CONCEPT
Attention Residue
The cognitive trace of an unfinished task that persists in working memory after switching to a new one — contaminating subsequent performance in ways the person cannot detect.
Attention residue is the measurable cognitive cost incurred when a person switches from one task to another before the first is complete. Identified by Sophie Leroy in her 2009 paper, the phenomenon describes how unresolved elements of Task A — its open decisions, emotional investment, and activated representations — continue to occupy working memory resources that Task B requires. The interference is specific rather than general: residue competes directly with new task demands for the limited bandwidth of the central executive. The effect is robust across experimental conditions and invisible to the person experiencing it, who feels busy and productive while performing measurably worse on complex judgments, information integration, and evaluations requiring sustained attention.
In The You On AI Field Guide
The phenomenon operates through a precise cognitive mechanism. When a knowledge worker engages with a problem — designing a feature, debugging code, evaluating a strategic option — her working memory populates with that problem's specific context: variables being tracked, constraints being respected, options being weighed, criteria