OPINION28 July 2015

Bias in the spotlight: reciprocity


Reciprocity bias is our tendency to reciprocate the actions of others creating a wave of indebtedness. If somebody does something for us, or gives us something, we are more likely to return the favour or pass the favour on to others. We have the tendency to behave toward others as they behave toward us.


The impulse to reciprocate is a powerful one and cultural anthropologists have suggested it is likely to be universal. The desire to return favours, pay back debts and treat others well is beneficial for the whole group, and the fact that it engenders cooperation could have offered an evolutionary advantage. However, although good actions trigger more good actions in their wake, bad can also trigger bad; we have a tendency to attack back if we are being attacked.

Reciprocity isn’t unique to humans – it is observable in all sorts of animals of varying levels of cognitive sophistication. For example, studies of crab-eating macaques find they show reciprocal behaviour in grooming – monkeys that are groomed by another are much more likely to groom or show support to their groomers than to monkeys that have not groomed them.

We may not spend much time scanning our colleagues for ticks and fleas, but we regularly engage in other forms of reciprocity. One example of reciprocity is tipping in restaurants. Anecdotally, waiters know that including sweets or small gifts with the bill increases the chance that they will get a tip and that the tip may be more generous. Psychologist Professor David Strohmetz and his colleagues conducted a study to test the anecdotal theory.

In a downtown restaurant in New York State they recruited two seasoned waiters to either give a small piece of wrapped chocolate to diners along with the bill, or to give nothing, at random.

On average, customers who had been given a chocolate gave a 17.8% tip compared with a 15.1% tip among those who had received nothing – over two percentage points higher. This would quickly add up over the course of a busy evening. If all customers had been given a chocolate, this would have meant an increase in total tips of 18% or an extra $76 per night.

Another entity leveraging reciprocity is LinkedIn, the social network for our professional life. I am sure anyone who has used this platform has noticed people ‘endorsing’ them for particular skills. If you see that your former colleague ‘Steve’ has endorsed you, your natural tendency is to want to endorse him in return.

This is the theory at least…. The reality may be different as people you don’t really know often endorse you for skills you don’t have, or friends and family who don’t know you at all in a professional context endorse you for your professional skills. It can be embarrassing for some: “…my mother endorsed me on LinkedIn. Seriously? I appreciate the thought, and we actually do share some professional contacts, but whose mother is not going to think you are the best chocolate teapot maker ever?” Try googling ‘LinkedIn endorsements annoying’ and you’ll see.

When drawn on effectively though, reciprocity can be incredibly powerful and it’s so simple to put into practice. Think what kind of positive waves you can create today simply by letting a car pull out ahead of you in traffic and who knows where they might end and what happiness you could engender along the way.

By Crawford Hollingworth at The Behavioural Architects