Abstract:

Volition, the ability to control oneself voluntarily, is the central characteristic that distinguishes humans from animals and machines, and is the cornerstone of physical and mental health and human society. Its main components include voluntary action and control belief. The former refers to the action based on one’s own will and is the external expression of volition; the latter refers to the belief that the implementation of a voluntary action can have an effect on the external world and is the internal representation of volition. Individuals express their volition to the external world through voluntary actions, but they also need to have control belief to ensure the will to implement voluntary actions.
Most previous studies have explored volition based on voluntary action, but have failed to empirically distinguish the effect of control belief from the effect of voluntary action. Based on an innovative experimental paradigm (volition-motivated performance paradigm, VMP paradigm), this study proposes to dissociate the effect of control belief from the effect of voluntary action on cognitive performance (Study 1), and further combine computational models, simultaneous EMG and EEG recordings (Study 2), and functional magnetic resonance imaging (Study 3) to reveal the common/unique dynamic neurophysiological mechanisms and neural basis of the voluntary action and control belief.
In particular, the present study proposes to adopt the VMP paradigm in which participants are asked to voluntarily/forcedly choose a picture and then complete a cognitive task (here the Simon task is used) with the chosen picture as a background. This classical VMP paradigm includes both the effect of control belief and the effect of voluntary action. Importantly, after completing this classical VMP paradigm task in the first day, participants are asked to conduct two revised VMP tasks in the second day. In the first revised VMP task, the background picture is fixed (i.e., irrelevant to the chosen picture). In this way, participants’ control belief would be defeated (i.e., “my choice would not affect the display of background”) and only the effect of voluntary action (i.e., the action of making a choice) is retained. In the second revised VMP task, participants would not make a choice. Instead, they conduct the Simon task directly with a background picture. Before the Simon task in each trial, participants would be informed by a cue that the following background is the chosen picture by you (voluntary choice condition) or the computer (forced choice condition) in the first day. In this way, participants would hold control belief (i.e., “the displayed background is my choice yesterday”) but the effect of voluntary action is eliminated (i.e., conduct the Simon task directly without making a choice).
By comparing the patterns of classical VMP task and the first/second revised VMP task, we can distinguish the effect of control belief from the effect of voluntary action. By fitting the diffusion model for conflict task (DMC), we can differentiate components of cognitive processing and reveal the unique/common impact of voluntary action and control belief on cognitive processing at the behavioral level. By simultaneous recording EMG and EEG, we can reveal the unique/common dynamic changes in cognitive processing affected by voluntary action and control belief at the of electrophysiological level (muscle activity vs. brain activity). By using fMRI technique, we can reveal the unique/common brain neural basis, functional connectivity, and activation patterns of the effect of voluntary action and control belief on cognitive processing at the level of blood oxygen level dependent (BOLD) signal.
This study aims to construct a “dual-path hypothesis of human volition processing” which can finely distinguish the role of external manifestation (voluntary action) and internal representation (control belief) of human volition. We assume that the process of human volition is processed through two paths simultaneously. One path is related to the voluntary action, reflecting the action attribute of volition (i.e., action expectation, planning, execution, etc.), such as expressing volition may promote subsequent response execution. Another path is related to the control belief, reflecting the motivational attribute of volition (i.e., “reward like effect”), such as expressing volition may affect an individual’s discrimination criteria (response tendency), and limited volition may be related to depression. In sum, human volition may possess with two attributes (action and motivation) to form a complete volition through dual path processing.

Key words: volition, voluntary action, control belief, voluntary choice, volition-motivated performance (VMP) paradigm