It's one of the most fundamental questions underpinning the human experience: is your experience of the world the same as mine? Do we feel the same happiness? Hunger? Love?
Although various philosophers have attempted to tackle the question, from a scientific standpoint the answer has remained mysterious. But a new study by a team of researchers from three Finnish universities has revealed that, when it comes to our feelings and emotions, people may not be as unique as we like to think.
Using the results of an online survey, researchers from Turku University, Aalto University, and the University of Tampere have revealed the connection between 100 conscious, subjective feelings and physical sensations in the body. Their results are published in the Proceedings of the National Academy of Sciences.
The study took the form of a three-stage, internet-based survey, in which over 1,000 participants answered questions about how they perceive various feelings. First, they were asked to rate how strongly they experienced a sensation in their mind and body, how much they enjoyed the feeling, and the extent to which they could control it. Next, they were asked to arrange the feelings in a grid, grouping similar feelings close together and keeping different feelings apart. Finally, participants were given blank human silhouettes and asked to color the areas where they experienced a feeling most strongly.
By analyzing the results of the survey, the researchers grouped the feelings into five distinct categories: positive emotions, negative emotions, cognition (for example, remembering, or imagining), illnesses (such as being itchy or hungover), and homeostasis (feelings like hunger and thirst). Using the results of the first two experiments, the team produced the "feeling space": a two-dimensional map showing how closely feelings are connected to each other. Heat maps were also created, showing the intensity of feeling in the mind and body, the emotional valence (how "good" or "bad" the feeling was), the controllability of the feeling, and finally the "lapse" – how often the survey participants experienced each feeling.
But it's the results from the third part of the survey that are perhaps the most intriguing. Although previous research has been able to link certain emotions to changes in brain activity, that doesn't necessarily translate to a familiar pang of hunger, or the full-body weariness we all know on a Monday morning. By asking people to highlight where they experienced a feeling in the body, the researchers were able to show the physical location – and intensity – of our feelings.
The results showed that for most of us, it's the same feelings that can set our heart a-flutter – or deliver an emotional gut punch.
"Feelings were systematically referenced to bodily states, even for states considered as purely cognitive, such as attending or reasoning," explains the study. "Additionally, the more strongly some feeling was experienced in the body, the more salient it was mentally."
And unlike the researchers' previous work, which looked at the bodily manifestations of just a few basic and complex emotions, studying such a wide range of feelings showed something interesting about how we experience the world.
"Nearly all subjective feelings were imbued with emotional qualities," reveals the study. "Despite both scientists and laypersons alike often considering affect [feeling or emotion] and cognition at least partially independent, we found that most feelings actually carry affective valence [a positive or negative emotional impact], further underlining the importance of affect to conscious states in general."
Intriguingly, the study may offer some insight into the role of feelings in society. Since the feeling spaces were so similar across participants, the authors suggest that an understanding of others' feelings may have provided an important evolutionary advantage to our ancestors. But there are practical applications too: the authors also believe their results may support the common advice that acting out an emotion could cause you to actually feel it.
But although the results are attractive, it's important to note that the study had some limitations. First of all, the feelings were examined in quite broad, crude categories – for example, the researchers note, "'seeing' would likely feel very different when we are seeing a growling black bear rather than a cute baby." On top of this, it relies on people being able to evaluate their own emotional state – something we're not necessarily that good at.
The authors caution that their study does not answer what's known as the "hard problem" of consciousness – how physical phenomena, such as increased activity in some regions of the brain, are connected to experience, like sadness – but there are still some conclusions to be drawn.
"Although consciousness emerges due to brain function and we experience our consciousness to be 'housed' in the brain, bodily feedback contributes significantly to a wide variety of subjective feelings," said lead author Lauri Nummenmaa in a statement. "Our findings help to understand how illnesses and bodily states in general influence our subjective well-being. Importantly, they also demonstrate the strong embodiment of cognitive and emotional states."
The survey used for this study is still live and collecting data for future work. If you want to take it, click here.