Do We Make Better Choices When It's All About Us?

Understanding animal behavior helps us test when humans make the best decisions.

Reviewed by Kaja Perina

Key points

• We tend to make better decisions when we're doing something for ourselves rather than for others.
• Theories of how animals collect food can provide insight into how humans make decisions.
• People with autistic traits may respond to rewards differently, being less optimal in choices for themselves.

Does a Self-Bias Makes Us Better at Decision-Making?

Humans have many biases that affect how we act. One of these, the self-bias, makes us like, value, and work harder at actions when we will benefit, compared to actions that benefit other people. However, a big question is whether this self-bias is actually helpful or harmful? Does it mean we make better decisions, or does it lead us to make poor choices because we get too excited about the big reward we can get for ourselves?

A recent study turned to a powerful theory from animal behaviour to try and answer that question. The theory is called the Marginal Value Theorem (MVT) and can explain how animals get so good at making decisions when foraging for food. In the study, Contreras-Huerta and colleagues used this theory to design a study that showed that self-bias makes us better at making decisions for our own benefit.

Making Optimal Decisions During Foraging

How do you decide when a job or a relationship is not working out, and move on to a new opportunity? Knowing when to leave can be tricky in many of these contexts. The same dilemma is present in animals looking or ‘foraging’ for food, such as a squirrel collecting berries from bushes. Survival depends on this ability to gather rewards, and to do it efficiently, and indeed animals are often quite close to being optimal at making these decisions in the way that gathers the most food.

To make decisions accurately, an animal has to think about three key features about how food is spread across the environments where they are foraging. Firstly, not all food locations (known as patches) are equal, for example some bushes have more berries than others. Secondly, the more of the food you collect in a patch, the less there is left in it. This means that over time the patch becomes depleted, so as the squirrel spends more time there, it gets fewer and fewer berries. Lastly, some areas or ‘environments’ are richer than others, they have lots of patches with lots of food. The squirrel might go to one park where the bushes have lots of berries in them, but then go to another park where most of the bushes have very few berries to collect.

So when is the right moment to leave one bush and try the next one? According to the MVT, the best time to leave is when the amount of food you are getting in a patch has depleted to the average amount of food you get over time in that environment. You stay longer when in a bush with lots of berries, but you spend less time in each bush in an environment where there are lots of good berry bushes around you, because if you move on sooner the next bush is likely to be full of fruit.

Previous work has shown that, to survive, animals are able to be almost optimal when making these decisions. But do similar decision-making mechanisms also exist in humans? Previous research has shown that in computer-based foraging tasks, we are close to being optimal and behave in a similar way to what MVT would predict. But what if you were foraging to help someone else? Does the bias we have towards valuing rewards we can get for ourselves mean we forage more (or less) optimally when foraging for ourselves versus someone else?

Foraging for Self vs. Others

To answer that question, researchers developed a game based on MVT where human participants tried to collect as many virtual berries as they could for themselves and played the game to benefit an anonymous other person. They collected rewards from two types of patches: high or low value (i.e. how many berries in the bush) in two types of environments: rich and poor (defined by the amount of high or low value bushes). All the participants had to do was decide when to leave a patch to move on to the next one, but travelling between patches took some time. Crucially, half of the time, they collected rewards for themselves, and the other half they collected rewards for another person.

Interestingly, they found that people stayed longer in high value bushes than low value ones, and left bushes earlier on average in the rich environments both when foraging for self or other, but, crucially, they were closer to the optimal according to MVT when making these choices for themselves. This led to them collecting more berries, and getting a higher bonus payment, for themselves compared to the other person.

This suggests that the self-bias that makes us more sensitive to our own rewards, and makes us work harder to get ourselves rewards, also makes us more optimal when making foraging decisions about when to leaving location to get the maximum reward we can.

Autism and Reward Sensitivity

Previous research has suggested that people with higher levels of autistic traits might be less sensitive to rewards, and particularly to social rewards. The researchers were also therefore interested in whether autistic traits affected foraging for reward for self and for other. Interestingly, decisions of when to leave were associated with autistic traits, with people higher in these traits less sensitive to the value of patches and less sensitive to the environment. However, this pattern was only present when people foraged for self, not for other. This challenges previous views suggesting that people with high autistic traits attend less to social information and have diminished social motivation. Instead, it implies that higher levels of autistic traits may be linked to self-bias, and a potential reduction in its effect on foraging decisions.

Conclusion

When to leave a rewarding situation to move on to another one is a key decision-making problem that applies to many situations in day-to-day life. In an exciting new study, researchers showed that people are more optimal when foraging for self rather than others. This provides another demonstration of how helpful using theories from animal foraging might be for understanding human behaviour highlighting that self-bias may actually serve as a beneficial adaptation.