This episode is brought to you by Shopify.

Looking to start a side hustle or become your own boss, do it with Shopify.

Whether you're selling succulents or stilettos,

Shopify has the industry leading tools to help you create, control and grow your own business.

So get serious about selling and get Shopify today.

Sign up for a £1 per month trial period at Shopify.com.com slash special offer, or lowercase.

That's Shopify.comaek slash special offer.

That's not fair.

Every parent has heard that cry dozens, if not hundreds of times.

From a very early age, we humans seem wired to notice when other people are getting

more than we are and to complain about it loudly when they do. As adults, our sense of fairness and

justice becomes broader and more nuanced. We care about equal pay for equal work, for example,

or about which countries are right or wrong in global conflicts, even when those issues might not touch our lives directly.

Questions such as these of fairness, justice, and morality might seem unique to humans,

but research suggests that non-human animals notice inequality as well,

and that by studying how they react to unfair situations, we can better understand how our human

sense of justice evolved. So how do animals, from crows to chimpanzees, understand fairness? Do

they get mad when they're treated unfairly? How can researchers tell? How much do different

species differ in how they react to inequality?

What about individual animals?

And what can we learn from studying these questions about why humans care so much about equality and fairness and about how we cooperate and compete with one another?

Welcome to Speaking of Psychology, the flagship podcast of the American Psychological Association

...