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Local darkness (LD 0 ) averaged across participants versus pupil diameter change PC 1 averaged across participants, for the images of five themes in Experiment 1.

Local darkness (LD 0 ) averaged across participants versus pupil diameter change PC 1 averaged across participants, for the images of five themes in Experiment 1.

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Several papers by Eckhard Hess from the 1960s and 1970s report that the pupils dilate or constrict according to the interest value, arousing content, or mental demands of visual stimuli. However, Hess mostly used small sample sizes and undocumented luminance control. In a first experiment (N = 182) and a second preregistered experiment (N = 147), w...

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... same meaning in English and Dutch. The words were presented in a black outline of 2-pixel thickness, in Mangal font with a height of 253 pixels (4.5 • ) from the top of the ascenders to the bottom of the descenders (151 pixels or 2.7 • when excluding ascenders and descenders) and a width between 387 pixels (6.9 • ) and 1288 pixels (22.7 • ) (see Fig. J5 for an example). Table 2 shows the twelve words together with their ratings of valence, arousal, and ...
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... (original vs. modern) and image theme as within-subject factors showed a significant difference between original and modern images, = 0.88) indicates that local darkness is theme-specific. For example, the two 'Male' images yielded low LD 0 because participants initially looked at the male's body, which was bright, and not at the dark background. Fig. 5 shows a scatter plot of LD 0 averaged across participants versus PC 1 averaged across participants. The strong correlation (Pearson's r = 0.89, p < 0.001, n = 10 images) suggests that the initial pupil constriction was due to the luminance of the location where people looked when the side ...
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... measurements were conducted in batches of three slide changes, as the recording time of the camera at this frequency was limited to 4 s. (2) Video and sound of a continuous sequence of 24 slide changes were recorded at 50 Hz with the camera positioned in front of the viewing aperture of the box and pointing towards the projection screen (see Fig. D5 for the experimental configuration and Fig. D7, top right, for the corresponding camera view). (3) The luminance of the projection screen (defined as the amount of light reflected from a surface) was measured during a sequence of 24 slide changes using a luminance meter (Konica Minolta LS-150) positioned in front of the viewing ...
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... for the corresponding view from the location of the luminance meter -that is, the same as in Measurement series 2). (4) Videos of 24 pushbutton presses were recorded at 1000 Hz, together with the projection of the slide on the screen, in batches of three slide changes, with the camera positioned in front of the viewing aperture of the box (see Fig. D5 for the experimental configuration and Fig. D7, bottom, for a corresponding camera ...

Citations

... According to this point, we raise two possibilities. First, the pupillary light response is enhanced by focused attention (Binda et al., 2013;Mathôt et al., 2013;De Winter et al., 2021). Derksen et al. (2018) conducted several experiments with luminance-controlled and luminance-not-controlled stimuli of static and dynamic pupils of various sizes, and indicated that the pupil contagion phenomenon occurs due to luminance and participants' attention shift toward the eye region. ...
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Pupil contagion is the phenomenon in which an observer’s pupil-diameter changes in response to another person’s pupil. Even chimpanzees and infants in early development stages show pupil contagion. This study investigated whether dynamic changes in pupil diameter would induce changes in infants’ pupil diameter. We also investigated pupil contagion in the context of different faces. We measured the pupil-diameter of 50 five- to six-month-old infants in response to changes in the pupil diameter (dilating/constricting) of upright and inverted faces. The results showed that (1) in the upright presentation condition, dilating the pupil diameter induced a change in the infants’ pupil diameter while constricting the pupil diameter did not induce a change, and (2) pupil contagion occurred only in the upright face presentation, and not in the inverted face presentation. These results indicate the face-inversion effect in infants’ pupil contagion.
