Multiple-Time-Scale Analysis of Attention as Revealed by EEG, NIRS, and Pupil Diameter Signals During a Free Recall Task: A Multimodal Measurement Approach.

Takashi Numata,Hiroki Sato,Masashi Kiguchi

doi:10.3389/fnins.2019.01307

Takashi Numata, Hiroki Sato + Show 1 more

Open Access

https://doi.org/10.3389/fnins.2019.01307

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Abstract

Attention plays a fundamental role in acquiring and understanding information. Therefore, it is useful to evaluate attention objectively in such fields as education and mental health. Aimed at extracting objective indicators of attention from physiological signals, this study examined the characteristics of electroencephalography (EEG), near-infrared spectroscopy (NIRS), and pupil diameter signals during a free recall task. The objective was to clarify the temporal characteristics of these signals in relation to attention. We used a free recall task as a cognitive task with an attentional load. The participants attempted to memorize and then recall 13 serially presented words. Our hypothesis was that the significant physiological responses should differ depending on the time scale of the attention evaluation. The physiological responses were compared on the basis of differences between success and failure to recall a word on a short time scale, in terms of the attentional state among five serial position groups on a middle time scale, and on the basis of differences between trials with many and few words recalled on a long time scale. We found that the response of each physiological signal depended on the attention in the different time-scale comparisons. (1) The P300 amplitudes of the EEG signals for the words that were recalled were significantly higher than those for the words that were not recalled. (2) Pupillary dilation differed significantly depending on the serial position group. (3) Functional connectivity in the right hemisphere revealed by NIRS was significantly stronger in trials with many words recalled than in those with few words recalled. Different temporal characteristics of physiological signals with respect to attention were suggested by multimodal measurement and multiple-time-scale analysis. Consideration of these characteristics should help in the development of applications requiring objective attention evaluation.

Highlights

Attention is a cognitive process that involves acquiring and understanding information
Post hoc testing revealed that the success rate for the first serial position group was significantly better than that for the fourth one (p < 0.01)
Physiological Responses Regarding the physiological responses, P300 was observed in the EEG signals for all channels after word presentation (Figure 3B)

Summary

Introduction

Attention is a cognitive process that involves acquiring and understanding information. The quantity and quality of information acquired and the degree of understanding depend on the strength of the attention. Since the strength depends on the person’s current state and the external environment, practical applications and techniques for sharpening attention have been developed in various fields, including education (Schmidt, 1995; Lin, 2011), advertising (Pechmann and Stewart, 1990), marketing (Pieters et al, 2002), and mental health (Schmidt et al, 2009; Tamm et al, 2010). To develop effective interventions and techniques for improving attention, it is important to evaluate attention objectively because doing so enables the effects of interventions and techniques to be quantified and attention to be sharpened appropriately on the basis of the person’s current attention

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