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Cueing the Necker Cube: Pupil Dilation Reflects the Viewing-From-Above Constraint in Bistable Perception

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Cueing the Necker Cube: Pupil Dilation Reflects the Viewing-From-Above Constraint in Bistable Perception Journal of Vision (2020) 20(4):7, 1–14 1 Cueing the Necker cube: Pupil dilation reflects the viewing-from-above constraint in bistable perception Department of Computer Science and Engineering, Toyohashi University of Technology, Toyohashi, Aichi, Fumiaki Sato Japan Department of Psychology, University of Oslo, Oslo, Norway RITMO Centre for Interdisciplinary Studies in Rhythm, Bruno Laeng Time, and Motion, University of Oslo, Oslo, Norway Department of Computer Science and Engineering, Toyohashi University of Technology, Toyohashi, Aichi, Shigeki Nakauchi Japan Department of Computer Science and Engineering, Toyohashi University of Technology, Toyohashi, Aichi, Tetsuto Minami Japan We hypothesized that a perceptually ambiguous or bistable object (Necker cube) can be more effectively Introduction biased to assume a point of view-from-above (VFA) than from below the object by cueing attention. Participants Our visual system receives two-dimensional viewed a Necker cube in which one surface was information from each image on the retina. From temporarily shaded so as to prime a specific perspective these two-dimensional images, it restores to vision on the cube. Subsequently, the standard (wireframe) the three-dimensional shape of the object, sometimes Necker cube was viewed for 3 seconds, and participants resolving ambiguities in the visual input in an automatic reported what perspective they had seen initially and and unconscious manner. As a way of resolving whether their perception shifted to the alternative perceptual ambiguity, Nakayama and Shimojo (1992) perspective during the brief viewing. Concomitantly, proposed a theoretical framework in which the visual pupil size was monitored with an eye-tracker to obtain system tends to interpret images and surfaces as an index of cognitive effort. There were two conditions: seen from a generic point, instead of an accidental passive viewing and forced attention to sustain the vantage point. In other words, the object properties of initially primed perspective. We confirmed the presence ambiguous images are estimated based on constraints of a VFA bias with forced attention, which was derived from past visual experiences. accompanied by reduced attentional effort, as indexed by a reduced pupil diameter, compared with the Several visual generic principles have been proposed view-from-below. Participants showed no bias during for disambiguating the perception of objects (e.g., the passive viewing. We suggest that the level of intensive light-from-above constraint; Ramachandran, 1988). attention, when retrieving and maintaining a specific The view-from-above (VFA) constraint or heuristic is view from memory, is mirrored in the size of the eye a bias in vision so that whenever the input information pupils and may reflect ecological constraints on visual is ambiguous and consistent with different viewpoints perception. on a same object (Troje & McAdam, 2010), the VFA is preferred in perception over the alternative view-from-below. Kornmeier and colleagues suggested that observers prefer the VFA due to an asymmetry of perceptual experiences or statistical learning, according to which Citation: Sato, F., Laeng, B., Nakauchi, S., & Minami, T. (2020). Cueing the Necker cube: Pupil dilation reflects the viewing-from- above constraint in bistable perception. Journal of Vision, 20(4):7, 1–14, https://doi.org/10.1167/jov.20.4.7. https://doi.org/10.1167/jov.20.4.7 Received December 5, 2018; published April 15, 2020 ISSN 1534-7362 Copyright 2020 The Authors Downloaded from jov.arvojournals.orgThis work ison licensed 02/18/2021 under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. Journal of Vision (2020) 20(4):7, 1–14 Sato, Laeng, Nakauchi, & Minami 2 we more often look down on objects (e.g., artifacts) Several previous studies have investigated voluntary than look up at them (Kornmeier, Hein, & Bach, 2009). control in bistable stimuli (e.g., Strüber & Stadler, 1999; Remarkably, Sundareswara and Schrater (2008) showed Toppino, 2003; Van Ee, Van Dam, & Brouwer, 2005; that the VFA preference of Necker cubes is close to Kornmeier et al., 2009), suggesting that the rate of 100% for very short presentations and declines for long perceptual switching is modulated by voluntary control, exposures, but it remains the most likely interpretation. which seems consistent with our present results. For As these authors pointed out, in Bayesian models example, eye movements and eye position can affect of perception, the visual system tends to choose the perceptual switching, including eye movements or optimal interpretation among alternatives, typically saccades (Toppino, 2003; Van Dam & Van Ee, 2006) the viewpoint with maximal posterior probability. and eye positions (Einhäuser et al., 2004). In this Hence, a Bayesian account suggests that VFA may study, we designed an experimental paradigm that be the most frequent experience with many types of avoids the influence of eye gaze positions by requesting