Eyes don't reveal when a person is lying despite the common belief that no fibber can hide behind them, research has shown.
For decades experts have been convinced that eye movements can reveal when someone is lying.
Many psychologists believe that when a person looks up to their right they are likely to be telling a lie.
Glancing up to the left, on the other hand, is said to indicate honesty.
But the experts are wrong, according to Professor Richard Wiseman and his team of researchers, who tested whether eyes really can reveal lies.
Do you know how to spot a liar? Scroll down (PICTURES)
The claimed link between lying and eye movements is a key element of neuro-linguistic programming (NLP), a method of enhancing people's lives using psychological techniques.
An important aspect of NLP involves teaching people about the relationship between eye movements and thought.
According to the theory, when right-handed people look up to their right they are likely to be visualising a "constructed" or imagined event.
In contrast when they look to their left they are likely to be visualising a "remembered" memory.
For this reason, when liars are constructing their own version of the truth, they tend to look to the right.
Watch out for an avoidance of eye contact or eyes moving too quickly
Do they look more 'smug' than normal?
Are they displaying high levels of 'calm'?
Are their words accompanied with frequent 'small shrugs'?
Do they play with their hair while talking?
Does their smile reach all the way to their eyes?
Does this person deliberately place an object/piece of furniture between you and them while talking?
Are they sweating more than normal?
Do they touch their face while talking?
The idea was tested by filming volunteers and recording their eye movements as they told the truth or lied.
A second group of volunteers was then asked to watch the films and try to detect the lies by watching the eye movements.
Psychologist Prof Wiseman, from the University of Hertfordshire, said: "The results of the first study revealed no relationship between lying and eye movements, and the second showed that telling people about the claims made by NLP practitioners did not improve their lie detection skills."
A follow-up study involved analysing videos of high-profile press conferences in which people appealed for help in finding missing relatives, or claimed to have been victims of crime.
While some were telling the truth, others turned out to be lying.
Again, there was no evidence of a correlation between lying and eye movements.
Find out what your eyes reveal about your health below (PICTURES)
Co-author Dr Caroline Watt, from the University of Edinburgh, said: "A large percentage of the public believes that certain eye movements are a sign of lying, and this idea is even taught in organisational training courses. Our research provides no support for the idea and so suggests that it is time to abandon this approach to detecting deceit."
The research appears in the online journal Public Library of Science ONE.
Prof Wiseman also added these tips on how to spot a liar:
-Me, myself I: Liars make up stories that never actually happened, and so tend to reduce the number of times they refer to themselves. Look out for any sudden drop in words like me, mine and I.
-Shifty: Lying is difficult and people tend not to move around when they are concentrating on something. Be wary if a person suddenly becomes very still.
-Umm ... err: Liars are far more hesitant than truth tellers and tend to stumble over their words. Listen out for tell-tale umms and errs.
-Timing: Liars often have to think about what they are going to say before they speak. Be suspicious if someone suddenly pauses before starting to answer a question.
- Token gesture: Liars tend to move their hands around more than truth tellers. Be wary if someone suddenly starts covering up their mouth or touching their hair as they chat.
Different Shaped Pupils
The pupils (the black circle in the centre of the eye) in normal people are usually symmetrical, the same size and react in the same way when exposed to sunlight. If one pupil is bigger or smaller than the other, there could be an underlying medical problem. Experts claim that differences in pupil size could indicate that the person is at a higher risk of having a stroke, brain or optic nerve tumour, or brain aneurysm. <strong>If you spot any changes to your pupils, raise this with your GP, optometrist or ophthalmologist.</strong>
Dry Eyes (Sensitive To The Light)
If your eyes are always dry and ultra sensitive to light, it could signal an immune system disorder, <a href="http://www.nhs.uk/conditions/Sjogrens-syndrome/Pages/Introduction.aspx" target="_hplink">Sjogren</a>, which impairs the glands in the eyes and mouth. The condition affects women over 40 with autoimmune disorders, such as rheumatoid arthritis or lupus. <strong>Seek advice from your GP if this sounds like you, as artificial lubricant can be prescribed and you'll be advised to drink plenty of water.</strong> "Dry eyes are more common in women over 50 due to hormonal changes," adds Larry Benjamin from <a href="http://www.rcophth.ac.uk/" target="_hplink">The Royal College of Ophthalmologists. </a>
If your eye is covered in a 'cloud' and your vision is impaired because of it, you may have a cataract. This causes a clouding of the lens inside the eye and can be corrected with surgery. This condition mainly occurs in older people but in younger people, it is commonly caused as a side effect of diabetes, tumours and some medication.
