Changes In Pupil Size Research Articles

Pupillary manifolds: uncovering the latent geometrical structures behind phasic changes in pupil size

The size of the pupils reflects directly the balance of different branches of the autonomic nervous system. This measure is inexpensive, non-invasive, and has provided invaluable insights on a wide range of mental processes, from attention to emotion and executive functions. Two outstanding limitations of current pupillometry research are the lack of consensus in the analytical approaches, which vary wildly across research groups and disciplines, and the fact that, unlike other neuroimaging techniques, pupillometry lacks the dimensionality to shed light on the different sources of the observed effects. In other words, pupillometry provides an integrated readout of several distinct networks, but it is unclear whether each has a specific fingerprint, stemming from its function or physiological substrate. Here we show that phasic changes in pupil size are inherently low-dimensional, with modes that are highly consistent across behavioral tasks of very different nature, suggesting that these changes occur along pupillary manifolds that are highly constrained by the underlying physiological structures rather than functions. These results provide not only a unified approach to analyze pupillary data, but also the opportunity for physiology and psychology to refer to the same processes by tracing the sources of the reported changes in pupil size in the underlying biology.

Role of the medial posterior parietal cortex in orchestrating attention and reaching.

The interplay between attention, alertness and motor planning is crucial for our manual interactions. To investigate the neural bases of this interaction, and challenging the views that attention cannot be disentangled from motor planning, we instructed human volunteers of both sexes to plan and execute reaching movements while attending to the target, while attending elsewhere, or without constraining attention. We recorded reaction times to reach initiation and pupil diameter and interfered with the functions of the medial posterior parietal cortex (mPPC) with online repetitive transcranial magnetic stimulation to test the causal role of this cortical region in the interplay between spatial attention and reaching. We found that mPPC plays a key role in the spatial association of reach planning and covert attention. Moreover, we have found that alertness, measured by pupil size, is a good predictor of the promptness of reach initiation only if we plan a reach to attended targets, and mPPC is causally involved in this coupling. Different from previous understanding, we suggest that mPPC is neither involved in reach planning per se, nor in sustained covert attention in absence of a reach plan, but it is specifically involved in attention functional to reaching.Significance Statement Attention is required to perform dexterous arm movements. In this work we show the neural bases of the interplay between attention and reaching preparation, with the aim to provide information useful to address effective rehabilitation strategies to treat functional deficits observed in attention-related diseases. We discuss how brain areas are involved in orchestrating attention and reaching by signaling the alignment of their spatial coordinates. Moreover, we found that pupil size changes during reach preparation are related to reach initiation, suggesting a coordination between vigilance and reach promptness when preparing a reach to attended targets.

Pupillary dilation response to the auditory food words in adolescents with obesity without binge eating disorder

Childhood obesity is a growing global public health problem. Studies suggest that environmental cues contribute to developing and maintaining obesity. We aimed to evaluate pupillary changes to auditory food words vs. nonfood words and to conduct a dynamic temporal analysis of pupil size changes in adolescents with obesity without binge eating disorder by comparing healthy-weight adolescents. In this study, a total of 63 adolescents aged 12–18 years (n = 32, obesity group (OG); n = 31, control group (CG)) were included. In an auditory paradigm, participants were presented with a series of high and low-calorie food and nonfood words. A binocular remote eye-tracking device was used to measure pupil diameter. Generalized additive mixed models (GAMMs) were used for dynamic temporal analysis of pupillometry data. The results of GAMM analysis indicated that CG had larger pupil dilation than the OG while listening to auditory food words. CG had larger pupil dilation in food words than in nonfood words. However, the OG had a similar pupillary response in food and nonfood words. Pupil dilation response to higher-calorie foods was extended over the later stages of the time period (after 2000 ms) in the OG. In summary, our findings indicated that individuals with obesity had lower pupil dilation to auditory food words compared to normal-weight peers. Adolescents with obesity had prolonged pupillary dilation in higher calories of food words. The individual psychological factors affecting the dynamic changes of pupil responses to food cues in adolescents with obesity should be examined in further studies.

Jacobi-Fourier phase masks as ophthalmic elements to correct presbyopia.

