Dissociable Aspects of Mental Workload: Examinations of the P300 Erp Component and Performance Assessments

Abstract

Advanced technologies have enabled the choice of either visual or auditory formats for avionics and surface transportation displays. Methods of assessing the mental workload imposed by displays of different formats are critical to their successful implementation. Towards this end a series of investigations were conducted with the following aims: 1) developing analogous auditory and visual versions of a secondary task that could be used to compare display modalities; and 2) to compare the sensitivity of neurophysiological, behavioral and subjective indices of workload. Experiments 1 and 2 confirmed that analogous auditory and visual secondary oddball discrimination tasks were of equivalent difficulty as indicated by P300 amplitude, RT, accuracy and subjective ratings of workload. Experiments 1-3 revealed that RT and accuracy for target detections were generally more sensitive to changes in primary task difficulty than P300 responses and subjective ratings. However, Experiment 3 indicated that P300 amplitude was sensitive to increased perceptual demands (resulting from driving in heavy fog versus clear visibility) not revealed by changes in either behavioral or subjective indices. Together the results of the current investigations indicate that a battery of assessment techniques will provide the most sensitive assessment of workload in complex environments.

Event-related potentials as indices of mental workload while using an in-vehicle information system

“…However, it failed to detect gradual increases in MWL (i.e., from single to multiple commands conditions), which were better detected by the behavioral measurements. Also, contrary to the predictions of the multiple resource theory, no effects of intramodal combinations of the information system and oddball task were found, which is consistent with other studies (Baldwin and Coyne 2005;Merat and Jamson 2008).…”

“…Similar tasks have been previously used in other studies analyzing the effects of IVIS on operators' MWL (e.g., Baldwin and Coyne 2005;Strayer et al 2015). In each condition, a sequence of high-pitch tones (target, 1200 Hz) and low-pitch tones (standard, 800 Hz) sounds was randomly presented binaurally via headphones (70 dB) at fixed intervals of 1 s. Each tone was presented for 50 ms and the probability ratio was 80% for the standard tones and 20% for the target tones.…”

“…It was observed that those in-vehicle tasks that required verbal and visual interaction (e.g., a speech-to-text e-mail system) significantly decreased P3 amplitude and the performance on a secondary detection task. In another set of studies, Baldwin and Coyne (2005) used a similar setting in which a detection task (i.e., an auditory or a visual oddball task) was used to detect changes in the primary task demands. The primary task consisted of a flight task to be performed while executing a single command (low-demand condition) or multiple commands (high-demand condition) presented via an information system in a visual or auditory modality.…”

“…In many cases, the level of demand has been increased by manipulating the amount of information to be processed (e.g., Allison and Polich 2008;Baldwin and Coyne 2005). However, it is possible that, by itself, this is not enough to increase MWL.…”

“…As in previous studies (Baldwin and Coyne 2005;Strayer et al 2015) different MWL measurements were used, including ERPs. Such measurements were expected to inform about the mental demands placed by the different factors on different stages of processing described in the multiple resource theory (Wickens 2008).…”