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LISTEN LIVE: All Things Considered



Professors Find Sounds Can Direct Our Gazes — And Maybe Affect Our Purchases07:56

"When the high frequency music was playing, more people took bananas from the light-colored shelves as compared to the dark-colored shelves -- and vice versa," said BC professor Henrik Hagtvedt, of his experiment. (un_owen/Flickr)
"When the high frequency music was playing, more people took bananas from the light-colored shelves as compared to the dark-colored shelves -- and vice versa," said BC professor Henrik Hagtvedt, of his experiment. (un_owen/Flickr)
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These days it seems someone is always trying to sell us something. We're inundated with ads vying for our attention. And advertisers are forever searching for ways to cut through the cacophony and visual clutter.

Now, researchers at Boston College say they've discovered a subliminal, automatic and irresistible way to direct our sight and focus our attention using different sound frequencies.

The Sound-Sight Connection

These early findings offer the promise of powerful, perhaps even profound techniques that might be able to tap deep into our psyches, direct our perceptions, as well as influence what we purchase and the information we retain.

Professor Adam Brasel, head of the BC marketing department, said this has to do with a field of psychology called "cross-modal correspondence."

"A stimulus in one sense kind of primes us for to receive a stimulus in another sense," he explained. "So feeling a certain temperature might associate you more likely to see a certain color."

You feel hot? That's associated with red. Cold? That's blue. Advertisers use this all the time in visual marketing.

One day, Brasel's colleague, marketing professor Henrik Hagtvedt, mentioned something he noticed: Different sounds influenced his visual perception.

"I personally associated high frequency with lighter colors and lower frequencies with darker colors, and I became curious about whether or not that was just me or if it was other people as well," Hagtvedt said.

"When you hear these low tones your eyes are automatically drawn toward darker areas of the screen..."

BC professor Adam Brasel

So Hagtvedt and Brasel devised a series of experiments using a device in Brasel's visual perception lab.

"The nice thing with the eye tracker that we use, [the students] don't have to wear any headware. They don't have to put their chin on a rest or anything," Brasel explained. "It's a very normal experience. It's just like using a normal computer."

The researchers paid BC students a few bucks to participate and set them up in front of the eye-tracking computer. The computer was then able to "map the actual movements of the pupil to tell us where they are looking on the screen," Brasel said.

The students saw light and dark shapes — spheres and squares — flash on their screens as different frequency sounds were played. The students heard seven different frequencies, ranging from low to high. All the while, the eye tracker followed their pupils.

The experiment confirmed the researchers' hypothesis.

"Indeed, when you hear these low tones your eyes are automatically drawn toward darker areas of the screen, versus when you hear the high tones your eyes are automatically drawn toward lighter areas of the screen," Brasel explained.

The researchers explained that the association the participants built between the sounds and visuals happened very fast. "It's extremely quick," Brasel said, snapping his finger. They added that the students were also given no instructions during the experiment. The effect operated without their awareness.



You (And Your Eyes) Scream For ... Frequencies?

In another experiment, researchers found different frequencies of a familiar song could even divert normal visual responses.

Take, for example, a melody dating from the early 19th century called "Turkey in the Straw" that very often reminds people of the call of an ice cream truck.

"So when you hear this 'Turkey in the Straw' song, there's a conscious effort, 'OK, I'm hearing the "Turkey in the Straw," I should be looking at the ice cream truck,' " explained Hagtvedt.

But when student subjects heard the high frequency song their attention was drawn not to a dark color ice cream truck, but a light color picture of a bus — and vice versa. Low frequency sound meant they saw a dark image.

Hagtvedt said the sound frequencies directed the eyes' attention.

"Here you have basic sensory input," he said. "Right? It's just sound frequency and color lightness. And to see that kind of a correspondence guide behavior is absolutely fascinating."

And there is nothing you can do about it. Even when participants were explicitly told to focus on the dark or light objects, the correspondence with the sound frequencies took precedence.

"So they can't override it immediately," said Hagtvedt. "It's clearly an automatic response, presumably hardwired."


In another experiment, the researchers discovered the connection between sound and sight could also affect memory and the information we retain.

They created two versions of a TV commercial for a fictitious restaurant, putting information about the place on a white background or a dark-colored background. Then, they played two versions of a song they created — one pitched low, the other high.

"And what we were able to show is that when we played the soundtrack with the very low tones, people remembered the restaurant information that was on the dark background versus when we played the high tones, people remembered the information that was on the bright background," explained Brasel.

This brings us to their fifth and final experiment. This one was conducted in a Norwegian supermarket. (Hagtvedt is Norwegian and regularly visits Norway on summer breaks.)

Hagtvadt stacked two shelves with bananas — one shelf light-colored, the other dark.

"Then we played music in the supermarket that was low frequency or high frequency. It was the same music — the only differences were in the frequencies," he explained. "And then [we] observed: The people who were buying bananas, from where are they actually taking those bananas? From the light-colored shelves, or from the dark-colored shelves?

"And, as it turned out, when the high frequency music was playing, more people took bananas from the light-colored shelves as compared to the dark-colored shelves — and vice versa," he said.

A Powerful Marketing Tool

"Being able to actually show this effect is taking place in the real world with actual behavioral consequences is one of the key pieces of the paper," Brasel said.

Hagtvedt's and Brazel's paper, "Cross-Modal Communication: Sound Frequency Influences Consumer Responses to Color Lightness," was published in the Journal of Marketing Research in August.

"We can use this not only in a retailing context, but what about online, where color and sound might be among the only stimuli that you have?" said Hagtvedt. "We can guide visual attention online or on TV. Yeah, there are so many applications that it would be difficult to list them."

Don't worry. While frequencies can help guide your gaze, they won't direct all of your behavior.

"We have shown that marketers or educators or politicians or whoever, can, to some degree, guide your visual attention depending on the tones that you're hearing, and that might cause you to attend to some visual information more so than others," Brasel said. "So you may be able to shape a narrative a little bit, but it's not quite to the point of psychological programming or that old subconscious research where we're making people do things illicitly."

So, the next time you're at a supermarket or political rally, keep your eyes and ears open. And watch what you're listening to.

This segment aired on February 7, 2017.

Bruce Gellerman Twitter Senior Reporter
Bruce Gellerman is an award-winning journalist and senior correspondent, frequently covering science, business, technology and the environment.