• Autonomy
• Behaviour Modification
• Health Promotion
• Public Health Ethics

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 …