Modulation of Neural Activity in the Temporoparietal Junction with Transcranial Direct Current Stimulation Changes the Role of Beliefs in Moral Judgment

Abstract

Judgments about whether an action is morally right or wrong typically depend on our capacity to infer the actor’s beliefs and the outcomes of the action. Prior neuroimaging studies have found that mental state (e.g., beliefs, intentions) attribution for moral judgment involves a complex neural network that includes the temporoparietal junction (TPJ). However, neuroimaging studies cannot demonstrate a direct causal relationship between the activity of this brain region and mental state attribution for moral judgment. In the current study, we used transcranial direct current stimulation (tDCS) to transiently alter neural activity in the TPJ. The participants were randomly assigned to one of three stimulation treatments (right anodal/left cathodal tDCS, left anodal/right cathodal tDCS, or sham stimulation). Each participant was required to complete two similar tasks of moral judgment before receiving tDCS and after receiving tDCS. We studied whether tDCS to the TPJ altered mental state attribution for moral judgment. The results indicated that restraining the activity of the right temporoparietal junction (RTPJ) or the left the temporoparietal junction (LTPJ) decreased the role of beliefs in moral judgments and led to an increase in the dependance of the participants’ moral judgments on the action’s consequences. We also found that the participants exhibited reduced reaction times both in the cases of intentional harms and attempted harms after receiving right cathodal/left anodal tDCS to the TPJ. These findings inform and extend the current neural models of moral judgment and moral development in typically developing people and in individuals with neurodevelopmental disorders such as autism.

Electric stimulation of the right temporo-parietal junction induces a task-specific effect in deceptive behaviors

“…right). Although there have been several TMS and tDCS studies stimulating rTPJ (Mai et al, 2016;Santiesteban et al, 2012Santiesteban et al, , 2015Sellaro et al, 2015;Sowden et al, 2015;Ye et al, 2015), this is the first study, to our knowledge, reporting an influence of the rTPJ stimulation on performances of deceptive behaviors.…”

“…The tDCS was delivered with two saline-soaked surface electrodes (size: 5 × 7 cm 2 ) connected to a constant-current stimulator (DC-STIMULATOR Plus, neuroConn GmbH, Germany). In the rTPJ session, an anodal electrode was placed over central parietal 6 (CP6), according to the international EEG 10/20 system (Santiesteban et al, 2012;Sellaro et al, 2015;Sowden et al, 2015;Ye et al, 2015). A cathodal electrode was positioned over the vertex (Cz) of each participant as a reference.…”

Autism‐relevant traits interact with temporoparietal junction stimulation effects on social cognition: a high‐definition transcranial direct current stimulation and electroencephalography study

“…Though the impacts of varying protocols are complex (Horvath et al ., ), anodal tDCS generally promotes depolarisation of resting membrane potentials in underlying cortical tissue (increasing rates of neuronal firing), while cathodal tDCS is understood to increase hyperpolarisation and reduce firing rates (Nitsche et al ., ). tDCS studies suggest TPJ modulation can influence performance in tasks involving mentalising (or related constructs such as moral reasoning, cognitive empathy, visual perspective taking, imitation inhibition, humour appreciation, lie detection, vicarious experience and integrating top‐down and bottom‐up attention) (Santiesteban et al ., ; Sellaro et al ., ; Slaby et al ., ; Sowden et al ., ; Wu et al ., ; Ye et al ., ; Leloup et al ., ; Mai et al ., ; Vandenbroucke et al ., ). This study also improves on prior methodologies using high‐definition transcranial direct current stimulation (HD‐tDCS) rather than standard tDCS.…”

Using tDCS to Explore the Role of the Right Temporo-Parietal Junction in Theory of Mind and Cognitive Empathy

“…More recently, using tDCS, several studies reported that the application of anodal or cathodal stimulation over the rTPJ could modulate the belief attribution ( Sellaro et al, 2015 ; Sowden et al, 2015 ; Ye et al, 2015 ). Sellaro et al (2015) found that participants who received anodal stimulation assigned less blame to accidental harms compared to participants who received cathodal or sham stimulation, emphasizing the role of rTPJ in mediating the belief attribution for moral judgements.…”