Lisa Barrett in Delancey Place:
“Emotions are … thought to be a kind of brute reflex, very often at odds with our rationality. The primitive part of your brain wants you to tell your boss he's an idiot, but your deliberative side knows that doing so would get you fired, so you restrain yourself. This kind of internal battle between emotion and reason is one of the great narratives of Western civilization. It helps define you as human. Without rationality, you are merely an emotional beast. …
“And yet … despite the distinguished intellectual pedigree of the classical view of emotion, and despite its immense influence in our culture and society, there is abundant scientific evidence that this view cannot possibly be true. Even after a century of effort, scientific research has not revealed a consistent, physical fingerprint for even a single emotion. When scientists attach electrodes to a person's face and measure how facial muscles actually move during the experience of an emotion, they find tremendous variety, not uniformity. They find the same variety — the same absence of fingerprints — when they study the body and the brain. You can experience anger with or without a spike in blood pressure. You can experience fear with or without an amygdala, the brain region historically tagged as the home of fear. …
“So what are [emotions], really? When scientists set aside the classical view and just look at the data, a radically different explanation for emotion comes to light. In short, we find that your emotions are not built-in but made from more basic parts. They are not universal but vary from culture to culture. They are not triggered; you create them. They emerge as a combination of the physical properties of your body, a flexible brain that wires itself to whatever environment it develops in, and your culture and upbringing, which provide that environment. Emotions are real, but not in the objective sense that molecules or neurons are real. They are real in the same sense that money is real — that is, hardly an illusion, but a product of human agreement. This view, [is] call[ed] the theory of constructed emotion.”
More here.