The failure to notice a fully visible but unexpected stimulus when attention is focused on another task or object.
From 'in-' (not) + 'attentional' + 'blindness.' Blindness from not attending. Demonstrated by the famous 'invisible gorilla' experiment.
Inattentional blindness is why you can miss a gorilla walking through a basketball game — when you're focused on counting passes, you literally don't SEE it!
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