Women may be better at sniffing out biologically relevant information from underarm sweat, a US study suggests.
Researchers found it was difficult to mask underarm odour when a woman was doing the smelling, but quite easy to do so when it was a man.
They speculate that a woman's highly attuned smell radar might help her select a mate.
The study, by Philadelphia's Monell Center, appears in Flavour and Fragrance Journal.
In the study, women and men rated the strength of underarm odours, both alone and in conjunction with various fragrances.
The fragrances were selected to test their ability to block underarm odour through a method known as olfactory cross-adaptation.
This occurs when the nose adapts to one odour, and then also becomes less sensitive to a second odour.
Sniffed alone, the underarm odours smelled equally strong to men and women.
But when fragrance was introduced, only two of 32 scents successfully blocked underarm odour when women were doing the smelling.
In contrast，19 fragrances significantly reduced the strength of underarm odour for men.
Lead researcher Dr Charles Wysocki, a behavioural neuroscientist, said: "Taken together, our studies indicate that human sweat conveys information that is of particular importance to females.
Not only were women better smellers than men, but male odours were harder to block than female odours.
Underarm odours from the two sexes did not differ in how strong they smelled. However 19% of the fragrances successfully reduced the strength of male underarm odour, compared to over 50% for the female equivalent.
Dr Leslie Knapp, an expert in biological anthropology at the University of Cambridge, said there were good evolutionary reasons why a woman's ability to detect body odours should be more acute could literally be an effective way to sniff out a suitable mate.
She said: "Women perhaps need to be more discriminating when they choose who to mate with to produce offspring, as they invest more than males in the reproductive process.
"Men don't need to be so choosy，they have lots of sperm, and can reproduce with lots of females, but once a woman reproduces with a partner she is tied up for nine months."
Dr Knapp said there was evidence that odour gave a hint about genetic make-up. She highlighted HLA genes involved in the immune response.
She said in evolutionary terms it was desirable for a women to mate with a man whose genes were different from hers, as this was likely to produce more robust offspring.
女性可更好地識別體味
美國一項研究顯示，女性通過腋下氣味識別生物性相關信息的能力很可能更強。
研究人員發(fā)現(xiàn)，用其他氣味來蒙蔽女性對腋下氣味的識別是比較困難的。相比之下，男性則更好蒙騙。
研究人員由此猜測，女性敏銳的嗅覺可能有助于她們選擇適合自己的伴侶。
由費城蒙尼奧研究中心組織的這項研究成果已經(jīng)在《香料與香味雜志》上發(fā)表。
參與試驗的女性和男性分別用鼻子去聞兩組腋下氣味，一組是獨立的腋下氣味，另一組是腋下氣味與其他多種香味混合而成的氣味。
研究人員利用嗅覺交到主應的方法來測試他們辨別腋下氣味的能力。
采用這種測試方法是因為一旦鼻子對第一種氣味適應之后，它對第二種氣味的判斷靈敏度就減弱了。
當男女在聞獨立腋下氣味的時候，男女的辨別能力旗鼓相當。
但是當腋下氣味中混合了其他香味的時候，32種氣味中只有兩種腋下混合氣味讓女性無法成功識別。
與之相比，19種腋下提合氣味成功蒙騙了男性的鼻子。
研究小組的首席研究員、行為神經(jīng)科學家查爾斯·維索斯基博士表示，綜合實驗結果，人類汗腺分泌的氣味所傳達的信息對于女性尤為重要。
不僅女性的嗅覺比男性敏銳，而且男性的體味比女性的更難隔離。
男女腋下體昧的強度其實并無差異。但是，男性香水能有效地減弱男性腋下19%的氣味，而女性香水則能掩蓋超過50%的體味。
劍橋大學生物人類學專家萊斯利-納普博士表示，女性辨別體昧的能力之所以更強是因為進化的原因，因為這樣女性就可以更有效地聞出適合自己的伴侶。
她說:"女性可能在選擇與之生育后代的伴侶時需要更有效地識別能力，所以她們在繁衍過程中具備了優(yōu)于男性的某種能力。"
"男性不需要如此的謹慎，他們有許許多多的精子，他們可以和許多女性生育后代。而一旦女性懷孕，她們需要經(jīng)歷9個月的忍耐。"
納普博士說，有證據(jù)表明，體味同時也會發(fā)出一個人基因組成的信號。她強調(diào)，人類白細胞抗原基因就與免疫功能相關。
她表示，從進化的角度來說，女性若能和與自己基因組合不同的男性結合是很好的選擇，因為那樣他們的下一代很可能更健康。
句型講解：
1. Researchers found it was difficult to mask underarm odour when a woman was doing the smelling, but quite easy to do so when it was a man.
本句是一個復合句。 found后面是省略了引導詞的賓語從句，作found的賓語。其中it是形式主語，真正的主語是后面的不定式短語to mask underarm odour。后面兩個when分別引導兩個時間狀語從句。
語法重點：賓語從句，時間狀語從句
2. Dr Leslie Knapp, an expert in biological anthropology at the University of Cambridge, said there were good evolutionary reasons why a woman's ability to detect body odours should be more acute could literally be an effective way to sniff out a suitable mate.
本句是一個復合句。 an expert...Cambridge是Dr Leslie Knapp的同位語。 Said后面是省略了引導詞的賓語從句，充當said的賓語。其中why引導限制性定語從句，修飾reasongs。 as引導原因狀語從句
語法重點：同位語，賓語從句，定語從句，原因狀語從句
3. She said in evolutionary terms it was desirable for a women to mate with a man whose genes were different from hers, as this was likely to produce more robust offspring.
本句是一個復合句，said后面是省略了引導詞的賓語從句，充當said的賓語。其中it是形式主語，真正的主語是后面的不定式短語to mate with a man. whose引導定語從句，修飾man. as引導原因狀語從句。
語法重點：賓語從句，形式主語，定語從句，原因狀語從句
