Australasian Science: Australia's authority on science since 1938

Transcranial Brainwashing

By Tim Hannan

Is it possible to significantly change a person’s beliefs by stimulating the brain?

Religious convictions and parochial beliefs about racial or national groups are strong motivators of human behaviour, with both beneficial and harmful social consequences. These beliefs play a significant role in human decision-making: when facing a challenge or threat, people are most likely to demonstrate their adherence to religious and political ideologies.

Yet a study reported in Social Cognitive and Affective Neuroscience has reported that the strength of such beliefs may be open to modification through transcranial magnetic stimulation (TMS), with treated participants reporting a diminished degree of agreement with religious statements and less negative attitudes towards immigrants.

Previous studies have established that, when confronted by situations characterised by conflicting values or complex dilemmas, decision-making is strongly influenced by pre-existing and often parochial ideologies. The strength of these beliefs varies across contexts, along with their impact on decisions. Previous research has found that cues for threat tend to elicit stronger expressions of adherence to beliefs, and neuroimaging has demonstrated that the brain region that’s central to invoking relevant beliefs in decision-making is the posterior medial frontal cortex (pMFC).

The study by US and UK researchers recruited 38 undergraduate students, with each reporting they held significant religious beliefs and conservative political views. Participants in the experimental condition received TMS to the pMFC for a period of 40 seconds, a process that reduces neural activity in this region for up to an hour. Control participants underwent a similar process, but with a low level of TMS that has no effect on the functioning of the pMFC.

To induce threat, all participants were asked to write brief comments on the subject of their own death, a task selected due to its association with religious beliefs. The strength of religious belief was subsequently assessed through a questionnaire asking participants to indicate their agreement with statements such as “There exist good personal spiritual beings, whom we might call angels” and “Some people will go to Hell when they die”.

Group prejudice was examined by having participants read an article critical of their country (USA) ostensibly written by a recent immigrant, and assessing their responses through degree of agreement with statements such as “I like the person who wrote this” and “I think this person’s opinions of America are true”.

The researchers found that those who had received TMS reported significantly less conviction in their beliefs concerning God, angels and Heaven following a reminder of death than those in the non-TMS control group. Those receiving TMS rated the immigrant’s article significantly more positively than the non-TMS controls. Together, these findings of reduced religiosity and lessened disparagement of immigrants supported the hypothesis that disruption of the pMFC temporarily weakens the strength of previously established beliefs or attitudes, limiting their effect on decision-making.

How does TMS of the pMFC affect people’s beliefs? The researchers speculated that the pMFC is usually active when a person is confronted with a problem related to conflicting ideological values or insoluble dilemmas, and that it engages relevant belief systems in decision-making. In this experiment, when the participants are primed to think about their own deaths, the pMFC draws upon and amplifies established religious beliefs. When presented with an immigrant’s criticism of their nation’s values, the pMFC elicits and intensifies existing beliefs about “out-group” members. If the pMFC has been experimentally inhibited through application of TMS, the participants are less prone to draw upon these established beliefs, and thus display reduced religiosity and denigration of critical out-group members.

The study illuminates aspects of the neurobiology of belief and decision-making, and demonstrates that it is possible to influence the strength of religious convictions and parochial beliefs through transcranial magnetic stimulation. This is a fascinating notion that also raises profound ethical questions about individuality and the right to one’s own beliefs, however strange or bigoted they might appear to others, or however extreme the behaviours to which they lead.

A/Prof Tim Hannan is Head of the School of Psychology at Charles Sturt University, and the Past President of the Australian Psychological Society.