Two kinds of nudging and the power of cues: Shifting salience of alternatives and shifting salience of goals

Nudging has become a major form of intervention in the domains of sustainable behaviour, health behaviour, financial behaviour, and many others. But how does nudging work? Research so far has paid more attention to the effects of nudging than to the underlying mechanisms. The most prominent mechanisms associated in the literature with nudging are human biases and automatic decision-making. However, we argue that the heart of nudging mechanism is a shift in salience. Attention to this mechanism leads to an important distinction between two kinds of nudging: first, there is goal nudging, in which the salience of overarching goals is affected, leading to changes in activated preferences and attention to specific classes of alternatives. Second, there is behavioural nudging, in which the salience of a concrete alternative is being affected. In most cases, the two kinds of nudging work hand in glove, but without paying attention to their separate and joint effects, nudging interventions can be ineffective or even counterproductive.