... The characteristics of the approaches and protocols used for measuring pupillary responses for the studies included in this meta-analysis is summarized in Table 2. The majority of studies confirmed sexual interests of the participants with a measure of self-report sexual orientation (k = 15), while four studies (De Winter et al., 2021;Hamel, 1974;Scott et al., 1967) did not record sexual orientation and instead assumed all participants were heterosexual. All included studies used images (k = 15) or video footage (k = 4) comprising either an adult male or female presented completely nude (k = 5), partially nude (i.e., sexual regions only obscured with clothing or image manipulation; k = 5), dressed (k = 1), or mixed stimulus sets depicting people in a range of explicitness (i.e., a mixture of nude, partially nude, and dressed images; k = 8). ...
... The specific effects of stimulus type and approach to measuring pupillary response are difficult to untangle because the three categories of explicitness (fully nude, partial or no nudity, and mixed nudity) do not span across the different types of pupillary response measures. For heterosexual men, for example, all studies with partially nude stimuli in the meta-analysis also applied EyeLink eye trackers to measure pupil response (Attard-Johnson et al., 2016;De Winter et al., 2021), while none of the studies using other techniques (i.e., SMI/Tobii eye trackers, manual measurement) included comparable stimuli of in low explicitness. In contrast, fully nude stimuli were employed by studies using EyeLink (Rieger et al., 2013;Watts et al., 2018) and SMI eye trackers (Finke et al., 2018), but not by any of the studies with Tobii eye trackers or manual pupil measurement. ...
... We also cannot exclude the possibility that other moderating factors could have contributed to this finding. For example, studies in both these subcategories included participants who were not asked to report their sexual orientation and were therefore assumed to be of heterosexual orientation (for example, De Winter et al., 2021;Hamel, 1974;Scott et al., 1967). Yet, the prevalence of same-sex behavior is reported to be higher in women compared to men (Diamond, 2016) with a difference of around 9% (7% of men versus 16% of women; Mercer et al., 2013). ...
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Objective measures of sexual interest are important for research on human sexuality. There has been a resurgence in research examining pupil dilation as a potential index of sexual orientation. We carried out a meta-analytic review of studies published between 1965 and 2020 (Mdn year = 2016) measuring pupil responses to visual stimuli of adult men and women to assess sexual interest. Separate meta-analyses were performed for six sexual orientation categories. In the final analysis, 15 studies were included for heterosexual men (N = 550), 5 studies for gay men (N = 65), 4 studies for bisexual men (N = 124), 13 studies for heterosexual women (N = 403), and 3 studies for lesbian women (N = 132). Only heterosexual and gay men demonstrated discrimination in pupillary responses that was clearly in line with their sexual orientation, with greater pupil dilation to female and male stimuli, respectively. Bisexual men showed greater pupil dilation to male stimuli. Although heterosexual women exhibited larger pupils to male stimuli compared to female stimuli, the magnitude of the effect was small and non-significant. Finally, lesbian women displayed greater pupil dilation to male stimuli. Three methodological moderators were identified—the sexual explicitness of stimulus materials, the measurement technique of pupillary response, and inclusion of self-report measures of sexual interest. These meta-analyses are based on a limited number of studies and are therefore preliminary. However, the results suggest that pupillary measurement of sexual interest is promising for men and that standardization is essential to gain a better understanding of the validity of this measurement technique for sexual interest.
... New methods of design and time series analysis hold promise for improving the rigor of pupillometry. Yet, the field remains limited by an anemic history of replication (but see de Winter et al., 2021) and the lack of age-stratified norms against which effect sizes might be derived. A deeper understanding of the neural and neuromuscular substrates of the cognitive pupil response function is essential for understanding which cognitive processes are indexed by specific parameters and how these parameters might be selectively perturbed. ...
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This chapter presents an accessible overview of methodological considerations, open questions, and solutions to common problems encountered conducting a valid and reliable cognitive pupillometry study. Topics include historical evolution of pupillary measurement techniques, parameterization of the human task-evoked (cognitive) pupil response, individual differences, and idiosyncratic anatomical constraints imposed by the human eye.
