The problem with human guinea pigs

Behavioural scientists use university students by the thousands as cheap subjects in experiments on everything from kindness to strangers and happiness to brainwave patterns and short-term memory.

But psychologists are experiencing a crisis of confidence owing to the long-running practice of using students as representatives of the human race. The truth is these human guinea pigs have little in common with the rest of humanity.

“We study North American undergrads because they are convenient, but it’s easy to forget about the limitations of the results,� said Steven Heine, a psychologist who co-authored a 2010 study on the problem with Harvard evolutionary biologist Joe Henrich, formerly of the University of B.C. “We do research on undergrads, but then we start calling them humans.�

When research is replicated on different continents, the results can be startlingly different. North American notions of fairness — such as splitting found money evenly — don’t appear to apply in non-industrial societies.

Even perception of line length in the classic Muller-Lyer illusion differs in cultures where carpenter corners aren’t common.

By conducting research using people from so-called WEIRD cultures — western, educated, industrialized, rich and democratic — psychologists have amassed a body of research over decades that generalizes only to North Americans and in many cases only to American university students, the study says.

Undergraduates are an all-too-tempting shortcut, Heine said.

A review of studies published in six peer-reviewed psychology journals between 2003 and 2007 found that psychology undergraduates were the sole subjects in two-thirds of studies in the United States and WEIRD people represented 96 per cent of all research subjects in studies conducted at universities in western societies.

Psychology researchers at UBC use students as their main subject pool, especially the thousands of students who can improve their grade by up to three per cent in certain psychology classes after serving as subjects. Many more are recruited from the student population and paid about $10 to $20 an hour for their time.

The tasks range from interviews and filling out simple questionnaires to sitting in a darkened booth pressing buttons in response to sounds and lights.

UBC PhD candidates Ben Cheung and Ashley Whillans participated in experiments as young students, which drew them into the world of research even though it was sometimes uncomfortable.

The relative scarcity of grant money for research limits the number of paid subjects a study will use, discourages travel for field research and makes it difficult to compensate people for their time, Cheung said.

“The student population is still a big chunk of the subject pool for a lot of studies,� Cheung said.

It’s a problem that young psychologists have top of mind.

“Joe Henrich and Steve Heine’s WEIRD paper was seminal in bringing this problem to the fore,� Whillans said.

She said she prefers to use the university subject pool for “quick and dirty� preliminary studies.

“Sometimes we are just looking for initial evidence of something and when that’s the case undergrads are great because they are cheap and plentiful,� Cheung said. “We can use those results to raise grant money for better research.�

To find more diverse populations, researchers have turned to crowdsourcing services such as Amazon’s Mechanical Turk, a pool of on-demand workers that complete tasks such as questionnaires for a few dollars.

“If a researcher is looking for an alternative (to students), that’s where they would go,� Cheung said.

The system, while convenient, may also produce skewed subject pools.

“Anyone who is willing to give up their time to do all these online studies for little to no money are also going to be weird. They certainly won’t be normal working adults,� Whillans said.

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