Title
EEG and eye tracking signatures of target encoding during structured visual search
Author
Brouwer, A.M.
Hogervorst, M.A.
Oudejans, B.A.
Ries, A.J.
Touryan, J.
Publication year
2017
Abstract
EEG and eye tracking variables are potential sources of information about the underlying processes of target detection and storage during visual search. Fixation duration, pupil size and event related potentials (ERPs) locked to the onset of fixation or saccade (saccade-related potentials, SRPs) have been reported to differ dependent on whether a target or a non-target is currently fixated. Here we focus on the question of whether these variables also differ between targets that are subsequently reported (hits) and targets that are not (misses). Observers were asked to scan 15 locations that were consecutively highlighted for 1 s in pseudo-random order. Highlighted locations displayed either a target or a non-target stimulus with two, three or four targets per trial. After scanning, participants indicated which locations had displayed a target. To induce memory encoding failures, participants concurrently performed an aurally presented math task (high load condition). In a low load condition, participants ignored the math task. As expected, more targets were missed in the high compared with the low load condition. For both conditions, eye tracking features distinguished better between hits and misses than between targets and non-targets (with larger pupil size and shorter fixations for missed compared with correctly encoded targets). In contrast, SRP features distinguished better between targets and non-targets than between hits and misses (with average SRPs showing larger P300 waveforms for targets than for non-targets). Single trial classification results were consistent with these averages. This work suggests complementary contributions of eye and EEG measures in potential applications to support search and detect tasks. SRPs may be useful to monitor what objects are relevant to an observer, and eye variables may indicate whether the observer should be reminded of them later.
Subject
EEG
Pupil size
Fixation
SRP
FRP
Visual search
Target detection
BCI
Human & Operational Modelling
PCS - Perceptual and Cognitive Systems
ELSS - Earth, Life and Social Sciences
To reference this document use:
http://resolver.tudelft.nl/uuid:6b141a4b-6849-45ff-87e6-9ccf801e5b70
DOI
https://doi.org/10.3389/fnhum.2017.00264
TNO identifier
762499
Source
Frontiers in Human Neuroscience, 11 (11)
Bibliographical note
1-11
Document type
article