Behavioral scientists need to move away from using terms like “fear” when discussing the workings of the brain, to better integrate the study of the mind. That was Joseph LeDoux’s message during Tuesday morning’s keynote session at CNS 2013. The New York University-based scientist argued that, to minimize confusion around such terms as “fear” and “emotion,” an over-arching “mind science” could help match behavior with what we now know about the physiological workings of the brain.
LeDoux acknowledged that the suggestion might sound strange, especially from someone who wrote a book called The Emotional Brain. But, based in his research, he said: “There is no emotional brain in the sense of a brain system that’s dedicated to feeling emotions like fear.” Rather, LeDoux said the brain evolved to help us and other organisms react appropriately when stimulated, whether that means the instinct to pursue an object we think might be food, or to run away from something that might be dangerous.
What the general public thinks of as fear is really evidence for the consciousness we humans often have of how our brain responds to outside triggers. But, LeDoux pointed out that it is dangerous for scientists to use such terms in anthropomorphizing emotion. For example, when neurons in a rat’s brain signal for it to freeze when a hungry cat might be near, we say that the rat is afraid – ascribing to the rat the emotions that we feel when we’re afraid.
The cognitive revolution in the study of the mind, however, has gone a long way to pry apart that response-emotion connection. The brain’s automatic response to outside events depends on certain triggers, a cascade of communication between neurons, and ultimately the compulsion of the rest of the organism to act. “You don’t have to feel fear for this stuff to work,” LeDoux said.
To demonstrate his point, LeDoux asked the audience to consider what happens when you add acid to a plate of single-celled E. coli. No one in attendance would argue that bacteria experience emotion, and they certainly don’t have a nervous system. But each bacterium spins its flagella as fast as it can to move away from the caustic liquid.
LeDoux took his case a step further by showing that many of the circuits in the brain and the molecular signatures responsible for reactions to stimuli are more or less the same, whether you look at a human or an invertebrate. The ways in which different species respond is another story. One animal might react to a threat by running away. Another might fight back. Research data supporting this assertion show vast differences in the neuronal circuitry that tells different organisms to respond differently in a particular situation.
LeDoux closed his talk by reiterating the need to unify the brain sciences, saying that: “If all areas of psychology were under one tent, we might be able to adopt standardized constraints on the language of psychology that could more effectively guide brain research.” He added that neuroscientists will only get to the heart of what feelings are if everyone agrees on the same definition for consciousness.