Subliminal Smiles Can Sway You

Study found they made people more likely to try new things

Randy Dotinga

Randy Dotinga

Updated on March 06, 2006

FRIDAY, May 27, 2005 (HealthDay News) -- Subliminal images of smiling faces may make consumers more willing to try new things, new research suggests.

Researchers at the University of California at San Diego found people were more likely to be interested in a "mystery beverage" if they'd just looked at a series of photos including fleeting glimpses of smiling people. Subliminal images of frowning faces, meanwhile, made the subjects less interested in the drink.

The findings suggest that the human mind is much more attuned to facial expressions -- including ones barely noticed -- than people might realize, said study author Piotr Winkielman, an associate professor of psychology.

"Our mind becomes very practiced at picking up these cues, whether it's smiling or frowning," Winkielman said. Smiles "can activate a process in your brain that basically makes you more positively predisposed to whatever comes next."

Winkielman and his colleagues designed two experiments to force students to focus their thoughts on a mystery beverage -- actually a concoction of water, sugar and lemon-lime Kool-Aid.

Before each experiment, the students looked at photos of a series of neutral faces. Smiling or frowning faces were also embedded in the photos, but were displayed too fleetingly for subjects to consciously notice. The researchers had previously tested the students to make sure they couldn't detect the subliminal photos.

The idea was to see whether the smiling and frowning faces primed the students to be more willing to try something new.

Winkielman presented his findings May 26 at the American Psychological Society annual meeting, in Los Angeles.

In the first experiment, 39 undergraduate students were allowed to drink as much of the unnamed beverage as they wanted. Thirsty subjects drank twice as much after viewing the happy faces as those who looked at unhappy faces, Winkielman reported.

In the second experiment among 29 students given a sip of the beverage, the thirstiest subjects primed by a smiling face wanted to spend 38 cents for a full drink, while those primed by a frowning face only wanted to spend 10 cents.

Since people have been accustomed to reading faces since infancy, it makes sense that they'd be fine-tuned to these expressions, Winkielman explained. "Your brain has maybe learned to use those cues and adjust your behavior without you realizing it," he said. "You can think of it as happy faces being a general 'go' signal."

Craig A. Smith, an associate professor of psychology at Vanderbilt University, said the findings suggest that people don't always consciously feel the emotions that actually influence what they do or buy. "You're not aware that you're feeling angry or sad, yet you behave in ways that are consistent with that feeling," Smith said.

By providing evidence of "unconscious" emotion, the study adds more support to the idea that emotions have a physical basis in the brain, he said.

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