced viewing from above bias when flying to avoid overestimating altitude or viewing angle when the visual conditions are ambiguous.

Aggressive and psychopathic traits are linked to the acquisition of stable but imprecise hostile expectations

Individuals with hostile expectations (HEX) anticipate harm from seemingly neutral or ambiguous stimuli. However, it is unclear how HEX are acquired, and whether specific components of HEX learning can predict antisocial thought, conduct, and personality. In an online sample of healthy young individuals (n = 256, 69% women), we administered a virtual shooting task and applied computational modelling of behaviour to investigate HEX learning and its constellation of correlates. HEX acquisition was best explained by a hierarchical reinforcement learning mechanism. Crucially, we found that individuals with relatively higher self-reported aggressiveness and psychopathy developed stronger and less accurate hostile beliefs as well as larger prediction errors. Moreover, aggressive and psychopathic traits were associated with more temporally stable hostility representations. Our study thus shows that aggressiveness and psychopathy are linked with the acquisition of robust yet imprecise hostile beliefs through reinforcement learning.

Tickling and its effects on the affective states of laying hens

Human-animal interactions may significantly influence the productivity and welfare of animals in the livestock industry. The nature of manipulation influences the physiology and behaviour of animals positively or negatively. To improve animal welfare, it is important to not only reduce unwanted negative states (fear, pain, suffering) but also to induce positive affective states in animals. Tickling has been described in multiple studies to evoke positive affective states in rats. We tested whether a similar form of tactile stimulation induces changes in the valence of affective states of laying hens using an operant judgement bias test. Sixteen laying hens housed in deep litter pens were divided into two groups with different forms of manipulation: a handled group (n = 8) or a tickled group (n = 8). First, the animals were trained to discriminate between the positive (PS, pecks rewarded with mealworms) and negative stimuli (NS, pecks punished with white noise) in a visual discrimination task (Go/NoGo). They were then subjected to the judgement bias test, in which responses to PS, NS and ambiguous middle stimulus (MS) were recorded. All hens successfully learned to discriminate between PS and NS. The treatment did not induce changes in judgement bias test performance. Tickling in the manner we administered it and applied in adulthood, did not appear to be perceived by hens as a positive event. The treatment did not affect judgement because the behavioural assay was not sensitive enough to detect a possible effect, or chickens did not find the tickling as administered to be positive enough. Perhaps the other more playful interactions with hens, a larger dosage or the treatment at an early period of life could have greater impact.

Environmental dynamics shape perceptual decision bias.

To interpret the sensory environment, the brain combines ambiguous sensory measurements with knowledge that reflects context-specific prior experience. But environmental contexts can change abruptly and unpredictably, resulting in uncertainty about the current context. Here we address two questions: how should context-specific prior knowledge optimally guide the interpretation of sensory stimuli in changing environments, and do human decision-making strategies resemble this optimum? We probe these questions with a task in which subjects report the orientation of ambiguous visual stimuli that were drawn from three dynamically switching distributions, representing different environmental contexts. We derive predictions for an ideal Bayesian observer that leverages knowledge about the statistical structure of the task to maximize decision accuracy, including knowledge about the dynamics of the environment. We show that its decisions are biased by the dynamically changing task context. The magnitude of this decision bias depends on the observer's continually evolving belief about the current context. The model therefore not only predicts that decision bias will grow as the context is indicated more reliably, but also as the stability of the environment increases, and as the number of trials since the last context switch grows. Analysis of human choice data validates all three predictions, suggesting that the brain leverages knowledge of the statistical structure of environmental change when interpreting ambiguous sensory signals.

