The main objective of this study is to investigate the causal relationship between prefrontal cortex activity and antisocial behavior, as well as risk factors for antisocial behavior. Specifically, this study tests the hypothesis that upregulating activity in the prefrontal cortex through a non-invasive form of brain stimulation, transcranial direct current stimulation (tDCS) will reduce antisocial and aggressive behavior. The effects of 3 days of anodal stimulation over the prefrontal cortex are assessed.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
101
Non-invasive stimulation will be conducted using a tDCS device (StarStim, Neuroelectrics, Spain).
The same device will be used as in the active stimulation group, but stimulation will be terminated after 30 seconds.
Nanyang Technological University
Singapore, Singapore
Points in the Point Subtraction Aggression Paradigm after stimulation
The number of points earned on the lab task will be assessed.
Time frame: Within 1 hour after the third consecutive active tDCS or sham session
Antisocial behavior inclinations after stimulation
This will be assessed using 5 hypothetical scenarios in which someone commits a criminal or antisocial act. Participants will respond to the likelihood that they would commit the act in the scenario according to a 10-point Likert scale. Responses are measured on a scale ranging from zero (no chance at all) to 10 (100% chance). A higher value reflects a greater intention to engage in the antisocial act.
Time frame: Within 1 hour after the third consecutive active tDCS or sham session
Moral judgment ratings after stimulation
This will be assessed using 5 hypothetical scenarios in which someone commits a criminal or antisocial act. Participants will rate the moral wrongfulness of the act in the scenario on a scale from 0 (not at all) to 10 (very). A higher score reflects a greater perception of moral wrongfulness regarding the antisocial act.
Time frame: Within 1 hour after the third consecutive active tDCS or sham session
Delay discounting rates after stimulation
Participants' responses to 5 questions indicating if they would prefer a smaller reward today or a larger reward in the specified number of days will be assessed. The delay discount rates (k) of monetary rewards will be calculated based on the responses to the 5 trials.
Time frame: Within 1 hour after the third consecutive active tDCS or sham session
Helping behavior after stimulation
This will be assessed based on the number of easy and hard puzzles participants choose to assign to another participant in the study.
Time frame: Within 1 hour after the third consecutive active tDCS or sham session
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Antisocial behavior after stimulation
This will be assessed based on the participants' accurate reporting of the number of problems correctly solved in a task.
Time frame: Within 1 hour after the third consecutive active tDCS or sham session
Number of participants with adverse events
The number of participants reporting the experience of sensations resulting from tDCS will be recorded.
Time frame: Within 1 hour after each of the 20-minute active tDCS or sham sessions