Action bias.
In plain English
Action bias is the pull to act, to feel that doing something beats sitting still, even when the evidence favors doing nothing. Bar-Eli and colleagues documented it in 2007 among elite soccer goalkeepers, who almost always dive left or right on penalty kicks even though staying in the center would stop more shots, because standing still and conceding feels worse than diving and conceding. In money, action bias shows up as tinkering with a portfolio during a scary market when the plan already says hold.
01Why it matters
Acting for the sake of acting adds costs and mistakes, so recognizing action bias helps people see that during volatility, holding to a sound plan is a real choice and often the harder, better one.
02The math, step by step
The market drops sharply and doing nothing feels unbearable, so someone sells or reshuffles. Like the keeper diving on instinct, the move satisfies the urge to act but, against a plan built to ride out drops, tends to lock in losses and add trading costs.
03What this is NOT
It is not the same as good discipline. Discipline can mean deliberately doing nothing when the plan says so. Action bias is acting to relieve the discomfort of stillness, not because acting is the better decision.
04Receipts
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