The action bias describes our tendency to favor action over inaction.

However, there are times when we feel compelled to act, even if there’s no evidence that it will lead to a better outcome than doing nothing would. Our tendency to respond with action as a default (automatic reaction), even without solid rationale to support it, has been termed the action bias.

The hysterical response from most of the World Governments to the Covid-19 pandemic has been featured by measures not supported by solid rationality nor scientific evidence, but just driven by the feeling that inaction might be worse. In fact, in situations where the correct decision is unclear, our automatic response is leant to action, ignoring – by default – the potential benefits of inaction.

A study by Bar-Eli et al. (2007) has analyzed how the action bias works in soccer, when a penalty kick is awarded. In soccer a penalty kick is a contest among the keeper and goal keeper.

The authors examined 331 penalty kicks from top leagues and championships world wide. A panel of three independent judges was used to analyze the direction of the kicks and the direction of the movements by the goalkeeper.

The kicks were equally distributed with one third of the kicks aimed to the left, one third aimed to the right and one third to the left of the goal mouth.

However, the goalkeepers displayed a distinct action bias: they either dive left or right 94% of the time, hardly ever choosing to remain in the middle of their goal mouth.

The researchers, then, calculated the success rate from the combinations of kicks and jumps. The best strategy was when the goalkeeper stayed in the centre of the goal mouth: he saved 60% of the kicks aimed to the centre, far higher than his 30% saving rate when he dived either left or right.

However, far from following the optimal strategy of the centre, goalkeepers would stay in the centre just 6.3% of the time!

The action bias, displayed by the goalkeepers, is clearly a suboptimal behavior pattern.

The reason for this action bias is related to the feeling of effort, that the goalkeeper feel when he dives left or right (the feeling of doing something). Standing in the centre and watching a goal scored to the left or to the right of him, he would feel much worse!!

The action bias is widespread in the field of investment and trading. Because the investor would not consider that inaction is also a decision. As Paul Samuelson once opined “Investing should be dull. It should not be exciting. Investing should be more like watching paint dry or watching grass grow“. If you want excitement, take $800 dollars and go to Las Vegas”.

The action bias regularly manifests in the health sector, specifically, when it comes to treating patients with unusual symptoms that do not seem to require urgent care. It’s been shown that – if there’s no clear diagnosis – the majority of doctors prefer to run tests attempting to find the root of the problem, rather than to schedule a follow-up checking if symptoms have changed. The action bias in medicine would lead to Overdiagnosis and Overtreament, magnifying the field of Incidentalomas.