In the 1950s, advertisers claimed they could get inside people's heads with subliminal ads, which supposedly flashed words like "Drink Coke" for a fraction of a second during a movie. Today, they're trying to get into your head by actually getting inside of it.
Inside a lab at a company called NeuroFocus, test subjects are having their eye movements and brainwaves measured as they watch commercials to see what they respond to at a subconscious level.
Watch "World News with Diane Sawyer" for more on this story tonight on ABC.
Researchers at NeuroFocus say people's likes and dislikes are governed by something deeply subconscious, and that 99 percent of all thinking and decision-making processes are performed without us actually knowing it.
Dr. A.K. Pradeep is a pioneer in "neuro-marketing," research based on measuring three key types of brainwaves: attention, emotion and memory.
NeuroFocus probes consumers' subconscious using EEGs, or Electroencephalography. Researchers place 32 electrosensors on the test subjects' heads, including three sensors on their face, and skin sensors on their fingers to measure their skin response. As the screen begins showing a moving picture, a map of the subject's brainwaves appears on a monitor. Special cameras track subjects' eyes as they watch.
"That's what her brain is doing and that's what she's actually seeing," said Dr. Steve Miller, the Global Director for Neurolabs at Neurofocus, describing a test subjects' brain images on the monitor. "So when we look at the brain activity, each one of these points is covering a different part of the brain."
Whether you know it or not, he says, brainwaves show that you prefer certain images. For example, people would rather look at items with rounded edges than those with sharp corners. Mannequins and photos with missing heads turn consumers off. And while men typically respond to a product's features, women are more interested in getting a deal.
"Our studies show that in over 90 percent of our studies, men and women differ," said Miller. "Women are much more sensitive and aware of pricing."
This sort of research led to the changes in the iconic Campbell Soup can which led to the disappearance of the spoon and made the bowl bigger and steamier, an image scientists have learned ignites happy memories of hot soup.
ABC News' Neal Karlinsky agreed to have his own brainwaves measured while watching an old Super Bowl commercial for Mountain Dew. While he was watching the ad he thought it was entertaining, but the monitor said something completely different. The ad didn't stick with him or engage him on an emotional level except for one surprising exception.
"I don't know if you're a biker, or a road biker, or a mountain biker," asked Pradeep. "Are you anything like that?"
"I am," said Karlinsky. "That showed up?"
"Yes, the full scene of the guy scrunching on the bike -- somehow your brain connected to that," Pradeep said.
Critics call the process mind reading and worry consumers will be taken advantage of without even knowing it.
"These advertisements are being created and honed and then delivered directly into our subconscious mind," Jeff Chester, Executive Director of the Center for Digital Democracy, a Washington D.C.-based watchdog group that has called on the Federal Trade Commission to regulate neuro-marketing, told ABC News.