Centre for Gambling Research at UBC, Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada.
Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
PLoS One. 2022 Jul 25;17(7):e0272070. doi: 10.1371/journal.pone.0272070. eCollection 2022.
Modern slot machines are among the more harmful forms of gambling. Psychophysiological measures may provide a window into mental processes that underpin these harms. Here we investigated pupil dilation derived from eye tracking as a means of capturing changes in sympathetic nervous system arousal following outcomes on a real slot machine. We hypothesized that positively reinforcing slot machine outcomes would be associated with increases in arousal, reflected in larger pupil diameter. We further examined the contribution of game luminance fluctuations on pupil diameter. In Experiment 1A, experienced slot machine gamblers (N = 53) played a commercially-available slot machine in a laboratory for 20 minutes while wearing mobile eye tracking glasses. Analyses differentiated loss outcomes, wins, losses-disguised-as-wins, and (free-spin) bonus features. Bonus features were associated with rapid increases in pupil diameter following the onset of outcome-related audiovisual feedback, relative to losses. In Experiment 1B, luminance data were extracted from captured screen videos (derived from Experiment 1A) to characterize on-screen luminance changes that could modulate pupil diameter. Bonus features and wins were associated with pronounced and complex fluctuations in screen luminance (≈50 L and ≈25L, respectively). However, the pupil dilation that was observed to bonus features in Experiment 1A coincided temporally with only negligible changes in screen luminance, providing partial evidence that the pupil dilation to bonus features may be due to arousal. In Experiment 2, 12 participants viewed pairs of stimuli (scrambled slot machine images) at luminance difference thresholds of ≈25L, ≈50L, and ≈100L. Scrambled images presented at luminance differences of ≈25L and greater were sufficient to cause pupillary responses. Overall, pupillometry may detect event-related changes in sympathetic nervous system arousal following gambling outcomes, but researchers must pay careful attention to substantial in-game luminance changes that may confound arousal-based interpretations.
现代老虎机是更有害的赌博形式之一。心理生理学测量可能为理解这些危害背后的心理过程提供一个窗口。在这里，我们研究了眼动追踪得出的瞳孔扩张，作为一种捕捉真实老虎机结果后交感神经系统唤醒变化的方法。我们假设，积极强化的老虎机结果将与唤醒增加相关，反映在更大的瞳孔直径上。我们进一步研究了游戏亮度波动对瞳孔直径的贡献。在实验 1A 中，有经验的老虎机赌徒（N=53）在实验室中佩戴移动眼动追踪眼镜玩了 20 分钟的商业老虎机。分析区分了损失结果、赢、伪装成赢的损失和（免费旋转）奖金功能。与损失相比，奖金功能与与结果相关的视听反馈开始后瞳孔直径的快速增加相关。在实验 1B 中，从实验 1A 中捕获的屏幕视频中提取亮度数据，以描述可能调节瞳孔直径的屏幕亮度变化。奖金功能和赢与屏幕亮度的明显而复杂的波动有关（分别为≈50L 和≈25L）。然而，在实验 1A 中观察到的对奖金功能的瞳孔扩张与屏幕亮度的微不足道变化同时发生，这提供了部分证据表明，对奖金功能的瞳孔扩张可能是由于唤醒。在实验 2 中，12 名参与者在亮度差阈值为≈25L、≈50L 和≈100L 观看了对刺激（乱序老虎机图像）。呈现亮度差为≈25L 或更大的乱序图像足以引起瞳孔反应。总体而言，瞳孔测量可能会检测到赌博结果后交感神经系统唤醒的与事件相关的变化，但研究人员必须仔细注意可能混淆基于唤醒的解释的大量游戏内亮度变化。
