Monkey business: Researchers discover primitive forms of wealth

September 10, 2013, University of Sydney
Monkey Business: Researchers discover primitive forms of wealth
Researchers including Dr Agnieszka Tymula have found rhesus macaques are capable of rational decision-making, revealing insights into how humans take risks based on their wealth level. Credit: Henrik Schou Hansen

( —Comparisons between the stock market floor and a zoo are not far from the mark, according to a new study published today in the journal Proceedings of the National Academy of Sciences (PNAS).

A team of researchers, including Dr Agnieszka Tymula from the University of Sydney's School of Economics, has found evidence of increased risk-taking amongst the 'wealthier' of our , suggesting an to human sensitivities around affluence levels.

Dr Tymula says the findings indicate that monkey behaviour is very similar to humans' risk choices, and as a result can provide insight into the evolutionary roots of our behaviour.

"Human sensitivity to wealth levels developed before the advent of money," she says. "Understanding the underlying risky that evolved around satiety may provide unique insights about decision-making and consumption wealth.

"We found that after training, are very rational. Just like humans, monkeys are able to select objectively better options from a menu of choices. If there is an alternative that offers better outcomes in all circumstances, they will go for it.

"The monkeys also seem to share human risk preferences. They were slightly risk averse and we know that humans would behave similarly in these experimental conditions."

The study, titled 'Thirst-dependent risk preferences in monkeys identify a primitive form of wealth', set out to discover whether monkeys share human risk attitudes and economic rationality, as well as how wealth alters risk-taking behaviours.

Using among the monkeys as a non-pecuniary measure of wealth, researchers examined the level of water the rhesus macaques held internally to differentiate the 'rich' from the 'poor'.

After significant training over 20 days, the macaques were able to engage in visual gambling tasks, associating pie graphs showing various increments to the probability of fluid rewards. By shifting their gaze from left or the right, the monkeys made their choice between a safe option (of some amount of water for sure) and a risky option that offered a positive (most of the time higher) payoff or nothing, each with 50% chance. The amounts associated with the sure and risky options varied from trial to trial and were presented in a random order.

The 'richer' (more satiated) monkeys who possessed a higher blood osmolality were found to be less risk averse and take greater gambles than the 'poorer' less-hydrated subjects, who avoided uncertainty in their decision-making.

"It seems likely that the biological mechanisms that mediate changes in risk attitudes with wealth evolved around satiety mechanisms rather than around mortgages," the authors note in the publication.

Studies into how affluence impacts on human risk-tolerance have proven inconclusive due to difficulties in simulating varying financial conditions and a reliance on self-reporting amongst human subjects. Similarly, past research into risk attitudes and consumption-related using other animals such as sparrows and starlings has presented inconsistent and contradictory results.

However, the new study reveals that monkeys are a good model for human decision-making, and highlights the potential questions that can be asked in a more controlled way with primate subjects, according to Dr Tymula.

"We would never have such control over water consumption among human populations; people often say one thing and do another."

Explore further: Study suggests humans, apes and monkeys all expect something in return for generosity

More information: Thirst-dependent risk preferences in monkeys identify a primitive form of wealth,

Related Stories

Less is more when choosing between groups of assorted items

October 3, 2012

When making decisions about the value of an assortment of different objects, people approximate an average overall value, which though frequently useful can lead to apparently irrational decision-making. A new study published ...

Genetic variation cues social anxiety in monkeys and humans

January 14, 2009

A genetic variation involving the brain chemical serotonin has been found to shape the social behavior of rhesus macaque monkeys, which could provide researchers with a new model for studying autism, social anxiety and schizophrenia. ...

Recommended for you

Genome of American cockroach sequenced for the first time

March 23, 2018

A team of researchers with South China Normal University and the Chinese Academy of Sciences has for the first time sequenced the genome of the American cockroach. In their paper published in the journal Nature Communications, ...

New innovations in cell-free biotechnology

March 23, 2018

A Northwestern University-led team has developed a new way to manufacture proteins outside of a cell that could have important implications in therapeutics and biomaterials.

Study tracks protein's role in stem cell function

March 23, 2018

MCL-1 is a member of the BCL-2 family of proteins important for blocking apoptosis, or programmed cell death. Many types of cancer cells escape the body's effort to kill them by overexpressing MCL-1.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.