Use when choosing what to read, watch, or follow — run the 'do I want to become this?' test. Use when mentoring someone mirroring their environment without noticing. Use when evaluating a team or company culture — people become like whatever the culture keeps in view.

It converts a vague worry about media and environment into a precise, testable mechanism. You are not merely consuming content; you are becoming like the thing you consume. It gives a concrete standard for choosing what to feed your attention: don't ask 'is this true or entertaining?', ask 'is this a thing I want to become?'