Fundamental Attribution Error

Explaining why people do what they do is the central focus of Social Psychology. These explanations are referred to as Attributions and tend to fall into two categories: Internal and External.

Internal Attributions are those that are explained by invoking core characteristics of a person.

External Attributions are those that can be explained by examining the situation in which (or after which in some cases) they occur.

One way of examining attribution is the Covariation model created by Harold Kelley. In this model, deciding whether attributions are internal or external is generally determined by examining three aspects of the behavior.  These aspects are:

• Consistency (Do they act this way frequently?)
• Distinctiveness (Do they act this way in other situations?)
• Consensus (Do others act this way?)

 So if you have a situation (ie: Sam is an hour late to meet his tutor.) you could use the Covariation model to make a clear attribution as to cause. 

So, Sam is an hour late. 

• Is he frequently late to tutoring ? 
• Yes: High Consistency 
• No: Low Consistency
• Does Sam tend to be late to other meetings? 
• Yes: Low Distinctiveness 
• No: High Distinctiveness
• Do other people tend to be an hour late to tutoring? 
• Yes: High Consensus 
• No: Low Consensus

So, in this example, Sam's behavior could be explained as internal or external depending on how these questions were answered. If he was frequently late to tutoring and other meetings while most people were not late, it would suggest that the reason for his lateness is internal (he's bad at time management). If he was frequently late to tutoring, rarely late to other meetings and others tended to be an hour late to tutoring with this person, it could be assumed that the situation or target was at fault (perhaps the tutor was difficult to find). If he wasn't frequently late to tutoring and rarely late to other meetings and most others were also on time, it could be inferred that the reason for his lateness is a combination of actor and situation (he had car trouble or forgot his books and had to return home for them).

So... 

I actually did have a reason for laying all of that out first. 

All of the previous information is how to make good sound judgements about situations and people, but unfortunately, it also takes a fair amount of practice to keep it straight in your brain and it also tends to require that people keep an open mind until they have enough data to make a good call as to the reason that something happened. That generally doesn't happen. Instead, people tend to take the easy route and blame the actor. This is Fundamental Attribution Error, or the tendency of observers to underestimate situational influences and overestimate dispositional influences on others behavior.

This video provides a fairly good breakdown of the thought process, but unfortunately, I can't embed it on here.