ReviewDemystifying “free will”: The role of contextual information and evidence accumulation for predictive brain activity
Section snippets
The “free will” problem and brain activity
The belief that we have free will – that we are the authors of our own fate – is fundamental to our self-concept and our identity as human beings. Our intuition tells us that we are able to ignore the constraints of nature to some extent: we can reflect on our reasons, deliberate on our options, and consciously choose to do otherwise if we wish. The question of whether this is actually true or an illusion, or which aspects of our decisions are free and which are not, is as old as philosophy
Definitions in current brain research
Before we address those three questions, it is necessary to briefly review some definitions, because one source of confusion and controversy in current research on voluntary actions arises from a lack of a clear definition of what is being investigated. Different authors focus on different aspects of free decisions (or volition in general), including intentions, the “will”, decision-making, initiation of actions, and authorship (see Roskies, 2010). In the present paper, we will discuss them
Neuroscience research on free decisions
Despite the lack of a clear definition (Roskies, 2010), many studies have sought to investigate the cognitive and neural basis of free (or voluntary) decisions. One stream of research has focused on creating experimental situations in which some kind of action has to be initiated by the participant while either the timing (e.g., Brass and Haggard, 2007, Haggard et al., 2002, Lau et al., 2004, Lau et al., 2006, Libet et al., 1983), or the action itself (usually within a limited range of possible
Evidence accumulator models for free choice
While recent models are more concerned with dividing the decision stream into sub-processes (e.g. Haggard, 2008), the question of how decision formation takes place for voluntary choices still remains unknown. However, other recent studies help to find an appropriate decision model for voluntary decisions. It has been shown that the predictive activation patterns preceding decisions become increasingly similar over time to the patterns found at the time of the conscious decision (Bode et al.,
Brain imaging and the philosophical free will problem
We argue that the fMRI findings reviewed here do not speak to the philosophical debate about the nature of free will. There are several reasons for this conclusion. Following Batthyany (2009), from a reductionist point of view, one might argue that these studies do not speak to the free will problem more than any other study of brain activity. If we ignore concepts such as quantum randomness, and assume that all our actions, motivation, thoughts and intentions rely on brain processes in a
Conclusions
Here we have argued that the results of recent neuroimaging studies showing the predictability of decision outcomes prior to the reported conscious awareness of the decision-maker do not require a new model, nor are they mysterious. We reviewed studies suggesting that evidence accumulator models are applicable to free decisions—although the sources of this accumulated evidence are sometimes hidden. However, decisions are never made without context. In everyday life, decision-making draws upon a
Acknowledgements
The authors thank John Armstrong, Olivia Carter, Damien Crone, Daniel Bennett, Daniel Rosenblatt, Bowen Fung, Hayley McFadyen, Maia Tarrell, Christina Van Heer, Katharina Voigt, Kathleen Charles-Walsh and Carmen Morawetz for support and comments on earlier versions of the manuscript. The authors declare no conflict of interests. This work was supported by an Australian Research Council Discovery Early Career Researcher Award (DE 140100350) to S.B., a Department of Finance Initiative Project
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2019, Neuroscience and Biobehavioral ReviewsCitation Excerpt :And finally, the decision to act can be vetoed in a short time window after the decision threshold is reached and before the point of no return. As outlined above, the basic assumption of such an ITB model of intentional action is the idea that choices about when and what to do are based on decision-making processes that are not fundamentally different from other decision processes in an interesting respect (see Bode et al., 2014; Roskies, 2010a; Schurger et al., 2016 for a similar approach). Similar to perceptual decision-making, information for different options is accumulated until a specific threshold is crossed.
Freely chosen and instructed actions are terminated by different neural mechanisms revealed by kinematics-informed EEG
2019, NeuroImageCitation Excerpt :The current understanding of how the brain implements this important cognitive capability for voluntary action is, however, complicated by volition's multiple connotations (Libet et al., 1983; Wegner, 2002; Roskies, 2010). Due to the dominant focus on resolving ambiguities surrounding the neural origin of a voluntary choice (Haggard, 2008; Soon et al., 2008; Desmurget et al., 2009; Bode et al., 2014; Schurger and Uithol, 2015), the neurophysiological consequences of choosing an action voluntarily remain poorly understood. The unknown scope of volition's consequences raises a basic question (Becchio et al., 2014): is it possible to reliably predict whether or not an action was voluntarily selected based only on how that action was motorically executed?