Although there are many things that can cause itchiness around the eyes, the most common reason could be pinpointed to an allergic reaction. The eye, and the area around it, is delicate and sensitive and more vulnerable to infections and allergies. Triggers could be anything from airborne pollens, dust or animal fur. <strong>If you suffer from red itchy eyes, try antihistamines to ease the redness, or visit your GP to organise an allergy test. </strong> If your eye and eyelids become puffy and sore, this could be a sign that you're sleep deprived. "Fluid moves around your head when you sleep and normally disperses when you wake from a good night's sleep. "However, lack of sleep causes this fluid to retain around the eye area for longer," explains Larry Benjamin from <a href="http://www.rcophth.ac.uk/" target="_hplink">The Royal College of Ophthalmologists</a>.
If your eye has a light grey ring around the cornea (the coloured circle in your eye), you may have a condition called <a href="http://www.mayoclinic.com/health/arcus-senilis/AN01493" target="_hplink">arcus senilis</a>, which is often linked to high cholesterol levels and triglycerides - fatty acids found in the blood. These are linked to higher risk of heart disease and strokes, so if you spot a grey ring circling your eye, <strong>visit your GP to discuss changing your diet. </strong>
Although it's natural for eyebrows to become thinner as we age, if you notice your brows literally 'disappearing' from the outer third of the eyebrow, this could signal a thyroid dysfunction. Loss of eyebrow hair from the outer edges of your face is a common sign of hyperthyroidism (overactive thyroid) or hypothyroidism (under active thyroid). Thyroids help regulate the metabolism and thyroid hormones are vital for hair production. <strong>If in doubt, book an appointment with your GP.</strong>
"Watery eyes can indicate infection," explains Larry Benjamin from <a href="http://www.rcophth.ac.uk/" target="_hplink">The Royal College of Ophthalmologists</a>. "If the eye is watery, you've most likely got an infection caused by a virus. If it's sticky, you might have a bacterial infection." If your vision becomes blurry, this could also be the result of <a href="http://www.allaboutvision.com/cvs/" target="_hplink">Computer Vision Syndrome</a> (CVS), caused by eyestrain from lack of contrast on a computer screen. This makes the eyes work harder focusing on the pixels on the screen. <strong>If in doubt, speak to your employer about booking an eye test, which is free if you use visual display units (VDU) for long periods of time. </strong>
Yellow lumps, also known, as xanthelasma palpebral, which appear on your eyelids could be a warning signal that your cholesterol levels are sky high. These are fatty deposits, which clump together and live in the eyelid. These are very often mistaken for a stye. Although these are quite common, <strong>it's best to get them checked by your optician or GP, as it can sometimes be an early sign of coronary artery disease. </strong> If you spot any coloured spots on your eyelids, in particular brown spots, <strong>visit your GP immediately</strong> as it could be an early sign of skin cancer. These usually appear on the lower part of the eyelid and will look a brownish colour with tiny blood vessels.
If your eyes are always blood-shot with broken blood vessels making them look blotchy and sore, this could be a sign that you have high blood pressure. Your optician will be able to confirm this by looking at your retina (the inner part of the eye). High blood pressure causes the blood vessel in the retina to 'kink and twist', causing them to break and look red. This could increase your risk of a stroke, so <strong>raise it with your GP as soon as possible. </strong>
If the whites of your eyes have a yellow tint rather than pearly white, you may have jaundice, which is linked to various liver and gall bladder problems. A simple blood test will confirm this, so if you're in doubt, <strong>book an appointment with your GP. </strong>