Individual difference of the Mental Workload observed by P300

Fujii, Tatsufumi · 2012 · Crossref

DOI: 10.4992/pacjpa.76.0_3pma45

archive: archived pipeline: cataloged verified

Get this paper ↗ (DOI — opens at the source; we link to it, we don't host it)

Summary

This study investigates individual differences in mental workload, specifically examining how working memory (WM) capacity influences the P300 event-related potential (ERP) components, P3a and P3b. Mental workload is known to impair attention and task performance, while P300 components serve as physiological markers of attentional allocation: P3a reflects passive attention to irrelevant stimuli, and P3b reflects active attention to task-relevant targets. Although previous research suggests that WM capacity affects these responses, this study aims to clarify these individual differences within a single task framework by manipulating cognitive load levels. The experiment involved 21 participants (mean age 21.14 years) who were divided into high and low WM capacity groups based on their performance on a Japanese reading span test and a Stroop task. The study was conducted over two days. On the first day, difficulty levels for an auditory oddball task were calibrated for each participant. On the second day, EEG data were recorded while participants performed the oddball task under two conditions: low load (large sound pressure difference between standard and target stimuli, resulting in 80–100% accuracy) and high load (small sound pressure difference, resulting in 50–60% accuracy). Participants were instructed to silently count target stimuli and ignore non-targets. EEG electrodes were placed at Fz, Cz, and Pz, with data filtered and artifact-corrected. Subjective mental workload was assessed using the Japanese version of the NASA-TLX after each condition. The results revealed a significant interaction between WM span score, load condition, and electrode position for P3a amplitude. Specifically, in the high-load condition, the high WM span group exhibited larger P3a amplitudes at the Fz electrode compared to the low span group. This suggests that individuals with higher WM capacity allocate more attentional resources to irrelevant stimuli when under high cognitive demand, possibly due to a tendency to divide attention across multiple stimuli. For P3b, a significant interaction between load condition and electrode position was found, with larger amplitudes observed in the low-load condition at Cz and Pz electrodes. However, no significant group differences were found for P3b, likely because the task did not require complex cognitive processing that would differentiate WM capacities. The findings indicate that WM capacity influences attentional allocation under high mental workload, as evidenced by enhanced P3a responses in high-capacity individuals. This implies that high WM capacity individuals may maintain broader attentional monitoring even when primary task demands are high. The study highlights the utility of P300 components in assessing individual differences in mental workload and suggests that the nature of the task and load level significantly modulate these physiological responses. These insights contribute to understanding how cognitive resources are managed under varying demands, with potential implications for designing tasks that account for individual cognitive differences.

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed.

Summary generated by qwen3.6-27b-nvidia on 2026-08-10; verification: verified.

Topics

Ranked by relevance to this paper. Hover a topic for its definition.

• neuro workload indices