Intolerance of uncertainty enhances generalisation of cued conditioned threat: An event-related potential study

Overgeneralisation is one of the aetiologies of anxiety disorders and is closely associated with elevated intolerance of uncertainty (IU) levels. However, the underlying mechanisms are unclear. Considering the inconsistency of previous results and the high sensitivity of IU to uncertainty, the present study investigated the effect of IU on threat generalisation in predictable and unpredictable conditions. We compared self-reported unconditioned stimuli (US) expectancy and event-related potentials (ERPs) during generalisation in high IU (n = 34) and low IU (n = 35) participants. The results indicated that high IU was associated with higher US expectancy for generalisation stimuli (GS) than with low IU. At the electrophysiological level, compared to low IU, high IU showed increased P1 to ambiguous GS as well as decreased early late positive potential (LPP) to GS in unpredictable conditions, and no differential response to GS in late LPP in predictable conditions. These findings suggest that IU enhances threat generalisation and may be related to increased early automatic attention to ambiguous stimulus and inadequate late elaborate processing in a high uncertainty context. These findings might contribute to the treatment of mood disorders characterized by high IU.

Negative interpretation bias connects to real-world daily affect: A multistudy approach.

Negative interpretation bias, the tendency to appraise ambiguous stimuli as threatening, shapes our emotional lives. Various laboratory tasks, which differ in stimuli features and task procedures, can quantify negative interpretation bias. However, it is unknown whether these tasks globally predict individual differences in real-world negative (NA) and positive (PA) affect. Across two studies, we tested whether different lab-based negative interpretation bias tasks predict daily NA and PA, measured via mobile phone across months. To quantify negative interpretation bias, Study 1 (N = 69) used a verbal, self-referential task whereas Study 2 (N = 110) used a perceptual, emotional image task with faces and scenes. Across tasks, negative interpretation bias was linked to heightened daily NA. However, only negative interpretation bias in response to ambiguous faces was related to decreased daily PA. These results illustrate the ecological validity of negative interpretation bias tasks and highlight converging and unique relationships between distinct tasks and naturalistic emotion. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Spontaneous Necker-cube reversals may not be that spontaneous.

During observation of the ambiguous Necker cube, our perception suddenly reverses between two about equally possible 3D interpretations. During passive observation, perceptual reversals seem to be sudden and spontaneous. A number of theoretical approaches postulate destabilization of neural representations as a pre-condition for reversals of ambiguous figures. In the current study, we focused on possible Electroencephalogram (EEG) correlates of perceptual destabilization, that may allow prediction of an upcoming perceptual reversal. We presented ambiguous Necker cube stimuli in an onset-paradigm and investigated the neural processes underlying endogenous reversals as compared to perceptual stability across two consecutive stimulus presentations. In a separate experimental condition, disambiguated cube variants were alternated randomly, to exogenously induce perceptual reversals. We compared the EEG immediately before and during endogenous Necker cube reversals with corresponding time windows during exogenously induced perceptual reversals of disambiguated cube variants. For the ambiguous Necker cube stimuli, we found the earliest differences in the EEG between reversal trials and stability trials already 1 s before a reversal occurred, at bilateral parietal electrodes. The traces remained similar until approximately 1100 ms before a perceived reversal, became maximally different at around 890 ms (p = 7.59 × 10-6, Cohen's d = 1.35) and remained different until shortly before offset of the stimulus preceding the reversal. No such patterns were found in the case of disambiguated cube variants. The identified EEG effects may reflect destabilized states of neural representations, related to destabilized perceptual states preceding a perceptual reversal. They further indicate that spontaneous Necker cube reversals are most probably not as spontaneous as generally thought. Rather, the destabilization may occur over a longer time scale, at least 1 s before a reversal event, despite the reversal event as such being perceived as spontaneous by the viewer.

Joyful by nature: approaches to investigate the evolution and function of joy in non-human animals.