... When using stimulus spectra along the Planckian locus for triggering the pupil light response, it is essential in measurements that amplitudes in the range of 0.1 to 0.4 mm are captured accurately to specify intrasubject variability (Kobashi et al., 2012) in a pupil model. However, a special requirement for pupil measurements arises when the pupil is used as a biomarker for quantifying the cognitive state (Morad et al., 2000;Merritt et al., 2004;Murphy et al., 2014;Ostrin et al., 2017;Tkacz-Domb and Yeshurun, 2018;Hu et al., 2019;Van Egroo et al., 2019;de Winter et al., 2021;Van der Stoep et al., 2021) or clinical symptoms of diseases (Hreidarsson, 1982;Maclean and Dhillon, 1993;Connelly et al., 2014;Lim et al., 2016;Granholm et al., 2017;Wildemeersch et al., 2018;Chougule et al., 2019). Cognitive processes such as memory load, arousal, circadian status, or sleepiness have a transient impact (Watson and Yellott, 2012) on the pupil diameter with aperture changes of 0.015 to 0.53 mm (Beatty and Wagoner, 1978;Beatty, 1982;Schluroff et al., 1986;Jepma and Nieuwenhuis, 2011;Pedrotti et al., 2014;Bombeke et al., 2016;Tsukahara et al., 2016;Winn et al., 2018), making the reproducibility of such effects difficult if the accuracy of the measurement equipment has not been sufficiently validated. ...
Article
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The human pupil behavior has gained increased attention due to the discovery of the intrinsically photosensitive retinal ganglion cells and the afferent pupil control path’s role as a biomarker for cognitive processes. Diameter changes in the range of 10 –2 mm are of interest, requiring reliable and characterized measurement equipment to accurately detect neurocognitive effects on the pupil. Mostly commercial solutions are used as measurement devices in pupillometry which is associated with high investments. Moreover, commercial systems rely on closed software, restricting conclusions about the used pupil-tracking algorithms. Here, we developed an open-source pupillometry platform consisting of hardware and software competitive with high-end commercial stereo eye-tracking systems. Our goal was to make a professional remote pupil measurement pipeline for laboratory conditions accessible for everyone. This work’s core outcome is an integrated cross-platform (macOS, Windows and Linux) pupillometry software called PupilEXT, featuring a user-friendly graphical interface covering the relevant requirements of professional pupil response research. We offer a selection of six state-of-the-art open-source pupil detection algorithms (Starburst, Swirski, ExCuSe, ElSe, PuRe and PuReST) to perform the pupil measurement. A developed 120-fps pupillometry demo system was able to achieve a calibration accuracy of 0.003 mm and an averaged temporal pupil measurement detection accuracy of 0.0059 mm in stereo mode. The PupilEXT software has extended features in pupil detection, measurement validation, image acquisition, data acquisition, offline pupil measurement, camera calibration, stereo vision, data visualization and system independence, all combined in a single open-source interface, available at https://github.com/openPupil/Open-PupilEXT .
... PD s,[11][12][13][14][15][16][17][18][19][20][21][22][23][24]R s,[11][12][13][14][15][16][17][18][19][20][21][22][23][24]and VA s,[11][12][13][14][15][16][17][18][19][20][21][22][23][24]and PDC max,s,[11][12][13][14][15][16][17][18][19][20][21][22][23][24] were computed between 11 and 24 s. That is, we omitted the first and the last 1 s of the stimulus slides, consistent with Hess and Polt (1964) and De Winter, Petermeijer, Kooijman, and Dodou (2021). A potential issue is that the first few seconds of pupil diameter follow a similar pattern regardless of mental demand (e.g., Marquart & De Winter, 2015). ...
... Accordingly, PDC resp is intended to be more responsive to mental demands than PDC. PD c,7.5− 10 , R c,7.5− 10 , and VA c,7.5− 10 were computed between 7.5 and 10 s (De Winter et al., 2021;Hess & Polt, 1964). We used the last 2.5 s of control slide to compute the baseline to avoid including possible effects from the preceding stimulus. ...
... There are examples in the literature where a shorter baseline period has been used (e.g., 0.4 s in Klingner, 2010, 1 s in Geangu, Hauf, Bhardwaj, & Bentz, 2011). However, averaging over a longer baseline duration is preferable when the mean pupil diameter has become stable as it is more robust to noise in the pupil diameter recordings (De Winter et al., 2021). ...
