NYU Professor Explains How Emotions Work

James Glenwright
Staff Writer

“Everyone knows what emotion is until they are asked to define it,” according to Joseph LeDoux, professor of science and psychology at New York University.

Unfortunately, even neuroscientists are having difficulty trying to define emotion, let alone understand it. Along with the mind, emotion has been understood as an intangible part of the human psyche, transcending the realm of biological mechanisms. In the words of the 20th century philosopher Gilbert Ryle, “the body and the mind are ordinarily harnessed together, but after the death of the body the mind may continue to exist and function.”

This theory has long been known as the ghost in the machine- inspiration for The Police album not vice-versa- and has proved to be comforting to the believer and non-believer alike. However, advances in technology over the past two decades have allowed cognitive neuroscientists to deduce that the mind and emotions are dependent on biological reactions taking place in the brain. But when the brain has over 100 billion neurons with millions of miles of wiring how can scientists even begin to grasp how emotion works?

During his lecture at University of California Santa Barbara on March 1, LeDoux was quick to emphasize that his research does not aim to explain how human emotions are represented in animals but rather to understand the “survival circuitry,” a term that refers to brain functions and behaviors such as fight or flight responses, energy management, and homoeostasis. Joseph LeDoux works at NYU’s Center of Neural Science to understand the preeminent authority on how memory triggers emotion.

LeDoux’s research starts off mapping neural pathways in rats responsible for interpreting sensory stimuli and converting it to learning. This is done by utilizing fear-conditioning techniques on rats to induce emotional memory. For example, a rat exposed to a tone receives a shock then over the course of several shocks the rat learns to “fear” the tone because he associates pain with it. Though this psychological mechanism has been documented for close to one hundred years, LeDoux is unique because he studies the neural pathways responsible for this reaction.

However, this technique raises an immediate red flag. Though this research deduces how emotions or feelings operate in rats, the same can’t be said for humans. Besides the obvious size difference, it cannot be assumed that a rat can experience human emotions such as fear, anger, and love in a similar manner. So then one must question the point of studying animals when trying to understand human emotion.

By studying the existence of survival circuitry in rats, LeDoux can see if they are similar to those found in humans, which is in fact the case. By identifying these survival circuits, neuroscientists can see how they generate adaptive behaviors associated with emotion.

According to LeDoux, emotion is a byproduct of behavioral responses that are triggered by survival circuits. Therefore neural pathways responsible for the acquisition of food can trigger emotions of happiness and pleasure after Thanksgiving dinner. Inversely, survival circuits responsible for defenses behavior initiate a fight or flight response, which constitutes fear when the organism has realized that such a response has been triggered.

However, LeDoux is tentative about his own conclusions and does not believe his work provides an all-encompassing explanation for all emotion. He recognizes that some feelings are not triggered by survival circuitry. Given that neuroscience is still in its infancy and there is much to be learned this is an appropriate stance to take. For now, however, preliminary explanations for how the most cherished human characteristics function is proving quite promising.