People can tell how old you are by how you smell, according to new research published in the journal PLoS One. It appears that “old person smell” some people complain about is for real, that elderly people emit a unique identifying odor. An elderly individual’s “old person smell” is actually acknowledged and accepted in cultures throughout the world. However, researchers say all age groups rated “old person smell” as less intense and less unpleasant than the body odors of middle-aged and young individuals. Although often masked with deodorants and perfume, body odor is thought to send out an array of messages that people receive on an unconscious level. In the study, scientists gathered data from three age groups – young (20 to 30 years), middle-aged (45 to 55 years), and old-aged (75 to 95 years). The participants slept in t-shirts with pads located under the armpits. After five nights the armpit pads were removed and placed in jars. Other participants were then asked to rate the scent and group the jars according to age. The research found that people were easily, and correctly, able to group the armpit pads according to age categories.