Imagine being awake and yet parts of your brain drift off to “sleep”. Recent research suggests that such a phenomenon can occur in awake humans, therefore bringing into question the assumption that you can only experience sleep when not awake. This study aimed to investigate local sleep in awake, healthy, non-sleep-deprived individuals as a result of performing cognitively demanding tasks. Participants performed the Texture Discrimination Task (TDT), known to cause performance deterioration over time. Electroencephalography (EEG) data was analyzed across multiple sessions to detect localized sleep-like brain activity, particularly in visual cortex regions. The study hypothesized increased local slow-wave activity and decreased task performance over repeated sessions. Behaviorally, the study confirmed that stimulus-onset asynchrony (SOA) thresholds fell over time, indicating a clear reduction in texture-discrimination performance. Methodologically, we successfully implemented a slow-wave detection algorithm in Python. However, the EEG analysis revealed no change in slow-wave density across sessions. Together, these results show that measurable behavioural fatigue can arise in non-sleep-deprived brains during sustained cognitive load without parallel increases in local slow-wave activity. This dissociation challenges our understanding of the causes and functional significance of local sleep-in awake humans.