Investigations into the correction of presbyopia have considered lens design, clinical implications and the development of objective metrics such as the visual Strehl ratio. This study investigated the Jacobi-Fourier phase mask as an ophthalmic element in the correction of presbyopia. The goal was to develop a contact or intraocular lens whose performance was largely insensitive to changes in pupil diameter. Numerical simulations based on Fourier optics were performed to evaluate three different Jacobi-Fourier polynomials, with the aim of providing a range of clear vision (1 Dioptre (D)). Performance was evaluated for three pupil sizes (6, 4 and 2 mm), while polychromatic images were simulated using three different wavelengths (656.3, 587.6 and 486.1 nm). The Neural Transfer function was included in the simulation. To validate the method and results, we used the Visual Strehl combined objective metric (VSCombined) currently used in visual optics. This metric gives more weight to the phase transfer function and is more suitable for non-symmetrical phase functions. Numerical validation showed the suitability of the Jacobi-Fourier phase masks for extending the range of clear vision of presbyopic eyes, providing a visual acuity of at least 0.10 logMAR (6/7.5 Snellen) at all distances between 1 and 6 m. The results show a range of clear vision of 1D was not affected by changes in pupil size, an increase in retinal image contrast accompanied by image artefact reduction by increasing the radial order of the Jacobi-Fourier phase mask and a reduction of wavelength dependence of the retinal images. These results are supported by simulated images and the objective criterion VSCombined. The use of Jacobi-Fourier phase masks as ophthalmic elements for presbyopic correction show promising results, with a good range of clear vision andreduced dependence on pupil size and chromatic aberration.

Pupillometry and autonomic nervous system responses to cognitive load and false feedback: an unsupervised machine learning approach.

Pupil dilation is controlled both by sympathetic and parasympathetic nervous system branches. We hypothesized that the dynamic of pupil size changes under cognitive load with additional false feedback can predict individual behavior along with heart rate variability (HRV) patterns and eye movements reflecting specific adaptability to cognitive stress. To test this, we employed an unsupervised machine learning approach to recognize groups of individuals distinguished by pupil dilation dynamics and then compared their autonomic nervous system (ANS) responses along with time, performance, and self-esteem indicators in cognitive tasks. Cohort of 70 participants were exposed to tasks with increasing cognitive load and deception, with measurements of pupillary dynamics, HRV, eye movements, and cognitive performance and behavioral data. Utilizing machine learning k-means clustering algorithm, pupillometry data were segmented to distinct responses to increasing cognitive load and deceit. Further analysis compared clusters, focusing on how physiological (HRV, eye movements) and cognitive metrics (time, mistakes, self-esteem) varied across two clusters of different pupillary response patterns, investigating the relationship between pupil dynamics and autonomic reactions. Cluster analysis of pupillometry data identified two distinct groups with statistically significant varying physiological and behavioral responses. Cluster 0 showed elevated HRV, alongside larger initial pupil sizes. Cluster 1 participants presented lower HRV but demonstrated increased and pronounced oculomotor activity. Behavioral differences included reporting more errors and lower self-esteem in Cluster 0, and faster response times with more precise reactions to deception demonstrated by Cluster 1. Lifestyle variations such as smoking habits and differences in Epworth Sleepiness Scale scores were significant between the clusters. The differentiation in pupillary dynamics and related metrics between the clusters underlines the complex interplay between autonomic regulation, cognitive load, and behavioral responses to cognitive load and deceptive feedback. These findings underscore the potential of pupillometry combined with machine learning in identifying individual differences in stress resilience and cognitive performance. Our research on pupillary dynamics and ANS patterns can lead to the development of remote diagnostic tools for real-time cognitive stress monitoring and performance optimization, applicable in clinical, educational, and occupational settings.

The Effect of Alternating Monocular Instillation of 0.125% Atropine in Korean Children with Progressive Myopia.

