When Comparison Becomes an Intervention

Upward social comparison is usually discussed as something people encounter, but it can also be deliberately supplied as feedback about a behaviour. This chapter examines when comparison becomes a social-comparison behaviour-change technique, or SC-BCT, and what randomized trials can tell us about it. The practical judgment is narrower than “comparison works”: identify the target behaviour, the control condition, the accompanying ingredients, and the time at which change is measured.

That narrower question matters because an intervention changes the comparison environment. It can specify the dimension, show a person’s own performance beside a social standard, and make the desired direction visible. It can also add goals, reminders, knowledge, or repeated feedback. If behaviour changes afterward, the result may be useful without proving that comparison alone caused it. A randomized design improves the causal question, but it does not erase the need to understand what participants actually received.

What counts as a comparison intervention

The Nature meta-analysis defines an SC-BCT as an intervention that draws attention to other people’s performance so that participants can compare themselves with a social standard on a particular dimension. The comparison must be more concrete than a statement that a behaviour is popular or socially approved. A message such as “people support saving energy” expresses an injunctive norm—what people approve or disapprove of. A message that shows a household’s own energy use alongside the usage of a relevant social standard enables a descriptive comparison. The latter gives the participant a position to interpret.

A useful intervention therefore has at least three parts. It identifies a behavioural dimension, such as electricity use, steps per day, health behaviour, performance, or service participation. It provides information about the participant’s own position on that dimension, directly or through a measurable outcome. It supplies a social standard that can be compared with that position. The standard may be upward, downward, or not restricted to one direction, depending on how it is selected. Without a shared dimension and enough information to evaluate the gap, a message may influence behaviour for other reasons but is not clearly a social-comparison technique as defined in the review.

The intervention can occupy different roles inside a larger design. A stand-alone SC-BCT is intended to be the relevant behaviour-change component by itself. A primary SC-BCT is the main comparison component but is accompanied by other techniques. An add-on SC-BCT is tested by comparing two otherwise similar behaviour-change bundles, with social comparison present in one and absent in the other. These distinctions answer different questions. A successful bundle tells us that comparison-containing intervention may work. An add-on test asks whether adding comparison produces incremental value beyond what the bundle already does.

This is also where temporal comparison enters. Suppose participants receive repeated reports of their own performance alongside a social standard. They can compare themselves with others, but they can also compare their current performance with their previous performance. A goal, reminder, warning symbol, or instruction can introduce another route to behaviour change. The participant may act because the social standard clarified a norm, because the personal feedback made progress visible, because the goal reduced ambiguity, or because the intervention repeated the cue often enough to support a routine. The intervention can be effective while its causal ingredients remain partly entangled.