Neuroscience
Around 1 in 7,500 otherwise healthy people are born with no sense of smell, a condition known as isolated congenital anosmia (ICA). So dominant are sight and hearing to our lives, you might think this lack of smell would be fairly inconsequential. In fact, a study of individuals with ICA published last year showed just how important smell is to humans. Compared with controls, the people with ICA were more insecure in their relationships, more prone to depression and to household accidents.
Now, in a follow-up paper involving the same 32 patients with ICA, Ilona Croy and her colleagues have looked at how this lack of a sense of smell affects their sexual relationships. The researchers' analysis uncovered an intriguing sex difference. Compared with 15 age-matched controls, the 10 men with no sense of smell reported having substantially fewer sexual partners in their lifetime (male controls averaged five times the number of partners). In contrast, women with no sense of smell averaged just as many sexual partners as women with smell.
On the other hand, the 22 women (but not the men) without a sense of smell tended to report feeling more insecure in their relationship with their current partner, than did the healthy controls. This insecurity was specific to their sexual partner and wasn't found in relation to friendships or maternal attachment.
Across both sexes, the impact of a loss of smell makes sense given the mounting evidence for the social importance of smell, for example we can use smell to detect other people's anxiety; people with more empathy are more likely to remember your smell; and smells convey at least some personality traits. Also, common sense suggests people without a sense of smell might worry about any odours they could be exuding without their knowledge. But the question still remains - why should not having a sense of smell affect men and women differently?
The researchers surmised that not having smell reduces men's "exploratory sexual behaviour", perhaps due to their lack of social confidence. Consistent with this interpretation, there was a negative correlation between the male (but not female) patients' levels of social insecurity and their number of sexual partners.
On the other hand, the researchers think the effect of a lack of smell on women makes sense in light of past research suggesting that smell is more important for their relationship security, than it is for men. For instance, a study published in 2008 found that a half of the women surveyed had worn someone else's clothes (usually a partner's) because of its smell, compared with just 13 per cent of men. Also relevant - the female patients' had lower social confidence than the female controls, and this correlated with their lack of relationship security.
Other research has shown that odour is more important to women than it is to men in choosing a partner: women supposedly prioritise good odour over good looks, men the opposite, although it's not clear how this fits with the current findings. Women also seem to have a superior sense of smell, on average, compared with men, and value the sense more highly.
Croy and her colleagues acknowledged the need for caution given their small sample size, but they said their results emphasise "the importance of the sense of smell for intimate relationships."
_________________________________
Croy, I., Bojanowski, V., and Hummel, T. (2013). Men without a sense of smell exhibit a strongly reduced number of sexual relationships, women exhibit reduced partnership security – A reanalysis of previously published data. Biological Psychology, 92 (2), 292-294 DOI: 10.1016/j.biopsycho.2012.11.008
--Further reading--
Humans can track scents like a dog.
Brain response to putative pheromones in homosexual men.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
- Inside The Brains Of Men And Women Controlling Their Emotions
Women do seem to cry more readily than men, but is that because they are less able to control their emotions? According to Ute Habel and colleagues, research does suggest women are more 'emotional'. They cite the fact that women are more vulnerable...
- Humans Can Track Scents Like A Dog
Bloodhounds are unlikely to be out of work just yet, but researchers have found humans can track a scent on the ground in the same way that dogs do. While humans are traditionally considered to have a poor sense of smell compared with many of their mammalian...
- How Messages Are Scent
The idea that humans release chemical signals – pheromones – that affect people around them is controversial. If pheromones do exist, however, two chemicals that might fulfil this role are the testosterone derivative 4,16-androstadien-3-one (AND),...
- Anosmia
Tomorrow's New York Times Sunday Magazine has a short piece written by someone who lost her sense of smell and her effort to try to find it once again:Something's Off By ROBIN MARANTZ HENIG 17 October 2004 The New York Times [Snip] ...
- Stop And Smell The Coffee?
