Emotional contagion -> Empathy

Emotional contagion for pain is intact in autism spectrum disorders
Translational Psychiatry (2014) 4, e343
N Hadjikhani, et al.
http://www.nature.com/tp/journal/v4/n1/full/tp2013113a.html

Individuals with autism spectrum disorders (ASD) have impaired social understanding, and seemingly reduced reactions to others’ emotions, which may be interpreted as lack of empathetic concern.
Empathy can be defined as ‘the ability to form an embodied representation of another’s emotional state, while at the same time being aware of the causal mechanism that induced the emotional state in the other’.
Empathy is a multicomponent process, consisting mainly of experience sharing and mental state attribution.
The evolutionary precursor of empathy is emotional contagion, a phylogenetically old phenomenon, even observable in distressed mice.
Emotional contagion is a precursor of emotional empathy, whereby embodiment entails the forming of a representation of the other person’s feelings, and thereby sharing of their experience.
In the observer, this ‘perception-action’ coupling mechanism elicits the activation of the same neural networks as in the person experiencing the emotional state.

Eau de Elderly

Scents and Senescence: “Old Person Smell” Is Real, but Not Necessarily Offensive
Scientific American. May 30, 2012
http://www.scientificamerican.com/article.cfm?id=old-person-smell

A new study confirms that people, like many animals, easily recognize a unique—but not unpleasant—eau de elderly

the Japanese even have a word for it, kareishuu

sebaceous glands

apocrine sweat glands

people recognize a characteristic “old people smell” not because of the aroma’s intensity or offensiveness, but because of its uniqueness compared to the body odors of younger people

people over age 40 have higher levels of a fragrant organic compound known as 2-nonenal in their sweat and on their skin. The chemical, which the researchers described as having an “unpleasant grassy and greasy odor,” … But the compound has also been linked to the scent of cucumbers and aged beer, which are not distasteful to most people

or possibly pheromones … subtle chemical communication, much of it subconscious,
helps people recognize family,
changes women’s reproductive cycles and
makes it easier to empathize with others

see also:
https://franzcalvo.wordpress.com/2013/07/24/chemosignals-communicate-human-emotions