Presentation on theme: "Neural Correlates of Evaluations in Lying and Truth Telling in Different Social Contexts (Wu et al 2011) By Monica Wacker and Michelle Cho."— Presentation transcript:
Neural Correlates of Evaluations in Lying and Truth Telling in Different Social Contexts (Wu et al 2011) By Monica Wacker and Michelle Cho
Introduction "A lie is a statement made by a speaker with the intention to instil a false belief into the mind of the listener" (Chisholm and Feeham, 1977) Lies involve two people: The lie-teller and the lie-recipient (who the lie-teller hopes to deceive)
Intro. Continued Neural activities associated with lie-telling have been researched using fMRI, PET, and tDCS, all of which show similar patterns of brain activation in the prefrontal cortex and in posterior regions such as superior temporal sulcus. Neuroimaging is of course limited for the lie-recipients so behavioral studies are implemented instead.
Background Information Cross Cultural Studies – In some cultures, lies are viewed as acceptable and polite, whereas the truth may be socially inappropriate.
Background info. Western cultures- "White lies." It is considered acceptable to lie in order to come across as polite and enhance the well-being of the lie recipient. Why yes, that perm makes your hair look amazing! Eastern Asian societies- encourage humility and denial about one's achievements. Behavioral studies show that Chinese rate truth-telling about their good deeds as less positive than being truthful about one's flaws, such as antisocial behavior. Yet lying is rated as less negative for positive deeds than it is for antisocial acts.
Neural Basis Why is the neural basis of the differential evaluations of specific types of lies and truth important?
Neural Basis 1. Deeper understanding of our evaluative behavior in regards to honesty or dishonesty 2. Provides evidence for whether social contexts affect evaluations and also the brain activities that are correlated with distinguishing honesty from dishonesty. 3. Provides a normative basis for us to assess individuals with mental abnormalities, such as paranoid and pathological lying, who may have abnormal neural responses to other's lie- and truth- telling behaviors.
Functional Magnetic Resonance Imaging The study we looked at used fMRI methodology to compare the blood-oxygen level-dependent (BOLD) activities elicited by the participant's evaluations of lie and truths told in different social contexts. This information would help assess whether the researchers could successful capture the neural activity associated with positive behavior evaluations of lying and negative evaluations of lying and the reverse for truth- telling. Participants read stories involving a protagonist who either lied or told the truth about their good and bad deeds, and participants then judged whether the protagonist's statements were good or bad.
Predictions 1. Since lying violates social norms under special circumstances, these situations were predicted to be associated with emotionally negative reactions 2. Lying intentionally instills false beliefs into the lie-receiver and the ability to understand other's intentions – LG, IPL, MPFC, STS, TPJ 3. Moral judgments involves both rational reasoning and emotional processes (IPL)
Experimental Procedures Participants – 20 right-handed healthy subjects 6 males (M age=21.4 years, range=18-26 years) – Native Chinese with normal vision – No history of neurological or psychiatric illness
Methods BL stories: protagonists committed a transgression and lied about it GL stories: protagonists performed a good act but lied about it BT stories: protagonists told the truth after committing a transgression GT Stories: protagonists told the truth after performing a good act
Methods The act part: described the protagonist’s act (Chris broke the new case at home and his dad saw the broken case and asked Chris) The questions Part: depicted another individual asking the protagonist about the act ( did you break this? Chris said…) The answer part: Protagonist’s answer (yes or no) to the question
Behavior Results – Lying (-1.41) vs. truth-telling (1.95) – Bad act (-0.17) vs. good act (0.72) Participants’ judgments of truthfulness (lying, truth-telling) and act valence (bad, good) showed a significant main effect of truthfulness
fMRI Results While judging the stories… BL > BT GL > GT
fMRI Results Left Postcentral gyrus
Conclusion FMRI results showed a differentiation of brain activation between lies and truth and also between types of lying associated with rational and non- emotional evaluations. Also, activity in the right LG, left IPL, and the left PoCG correlated with off-line evaluations of truthful and untruthful communications about good and bad deeds. "This study was among the first to demonstrate that evaluations of truthful and untruthful communication in different social contexts can be differentiated in terms of brain BOLD activities."
Discussion The results of the study demonstrated that evaluations of truthful and untruthful communication in varying social contexts produces significant differences in BOLD activities.
Discussions 1. Relative to truth-telling, judgments of bad-act lies showed increased activity in the right LG, PoCG, right precuneus, bilateral IPL. 2. Brain areas that showed different levels of activation based on good and bad-act lies were the SFG, bilateral cuneus, left IPL. 3. Activation in the right LG, left PoCG, and left IPL were negatively correlated with off-line evaluations of stories involving lies or truth telling in different social contexts. Specifically, the left PoCG was highly sensitive to the evaluations of lying about good acts, and the activations were greater when participants rated it negatively off-line.
Implications "Activations in these areas (LG, PoCG) may be interpreted in terms of enhanced negative valence associated with bad-act lying relative to to bad-act truth-telling.” However, the study found that brain regions that were predicted to be activated during emotional processing actually showed no significant differences in lie and truth telling story evaluations. This may be due to the use of a fictional protagonist which may have decreased the emotional response of the participants.
Theory of Mind A lot of the results are consistent with theory of mind, which correlates certain emotions with specific brain regions.
Theory of Mind 1. LG activation related to reasoning about beliefs and intentions, and also correlated with empathy. 2. IPL (and LG) demonstrate increased activity for false belief stories. 3. Precuenus associated with processing beliefs during moral judgments. 4. PoCG activity correlates with reasoning about social contracts
Some results were inconsistent STS and TPJ were not activated. However, this could be because of the experimental set-up. The STS functions in representing the intentions of others and the detection of visual motion, which were not needed for the participant's evaluations of the story. The TPJ is selective for belief attributions which were not apparent in the experiment because the fictional character's thoughts and beliefs were not stated.
Future Studies To further clarify the underlying neural mechanisms of evaluations of truthfulness and lying, future studies should use other types of stories that will assess whether these brain regions are unique to positive- negative valence evaluations of truths and lies or more generally to the evaluations of any positive or negative acts.