If I describe the psychological characteristics of a violent person (e.g., has autism, a brain tumor, or a history of child sexual abuse), does that tend to be heard as absolution for crimes committed? In turn, does that make you skeptical about the value of psychology?
My latest edition of the American Psychologist (2012, v. 67:9) has a brief comment/discussion about the phenomenon of public skepticism of the field of psychology. The comments refer to a previous article published by the same journal earlier in the year. That essay reviewed common reasons for skepticism and how the field should counter them.
I’m not going to discuss the initial article nor whether or not the rebuttals are helpful. What I want to point out is one comment by Newman, Bakina, and Tang. They provide an anecdotal experience of suspicion after making public statements to a newspaper following criminal behavior. They noted that a person wrote a letter to the editor stating, “These remarks consist of convoluted thinking that absolves all participants of any personal responsibility for what happened.” In response, here’s what Newman et. al have to say,
This anecdotal experience reflects a more general finding. Laypeople are suspicious of accounts of human wrongdoing that feature situational/contextual factors (as typical of social-psychological explanations), and they prefer dispositional ones. Clearly, the letter writer would have been much happier if the psychologist’s comments had focused on how cowardly and immoral the [criminals] were. (p. 805, emphasis mine)
Do you agree? Do we prefer characterological reasons for behavior rather than descriptive/contextual discussions? Do we think that discussions of context or mindset absolves others from responsibility for wrong behavior? Having taught physiology to counseling students, I can say that some students find discussions of brain abnormalities (an example of one contextual matter) as tantamount to saying that the person must not be responsible for their actions.
How do we do a better job in being highly descriptive of human behavior without denying moral responsibilities? (i.e., that I cannot help certain matters but yet I am still responsible for what I do)
Musings on Faith and Psychology 
Clearly people prefer dispositional reasons rather than situational reasons when describing human wrongdoing, since we as humans tend to make the fundamental attribution error and overvalue dispositional reasons for behavior over situational ones. I imagine that your students saying that brain abnormalities could result in someone not being responsible for their actions came to that conclusion because they were overemphasizing the effects of those abnormalities, and thus conclude that they not be responsible for the results of something they had little to no control over.