Mood as input and rumination Ed Watkins*, Adam Mason Department of Psychology, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London, SE5 8AF, UK Received 20 July 2000; received in revised form 14 February 2001; accepted 1 March 2001 Abstract Rumination has been recognised as an important maintaining factor in depression. Adapting the mood- as-input theory to rumination, we hypothesised that high ruminators have a default ‘‘as many as can’’ stop rule for determining when to stop analysing the causes and consequences of any problem, such that nega- tive mood signals insufficient problem solving, leading to recurrent analysis and self-focus (i.e. rumination). To explore this hypothesis, 60 participants were randomly instructed to continue generating reasons for a recent depressed mood under three conditions: an ‘‘as many as you can’’ stop-rule, an ‘‘as long as you feel like continuing’’ stop-rule, and a ‘‘no stop-rule’’ condition. Participants were split into high and low ruminators on a median split on Ruminative Response Scale scores. As predicted, the high ruminators in the ‘‘as many as you can’’ and ‘‘no stop rule’’ conditions produced significantly more reasons for their depressed mood (without significantly differing from each other), than either the high ruminators in the ‘‘feel like continuing’’ condition or the low ruminators in all conditions. These results suggest that high ruminatorsadoptadefault‘‘asmanyascan’’stopruleandthatteachinghighruminatorstousea‘‘feellike continuing’’ rule may reduce rumination. # 2002 Elsevier Science Ltd. All rights reserved. Keywords: Depression; Rumination; Mood-as-input; Stop-rules 1. Introduction Rumination has been increasingly recognised as an important component of depression. Nolen-Hoeksema (1987, 1991) defined rumination as thoughts and behaviours that focus the depressed individual’s attention on his or her symptoms and the possible causes and con- sequences of those symptoms. Rumination therefore includes much of the repetitive and recurrent self-focused thinking found in depression, which includes analysing the reasons for failure and low mood. Such thinking is often characterised by questions, such as ‘‘Why did this happen to 0191-8869/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved. PII: S0191-8869(01)00058-7 Personality and Individual Differences 32 (2002) 577–587 www.elsevier.com/locate/paid * Corresponding author. Tel.: +44-20-7848-0226; fax: +44-20-7-708-3497. E-mail address: e.watkins@iop.kcl.ac.uk (E. Watkins).