Objectives: To identify the effect of alternating monocular instillation (AMI) of 0.125% atropine in Korean children with progressive myopia. Methods: This retrospective single-center study included 120 children with progressive myopia. A total of 60 children (mean age 9.2 ± 2.0 years) wearing glasses who received AMI of 0.125% atropine for one year were allocated to the treatment group. The remaining 60 children (mean age 9.2 ± 1.9 years) with the same refraction, SE, and axial length (AL) who did not receive any treatments except for wearing glasses were allocated to the control group. Ocular findings and the progression rate were compared between the groups pre- and post-treatment, and adverse events were investigated in the treatment group. Results: The mean spherical equivalent (SE) at baseline was -3.87 ± 1.55 D in the control group and -3.90 ± 1.56 D in the treatment group. Pre-treatment SE, age, and AL were similar between the groups; however, post-treatment SE and AL changes were smaller in the treatment group (-0.36 ± 0.46 D/y, 0.21 ± 0.20 mm/year in the treatment group vs. -1.02 ± 0.57 D/y, 0.51 ± 0.20 mm/year in the control group) (Ps < 0.001). The pre-treatment progression rate diminished in the treatment group compared to the control group after one year (p < 0.001), and the changes in pupil size under mesopic and photopic conditions in the treatment group increased by 0.03 ± 0.05 mm and 0.76 ± 0.90 mm, respectively. Regarding adverse events, a tingling sensation was noted in two patients (3.3%) in the treatment group. Conclusions: Alternating monocular 0.125% atropine eye drop instillation may be effective and suitable for progressive myopia in Korean children.

Pupil contagion variation with gaze, arousal, and autistic traits

Pupillary contagion occurs when one’s pupil size unconsciously adapts to the pupil size of an observed individual and is presumed to reflect the transfer of arousal. Importantly, when estimating pupil contagion, low level stimuli properties need to be controlled for, to ensure that observations of pupillary changes are due to internal change in arousal rather than the external differences between stimuli. Here, naturalistic images of children’s faces depicting either small or large pupils were presented to a group of children and adolescents with a wide range of autistic traits, a third of whom had been diagnosed with autism. We examined the extent to which pupillary contagion reflects autonomic nervous system reaction through pupil size change, heart rate and skin conductance response. Our second aim was to determine the association between arousal reaction to stimuli and degree of autistic traits. Results show that pupil contagion and concomitant heart rate change, but not skin conductance change, was evident when gaze was restricted to the eye region of face stimuli. A positive association was also observed between pupillary contagion and autistic traits when participants’ gaze was constrained to the eye region. Findings add to a broader understanding of the mechanisms underlying pupillary contagion and its association with autism.

Blink-induced changes in pupil dynamics are consistent and heritable.

Pupil size and blink rates are heritable but the extent to which they interact with one another has not been properly investigated. Though changes in pupil size due to eye blinks have been reported, they are considered a pupillary artifact. In this study we used the HCP 7T fMRI dataset with resting state eye-tracking data obtained in monozygous and dizygous twins to assess their heritability and their interactions. For this purpose, we characterized the pupil dilation (positive peak) and constriction (negative peak) that followed blink events, which we describe as blink-induced pupillary response (BIPR). We show that the BIPR is highly consistent with a positive dilatory peak (D-peak) around 500ms and a negative constricting peak (C-peak) around 1s. These patterns were reproducible within- and between- subjects across two time points and differed by vigilance state (vigilant versus drowsy). By comparing BIPR between monozygous and dizygous twins we show that BIPR have a heritable component with significant additive genetic (A) and environmental (E) factors dominating the structural equation models, particularly in the time-domain for both D- and C-peaks and amplitude domain for the C-peak. (a2 between 42-49%). Blink duration, pupil size and blink rate were also found to be highly heritable (a2 up to 62% for pupil size). Our study documents an association between BIPR and wakefulness and indicates that BIPR should not be treated as a coincidental artefact, but part of a larger oculomotor system that we label here as Oculomotor Adaptive System, OAS, that is genetically determined.

Inter-individual variability (but intra-individual stability) of overt versus covert rehearsal strategies in a digital Corsi task.

The Corsi (block-tapping) paradigm is a classic and well-established visuospatial working memory task in humans involving internal computations (memorizing of item sequences, organizing and updating the memorandum, and recall processes), as well as both overt and covert shifts of attention to facilitate rehearsal, serving to maintain the Corsi sequences during the retention phase. Here, we introduce a novel digital version of a Corsi task in which i) the difficulty of the memorandum (using sequence lengths ranging from 3 to 8) was controlled, ii) the execution of overt and/or covert attention as well as the visuospatial working memory load during the retention phase was manipulated, and iii) shifts of attention were quantified in all experimental phases. With this, we present behavioral data that demonstrate, characterize, and classify the individual effects of overt and covert strategies used as a means of encoding and rehearsal. In a full within-subject design, we tested 28 participants who had to solve three different Corsi conditions. While in condition A neither of the two strategies were restricted, in condition B the overt and in condition C the overt as well as the covert strategies were suppressed. Analyzing Corsi span, (eye) exploration index, and pupil size (change), data clearly show a continuum between overt and covert strategies over all participants (indicating inter-individual variability). Further, all participants showed stable strategy choice (indicating intra-individual stability), meaning that the preferred strategy was maintained in all three conditions, phases, and sequence lengths of the experiment.

