Which theory describes how we explain others' behavior as being due to internal dispositions or external situations?

This is attribution theory.

Explanation:

This explains the perspective of individual interpretation of events,and how  this  influences  their decision making, thinking and behaviour.It was formulated by Heider  in 1858, but developed  by Jones and Wiener.Generally individuals   tend to  attributes causes to behaviour in order to   provide  reason(s) for an action or events, and  to justify  why people undertake certain actions. And the  theoretical framework for analysing this is the attribution theory.

It Involved three  stage processes

1.The behaviour under investigation must be well perceived by the investigator

2. Then the investigator must have the notion that the action was intentionally undertaken, and not stage to give false impression.

3.The investigator must analyse  to conclude whether individual  was under duress to perform the action (internal dispositions)or  the action was due to influence of another person (external situation).  Based on this the reason  why the individual performs the actions can be understood.

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