Commentary Why couldn't I be nudged to dislike a Big Mac? Journal of Medical Ethics, 39 (8), 495–6. Luc Bovens Correspondence to Luc Bovens, Philosophy, Logic and Scientific Method, London School of Economics and Political Science, Houghton Street, London WC2A2AE, UK; l.bovens@lse.ac.uk The central distinction in Yashar Saghai's thought-provoking article is between nudges and (behavioural) prods. What distinguishes a prod from a nudge is that a prod is 'substantially controlling' (SC-ing) whereas a nudge is 'substantially non-controlling' (SNC-ing). This has moral relevance in so far that a nudge but not a prod preserves freedom of choice.1 What is it to be influenced in a SNC-ing way? For Saghai, a subject is SNC-ed if she could easily resist the influence, meaning that she can effortlessly (i) become aware of the pressure exerted and (ii) 'inhibit the triggered propensity' if she wanted to. In The Ethics of Nudge,2 I discuss subliminal images sliced into films to increase, say, the consumption of Coke. Suppose that we could also use this technology to encourage healthier eating habits. I argue that subliminal images are not nudges because they do not satisfy 'token interference transparency', that is, it is not possible for a person to become aware that they are being influenced when the image is presented to them. Saghai's condition (i) maps onto this requirement. Condition (ii) is harder to understand. A commercial advertiser aims for prods, that is, to make 'irresistible offers' or offers which are such that the subjects could not inhibit the triggered propensity to drink Coke even if they wanted to. What is meant by 'even if they wanted to'? Clearly, if they had a first-order desire to drink Pepsi rather than Coke, then they could simply do so. That cannot be what is meant. Rather what is meant is that they cannot resist their first-order desire to drink Coke even if they had a secondorder desire not to have the first-order desire to drink Coke. This is what makes the campaign SC-ing and hence a prod. Campaigns can work in different ways. Suppose that the market share of Coke over Pepsi rises substantially. We interview Coke drinkers. They may report they can no longer bear the idea of drinking Pepsi. They could not bring themselves to do so even if they wanted to, they say. Or, they may just say that they are now more inclined to drink Coke. But ask them to try resist this first-order desire and they will say: sure, a Pepsi will do fine. So the first campaign would be SCing, the second would not. Now move to a successful healthy habits campaign and carry through the same distinction. Suppose that the interviewees report: I used to have a Big Mac for breakfast, but now, I could not bring myself to do so even if I wanted to. Or, they may report: I am now more inclined to have yoghurt for breakfast, but sure, I could have a Big Mac, if I wanted to; frankly, I still have a strong first-order desire for a Big Mac-it is just that I am now able to keep my cravings in check. For Saghai, the first kind of campaign would be SC-ing and hence a prod rather than a nudge. There is no preservation of freedom of choice. Furthermore, in some core areas of life this may be problematic because we want our lives to be self-determining rather than determined by others. Now I just do not see this. If a healthy habits campaign is so successful that it weans people off their desire for a Big Mac (rather than give them the tools to resist their desire for a Big Mac), then tant mieux! Saghai might respond that healthy eating is not an area of life in which we insist on selfdetermination and so we are happy to accept prods. But then think of anti-child abuse campaigns. Clearly we value self-determination in child-rearing. Suppose that a campaign is successful in the following sense. We interview parents who used to be irritable and hit their kids in rage. After the campaign they say that they would no longer be able to do so even if they wanted to. Does the campaign now become a prod which is not respectful of freedom of choice? Again, I just do not see this. I agree with Saghai that in certain areas of life we value self-determination and we would object to SC-ing influences. I also agree that condition (i) (or my token interference transparency) may not be enough. To see this, consider the following fanciful twist on subliminal images. Suppose that the Secretary of Health makes a public statement that the government will start a campaign with subliminal images and viewers can check the web to see what images are sliced into what shows. This satisfies condition (i). Saghai mentions end-of-life and reproductive choices as areas in which people do not wish to be subjected to SC-ing influences. Indeed, I submit that people would find it upsetting if they were so coaxed to become organ donors or limit their family sizes. Hence something more than condition (i) is needed: but it is not condition (ii). Condition (ii) is about the outcome of the intervention. My suspicion is that our resistance to subliminal images has something to do with the nature of the process of the shift of our propensities. In Cafeteria- a legitimate nudge-it is still through our choices (conditioned by the placement of the food) that we come to develop some appreciation for healthy foods. In the case of the subliminal images, we are in no way the author, or even coauthor, of these propensity changes. And this is why it offends a requirement of self-determination. I conclude with a comment on Saghai's choice of examples of prods. There is Pharmaceutical TV Ad (PTA), Asparagus Lovers (AL) and a tweaked case of Less Than You Think-let us call it LTYT'-in which false information about binge drinking is provided. In PTA, there is nonresistibility because the negative information is covered up. In AL and LTYT', the information is false. I understand that we have qualms because these cases involve cover up and deceit. But I do not see why easy resistibility is not satisfied here. Condition (i) is allegedly failing. But certainly it is not hard to recognise what advertisers are doing when they are showing pictures of floating swans while a text is being read that the medication may cause some horrific cancer. Similarly I can easily recognise that pressure is being exercised when I am told that I used to like asparagus and that most people do not binge drink. There is some confusion here. Indeed, it may be hard for me to become cognizant of the content of the message in PTA and of the falsity of the information in AL and LTYT'. But that is not what condition (i) requires. It requires only that it is easy to become aware that one is being manipulated in some way or other. References 1. Saghai Y Salvaging the concept of nudge. J Med Ethics 2013;39:487 93. 2. Bovens L The ethics of nudge. In: Grüne-Yanoff T, Hansson SO , eds. Preference Change: Approaches from philosophy, economics and psychology. Dordrecht: Springer, 2008:207–20.