common objects, which are usually manipulated at participants to maintain central fixation during stimulus hand level, and therefore examined from a top view. presentation. Supposedly, the Necker cube may be spontaneously Specifically, priming one particular surface of the interpreted as a representation of some kind of smaller- Necker cube by briefly making it opaque at the start ofa than-the-body box that could be “afforded” by the trial should be more effective in disambiguating the view hands. of the cube whenever the cued surface is consistent with Toppino (2003) suggested that the top-down a VFA than when consistent with a view-from-below activation or priming of perceptual representations (see Figure 1). Moreover, we predicted that when cueing affects a specific interpretation of the cube inthe a surface consistent with a view-from-below, reversals Necker cube. Some studies showed that one can control to the alternative view should be more frequently to some extent the perception of an ambiguous figure reported than when cueing a surface consistent with by focusing on specific portions of the figure, orby a VFA. In all of the earlier described cases, the less intentionally selecting appropriate focal features by “fluent” perspective should be indexed by a larger size using the Necker cube (Kawabata, Yamagami, & of the pupil (cf. Yoshimoto, Imai, Kashino, & Takeuchi, Noakl, 1978) or the so-called “my husband and my 2014) consistent with increased cognitive workload or father-in-law” drawings (Kawabata & Mori, 1992). in intensive attention (Kahneman, 1973). Wernery, Atmanspacher, and Kornmeier (2015) showed Finally, we hypothesize that maintaining the that the dwell time (i.e., periods of transiently stable perception of a specific view may be more likely to percepts), while passively observing the Necker cube for reveal a VFA bias in the forced attention condition than 3 minutes, was longer for the VFA than the one from during passive viewing of the Necker cube. We also note below. Importantly, Meng and Tong (2004) showed that that in previous studies of perceptual switching with selective attention can bias reversals of the perception pupillometry, it has been debated whether perceptual of the Necker cube. switching causes pupil dilation and whether it may be Despite many studies on the VFA bias, most of simply triggered by the motor response (Einhäuser et these are psychophysical experiments in which the al., 2008; Hupe, Lamirel, & Lorenceau, 2009). In this introspective reports of participants are the dependent study, participants’ responses regarding the perspective variable. We reason that evidence for a VFA bias can of perception were collected after the offset of the also be revealed independently by using a physiological stimuli; therefore the present paradigm can separate index. We specifically focused on the method of between the occurrence of a perceptual switch and the pupillometry, which has been previously used to motor response when reporting it. investigate bistable perception (Einhäuser, Stout, Koch, & Carter, 2008). A pupillary dilation temporally close to a reversal in perspective of the Necker cube has been interpreted as a physiological signal of a “reset” mode Experiment 1 in consciousness (for a review, see Laeng, Sirois, & Gredeback, 2012), driven by noradrenergic activity in In the first experiment, we ascertained whether the the brain. In the present study, we use pupillometry as pupil diameter can index reduced effort, as expected if an index of the intensity of cognitive processing or of there is a VFA bias, when viewing a bistable (Necker) attention, as originally suggested by Kahneman (1973), cube. In each trial, either the top or bottom sides of Hess and Polt (1964), Kahneman and Beatty (1966),and the Necker cube was filled-in for 3 seconds with an Just and Carpenter (1993). Specifically, we hypothesized opaque white hue. This was intended to cue attention that if one perspective of the two (above/below) has toward the surface and consequently bias a specific been more frequent in past encounters with similar perspective consistent with a front side position of the objects, then one view-specific memory should be less surface. Subsequently, the surface became transparent, effortful or more “fluent” than the other. and a classic (wireframe) Necker cube was shown for Downloaded from jov.arvojournals.org on 02/18/2021 Journal of Vision (2020) 20(4):7, 1–14 Sato, Laeng, Nakauchi, & Minami 3 Figure 1 . Stimuli used in Experiments 1 and 2 (top and bottom panels, respectively). Figures (A, B, D, and E) were used for priming. Figures (C and F) shows the standard Necker cube. 3 seconds. In a passive viewing blocked condition, Committee for Human Research at the Toyohashi participants simply kept fixation on a cross centered in University of Technology. Participants provided written the middle of the Necker cube. In the forced attention informed consent, and the experiment was conducted condition, the participants were asked to maintain in in accordance with the guidelines of the committee. their perception the perspective that had been initially To ensure adequate statistical power = 0.8 (1 – β; cued, while also keeping central fixation (see Figure 2).
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