Your eyes may not say it all when it comes to lying, according to a new study.
Despite the common belief that shifty eyes -- moving up and to the right -- indicate deception, researchers found no connection between where the eyes move and whether a person is telling the truth.
In three separate experiments, they tested whether people who lied tended to move their eyes up and to the right, more than people who were not lying. They found no association between which direction the eyes moved and whether participants were telling the truth.
"This is in line with findings from a considerable amount of previous work showing that facial clues (including eye movements) are poor indicators of deception," wrote the authors, led by Richard Wiseman of the University of Hertfordshire in the United Kingdom. The study is published in the online journal PLoS ONE.
Howard Ehrlichman, a professor emeritus of psychology at Queens College of the City University of New York, has done considerable research on eye movements, and said he also never found any link between the direction of eye movements and lying.
"This does not mean that the eyes don't tell us anything about what people are thinking," he said. "I found that while the direction of eye movements wasn't related to anything, whether people actually made eye movements or not was related to aspects of things going on in their mind."
He said that people tend to make eye movements -- about one per second on average -- when they are retrieving information from their long-term memory.
"If there's no eye movement during a television interview, I'm convinced that the person has rehearsed or repeated what they are going to say many times and don't have to search for the answer in their long-term memories."
He said he's not sure where the notion about directionality of eye movement and lying came from, but said it has spread despite little scientific evidence for it.
The study authors attribute part of the popularity of the belief that looking up to the right indicates lying while looking up to the left indicates truthfulness to many practitioners of neuro-linguistic programming (NLP). NLP -- controversial among scientists -- is a therapy approach that revolves around the connection between neurological processes, language and behavior.
"Many NLP practitioners claim that a person's eye movements can reveal a useful insight into whether they are lying or telling the truth," they wrote.
Some NLP practitioners dispute this assertion.
"We don't believe that eye movements are an indication of lying and have never taught it as such. I believe that someone started the idea as a marketing ploy. Perhaps they really believed it," said Steven Leeds, a co-director of the NLP Training Center of New York. "Eye movements, as we teach it, indicate how a person is processing information, whether it be visual, auditory, or kinesthetic, and whether is remembered or created."
Others say they believe that the direction of eye movements can give away a liar.
Donald Sanborn is president of Credibility Assessment Technologies, a company that specializes in lie detection technology, recently licensed new technology -- called ocular-motor detection testing -- based on research done by psychologists from the University of Utah that utilizes a combination of eye tracking and other variables to determine whether a person is lying.
"When a person is lying, their emotional load goes up, which causes changes in pupil diameter and gaze position," said Sanborn. The device also measures how long it takes to read and answer certain questions. Pupil size, gaze position and the length of time it takes to respond to questions reflect that the brain is working harder, which the psychologists determined is a sign of lying.
This device is designed to be used for pre-employment screening, but it is not legal for use by private companies, so the company is working with the U.S. government and with foreign firms. He estimates its accuracy to be around 85 to 87 percent.
But the authors of the new study said their work offers proof that no relationship exists between the direction of eye movements and truthfulness.
"Future research could focus on why the belief has become so widespread," they wrote.