Jeremy Schifeling is the author of Linked, a guide to using LinkedIn and your network to find the job of your dream. He is the Director of Consumer and Product Marketing at Khan Academy and often speaks of his own career journey going from a classroom teacher to a career in tech.
Also, since Jeremy mentions it during the conversation, make sure to check out the Duchenne smile post on Wikipedia:
While conducting research on the physiology of facial expressions in the mid-19th century, French neurologist Guillaume Duchenne identified two distinct types of smiles. A Duchenne smile involves contraction of both the zygomatic major muscle (which raises the corners of the mouth) and the orbicularis oculi muscle (which raises the cheeks and forms crow’s feet around the eyes). The Duchenne smile has been described as “smizing”, as in “smiling with the eyes”. An exaggerated Duchenne smile is sometimes associated with lying.
A non-Duchenne smile involves only the zygomatic major muscle. “Research with adults initially indicated that joy was indexed by generic smiling, any smiling involving the raising of the lip corners by the zygomatic major …. More recent research suggests that smiling in which the muscle around the eye contracts, raising the cheeks high (Duchenne smiling), is uniquely associated with positive emotion.”
The Pan Am smile, also known as the “Botox smile”, is the name given to a fake smile, in which only the zygomatic major muscle is voluntarily contracted to show politeness. It is named after the now-defunct airline Pan American World Airways, whose flight attendants would always flash every passenger the same perfunctory smile. Botox was introduced for cosmetic use in 2002. Chronic use of Botox injections to deal with eye wrinkle can result in the paralysis of the small muscles around the eyes, preventing the appearance of a Duchenne smile.https://en.wikipedia.org/wiki/Smile#Duchenne_smilehttps://en.wikipedia.org/wiki/Smile#Duchenne_smile