Trustworthiness judgments and pupil-size in individuals with schizophrenia

Individuals with schizophrenia show aberrant processing of social cues. In the current study, we (1) compared trustworthiness ratings of faces between patients with schizophrenia and healthy controls, (2) compared pupillary reactivity between patients and controls (3) examined whether trustworthiness judgments in schizophrenia are related to pupil reactivity, (4) and examined associations between trustworthiness judgements and symptom severity, specifically paranoia. Patients with schizophrenia spectrum disorders (N = 48) and healthy controls (N = 33) completed a Trustworthiness Task, during which their pupil size was measured via an eye-tracking device. The mean baseline-corrected pupil size was calculated from 24 pictures of real neutral faces, each presented for 2500 ms. Self-reported psychotic experiences were measured by Community Assessment of Psychic Functioning (CAPE–42), and symptom severity was rated by Brief Psychiatric Rating Scale (BPRS). No group differences were found in trustworthiness ratings or pupil reactivity parameters during trustworthiness judgments. Separately, among patients, absolute difference in pupil-size change and dilation after reaching minimum size were related to more severe positive symptoms and self-reported paranoia. Our results did not show social cognitive biases in the stable outpatients with schizophrenia, or the role of pupil reactivity in trustworthiness judgments. Future studies should use longer stimuli for pupillary reactivity and control the type and dosage of utilized antipsychotic medication. Further studies are required to explore relationships in larger and more symptomatic groups of patients.

The forgotten wave of early pupillometry research

Changes in pupil size offer a rich, continuous, and integrated neurophysiological readout of attention and cognition. I here briefly reintroduce examples of a vast, forgotten literature, full of inspiring ideas, which described attentional modulations of pupil size decades earlier than often assumed. I outline parallels between these early studies and recent developments in pupillometry.

Using virtual reality to enhance attention for autistic spectrum disorder with eye tracking

Attention deficit disorder is a frequently observed symptom in individuals with autism spectrum disorder (ASD). This condition can present significant obstacles for those affected, manifesting in challenges such as sustained focus, task completion, and the management of distractions. These issues can impede learning, social interactions, and daily functioning. This complexity of symptoms underscores the need for tailored approaches in both educational and therapeutic settings to support individuals with ASD effectively. In this study, we have expanded upon our initial virtual reality (VR) prototype, originally created for attention therapy, to conduct a detailed statistical analysis. Our objective was to precisely identify and measure any significant differences in attention-related outcomes between sessions and groups. Our study found that heart rate (HR) and electrodermal activity (EDA) were more responsive to attention shifts than temperature. The ‘Noise’ and ‘Score’ strategies significantly affected eye openness, with the ASD group showing more responsiveness. The control group had smaller pupil sizes, and the ASD group’s pupil size increased notably when switching strategies in Session 1. Distraction log data showed that both ‘Noise’ and ‘Object Opacity’ strategies influenced attention patterns, with the ‘Red Vignette’ strategy showing a significant effect only in the ASD group. The responsiveness of HR and EDA to attention shifts and the changes in pupil size could serve as valuable physiological markers to monitor and guide these interventions. These findings further support evidence that VR has positive implications for helping those with ASD, allowing for more tailored personalized interventions with meaningful impact.

Neural Mechanisms Determining the Duration of Task-free, Self-paced Visual Perception.

Humans spend hours each day spontaneously engaging with visual content, free from specific tasks and at their own pace. Currently, the brain mechanisms determining the duration of self-paced perceptual behavior remain largely unknown. Here, participants viewed naturalistic images under task-free settings and self-paced each image's viewing duration while undergoing EEG and pupillometry recordings. Across two independent data sets, we observed large inter- and intra-individual variability in viewing duration. However, beyond an image's presentation order and category, specific image content had no consistent effects on spontaneous viewing duration across participants. Overall, longer viewing durations were associated with sustained enhanced posterior positivity and anterior negativity in the ERPs. Individual-specific variations in the spontaneous viewing duration were consistently correlated with evoked EEG activity amplitudes and pupil size changes. By contrast, presentation order was selectively correlated with baseline alpha power and baseline pupil size. Critically, spontaneous viewing duration was strongly predicted by the temporal stability in neural activity patterns starting as early as 350msec after image onset, suggesting that early neural stability is a key predictor for sustained perceptual engagement. Interestingly, neither bottom-up nor top-down predictions about image category influenced spontaneous viewing duration. Overall, these results suggest that individual-specific factors can influence perceptual processing at a surprisingly early time point and influence the multifaceted ebb and flow of spontaneous human perceptual behavior in naturalistic settings.

