Full Idea
There is no noncircular way to specify dispositions; for they are dispositions to behave given certain situations, and the situations must be include beliefs about the situation, and desires concerning it.
Clarification
A 'disposition' is potential behaviour, or a tendency to behave in a certain way.
Gist of Idea
Defining dispositions is circular
Source
Gilbert Harman (Thought [1973], 3.3)
Book Reference
Harman,Gilbert: 'Thought' [Princeton 1977], p.41
A Reaction
This is nowadays accepted dogmatically as the biggest objection to behaviourism, but it could be challenged. Your analysis may begin by mentioning beliefs and desires, but if you keep going they may eventually fade out of the picture.