Free Will in the Brain? A Selective Review of the Empirical Evidence From Cognitive Neuroscience
It is generally believed that people have free will, according to which we can freely choose and control our own behaviors. However, such belief is strongly challenged by empirical evidence from cognitive neuroscience, which investigates human cognitive functions and their neuronal mechanisms through measuring brain activities. Specifically, research has shown that when people spontaneously move their hands, freely choose to move their right or left hand, or freely decide to perform addition or subtraction, the neuronal signals that are relevant to the following behaviors are first observed, followed by participants’ subjective awareness of the intention to act, and then the explicit behaviors are observed. Such findings seem to be directly against the existence of free will. To better understand functional and neural mechanisms of free will in the brain, several classic studies addressing this issue via cognitive neuroscience methods are reviewed in the present article. The theoretical assumptions, experimental procedures, and behavioral and neuroimaging results of these experiments are introduced. The results and their implications are described and discussed. Critically, the inconsistency of the underlying assumptions, the problems of the paradigms, and the limitations of the findings of these experiments are highlighted and elaborated. It is further proposed that, similar to behaviors in other cognitive domains such as memory, the functioning of free will may not be a unitary process but encompassing the implicit phase that is unaware of and the explicit phase that is clearly aware of by an agent. Based on the selective review of the studies in cognitive neuroscience, it is concluded that despite the belief that all human behaviors are supported by neural activities in the brain, the present evidence has not elucidated the operations of free will in the brain, nor has it overthrown the existence of free will of human beings.
|關鍵詞||主觀意識、自我控制、腦電波研究、準備電位、功能性核磁共振造影、subjective consciousness、self control、electrophysiological research、readiness potentials、functional magnetic resonance imaging|