Placebo Effect Produces Higher Test Scores

Scientists are increasingly convinced of the power of the placebo effect. Believing that one is receiving treatment when you're not—say, in the form of a pill that supposedly contains a powerful drug that is actually just sugar—can produce surprisingly strong results, at least for some patients, some of the time.

Newly published research suggests a placebo process can produce a similarly positive outcome for test-takers. In short, the belief that you have access to the answers makes it more likely you will get them right.

“People have powerful psychological resources to deal with challenges, but those resources cannot always be used deliberately,” German psychologist Ulrich Weger and Australian psychologist Stephen Loughnan write in the Quarterly Journal of Experimental Psychology. Just as a dummy pill can help people access their ability to tolerate pain, they report, a false conviction can help test-takers relax and improve their performance.

Their experiment featured 40 undergraduates, each of whom took a 20-question general-knowledge text. Questions ranged from the numerical value of pi to the artist who created Guernica; participants were given four possible answers and instructed to pick the correct one.

Before doing so, half the students were told that just before each question was asked, the correct answer was momentarily flashed onto the screen. They were informed that this happened too quickly for them to process the information consciously, but assured that it would register in their brains.

A “demonstration” showed them the process in slow motion, reinforcing their belief that this was really happening. In fact, the researchers write, “the subliminally presented answers of this experimental phase were random letter strings.”

No matter: “Participants in the placebo condition who believed they had been exposed to the correct answers subliminally scored higher than participants in the control condition,” Weger and Loughnan write.

The researchers suspect the false assurance produced  “a weakening of inhibitory mechanisms that normally impair performance on a task.” In other words, the participants’ belief that they had the answers allowed them to relax, focus—and answer more questions correctly.

When you’re confident, “anxieties that have previously taxed cognitive resources … become available for other tasks and processes,” they write.

Weger and Loughnan concede this is one small study, but it conforms with earlier research on confirmation bias and self-fulfilling prophecies. In this case, they note, the positive bias was not the product of internal self-talk, but rather an outside intervention—a mental sugar pill.

As such, they speculate, this technique could come in handy in situations “where a participant’s genuine skills profile needs to be assessed, uncontaminated by the impact of self-incapacitating fears.” Did that job applicant’s low score reflect a lack of brainpower, or merely the anxiety of an inherently stressful situation? Some version of this experiment could be a fine way way to find out.

For the rest of us, this study confirms that the best possible mantra to use before taking a test is: You know this.