it is said that you can learn a lot about someone from their handshake   but it appears they may be learning far more about you than we have perhaps ever realised scientists have discovered that the traditional sign of friendship is actually a way for us to get a good sniff of someone we have just met they found that humans unconsciously use the touch from a handshake as a way to sample smelly chemicals from each other scroll down for videos of the experiments conducted by the researchers  a firm handshake may also be a way of sampling the scent of the person you have just met, say scientists  in a study using hidden cameras, researchers observed people as they greeted each other with and without handshakes those that grasped hands upon meeting then touched their faces and around their nose far more often afterwards compared to a greeting where there was no physical contact a high five or fist bump may not be the most formal way of greeing someone, but they have one advantage over a handshake, say experts   they are better for our health a british study has found that slapping palms together at head height passes on fewer than half as many germs as the traditional greeting for the study, two aberystwyth university researchers donned thick rubber gloves and one dipped his hand in a bacterial soup before shaking the other’s hand the number of bugs transmitted to the second glove was counted and the contact area measured then the procedure was repeated with high fives and also with the even trendier fistbump, which involves two balled fists being gently and briefly rapped together the high five was more hygienic than the handshake but the fistbump was the cleanest of all, transferring around one twentieth of the bugs of the handshake it is thought that the brevity of the action and the smaller contact area helped slash transmission the scientists believe that the face touching is a way of subtly sniffing the hand used in the handshake and it was particularly prevalent when greeting people of the same sex professor noam sobel, chair of neurobiology at the weizmann institute of science, who led the research, said: 'it is well known that we emit odours that influence the behaviour and perception of others but, unlike other mammals, we don't sample those odours from each other overtly 'instead, our experiments reveal handshakes as a discreet way to actively search for social chemosignals' the researchers, whose work is published in the journal elife, believe their findings may provide some hints at why handshakes first evolved to become a greeting and cementing a friendship it has since become a way of sealing a deal and even a sign of sportsmanship limp and damp handshakes are often seen as being an unattractive trait but they may also provide us with unconscious olfactory clues about the other person many other animals use smell as a key part of learning more about each other, such as dogs that will regularly sniff each other upon greeting idan frumin, a neurologist at the weizmann institute who also conducted the research, said: 'it is quite possible that 'boardroom etiquette' is actually a later explanation for an early type of behaviour that appeared in order to compensate for scarcity of physical contact between human individuals 'as we don’t overtly sniff each other like other mammals, we needed a way to pass olfactory data between our peers the handshake might be the best way to convey chemosignals' the scientists secretly filmed 271 people as they greeted one of 20 members of the research team in a hospital setting they found that subjects who shook hands with people of the same sex sniffed their right hand twice as much than if they had not shaken hands when members of the opposite sex greeted, participants sniffed their right hand far less than before a handshake but tended to sniff their left 'non shaking' hand more often the participants in the study were filmed in a hospital, shown above) greeting researchers and were found to sniff their fingers and hands considerably more after shaking hands with the person they were meeting  touching the nose after physical contact (like above) may be a way of smelling chemical signals on others  the researchers believe this may be due to participants unconsciously comparing their own scent to that of the opposite sex in general the participants placed their hand close to their nose 22 per cent of the time after shaking hands for up to around 17 seconds at a time they found that increased airflow through a sample of participants nostrils also accompanied the face touching, indicating that they were sniffing when the scientists added strong artificial odours to wrists of those greeting the participants using scents associated with male or female body odour, the length of time they spent sniffing decreased however, when they added perfume to the wrists of those greeting, the amount of sniffing , they found the amount of time participants touched their face for doubled the researchers claim that his may be because artificial odours may mask the chemical signals from a handshake and so it requires more sniffing to detect them it could also be because the participants found the smells more pleasing than the body odour however, mr frumin said it was still unclear exactly what chemical signals were being exchanged during handshakes he said: 'for instance, we know from research by martha mcclintock in the 70s that women tend to synchronize their menstrual cycles 'a signal may be transferred between women to drive that effect we also know that the choice of a mate is influenced by a person having a compatible immune system 'such data could potentially be transferred skin to skin contact via a handshake but these are speculations and a more rigorous analysis is needed to explore these possibilities'
israel 22 per cent first weizmann institute
scientists at israel's weizmann institute secretly filmed strangers meeting  participants touched their nose 22 per cent of the time after shaking hands  the sniffing doubled when people of the same gender greeted each other  those of opposite sex sniffed their right hands less after shaking hands  researchers say handshakes allow us to subtly sample each other's odour  they say this may explain how the handshake evolved in the first place 