The Sept. 24, 2005 issue of New Scientist has an article about anosmia, the loss of one's sense of smell. It's a first-person account of losing the sense of smell after a viral infection, as well as a hopeful but untested treatment under cognitive...
Neuroscience
Investigating the love lives of the men and women who have no sense of smell
Now, in a follow-up paper involving the same 32 patients with ICA, Ilona Croy and her colleagues have looked at how this lack of a sense of smell affects their sexual relationships. The researchers' analysis uncovered an intriguing sex difference. Compared with 15 age-matched controls, the 10 men with no sense of smell reported having substantially fewer sexual partners in their lifetime (male controls averaged five times the number of partners). In contrast, women with no sense of smell averaged just as many sexual partners as women with smell.
On the other hand, the 22 women (but not the men) without a sense of smell tended to report feeling more insecure in their relationship with their current partner, than did the healthy controls. This insecurity was specific to their sexual partner and wasn't found in relation to friendships or maternal attachment.
Across both sexes, the impact of a loss of smell makes sense given the mounting evidence for the social importance of smell, for example we can use smell to detect other people's anxiety; people with more empathy are more likely to remember your smell; and smells convey at least some personality traits. Also, common sense suggests people without a sense of smell might worry about any odours they could be exuding without their knowledge. But the question still remains - why should not having a sense of smell affect men and women differently?
The researchers surmised that not having smell reduces men's "exploratory sexual behaviour", perhaps due to their lack of social confidence. Consistent with this interpretation, there was a negative correlation between the male (but not female) patients' levels of social insecurity and their number of sexual partners.
On the other hand, the researchers think the effect of a lack of smell on women makes sense in light of past research suggesting that smell is more important for their relationship security, than it is for men. For instance, a study published in 2008 found that a half of the women surveyed had worn someone else's clothes (usually a partner's) because of its smell, compared with just 13 per cent of men. Also relevant - the female patients' had lower social confidence than the female controls, and this correlated with their lack of relationship security.
Other research has shown that odour is more important to women than it is to men in choosing a partner: women supposedly prioritise good odour over good looks, men the opposite, although it's not clear how this fits with the current findings. Women also seem to have a superior sense of smell, on average, compared with men, and value the sense more highly.
Croy and her colleagues acknowledged the need for caution given their small sample size, but they said their results emphasise "the importance of the sense of smell for intimate relationships."
_________________________________
Croy, I., Bojanowski, V., and Hummel, T. (2013). Men without a sense of smell exhibit a strongly reduced number of sexual relationships, women exhibit reduced partnership security – A reanalysis of previously published data. Biological Psychology, 92 (2), 292-294 DOI: 10.1016/j.biopsycho.2012.11.008
--Further reading--
Humans can track scents like a dog.
Brain response to putative pheromones in homosexual men.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
- Inside The Brains Of Men And Women Controlling Their Emotions
Women do seem to cry more readily than men, but is that because they are less able to control their emotions? According to Ute Habel and colleagues, research does suggest women are more 'emotional'. They cite the fact that women are more vulnerable...
- Humans Can Track Scents Like A Dog
Bloodhounds are unlikely to be out of work just yet, but researchers have found humans can track a scent on the ground in the same way that dogs do. While humans are traditionally considered to have a poor sense of smell compared with many of their mammalian...
- How Messages Are Scent
The idea that humans release chemical signals – pheromones – that affect people around them is controversial. If pheromones do exist, however, two chemicals that might fulfil this role are the testosterone derivative 4,16-androstadien-3-one (AND),...
- Anosmia
Tomorrow's New York Times Sunday Magazine has a short piece written by someone who lost her sense of smell and her effort to try to find it once again:Something's Off By ROBIN MARANTZ HENIG 17 October 2004 The New York Times [Snip] ...
- Stop And Smell The Coffee?
The Sept. 24, 2005 issue of New Scientist has an article about anosmia, the loss of one's sense of smell. It's a first-person account of losing the sense of smell after a viral infection, as well as a hopeful but untested treatment under cognitive...