# Strategy and Motivation, Rather Than Fatigue, Drive Age‐Related Differences in Sustained Attention Performance: Evidence for Decoupled Beta‐Band Oscillations

## TL;DR

Young and older adults differ in how they perform sustained attention tasks due to strategy and motivation, not fatigue, as shown by brain activity patterns.

## Contribution

The study identifies distinct beta-band EEG signatures linked to age-specific strategies and motivation in sustained attention tasks.

## Key findings

- Young adults used faster but more error-prone strategies, while older adults were slower and more accurate.
- Motivation modulated fronto-parietal beta oscillations, while age-specific strategies were marked by fronto-central beta activity.
- Subjective fatigue increased over time but did not correlate with brain activity measures like prestimulus alpha power.

## Abstract

Reduced vigilance can be captured as attentional lapses in sustained attention tasks, but just how these lapses relate to task‐induced fatigue and motivation to maintain optimal performance across the age span is unclear. We induced fatigue in 18 young (mean age = 22.6 years) and 16 older participants (mean age = 66.5) using the Sustained Attention to Response Task while simultaneously recording electroencephalography (EEG). In the final block, we manipulated motivation levels in half of the participants by offering a financial incentive for best overall performance. We found that the young and older adults differed markedly in their response strategies from the outset (adopting distinct speed‐accuracy trade‐off strategies) with faster/more erroneous responses in the young adults and slower/more accurate responses in the older participants that remained stable over the experiment, while subjective fatigue increased irrespective of group. Poststimulus EEG activity showed two distinguishable beta signatures: a fronto‐central topography as a marker of the age‐specific response strategy and a fronto‐parietal signal modulated by motivation per se. We speculate that these two signatures contribute to offsetting performance declines over time. Finally, although subjective fatigue or mind‐wandering scores and prestimulus alpha power increased with time‐on‐task, we did not identify a correlation between these measures. Hence, strategy and motivation more than fatigue were associated with performance differences across age in a sustained attention task, reflected in decoupled beta signatures.

Markers of vigilance during sustained attention in both young and older participants: stable performance strategies, increase in subjective fatigue, increase in task‐related beta oscillations and distinct brain‐behaviour links.