horizontal–vertical illusion

the misperception that vertical lines are longer than horizontal lines when both are actually the same length. The vertical element of an upper case letter T, for example, looks longer than the cross bar, even when the lengths are identical. See also foreshortening; Helmholtz square illusion.

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Psychology term of the day

November 28th 2024

fatigue effect

a decline in performance on a prolonged or demanding research task that is generally attributed to the participant becoming tired or bored with the task. The fatigue effect is an important consideration when administering a lengthy survey or test in which participants’ performance may worsen simply due to the challenges of an extended task.