Measurement of dynamic pupillometry parameters in adult Indian population.

To determine normative dynamic pupillometry data in healthy Indian adults and to investigate the effect of age on various pupillary parameters. Pupillometry measurements were obtained on healthy participants using an automatic dynamic pupillometry device, the NPi-200 (NeurOptics Inc., Irvine, CA, USA). Various measurements, including neurologic pupil index (NPi), resting pupil size (Size), minimum pupil diameter (MIN), percentage change in pupil size (CH), constriction velocity (CV), maximum constriction velocity (MCV), latency (LAT), and dilatation velocity (DV), were obtained in routine clinical settings and analyzed statistically for change with age. A total of 470 participants (470 eyes) were analyzed. Mean NPi was 4.31 ± 0.31, Size was 4.38 ± 0.80 mm, MIN was 2.87 ± 0.49 mm, CH was 34.67 ± 4.15%, CV was 2.74 ± 0.68 mm/s, MCV was 4.16 ± 0.98 mm/s, LAT was 0.23 ± 0.02 s, and DV was 1.13 ± 0.25 mm/s. NPi and LAT were positively correlated (P < 0.01), whereas Size, MIN, CH, CV, MCV, and DV were negatively correlated with age (P < 0.01). No statistically significant difference was observed between males and females. The study offers normative data on dynamic pupillometry parameters across various age groups within a healthy Indian population, which would serve as a reference for future studies in diverse clinical scenarios. It also elucidates that age significantly influences values in the NPi algorithm.

Pupil Response in Visual Tracking Tasks: The Impacts of Task Load, Familiarity, and Gaze Position.

Pupil size is a significant biosignal for human behavior monitoring and can reveal much underlying information. This study explored the effects of task load, task familiarity, and gaze position on pupil response during learning a visual tracking task. We hypothesized that pupil size would increase with task load, up to a certain level before decreasing, decrease with task familiarity, and increase more when focusing on areas preceding the target than other areas. Fifteen participants were recruited for an arrow tracking learning task with incremental task load. Pupil size data were collected using a Tobii Pro Nano eye tracker. A 2 × 3 × 5 three-way factorial repeated measures ANOVA was conducted using R (version 4.2.1) to evaluate the main and interactive effects of key variables on adjusted pupil size. The association between individuals' cognitive load, assessed by NASA-TLX, and pupil size was further analyzed using a linear mixed-effect model. We found that task repetition resulted in a reduction in pupil size; however, this effect was found to diminish as the task load increased. The main effect of task load approached statistical significance, but different trends were observed in trial 1 and trial 2. No significant difference in pupil size was detected among the three gaze positions. The relationship between pupil size and cognitive load overall followed an inverted U curve. Our study showed how pupil size changes as a function of task load, task familiarity, and gaze scanning. This finding provides sensory evidence that could improve educational outcomes.

Ophthalmic findings and parameters in Western tiger salamanders (Ambystoma mavortium) from northern Colorado.

The aim of this study was to document ophthalmic examination findings and provide reference values for ocular examinations and diagnostics in clinically normal Western tiger salamanders (Ambystoma mavortium) and to evaluate the mydriatic effect of a topical rocuronium bromide and identify any adverse effects. Sixteen Western tiger salamanders. A complete ophthalmic examination, including intraocular pressure via rebound tonometry [iCare® TonoVet (dog-setting) or iCare® TonoVet Plus (dog-setting)], and fluorescein and Rose Bengal stains, was performed. Ocular surface flora culture swabs were collected for microbiology in four salamanders. Rocuronium bromide (50 μL; 0.01 mg) was administered into each eye in three salamanders. Pupil size and constriction ability were evaluated up to 60 min following administration of rocuronium bromide. Distant visual examination and Doppler heart rate were used to monitor for potential adverse effects of rocuronium bromide. Observed ocular abnormalities included lipid keratopathy/keratitis (19%; 3/16), parasitic ophthalmitis (19%; 3/16), and cataracts (6.3%; 1/16). A significant difference was found between tonometry with iCare® TonoVet (11.5 ± 2.7 mmHg) versus TonoVet Plus (15.4 ± 3.7 mmHg) (p = .025). Fluorescein and Rose Bengal stains were negative in all salamanders. Ocular surface microbiology revealed a high incidence of contamination from environmental flora, with the most common isolate being unidentified as Gram-negative nonfermenters (75%; 3/4). No significant change in pupil size or constriction ability was observed with rocuronium bromide. This is the first study to document ocular examination findings and diagnostics in captive and wild urodeles and may serve as a reference for clinical assessment and future studies of the Western tiger salamander.

