Focus of spatial attention during spatial working memory maintenance: Evidence from pupillary light response

ABSTRACT

In this experiment, we demonstrate modulation of the pupillary light response by spatial working memory (SWM). The pupillary light response has previously been shown to reflect the focus of covert attention, as demonstrated by smaller pupil sizes when a subject covertly attends a location on a bright background compared to a dark background. We took advantage of this modulation of the pupillary light response to measure the focus of attention during a SWM delay. Subjects performed two tasks in which a stimulus was presented in the periphery on either the bright or the dark half of a black and white display. Importantly, subjects had to remember the exact location of the stimulus in only one of the two tasks. We observed a modulation of pupil size by background luminance in the delay period, but only when subjects had to remember the exact location. We interpret this as evidence for a tight coupling between spatial attention and maintaining information in SWM. Interestingly, we observed particularly strong modulation of background luminance at the beginning and end of the delay, but not in between. This is suggestive of strategic guidance of spatial attention by the content of spatial working memory when it is task relevant.

KEYWORDS:

• Pupil size
• working memory
• attention

Data availability

All experiment scripts, data, and analysis scripts are available on Open Science Framework, DOI:10.17605/OSF.IO/X6PHN

Acknowledgements

We thank Kees Mulder for useful comments on the statistical analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

T. C. W. Nijboer http://orcid.org/0000-0001-6683-0267

Additional information

Funding

This work was supported by Nederlandse Organisatie voor Wetenschappelijk Onderzoek [grant number 452-13-008].