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.