Mental Rehearsal

What it is

Mental rehearsal, also called mental practice, is the deliberate, repeated imagining of a task being performed. A pianist silently runs the fingering of a passage. A presenter walks through a pitch before the meeting. A pilot sits with eyes closed and flies a whole sortie in the mind. In each case the person produces the sequence of actions internally and does not make them.

The idea has a longer research history than most of the practices that borrow its name. Early experiments on the effect of imagined practice on later performance date from the 1930s, and the first large meta-analysis of the literature, by Deborah Feltz and Daniel Landers, appeared in 1983. It pooled 60 studies, yielding 146 effect sizes, and found a positive average effect on later performance. It also found that the benefit depended on the kind of task: tasks with a substantial thinking component gained more from mental practice than tasks that were mainly strength or simple movement. A 1994 meta-analysis in the Journal of Applied Psychology by James Driskell, Carolyn Copper and Aidan Moran reached the same direction: a positive and significant effect on performance, moderated by the type of task, the interval between practice and performance and the length of the practice session.

Two laboratory studies are usually cited for the mechanism. Pascual-Leone and colleagues, in 1995, had people practise a piano sequence mentally and reported changes in the motor cortex and gains in performance, smaller than those from physical practice. Ranganathan and colleagues, in 2004, reported that mental training increased finger and elbow strength in small groups. Both studies concern motor rehearsal of a task the person already had some way of performing.

The consistent finding across these sources is that mental practice supplements the real thing. A review chapter for the United States National Research Council that summarised the literature reported average gains of 0.79 standard deviations for physical practice, 0.62 for physical and mental practice combined, and 0.22 for a control group across 48 studies. Mental practice alone does better than none and less than physical practice, according to the vault's verified note, and the research gives no basis for treating it as a replacement.

In effect

In the laboratory

The piano-sequence study is the clearest case. People who practised a sequence only in the mind improved, and changes were reported in the region of the brain that controls movement. The improvement was smaller than for people who played the sequence. The study shows that mental rehearsal can change something real. It does not show that it is as good as doing.

In the cockpit

Hasard Lee, a United States Air Force fighter pilot, describes a version called chair flying in The Art of Clear Thinking (2023). The pilot sits with eyes closed and rehearses an entire flight, repeating any manoeuvre botched in the mind until it comes out right. Lee places the practice at the top of a ladder that begins with simulator repetition and moves up through flights under load, weather and malfunctions. Chair flying supplements the real practice. The book credits the technique to Second World War aviators and cites no study of its effect.

In a plan for an exam

In 1999, Lien Pham and Shelley Taylor asked college freshmen to simulate either the process of studying for a midterm or the outcome of a good grade. Simulating the process increased studying and improved grades. The study concerns a plan and its steps and not a skill, and it is the nearest the research comes to rehearsing a decision. It is described on the process simulation page.

What it does not say

It does not say that imagining a task is as good as doing it. Every comparison in the literature puts physical practice ahead.

It does not say that every kind of mental imagery helps. Gabriele Oettingen's studies of positive fantasies about the future, in which people picture the wished-for result as already achieved, found that such fantasies predicted less effort and poorer outcomes. Rehearsing the steps and picturing the result are different activities with different records.

It does not say that rehearsal improves the quality of a decision. The studies measure performance of a rehearsed task, and none of those cited here scored a decision against a control group.

It does not say the effect lasts. The 1994 meta-analysis found it faded as time passed, and the mechanism studies are small.

The originator attribution on this page is the vault's own and carries medium confidence, because the research has several early roots.

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