Motivation is at once one of the most exciting and one of the most troubling areas of psychology. In asking what makes us human, motivation seems to hold the key to some of the most profound questions about our existence. And yet, by asking what drives human nature, it also exposes our dark hearts.

Vansteenkiste & Sheldon (2006) touch on these ideas in an article published in The British Journal of Clinical Psychology which attempts an integration of Self-Determination Theory (SDT) and Motivational Interviewing (MI). In this article the authors look for, and find, many commonalities between these two theories. It turns out SDT has a considerable theoretical contribution to make towards MI, which, itself, was largely an intuitive atheoretical creation.

Still, I find myself with mixed feelings about this article. One major reason why I admire Vansteenkiste & Sheldon's (2006) work is that it focuses on the integration of ideas. It searches for, and finds, links between the theoretical and practical domains such that each is informed by the other. Bearing in mind previous discussions on unity in psychology, this has to be applauded.

On the other hand, for me there is a problem with the fundamental assumptions of both SDT and MI. As essentially humanistic theories, they assume people already have the potential for positive change within them. In other words, by implication, it assumes people will choose goals and behaviours that are good for them.

Goals, presumably, come from needs. SDT identifies three main needs for which humans search. The first is a need for competence, the second a need for autonomy and the third a need for relatedness. All three, apparently good, positive, humanistic needs. Admittedly SDT does not constrain the world of motivational drives to just these three, but nevertheless these are thought, within this theory, to be the most important. Does that really cover everything?

For me it is difficult to reconcile even a small proportion of the human evil in the world with these three needs. Perhaps I'm not being creative enough: when I kill people I want to be good at it, to choose who I kill and to have backup. Does that satisfy the needs for competence, autonomy and relatedness?

Pulling my head back out of the clouds and thinking about the implementation of MI, however, there is an argument that this meta-theoretical quibbling is not practically relevant. SDT is a content-free theory so clients and therapists choose those motivations which are applied. Theoretically, then, it would be possible to use it to implant any types of motivation in another person; although, of course, if these were detrimental to the individual, extremely unethical. We would then have to assume the therapist discerns what is good for the client, or can help the client towards that realisation.

Vansteenkiste, M., & Sheldon, K. M. (2006). There's nothing more practical than a good theory: integrating motivational interviewing and self-determination theory. British Journal of Clinical Psychology, 45, 63-82. (Abstract)