The Development Of Deception:Role Of Prefrontal Cortex

Deception is an old topic, which is discussed in a wide range of disciplines: psychology, neuroscience, economics, sociology and religion. It is commonly seen in daily life and caused trillions loss of money every single year and the number keeps increasing every year. Despite damages deception has caused, it requires a variety of cognitive resource to commit a successful deception, from the perspective of cognitive psychology. It reflects the cognitive development. There were many studies finding that children younger than 4 years old would not tell a lie. This brings us valuable scientific questions: "why were children failed to point the false whereabouts of objects he/she hided before? ", "Is this phenomenon caused by the unwilling of deception or the incapable of deception?" and "what’s the role of prefrontal cortex in the development of deception?"Study 1 was designed to answer these questions. We modified the classic window task in which subjects were supposed to tell the truth to one puppet and tell a lie to the other. Hemodynamic data were collected using NIRSport88 during the test of window task. We hypothesized that:l.As to the children who failed in the window task, a) if they generated greater activation in the region of prefrontal cortex when they behaved honestly in the dishonest condition, it may indicated that they were willing to tell a lie but were incapable to tell a lie; b) Otherwise, if it generated the same pattern as in the condition where they should tell the truth, it may indicated that the children were willing to tell a lie.2.When children went through a deceptive task, a) if they generated greater activation in prefrontal cortex when we contrast deceptive response with honest response, it may indicated that the task is difficult for children; b) Otherwise, it may indicated that the task is easy for children.The results confirmed hypothesis La and 2.b and we concluded that:1.The immaturity of prefrontal cortex leaded to the failure of deception.2.1mmaturity of prefrontal cortex did not stop children trying to telling a lie with the compensatory activation of premotor cortex.3.It was difficult for 5-year-old children to telling a lie but became too easy for 6-year-old children. With the development of cognition, the deception process became more and more automatic.4. With the development of cognition, the activation region change from wide spread to narrow range, and from prefrontal cortex to the conjunction of temporal, parietal and frontal cortex.Study 2 compared the real guessing game with a control condition where the subjects were just required to act as the computer instructed. We hypothesized that:1.In the real guessing game session, if "telling the truth to deceive" elicited greater activation of prefrontal cortex than "falsely indication to deceive", we could conclude that "telling the truth to deceive" is a higher order deception.2.1f "falsely indication to deceive" in real guessing game elicited greater activation of prefrontal cortex than pure false statement, we could conclude that "falsely indication to deceive" is more complicated than pure false statement.The results confirmed hypothesis 1 and refuted hypothesis 2. We concluded that:1."Telling the truth to deceive" is a higher order deception.2."Falsely indication to deceive" is NO more complicated than pure false statement.From perspective of development, this study revealed the development of deception, from hard to easy; from the view of functional deconstruction, it compared different types of deception and pure false statement in the activation pattern of prefrontal cortex. Thus, these two experiments deepened understanding of the development of deception and role of prefrontal cortex.