Magnetic Morality Modulation

This September, PBS will re-broadcast an interesting episode of NOVA ScienceNOW, which touches on some points raised in PEL’s interview with Patricia Churchland. The episode demonstrates a procedure called Transcranial Magnetic Stimulation (TMS), which can influence a person’s moral judgments as they are being made, simply by messing with the neural activity located within the brain’s Right TemporoParietal Junction (RTPJ):

If you find the clip interesting, you can find the published research here.

In short, people subjected to TMS were more likely to call “no harm, no foul” when judging instances of attempted, but unsuccessful, evildoing. Here’s a blurb from the study:

When we judge an action as morally right or wrong, we rely on our capacity to infer the actor’s mental states (e.g., beliefs, intentions). Here, we test the hypothesis that the right temporoparietal junction (RTPJ), an area involved in mental state reasoning, is necessary for making moral judgments. In two experiments, we used transcranial magnetic stimulation (TMS) to disrupt neural activity in the RTPJ transiently before moral judgment (experiment 1, offline stimulation) and during moral judgment (experiment 2, online stimulation). In both experiments, TMS to the RTPJ led participants to rely less on the actor’s mental states. A particularly striking effect occurred for attempted harms (e.g., actors who intended but failed to do harm): Relative to TMS to a control site, TMS to the RTPJ caused participants to judge attempted harms as less morally forbidden and more morally permissible. Thus, interfering with activity in the RTPJ disrupts the capacity to use mental states in moral judgment, especially in the case of attempted harms.
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Transiently disrupting RTPJ activity with offline and online repetitive TMS reduced the influence of beliefs on moral judgments. Normal moral judgment often represents a response to a constellation of features, including not only the agent’s beliefs but the agent’s desires, the magnitude of the consequences, the agent’s prior record, the means used by the agent to cause the harm, the external constraints on the agent (e.g., coercion, self-defense), and so on. In the current experiments, we manipulated two of these factors, the agent’s belief and the outcome of the action, and found that the effect of TMS to the RTPJ was specific to the agent’s belief. We found an interaction between TMS site (RTPJ vs. control) and belief (i.e., whether the agent believed he or she would cause harm) in participants’ moral judgments and no interaction involving TMS site and outcome (i.e., whether the harm actually occurred).

TMS did not disrupt participants’ ability to make any moral judgment. On the contrary, moral judgments of intentional harms and nonharms were unaffected by TMS to either the RTPJ or the control site; presumably, however, people typically make moral judgments of intentional harms by considering not only the action’s harmful outcome but the agent’s intentions and beliefs. So why were moral judgments of intentional harms not affected by TMS to the RTPJ? One possibility is that moral judgments typically reflect a weighted function of any morally relevant information that is available at the time. On the basis of this view, when information concerning the agent’s belief is unavailable or degraded, the resulting moral judgment simply reflects a higher weighting of other morally relevant factors (e.g., outcome). Alternatively, following TMS to the RTPJ, moral judgments might be made via an abnormal processing route that does not take belief into account. On either account, when belief information is degraded or unavailable, moral judgments are shifted toward other morally relevant factors (e.g., outcome). For intentional harms and nonharms, however, the outcome suggests the same moral judgment as the intention. Thus, we suggest that TMS to the RTPJ disrupted the processing of negative beliefs for both intentional harms and attempted harms, but the current design allowed us to detect this effect only in the case of attempted harms, in which the neutral outcomes did not afford harsh moral judgments on their own.

-Daniel Horne

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