Blom Tessel, Mathôt Sebastiaan, Olivers Christian N L, Van der Stigchel Stefan
Department of Experimental Psychology, Helmholtz Institute, Utrecht University.
Aix-Marseille University, CNRS, LPC UMR 7290.
J Exp Psychol Hum Percept Perform. 2016 Nov;42(11):1716-1723. doi: 10.1037/xhp0000252. Epub 2016 Jul 18.
The pupillary light response has been shown not to be a purely reflexive mechanism but to be sensitive to higher order perceptual processes, such as covert visual attention. In the present study we examined whether the pupillary light response is modulated by stimuli that are not physically present but are maintained in visual working memory. In all conditions, displays contained both bright and dark stimuli. Participants were instructed to covertly attend and encode either the bright or the dark stimuli, which then had to be maintained in visual working memory for a subsequent change-detection task. The pupil was smaller in response to encoding bright stimuli compared to dark stimuli. However, this effect did not sustain during the maintenance phase. This was the case even when brightness was directly relevant for the working memory task. These results reveal that the encoding of task-relevant and physically present information in visual working memory is reflected in the pupil. In contrast, the pupil is not sensitive to the maintenance of task-relevant but no longer visible stimuli. One interpretation of our results is that the pupil optimizes its size for perception of stimuli during encoding; however, once stimuli are no longer visible (during maintenance), an "optimal" pupil size no longer serves a purpose, and the pupil may therefore cease to reflect the brightness of the memorized stimuli. (PsycINFO Database Record
瞳孔对光反射已被证明并非纯粹的反射机制，而是对诸如隐蔽视觉注意等高级感知过程敏感。在本研究中，我们考察了瞳孔对光反射是否会受到非实际存在但保持在视觉工作记忆中的刺激的调节。在所有条件下，显示器上都包含明亮和黑暗的刺激。参与者被指示隐蔽地关注并编码明亮或黑暗的刺激，然后这些刺激必须保持在视觉工作记忆中以用于后续的变化检测任务。与黑暗刺激相比，对编码明亮刺激的反应时瞳孔更小。然而，在维持阶段这种效应并未持续。即使亮度与工作记忆任务直接相关时也是如此。这些结果表明，视觉工作记忆中与任务相关且实际存在的信息的编码反映在瞳孔中。相比之下，瞳孔对与任务相关但不再可见的刺激的维持不敏感。我们结果的一种解释是，瞳孔在编码期间为刺激感知优化其大小；然而，一旦刺激不再可见（在维持期间），“最佳”瞳孔大小就不再起作用，因此瞳孔可能不再反映记忆刺激的亮度。（PsycINFO数据库记录）
