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Our Research Catalogue contains grants and outputs data up to the end of April 2014. Records will no longer be updated after this date.

From incubation to sleep: Effects of sleep on problem solving

Grant reference: RES-000-22-4049

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Impact Report details

From incubation to sleep: Effects of sleep on problem solving
In the Sleep Scientific American Library (1989), Allan Hobson noted: "Not simply the absence of waking, sleep is a special activity of the brain, controlled by elaborate and precise mechanisms. Not simply a state of rest, sleep has its own specific positive functions." A principal area of active functioning of sleep appears to be its effect on problem solving, supported by anecdotal reports on scientific discoveries apparently precipitated by sleep. In a series of studies we have identified key processes involved in finding solutions to problems: we must activate the answer, forget wrong answers, and inhibit misleading information. We have constructed a computational model to implement these processes and related it to a range of studies of problem solving. We have also tested the effect of sleep, compared to same length period of wake, for eliciting problem solutions.

Primary contributor

Author Padraic Monaghan

Additional contributors

Co-author Tom Ormerod


The project has made the following scientific discoveries: 1. Overnight sleep improves problem solving, previously sleep-dependent improvement was only found in nap studies and required the answer was presented to participants in an unrelated task. 2. Overnight sleep improves problem solving particularly for difficult problems, requiring distant information to be activated. 3. Overnight sleep improves problem solving for both verbal and visual/verbal mixed problems. 4. A spreading-activation model of semantic memory characterises participants' problem solving, and sleep boosts the spread of activation. 5. Misleading information affects problem solving in the short term, but incubation of the problem permits forgetting of this information over long time periods (12 hours). Spreading activation peaks after 10 minutes of wake, and then receives an additional boost due to sleep.

The research on overnight sleep improving problem solving, particularly for difficult problems (impacts 1 and 2 above) was reported in Sio, Monaghan & Ormerod (2012), Memory and Cognition. The research on generalisation of sleep-dependent problem solving improvement (impact 3 above) was reported in Sio, Monaghan & Ormerod (2011) at conference presentations at EPS and Cognitive Science Society conference. The modelling work is currently in preparation, but was reported in Monaghan, Ormerod, & Sio (2012) conference presentation at NCPW (impact 4 above). The work on misleading cues, and timescales of forgetting and remembering (impact 5 above) is in our under revision paper (Sio, Monaghan, Ormerod, & Scarna, submitted).

The research was disseminated through presentations at three academic conferences. The work on sleep effect on easy and difficult problem solving was presented at the Experimental Psychology Society conference, London, January 2011 and in a paper presented at the Cognitive Science Society conference, Boston, July 2011. The research on the computational modelling and the effects of misleading information on problem solving were presented at the Neural Computation and Psychology workshop, San Sebastian, July 2012.

Our work has reached UK experimental psychology academics through the EPS, and internationally, multidisciplinary researchers in cognitive science through the Cognitive Science conference. The NCPW conference presented our work to international computer scientists and psychologists interested in information representation in the brain. More specifically, the research on incubation and problem solving resulted in a project at CMU Department of Psychology, led by Ken Kotovsky, continuing this line of work, for which our postdoc Ut Na Sio was hired.

Our work has contributed to public understanding of science, and decision making in particular. Though not demonstrable changes have occurred, our work has reached through media outlets

Our research was widely disseminated through the media, appearing in the following outlets: BBC Radio Lancashire, Drive Time, broadcast 30/10/12, 07:40am. Our work was also featured in Society Now, summer 2012 issue, p.6, and on the front page of Lancaster University webpage (26/10/12-date).

Via dissemination through a talk at the British Science Festival, the premier UK public science communication annual event, in September 2012, through a press release issued through Lancaster University press office, and through a business communication paper submitted through the partnership development office at Lancaster University.

The general daily readership of the Daily Express is 1.7 million. The audience of Radio Lancashire is 202,000. The more specific outlets of Society Now reaches ESRC researchers and research users, and the BPS website reaches both practitioners and academics in the British psychology community. The British Science Association event was covered by local media (Aberdeen) and the presentation was attended by 200 members of the public.

Our work is currently being disseminated to potential industrial collaborators. We have a meeting with Unilever research division to discuss joint work progressing the role of sleep in decision making, problem solving, and creativity. We are working with American Airlines at London Heathrow Airport, where we made a presentation in May 2012 on our sleep research and its impacts for scheduling aviation screening staff shifts to the security managers.AA (Heathrow) are currently examining potential for shift changes as a consequence of our work.

Cite this outcome


Monaghan, Padraic and Ormerod, Tom. From incubation to sleep: Effects of sleep on problem solving: ESRC Impact Report, RES-000-22-4049. Swindon: ESRC


Monaghan Padraic and Ormerod Tom. From incubation to sleep: Effects of sleep on problem solving: ESRC Impact Report, RES-000-22-4049. Swindon: ESRC.