Changes in Pupil Size According to Age, Gender, and Refractive Power during Daytime and Nighttime

Changes in Pupil Size According to Age, Gender, and Refractive Power during Daytime and Nighttime

Emotional content reduces the cognitive effort invested in processing the credibility of social (mis)information.

Emotionality likely is a key factor affecting our susceptibility to misinformation. However, the mechanisms underlying this observation are not well understood. Specifically, when people derive social information from person-related news, they rely predominantly on emotional content, apparently unperturbed by the credibility of the source. To help explain this bias, we here contrast two hypotheses of information processing reflected in changes in pupil size during news-based judgments: Emotion and cognitive effort. Thirty participants were first exposed to websites of well-known trusted or distrusted news media sources exhibiting headlines about unfamiliar persons, followed by social judgments. As expected, emotional relative to neutral headline contents lead to faster and more strongly valenced judgments. In line with the cognitive effort hypothesis, credibility modulated pupil size with larger pupils for headlines from distrusted sources, however only in response to neutral headline contents. Source credibility did not modulate pupil size in response to emotional headline contents. Instead, pupil size was smaller for emotional compared to neutral headlines for both trusted and distrusted sources. This pattern of findings suggests that emotional contents yield fluent social judgments that are made with relatively little mental effort-even if based on untrustworthy news. Cognitive resources to evaluate the credibility of news may primarily be allocated when emotional contents providing (false) fluency are not available. This insight into the biases underlying the processing of potential misinformation may be used as a protection against biased opinions and judgments. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Interpersonal eye-tracking reveals the dynamics of interacting minds.

The human eye is a rich source of information about where, when, and how we attend. Our gaze paths indicate where and what captures our attention, while changes in pupil size can signal surprise, revealing our expectations. Similarly, the pattern of our blinks suggests levels of alertness and when our attention shifts between external engagement and internal thought. During interactions with others, these cues reveal how we coordinate and share our mental states. To leverage these insights effectively, we need accurate, timely methods to observe these cues as they naturally unfold. Advances in eye-tracking technology now enable real-time observation of these cues, shedding light on mutual cognitive processes that foster shared understanding, collaborative thought, and social connection. This brief review highlights these advances and the new opportunities they present for future research.

Are depressive symptoms linked to a reduced pupillary response to novel positive information?-An eye tracking proof-of-concept study.

Depressive symptoms have been linked to difficulties in revising established negative beliefs in response to novel positive information. Recent predictive processing accounts have suggested that this bias in belief updating may be related to a blunted processing of positive prediction errors at the neural level. In this proof-of-concept study, pupil dilation in response to unexpected positive emotional information was examined as a psychophysiological marker of an attenuated processing of positive prediction errors associated with depressive symptoms. Participants (N = 34) completed a modified version of the emotional Bias Against Disconfirmatory Evidence (BADE) task in which scenarios initially suggest negative interpretations that are later either confirmed or disconfirmed by additional information. Pupil dilation in response to the confirmatory and disconfirmatory information was recorded. Behavioral results showed that depressive symptoms were related to difficulties in revising negative interpretations despite disconfirmatory positive information. The eye tracking results pointed to a reduced pupil response to unexpected positive information among people with elevated depressive symptoms. Altogether, the present study demonstrates that the adapted emotional BADE task can be appropriate for examining psychophysiological aspects such as changes in pupil size along with behavioral responses. Furthermore, the results suggest that depression may be characterized by deviations in both behavioral (i.e., reduced updating of negative beliefs) and psychophysiological (i.e., decreased pupil dilation) responses to unexpected positive information. Future work should focus on a larger sample including clinically depressed patients to further explore these findings.