What does it mean to have an emotion? It seems obvious that having one means feeling it. If you’re happy but don’t know it, in what sense could you actually be happy?

Such reasoning seemed sound to William James. Conscious feeling, he thought, was precisely what distinguished the emotions from other mental states, like desire. Without conscious feeling, he wrote, “We find that we have nothing left behind, no ‘mind-stuff’ out of which the emotion can be constituted.” Sigmund Freud agreed: “It is surely of the essence of an emotion,” he wrote, “that we should feel it, i.e. that it should enter consciousness.”

But emotions are complicated things. Even if we do feel an emotion, there are parts associated with it that we aren’t usually aware of. Clinical psychologists, for example, recommend to patients with anger issues to look out for the warning signs—sweating in the palms, for example, or clenching of the jaws—so they can perhaps mitigate upcoming rage. And when we are frightened, or sexually aroused, our heart and breathing rates increase often without our notice (though we can recognize the change if its pointed out). What’s more, fear seems capable of covertly heightening sexual arousal—or being mistaken for it.

Consider one study from 1974. Researchers had an attractive female interviewer stop one group of men crossing a scary suspension bridge and another one crossing a bridge that wasn’t scary. The women asked the men to fill out a questionnaire. The men on the scary bridge responded to the questions with more sexual content, and were significantly more likely to try to contact the interviewer after it was over. This suggests that the men on the scary bridge interpreted (unconsciously) their body’s reaction to the bridge as added attraction to the interviewer.

But how might you demonstrate that an unconscious emotion is at work? Well, we know that emotions have effects. When we’re in a good mood, for example, we like things better. If we can find a situation in which an emotion has its predicted effect, but the people we are observing report no conscious feeling of that emotion, then we might be on to something.

This is what Piotr Winkielman and Kent Berridge, psychologists at the University of California, San Diego, and the University of Michigan, respectively, set out to do. In their 2004 experiments, they showed people pictures of happy and sad faces, but showed them subliminally—so fast that they had no conscious awareness of seeing any faces at all. Then they had subjects drink a new lemon-lime beverage and evaluate it. When asked how they felt, it was clear that they had no conscious awareness of any mood change. But the people shown happy faces not only rated the drink better than the other subjects did—they also drank more of it!

Why might some unconscious form of happiness affect us? Well, “from the standpoint of evolution and neuroscience, there are good reasons to suppose that at least some forms of emotional reaction can exist independently” of our awareness, say Winkielman and Berridge. “Evolutionarily speaking, the ability to have conscious feelings is probably a late achievement.”

Perhaps, if emotions used to work without conscious awareness, that explains why they still can. “The original function of emotion,” they say, “was to allow the organism to react appropriately” to the good and bad things in life, “and conscious feelings might not always have been required.”

Indeed, one 2005 study in humans showed a difference in brain pattern between unconscious and conscious—or “subliminal and supraliminal”—fear. The researchers thought this could help us understand the mechanisms underlying fear following trauma, which, they say, is “automatic and outside immediate conscious control.”

Come to think of it, isn’t it odd that unconscious emotions weren’t thought plausible? After all, who hasn’t heard someone angrily yelling, “I’m not angry!”

Jim Davies is an associate professor at the Institute of Cognitive Science at Carleton University in Ottawa, and author of Riveted: The Science of Why Jokes Make Us Laugh, Movies Make Us Cry, and Religion Makes Us Feel One with the Universe. His sister is novelist JD Spero.



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