Article
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Much psychological research uses pupil diameter measurements for investigating the cognitive and emotional effects of visual stimuli. A potential problem is that accommodating at a nearby point constricts the pupil. This study examined to what extent accommodation is a confounder in pupillometry research. Participants solved multiplication problems at different distances (Experiment 1) and looked at line drawings with different monocular depth cues (Experiment 2) while their pupil diameter, refraction, and vergence angle were recorded using a photorefractor. Experiment 1 showed that the pupils dilated while performing the multiplications, for all presentation distances. Pupillary constriction due to accommodation was not strong enough to override pupil dilation due to cognitive load. Experiment 2 showed that monocular depth cues caused a small shift in refraction in the expected direction. We conclude that, for the young student sample we used, pupil diameter measurements are not substantially affected by accommodation.
... 1. Pupil diameter change (PDC in mm): The subtractive difference between the mean pupil diameter for the stimulus slide ���� ,11−24 and the mean pupil diameter for the preceding control slide ���� ,7.5−10 (e.g., Mathôt ���� ,11−24 , � ,11−24 , and ���� ,11−24 , and , ,11−24 were computed between 11 and 24 s. That is, we omitted the first and the last 1 s of the stimulus slides, consistent with Hess and Polt (1964) and De Winter, Petermeijer, Kooijman, and Dodou (2020). A potential issue is that the first few seconds of pupil diameter follow a similar pattern regardless of mental demand (e.g., Marquart & De Winter, 2015). ...
... Accordingly, PDCresp is intended to be more responsive to mental demands than PDC. ���� ,7.5−10 , � ,7.5−10 , and ���� ,7.5−10 were computed between 7.5 and 10 s (De Winter et al., 2020;Hess & Polt, 1964). We used the last 2.5 s of control slide to compute the baseline to avoid including possible effects from the preceding stimulus. ...
... There are examples in the literature where a shorter baseline period has been used (e.g., 0.4 s in Klingner, 2010, 1 s in Geangu, Hauf, Bhardwaj, & Bentz, 2011). However, averaging over a longer baseline duration is preferable when the mean pupil diameter has become stable as it is more robust to noise in the pupil diameter recordings (De Winter et al., 2020). ...
Preprint
Full-text available
Much psychological research uses pupil diameter measurements for investigating the cognitive and emotional effects of visual stimuli. A potential problem is that accommodating at a nearby point constricts the pupil. This study examined to what extent accommodation is a confounder in pupillometry research. Participants solved multiplication problems and looked at line drawings with monocular depth cues while their eyes were recorded using a photorefractor. The results showed that the pupils dilated, especially for hard multiplications. However, refraction changes were not large enough to explain the pupil diameter changes. The monocular depth cues caused a small shift in refraction in the expected direction. The results further suggest a link between eye movements, refraction, and pupil diameter. We conclude that, for the type of cognitive task and young student sample we used, pupil diameter measurements are not confounded by accommodation. However, the effect of eye movements in pupillometry needs further consideration.
... Before the experiment, participants completed a standard EyeLink nine-dot calibration procedure. Participants first looked at a number of stimuli as part of an unrelated pupillometry study lasting about 15 min (De Winter, Petermeijer, Kooijman, & Dodou, 2020). Next, the IT experiment started. ...
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Inspection Time (IT) is regarded as one of the simplest psychometric indexes for intelligence, as it supposedly does not involve motor activity. Early research has interpreted IT as a pure index of mental speed, but more recent studies indicate that IT is associated with various higher-level cognitive mechanisms, including focused attention, learning, and the strategic use of perceived visual illusions. The extent to which these factors affect IT is presently a source of debate. Herein, we used an eye-tracking device to capture participants' (N = 147) visual attention within IT trials. Results showed that blinking was time-variant, with participants not blinking at the task-critical moment of the presentation of the target stimulus (known as the 'Pi' figure). An analysis of learning curves showed that response accuracy improved with task experience. Blinking during the presentation of the Pi-figure correlated negatively with response accuracy. Further analyses showed that participants who reported seeing a brightness illusion had a higher response accuracy and responded faster than those who did not. In conclusion, performance at the IT task is affected by learning and does involve motor activity, with the inhibition of blinking being helpful in the IT task. Visually experienced illusions may be an epiphenomenon of understanding the IT task.
