Moral reasoning can have specific psychometric meaning than is inconsistent with lay interpretations of moral reasoning.
''Professor Simon Baron-Cohen suggests that, unlike the combination of both reduced cognitive and affective empathy often seen in those with classic autism, psychopaths are associated with intact cognitive empathy, implying non-diminished awareness of another’s feelings when they hurt someone.[57] Moral judgment
Psychopaths have been considered notoriously amoral – an absence of, indifference towards, or disregard for moral beliefs. There are few firm data on patterns of moral judgment, however. Studies of developmental level (sophistication) of moral reasoning found all possible results – lower, higher or the same as non-psychopaths. Studies that compared judgments of personal moral transgressions versus judgments of breaking conventional rules or laws, found that psychopaths rated them as equally severe, whereas non-psychopaths rated the rule-breaking as less severe.[58]
A study comparing judgments of whether personal or impersonal harm would be endorsed in order to achieve the rationally maximum (utilitarian) amount of welfare, found no significant differences between psychopaths and non-psychopaths. However, a further study using the same tests found that prisoners scoring high on the PCL were more likely to endorse impersonal harm or rule violations than non-psychopaths were. Psychopaths who scored low in anxiety were also more willing to endorse personal harm on average.[58]
Assessing accidents, where one person harmed another unintentionally, psychopaths judged such actions to be more morally permissible. This result is perhaps a reflection of psychopaths’ failure to appreciate the emotional aspect of the victim’s harmful experience, and furnishes direct evidence of abnormal moral judgment in psychopathy.[59]" - Wikipedia
So says the title of an interesting recent paper I stumbled on yesterday (ungated link; h/t Chris Bertram). Here's the abstract:
This conclusion is very much along the lines of some of my recent LW comments (for example, those I left in this thread). To me it seems quite obvious that in the space of possible human minds, those that produce on the whole reasonably cooperative and reliably non-threatening behavior are overwhelmingly unlikely to produce utilitarian decisions in trolley-footbridge and similar "sacrificial" problems.
Of course, what people say they would do in situations of this sort is usually determined by signaling rather than a realistic appraisal. Kind and philosophical utilitarians of the sort one meets on LW would be extremely unlikely to act in practice according to the implications of their favored theories in real-life "sacrificial" situations, so their views are by themselves not strong evidence of antisocial personality traits. However, actually acting in such ways would be, in my opinion, very strong evidence for such traits, which is correctly reflected in the typical person's fear and revulsion of someone who is known to have acted like that. I would venture to guess that it is in fact the signaling-driven disconnect between people's endorsement of utilitarian actions and the actual decisions they would make that makes the found correlations fairly low. (Assuming also that these tests really are strong indicators of antisocial personalities, of course, which I lack the knowledge to judge.)
(Also, endorsement of utilitarianism even just for signaling value causes its own problems, since it leads to political and ideological support for all sorts of crazy ideas backed by plausible-sounding utilitarian arguments, but that's a whole different issue.)
Here is also a full citation for reference: “The mismeasure of morals: Antisocial personality traits predict utilitarian responses to moral dilemmas”, by Daniel M. Bartels and David A. Pizarro, Cognition 121 (2011), pp. 154-161.
Edit: As Wei Dai points out in a comment, I should also add that some of the previous literature cited by Bartels and Pizarro has concluded that, in their words, "individuals with higher working memory capacity and those who are more deliberative thinkers are... more likely to approve of utilitarian solution." One the face of it, taken together with the conclusions of this paper, this would mean that propensity for utilitarian responses may stem from different causes in different individuals (i.e. deliberative thinking versus antisocial traits).
My own hypothesis, however, is that deliberative thinking leads to verbal utilitarian responses that are likely due to signaling, and that propensity for actual utilitarian "sacrificial" acts would have a much weaker link to deliberative thinking and a much stronger link to antisocial traits than mere utilitarian statements. Unfortunately, I don't know how this could be tested empirically in an ethical manner.