Total Cognitive Load

What knowledge work actually costs, once task load, tool load, and mode-switching load are counted together.

Every interruption destroys a working context. The developer pulled out of deep work by a Slack notification doesn’t lose thirty seconds — they lose the cognitive state it took twenty minutes to build. Organizations measure task load because it has a column in the spreadsheet. They don’t measure tool load or mode-switching load, so those costs show up instead as errors, slower throughput, and burnout — symptoms managed because the cause was never named. Total Cognitive Load names it: every person doing knowledge work is managing a context budget, and most environments spend it before the actual work begins.