How do emotions work? This might seem like an odd question since we all experience emotions every day: happiness at seeing an old friend, sadness while watching a tragic film, fear of losing the ones we love. Emotions seem automatic. Your heart skips a beat, your nerves do a little dance, your face moves in familiar ways, and you are carried away by the experience. Nevertheless, from a scientific standpoint, what are emotions really?
For centuries, famous thinkers like Plato, Aristotle, Darwin and Freud, as well as countless other scientists, have tried to explain emotion using common sense. Emotions feel natural and uncontrollable, the reasoning went, so they surely must be built into us from birth. In recent years, however, the field of neuroscience – the study of how the human brain creates the human mind – has surged. With this interest has come intense research and renewed debate on the nature of emotions.
A few decades ago, scientists could only guess how the brain creates our emotional experiences. Now, though, we can use brain-imaging to harmlessly peer inside a head. This allows us to observe neural activity, moment by moment, inside living people. And when it comes to emotion, what we see in those brains seems to defy common sense. Emotions are not what most people think they are.
Here’s what I mean. Suppose you’re walking in the woods and you see a bear, and you instantly feel afraid. What happened inside you? The traditional explanation goes like this. As soon as you saw the bear, some dedicated part of you – like a ‘fear circuit’ in your brain – sprang into action, triggering your body to react in a predetermined way. Your heart raced, your blood pressure soared, and your face formed an expression of fear that’s said to be universal across all human cultures. In this classical view of emotion, the firing fear circuit, the bodily changes, and the facial expression supposedly form a distinct, detectable ‘fingerprint’ that distinguishes fear from all other emotions. That fingerprint was presumably passed down to humans through evolution, along with fingerprints for other emotions.
As compelling and intuitive as the classical view may be, it can’t possibly be correct. Scientists have been searching for emotion fingerprints in the face, body and brain for over 100 years without success. Occasionally, you’ll see a news story that scientists have found fingerprints of happiness, sadness, anger, fear, or other emotions in humans or other animals, but when other scientists retest those claims, they invariably don’t hold up. For example, for many years, scientists believed that the brain’s ‘fear circuit’ was a region called the amygdala. If you google ‘amygdala fear’ you can still find thousands of articles that make this claim. Nevertheless, it’s not true. We now know definitively that some people who lack an amygdala can still feel fear. Not only that, but the amygdala is involved in dozens of other mental functions (such as thinking, memory, empathy and all other emotions), so it’s clearly…
This is an extract from issue 322 of BBC Focus magazine.
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