The nature and evolution of positive emotion is a major question remaining unanswered in science and philosophy. The study of feelings and emotions in humans and animals is dominated by discussion of affective states that have negative valence. Given the clinical and social significance of negative affect, such as depression, it is unsurprising that these emotions have received more attention from scientists. Compared to negative emotions, such as fear that leads to fleeing or avoidance, positive emotions are less likely to result in specific, identifiable, behaviours being expressed by an animal. This makes it particularly challenging to quantify and study positive affect. However, bursts of intense positive emotion (joy) are more likely to be accompanied by externally visible markers, like vocalisations or movement patterns, which make it more amenable to scientific study and more resilient to concerns about anthropomorphism. We define joy as intense, brief, and event-driven (i.e. a response to something), which permits investigation into how animals react to a variety of situations that would provoke joy in humans. This means that behavioural correlates of joy are measurable, either through newly discovered 'laughter' vocalisations, increases in play behaviour, or reactions to cognitive bias tests that can be used across species. There are a range of potential situations that cause joy in humans that have not been studied in other animals, such as whether animals feel joy on sunny days, when they accomplish a difficult feat, or when they are reunited with a familiar companion after a prolonged absence. Observations of species-specific calls and play behaviour can be combined with biometric markers and reactions to ambiguous stimuli in order to enable comparisons of affect between phylogenetically distant taxonomic groups. Identifying positive affect is also important for animal welfare because knowledge of positive emotional states would allow us to monitor animal well-being better. Additionally, measuring if phylogenetically and ecologically distant animals play more, laugh more, or act more optimistically after certain kinds of experiences will also provide insight into the mechanisms underlying the evolution of joy and other positive emotions, and potentially even into the evolution of consciousness.

A Computational Model Reveals Learning Dynamics During Interpretation Bias Training With Clinical Applications

BackgroundSome psychopathologies, including anxiety and irritability, are associated with biases when judging ambiguous social stimuli. Interventions targeting these biases, or interpretation bias training (IBT), are amenable to computational modeling to describe their associative learning mechanisms. Here, we translated ALCOVE (attention learning covering map), a model of category learning, to describe learning in youths with affective psychopathology when training on more positive judgments of ambiguous face emotions. MethodsA predominantly clinical sample comprised 71 youths (age range, 8–22 years) representing broad distributions of irritability and anxiety symptoms. Of these, 63 youths were included in the test sample by completing an IBT task with acceptable performance for computational modeling. We used a separate sample of 28 youths to translate ALCOVE for individual estimates of learning rate and generalization. In the test sample, we assessed associations between model learning estimates and irritability, anxiety, their shared variance (negative affectivity), and age. ResultsAge and affective symptoms were associated with category learning during IBT. Lower learning rates were associated with higher negative affectivity common in anxiety and irritability. Lower generalization, or improved discrimination between face emotions, was associated with increasing age. ConclusionsThis work demonstrates a functional consequence of age- and symptom-related learning during interpretation bias. Learning measured by ALCOVE also revealed learning types not accounted for in the prior literature on IBT. This work more broadly demonstrates the utility of measurement models for understanding trial-by-trial processes and identifying individual learning styles.

Pain Catastrophizing Is Associated with a Pattern of Negative Emotional States and a Lack of Positive Emotional Priming

Abstract Pain catastrophizing (PC) is a predictor of pain outcomes that is typified by a host of negative changes in mood and cognition, and there is a need to continue defining PC's role in pain and daily life. This study sought to add to the body of literature on PC by investigating the influence of subconsciously presented cues on the interpretation of otherwise ambiguous stimuli. I assessed 216 participants for PC and completed questionnaires that quantified their emotional state and level of behavioral inhibition before and after being exposed to masked primers for either pain/negative emotion, neutral emotion, or happiness. Participants were then asked to interpret ambiguous stimuli (word stems). It was found that the presentation of unpleasant, pain-related masked images resulted in the generation of more negative words than pleasant, non-pain-related masked images. However, the pleasant images failed to result in lower levels of negative words for catastrophizers, indicating a bias to perceive negativity even in pleasant situations. PC was further found to be associated with more negative affect, greater behavioral inhibition, and higher levels of anxiety, pain, and depression. Catastrophizers reported significant negative emotional valence on several indices and did not benefit from masked priming for positive emotions compared to those with less PC. These findings may be useful in defining the parameters of future studies on PC and could be used by clinicians and physicians attempting to treat patients with chronic pain.