Free Will & Addiction

Principal Researchers:  Prof. J. Savulescu, Prof. W. Sinnott-Armstrong, Prof. N. Levy, Prof. B. Fulford.

Further Researchers:  Dr N. Shea, Dr B. Foddy.

Although some argue that the discovery of brain mechanisms underlying decision-making presents a threat to freedom (Tancredi 2005), most philosophers hold that free will is compatible with such findings. There are, however, other threats to free will and moral responsibility from neuroscience, especially from research suggesting that conscious choices play no direct causal role in producing behaviour (Libet 1999; Wegner 2002). Although philosophers have disputed this interpretation of the research (Flanagan 1996; Mele 2006), there is already extensive evidence that our ability to make rational choices is constrained in unexpected ways. A range of unconscious stimuli can affect choice through priming (Kiesel et al. 2006) and transcranial magnetic stimulation can affect choice without subjects’ awareness (Brasil-Neto 1992). Studies of ego depletion have demonstrated that self-control is a limited resource: the more temptation a subject has resisted in the recent past, the more likely they are to give in to later temptation (Baumeister 1998, 2002). The marketing potential of this work is obvious (Vohs and Faber, forthcoming). Ego-depletion also allows us to understand why addiction leads to temporary preference shifts (Levy 2006).

Neuroscience might help explain addiction and possibly give us grounds for mitigating the responsibility of addicts. The difficulty addicts have with delaying gratification is associated with activity in the parietal and prefrontal cortex, activity that is predicted by some genotypes ( Boettiger et al. 2007). Stress is a risk factor, apparently through its effects on mesocorticolimbic dopamine (Wang et al. 2005). These advances suggest ways in which addiction might be addressed. Individuals genetically predisposed to addiction might be identified and targeted by special programmes teaching methods of self-control (Strayhorn 2002), prescription of dopamine antagonists, vaccines, and genetic selection.

Brain dysfunction might also mitigate criminal responsibility. Some neuroscientists argue that younger offenders should be judged more leniently because frontal and pre-frontal brain areas involved in executive control are not fully developed (Beckman 2004). However this threatens to generalize: differences in executive control vary across adults, and weaker executive control is typical of prison populations.

In light of these advances, ethical expertise is clearly needed to guide the development of policies governing clinical legal and commercial applications of this knowledge.

1. Can neuroscientific knowledge increase our ability to attribute moral and criminal responsibility?

a. To what extent does our growing understanding of the neural pathways in decision-making have implications for moral responsibility? Does neuroscience support the claim that consciousness is epiphenomenal? Does this threaten responsibility?

b. Might neuroscience give us good grounds for excusing juveniles, people with reduced self-control, or psychopaths? How might excusing this class affect social understandings of agency and responsibility?

2. How might self-control be strengthened?

a. Which patterns of seemingly addictive behaviour result from subjects’ free choice? How can and should pathologies of the will be treated?

b. Do these findings generalize to other losses of self-control, such as in response to anger or in unwanted habits (e.g. over-eating or smoking)? 


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Vohs, K.D., & Faber, R. (2009), Self-regulation and impulsive spending patterns. To appear in Keller, P.A. & Rook, D.W. (eds.), Advances in Consumer Research, Provo, UT: Association for Consumer Research.

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