Date Published: April 17, 2015
Publisher: Public Library of Science
Author(s): Ray F. Lee, Daniele Marinazzo.
In order to scientifically study the human brain’s response to face-to-face social interaction, the scientific method itself needs to be reconsidered so that both quantitative observation and symbolic reasoning can be adapted to the situation where the observer is also observed. In light of the recent development of dyadic fMRI which can directly observe dyadic brain interacting in one MRI scanner, this paper aims to establish a new form of logic, dual logic, which provides a theoretical platform for deductive reasoning in a complementary dual system with emergence mechanism. Applying the dual logic in the dfMRI experimental design and data analysis, the exogenous and endogenous dual systems in the BOLD responses can be identified; the non-reciprocal responses in the dual system can be suppressed; a cerebral coordinate for reciprocal interaction can be generated. Elucidated by dual logic deductions, the cerebral coordinate for reciprocal interaction suggests: the exogenous and endogenous systems consist of the empathy network and the mentalization network respectively; the default-mode network emerges from the resting state to activation in the endogenous system during reciprocal interaction; the cingulate plays an essential role in the emergence from the exogenous system to the endogenous system. Overall, the dual logic deductions are supported by the dfMRI experimental results and are consistent with current literature. Both the theoretical framework and experimental method set the stage to formally apply the scientific method in studying complex social interaction.
In order to scientifically study the human brain’s response to face-to-face social interaction, the scientific method itself may need to be improved, so that both quantitative observation and symbolic reasoning can be adapted to the situation where the observer is also observed.
During social interaction such as eye contact, brain responses can be classified by a dual system: the exogenous system and the endogenous system. By definition, the exogenous system directly responds to any exteroceptive stimulus; the endogenous system can only be activated by interoceptive stimulus. The dual logic is proposed for deductive reasoning in these dual systems during the eye contact in the dfMRI experiment.
First of all, applying GLM on the baseline data (dyads closed eyes in entire scan) with the regressors in Fig 1c, no BOLD activation was observed in dyads, which suggests that neither non-visual stimuli nor physiological coupling contribute to the BOLD responses in the task A and B.
The dual logic is proposed for explicitly formulating the dual systems and emergence mechanism between the dual systems. It’s one of the few initial attempts to use the closed logic system to analyze agent-specific observations, especially when the observer is also being observed. It offers a deterministic approach to complement the existing common statistical approaches in neuroimaging analysis. By applying the dual logic in the dfMRI experiment design and analysis, the data-driven exogenous and endogenous systems that delineate the dual logic deduction provide a generic CCRI in which the exogenous and endogenous system consist of mainly the empathy network and mentalization network respectively. Moreover, the logical interpretation of the data-driven endogenous activations elucidates the intrinsic and social characteristics of the DMN; the logical formulation of the transition between the exogenous and endogenous system elicit the role of CG in agent recognition in the social domain. Overall, the dual logic deductions are supported by the dfMRI experimental results and are consistent with current literature. Both the theoretical framework and experimental method set a stage to formally apply the scientific method in studying complex social interaction.