Brain clutter - what's left undone lingers on

In the editor's choice of the Nov. 19 Science, Gilber Chin does a summary of recent work by Masicampo and Baumeister showing that unconscious unfilled goals can compromise our fluid intelligence.

...They demonstrate that humans suffer from a hangover due to unfulfilled goals: When people were primed to strive for honesty as a goal and then required to write about an episode in which they had acted dishonestly, the induced sense of incompleteness negatively affected their ability to solve anagrams, a task that relies on fluid intelligence. Neither the prime alone nor the recounting of the episode sufficed, and people who had been primed but then wrote about someone else's dishonesty were not similarly afflicted. Furthermore, the unfulfilled goal, though detectable with implicit measures of activation, did not rise to the level of reportable or conscious awareness.

Here is the Masicampo and Baumeister abstract:

Even after one stops actively pursuing a goal, many mental processes remain focused on the goal (e.g., the Zeigarnik effect), potentially occupying limited attentional and working memory resources. Five studies examined whether the processes associated with unfulfilled goals would interfere with tasks that require the executive function, which has a limited focal capacity and can pursue only one goal at a time. In Studies [Study 1] and [Study 2], activating a goal nonconsciously and then manipulating unfulfillment caused impairments on later tasks requiring fluid intelligence (solving anagrams; Study 1) and impulse control (dieting; Study 2). Study 3 showed that impairments were specific to executive functioning tasks: an unfulfilled goal impaired performance on logic problems but not on a test of general knowledge (only the former requires executive functions). Study 4 found that the effect was moderated by individual differences; participants who reported a tendency to shift readily amongst their various pursuits showed no task interference. Study 5 found that returning to fulfill a previously frustrated goal eliminated the interference effect. These findings provide converging evidence that unfulfilled goals can interfere with later tasks, insofar as they require executive functions.