Case 001 · Cognitive Fatigue Patterns
The Attritional Day
An analysis of decision degradation across a knowledge-worker cohort
The subject cohort — thirty-two operators across product, research, and finance — reported the same phenomenology by 15:00 local time: a subtle collapse of the ability to distinguish consequential choices from trivial ones. Slack pings, calendar shuffles, and billion-dollar allocations began to feel identical at the moment of contact.
Instrumentation confirmed the report. Reaction-time variance rose by 42% after roughly 180 discrete choices, independent of the cognitive difficulty of any single choice. The bottleneck was never intelligence. It was throughput.
The corrective architecture — pre-committed morning blocks, a formal moratorium on inbound interfaces between 09:00 and 12:00, and a single decision matrix executed once per week — reduced the afternoon collapse in 27 of 32 subjects within three weeks.
Full methodology, control conditions, and instrumentation notes are catalogued in the internal archive and released quarterly.