The Effects of Fatigue on Motivation

Fatigue is a ubiquitous experience and can have a profound effect on human behaviour. Diminished motivation is increasingly recognised as an important feature of fatigue. Yet fatigue can manifest in different ways and the role of diminished motivation across different types of fatigue remains poorly understood. Across the three studies, I found that reduced motivation to exert effort was closely linked to persistent, trait-like fatigue, fatigue experienced after sleep loss, and fatigue induced by physical exertion. The main conclusion of this thesis is that diminished motivation constitutes a fundamental feature across different types of fatigue.