Discussion is a well established method, but it must involve analysis of the processes of argument if it is to be effective in teaching thinking. Underlying all these methods is the principle of metacognition, or self-regulation, as the Europeans call it. Thus learning to learn means taking over from the teacher the control and management of your own learning and thinking. Too readily it is assumed that the strategies learned will be applicable to problem solving generally. Whether we adopt 'programmes' or 'infusion', the critical test in evaluating the teaching of thinking is transfer - whether competence acquired in one context can be applied in a different context.
Programmes aim to teach general skills, but they are 'weak' when it comes to specific applications.
In infusion, we teach specific skills which are 'strong' in their context but tend to be 'weak' in more general application. The general rule is to 'teach for transfer', demonstrating wider application and giving practice in related but different fields. Teaching for transfer of such skills involves practising them until they can be applied unthinkingly. Both forms of transfer are needed, and one needs to know when each is appropriate. For maximising transfer, they recommend 'hugging' and 'bridging'.