How to Deter Reasonable People from Undesirable Behaviour
Assuming that people are reasonable highlights the need to engage with people who are the targets of interventions. This turns them from targets into partners.
Origin
This framework draws on a paper by Nick Chater and George Loewenstein — Behavioral Science Should Start by Assuming People Are Reasonable — adapted by Pranay Kotasthane for the A Framework a Week series. It connects behavioural science insights to the logic of deterrence in international relations.
What it says
Conventional economics assumes humans are rational; behavioural science assumes they are irrational. A growing consensus suggests a middle ground: humans are reasonable — they try to make optimal use of available information that fits their own contexts and goals.
This matters enormously for deterrence. If we assume adversaries are irrational, our policy solutions tend towards coercion and paternalism. If we assume they are reasonable, we can explain their behaviour as responses to incentives, cultural context, and systemic factors — and design deterrence accordingly.
The lottery example illustrates the difference:
- Irrationality assumption: Playing the lottery is a cognitive bias. Solution: ban lotteries, run education campaigns.
- Reasonableness assumption: Lottery-playing is cheap entertainment, social participation, or a response to limited upward mobility. Solution: address systemic factors that make the lottery appealing.
Applied to states: if we assume China is “irrational” in its Himalayan aggression, we might favour purely military responses. If we assume it is reasonable — responding to domestic nationalism, strategic vulnerability, and perceived opportunity — we can design a richer mix of military, economic, and diplomatic deterrence.
Applied
In the India-China context, the framework suggests that Chinese actions on the LAC are not random or ideologically driven but responses to a calculable mix of incentives. Deterrence should therefore:
- Raise the costs of aggression in specific domains where India has tactical advantage.
- Address the systemic factors — such as the absence of settled boundaries — that make salami-slicing attractive.
- Engage with China as a reasonable actor while maintaining the capability to impose costs.
When it falls short
The framework works best when the adversary is indeed acting within a reasonable cost-benefit framework. It breaks down when leaders are genuinely irrational (risk-acceptant to the point of self-destruction) or when domestic political constraints make cost-benefit calculation impossible. It also risks being too charitable — interpreting aggression as “reasonable” when it is simply opportunistic expansion.