... Before the experiment, participants completed a standard EyeLink nine-dot calibration procedure. Participants first looked at a number of stimuli as part of an unrelated pupillometry study lasting about 15 min (De Winter, Petermeijer, Kooijman, & Dodou, 2020). Next, the IT experiment started. ...
Article
Full-text available
In the inspection time (IT) paradigm, participants view two lines of unequal length (called the Pi-figure) for a short exposure time, and then judge which of the two lines was longer. Early research has interpreted IT as a simple index of mental speed, which does not involve motor activity. However, more recent studies have associated IT with higher-level cognitive mechanisms, including focused attention, task experience, and the strategic use of visual illusions. The extent to which these factors affect IT is still a source of debate. We used an eye-tracker to capture participants’ (N = 147) visual attention while performing IT trials. Results showed that blinking was time-dependent, with participants blinking less when the Pi-figure was visible, as compared to before and after. Blinking during the presentation of the Pi-figure correlated negatively with response accuracy. Also, participants who reported seeing a brightness illusion had a higher response accuracy than those who did not. The first experiment was repeated with new participants (N = 159), enhanced task instructions, and the inclusion of practice trials. Results showed substantially improved response accuracy compared to the first experiment, and no significant difference in response accuracy between those who did and did not report illusions. IT response accuracy correlated modestly (r = 0.18) with performance on a short Raven’s advanced progressive matrices task. In conclusion, performance at the IT task is affected by task familiarity and involves motor activity in the form of blinking. Visual illusions may be an epiphenomenon of understanding the IT task.
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A variety of psychological and physical phenomena elicit variations in the diameter of pupil of the eye. Changes in pupil size are mediated by the relative activation of the sphincter pupillae muscle (decrease pupil diameter) and the dilator pupillae muscle (increase pupil diameter), innervated by the parasympathetic and sympathetic branches, respectively, of the autonomic nervous system. The current guidelines are intended to inform and guide psychophysiological research involving pupil measurement by (1) summarizing important aspects concerning the physiology of the pupil, (2) providing methodological and data‐analytic guidelines and recommendations, and (3) briefly reviewing psychological phenomena that modulate pupillary reactivity. Because of the increased ease and tractability of pupil measurement, the goal of these guidelines is to promote accurate recording, analysis, and reporting of pupillary data in psychophysiological research. This report provides guidelines for publishing pupillary studies in psychophysiology. In addition to reporting criteria, there are general recommendations, and background on physiology and recording techniques for pupillary studies
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The present study investigated the effect of background luminance on the self-reported valence ratings of auditory stimuli, as suggested by some earlier work. A secondary aim was to better characterise the effect of auditory valence on pupillary responses, on which the literature is inconsistent. Participants were randomly presented with sounds of different valence categories (negative, neutral, and positive) obtained from the IADS-E database. At the same time, the background luminance of the computer screen (in blue hue) was manipulated across three levels (i.e., low, medium, and high), with pupillometry confirming the expected strong effect of luminance on pupil size. Participants were asked to rate the valence of the presented sound under these different luminance levels. On a behavioural level, we found evidence for an effect of background luminance on the self-reported valence rating, with generally more positive ratings as background luminance increased. Turning to valence effects on pupil size, irrespective of background luminance, interestingly, we observed that pupils were smallest in the positive valence and the largest in negative valence condition, with neutral valence in between. In sum, the present findings provide evidence concerning a relationship between luminance perception (and hence pupil size) and self-reported valence of auditory stimuli, indicating a possible cross-modal interaction of auditory valence processing with completely task-irrelevant visual background luminance. We furthermore discuss the potential for future applications of the current findings in the clinical field.