Is Emotion Really The Enemy Of Reason?

If you let emotion guide your decisions, are you setting yourself up to fail? The answer depends largely on one key thing.

Is Emotion Really The Enemy Of Reason?
[Image: Emotions via Shutterstock]

A great leader makes great decisions, and for much of human history, great decisions were thought to be made with cold logic. The idea that emotion was the enemy of reason stretched from the ancient philosophy of Plato to the rationalism of Descartes to the pop culture of modern times. In The Godfather, Michael Corleone convinces us that his decision to avenge his father was not born of a passionate vendetta but a dispassionate rationale — “strictly business.”


The recent past has seen a push in the opposite direction. Neuroscientist Antonio Damasio found that patients suffering from brain damage that impaired their emotions had a hard time reaching any decision at all. Psychologist-writer Daniel Goleman realized that while business leaders needed a certain amount of rational intelligence to do the job, they needed “emotional intelligence” to thrive. Far from the enemy of reason, emotion may well be a friend.

Even newer work from psychologist Isabelle Blanchette of the University of Quebec at Trois-Rivieres drives the emotion-or-reason debate into a nuanced middle ground. Blanchette has been experimenting with the theory that it’s not emotion per se that influences a decision, but rather how relevant the emotion is to the decision itself.

Blanchette believes some emotions are “integral,” evoked by the complexity of a business problem, while others are “incidental,” caused by a completely irrelevant part of one’s personal life. The distinction may seem overly technical, but our brains make it loud and clear. Recent research led by Blanchette suggests that integral emotions can be the friend of reason while incidental ones are more like the enemy.

“It’s not just ’emotional or not,'” Blanchette tells Co.Design. “It’s about also the brain detecting what the context is. And whether the emotion is going to have a beneficial or detrimental impact is going to depend on the context.”


In one experiment, Blanchette and two collaborators showed 54 test participants a series of reasoning statements often used by researchers to assess logical performance. (Example: “If you are hungry, then you will eat.”) After a given statement, the participants saw a series of inferences. The task was to decide whether each one represented a valid logical conclusion (e.g. “Sally is hungry, therefore she is eating”) or a logical fallacy (“Sally is eating, therefore she is hungry”).

Here’s the twist: each inference was paired with a picture. Some pictures evoked a relevant or integral emotion (an emaciated starving person, extending the previous example). Other pictures evoked an irrelevant or incidental emotion (a slumped-over sleeping person). Still others were neutral (a pair of dolphins playing with a ball).

What Blanchette and company found was that integral emotion and reason worked well together, but that incidental emotion and reason did not. Compared to their performance on the logical task after seeing neutral images, test participants performed much worse after seeing irrelevant-emotion images but no worse after seeing relevant-emotional ones. The finding held true across two similar subsequent experiments and a fourth that substituted videos for pictures.

In far simpler terms, sometimes emotion hinders reason and sometimes it doesn’t, the researchers conclude in an upcoming article in Journal of Experimental Psychology: General. “The short story is that our results are consistent with a view that says it’s not all about automatic detection of emotion, and the brain having this emotion center that goes beep, beep, beep whenever there’s something emotional,” Blanchette says. “It’s actually more complicated than that.”

Blanchette acknowledges that the research doesn’t translate directly into a workplace setting. The study only examined negative emotions, for one thing, and most business problems can’t be reduced to a textbook deductive logic task. Then again, the strength of the emotions that Blanchette elicited in the laboratory is no doubt much weaker than what people feel in the real world. Scaling those feelings to actual human experience should only increase the influence emotions can have on decisions.

In that sense, the research offers many lessons for the work world. People capable of recognizing the source of their emotions–integral or incidental–may hold a distinct advantage when it comes to making up their minds. Knowing whether an anxious feeling comes from the importance of the task or from an argument with a coworker in the break room could be the difference between choosing right or wrong. Managers, too, can help workers appreciate that some emotions are merely meddlesome, while others are strictly business.

About the author

Eric Jaffe is an editor at CityLab, where he writes about transportation, history, and behavioral science, among other topics, through the lens of urban life. He's also the author of The King's Best Highway (2010) and A Curious Madness (2014).