​​​​​​​​​​​​​Van Putten, of CSIRO Australia, described such outcomes – unintended consequences – which happen when people don't behave as expected. This behaviour, as well as the social science that studies it, is underrepresented in management strategy evaluations.

These consequences are often detrimental, but can be positive, and combinations exist where policy succeeds or fails but also gives rise to the opposite consequence. For example, despite the success of an Australian marine protected area, fishing intensified in the years prior to its enforcement, setting back the starting point of the reserve. These effects often occur ​due to a lack or complexity of information or ignorance.

Behind the behaviour

Van Putten delved into the psychology behind our decision-making, showing that a positive or negative judgement of a behaviour coupled with the pressure to behave in certain way (social norm) and its ease or difficulty (for example due to time or money) combine to produce an eventual behaviour. The social norm element consists of our perception of what people typically do and of what they typically approve.

An illustration of this was when Great Barrier Reef authorities launched a campaign on the benefits of marine reserves assuming that poachers wouldn't fish, but instead the campaign drove poachers went there. Cognitive biases were behind this: if you knew someone who was fishing, you overestimated the poaching activity and also the number of fishers who broke the rules. One solution could have been to let poachers know they were in the minority.

A nudge in the right direction

Van Putten asked how to stimulate change, suggesting a balance of reward and punishment, but that a voluntary reward-based system is better for longer-term change.

One way to do this is through nudges, which indirectly steer people to alternative choices through for example changing policy defaults (ticking an opt-out box instead of an opt-in one) or the physical environment (painted steps to trash bins). For fisheries these come in market-driven forms like subsidiaries and social ones like nudges. In recreational fishing, social rewards are more needed than market ones as catch isn't traded.

The value of social norm nudges was highlighted in an experiment where participants were given varying catch quotas and a percentage chances of being stopped by an inspector. When deterrence was low, the nudge worked and when it was high the nudge had no effect. This implies that regulators already spending highly on deterrents might not want to spend extra on nudges.

“I think working on social norms is really important because that's how you get behavioural change. Deterrents and catching people out is expensive, so if you can change behaviour for longer periods of time for something that's quite simple to do, then why wouldn't you?" asked van Putten.

“But how do you decide to use that bit of information that people will comply more with rules if they are told that everyone else is complying as well? It's a little bit vague and esoteric, and I think that's the problem, we don't know how to use the information."

“We can plan regulations in terms of what we expect, but if we don't actually ​look at what we don't expect, we will end up making regulations that have large social consequences."