Note: Start at the bottom.
MAINTENANCE: practice required for the new behaviour to be consistently maintained, incorporated into the repertoire of behaviours available to a person at any one time
ACTION: people make changes, acting on previous decisions, experience, information, new skills, and motivations for making the change
PREPARATION: person prepares to undertake the desired change - requires gathering information, finding out how to achieve the change, ascertaining skills necessary, deciding when change should take place - may include talking with others to see how they feel about the likely change, considering impact change will have and who will be affected.
CONTEMPLATION: something happens to prompt the person to start thinking about change - perhaps hearing that someone has made changes - or something else has changed - resulting in the need for further change
PRECONTEMPLATION: changing a behaviour has not been considered; person might not realise that change is possible or that it might be of interest to them.
The Behaviour Change Spiral from "What do they want us to do now?" - FAO 1996.