Action Slips

Behavioral Studies of Action Slips

Action slips were first noted in the psychological literature by William James at the end of the 19th century, but they were not systematically investigated until the pioneering diary studies of James Reason in the late 1970s. Reason asked participants to record details of all of their action slips over periods of a week or two. These studies, together with work shortly after by Don Norman, provided a corpus of action errors that has allowed researchers to categorize action slips into a number of classes or types.

One frequent type of slip is the capture error, where actions directed toward an intended goal are “captured” either by a superficially similar sequence of actions with a different goal or by relevant objects in the immediate environment. Reason gives the following example from his study: “I meant to get my car out, but as I passed through the back porch on my way to the garage I stopped to put on my Wellington boots and gardening jacket as if to work in the garden” (Reason, 1979, p. 73). The earlier example concerning the office key might also be seen as an example of a capture error, where the operation of selecting a key is captured by the routine or habit of selecting one's house key.

Further types of error concern the ordering of individual actions within a longer sequence. Thus, an action might be performed before it is appropriate, resulting in an anticipation error. Alternatively, an action might be unnecessarily repeated (a perseverative error, as in the coffee and sugar example earlier) or left out (an omission error). One form of omission error that is particular prevalent is the post completion error. This is an error where the omitted step occurs after successful completion of a task's goal. Common examples include leaving the original documents in the photocopier after successfully making the necessary copies, or leaving the goods on the counter of a shop after paying and collecting the change.

...