Lauri Nummenmaa

Introduction

Lauri Nummenmaa (born 1977) is a Finnish psychologist and neuroscientist whose work has made the body central to the modern science of emotion. He is professor at the Turku PET Centre and the Department of Psychology at the University of Turku, where he directs the Human Emotion Systems Laboratory. He is best known for the "bodily maps of emotions": studies in which hundreds of volunteers coloured blank human silhouettes to show where in the body they felt each emotion, producing topographic maps in which anger lights up the head, chest and hands while sadness concentrates in the chest and head and happiness spreads across almost the whole body.

The maps became one of the most widely reproduced images in affective science and have been used in dozens of follow-up studies, including work on psychiatric populations and on cross-cultural comparison. They have also become a focal point for a methodological argument that predates them: whether self-reported bodily sensations tell us anything about physiology, or whether they tell us about the concepts and metaphors people hold about emotion. Nummenmaa's own research programme, which combines positron emission tomography, functional magnetic resonance imaging and behavioural measurement, is in large part an attempt to answer that question with data rather than assertion.

Early Life and Education

Nummenmaa studied psychology at the University of Turku, taking his master's degree in 2001 with minors in mathematics, statistics and education, and qualifying as a licensed psychologist in the same year. He stayed at Turku for doctoral work, defending his PhD in psychology in 2006 with a thesis on the orienting of social attention, awarded the highest grade and later recognised by the university foundation with a prize for an outstanding dissertation.

The doctoral work established the two interests that still structure his research: how attention is captured by socially salient stimuli such as faces and gaze, and how to measure those processes with a combination of behavioural and neuroimaging methods. His quantitative training is also visible throughout his later work, which has included substantial contributions to signal analysis and to the processing of PET and MRI data.

Academic and Professional Career

After his doctorate Nummenmaa spent a year at the Medical Research Council Cognition and Brain Sciences Unit in Cambridge, United Kingdom, working in Andrew Calder's group on the neural mechanisms of face perception. He returned to Finland in 2008 as an Academy of Finland junior fellow and later senior fellow, with positions at the Turku PET Centre and at Aalto University, where he was appointed assistant professor in cognitive neuroscience in 2012.

In 2016 he moved back to the University of Turku as associate professor in modelling and medical image analysis at the Turku PET Centre and the Department of Psychology, and he was promoted to professor in 2019. He holds adjunct professorships at Aalto University and at Turku, is chief executive of a spin-off company, and has served as a part-time research director at Turku University of Applied Sciences.

His group has been funded by the European Research Council, including an Advanced Grant in 2024 for whole-body imaging of emotion circuits with total-body positron emission tomography, and by the Academy of Finland, the Sigrid Jusélius Foundation, the Jane and Aatos Erkko Foundation and the Gyllenberg foundations. His awards include the Academy of Finland Award in 2016 and the Alfred Kordelin prize in 2012, and he was elected to Academia Europaea in 2021 and to the Finnish Academy of Science and Letters in 2022.

Major Contributions to Psychology

Bodily maps of emotions

The 2014 study with Enrico Glerean, Riitta Hari and Jari Hietanen, published in the Proceedings of the National Academy of Sciences, introduced the emBODY tool. Across five experiments with 701 participants, volunteers were shown emotional words, stories, films or facial expressions and asked to colour the regions of a body outline where they felt activity increasing or decreasing. Different emotions produced statistically separable maps, a machine classifier could distinguish them, and the maps were broadly concordant across Finnish, Swedish-speaking and Taiwanese samples. The authors proposed that emotions are represented in the somatosensory system as culturally universal, categorical somatotopic maps.

Maps of subjective feelings

In 2018 Nummenmaa and colleagues extended the approach from fourteen emotions to one hundred core feelings, drawn from a dictionary of psychological terms, in an online study of more than a thousand participants. Feelings clustered into five groups: positive emotions, negative emotions, cognitive processes, homeostatic states such as hunger and thirst, and illness states. Nearly every feeling, including apparently mental ones such as remembering, carried some bodily signature, which the authors took as evidence that conscious feeling is strongly embodied and that bodily feedback contributes even to cognition.

A parallel line of work examines how emotions coordinate people rather than merely happen inside them. A 2012 study showed that emotional films synchronise brain activity across individuals in networks involved in emotion, attention and mentalising, suggesting a neural mechanism by which shared feelings support social interaction. Related work mapped where people allow others to touch them as a function of emotional closeness, finding a strikingly regular topography of social touch that tracks the strength of the relationship.

Molecular and whole-body imaging

More recently Nummenmaa's laboratory has combined emotion research with positron emission tomography of neurotransmitter systems, studying opioid and cannabinoid receptors in relation to feeding, attachment and mood, and developing quantitative perfusion imaging with total-body PET. The aim is to move from mapping where emotions are felt to identifying the molecular and peripheral circuitry that produces those feelings.

Major Publications

Nummenmaa, L., Glerean, E., Viinikainen, M., Jääskeläinen, I. P., Hari, R., & Sams, M. (2012). Emotions Promote Social Interaction by Synchronizing Brain Activity Across Individuals. Proceedings of the National Academy of Sciences, 109(24).
Nummenmaa, L., Glerean, E., Hari, R., & Hietanen, J. K. (2014). Bodily Maps of Emotions. Proceedings of the National Academy of Sciences, 111(2).
Suvilehto, J. T., Glerean, E., Dunbar, R. I. M., Hari, R., & Nummenmaa, L. (2015). Topography of Social Touching Depends on Emotional Bonds Between Humans. Proceedings of the National Academy of Sciences, 112(45).
Nummenmaa, L., Hari, R., Hietanen, J. K., & Glerean, E. (2018). Maps of Subjective Feelings. Proceedings of the National Academy of Sciences, 115(37).
Knuuti, J., Tuisku, J., Kärpijoki, H., Iida, H., Nesterov, S. V., & Nummenmaa, L. (2023). Quantitative Perfusion Imaging with Total-Body Positron Emission Tomography. Journal of Nuclear Medicine, 64(1).

Impact and Legacy

The bodily maps have been unusually consequential for a self-report instrument. They gave a visual, easily communicated answer to a question that had been mostly philosophical, they offered a cheap and language-light way to assess emotional experience, and they have been applied to depression, anxiety, autism and schizophrenia on the assumption that altered bodily maps might serve as a biomarker.

That assumption is precisely what critics contest. The most fundamental objection is that the maps are self-report. Commenting on the original study, Paul Zak argued that people routinely feel more than one emotion at a time and that much emotional processing occurs outside conscious awareness, so that coloured silhouettes may record cultural stereotypes rather than bodily change. A preregistered review of bodily mapping in psychiatry concluded that responses may reflect interoceptive processes, autonomic reactivity, recall bias and conceptual knowledge in unknown mixture, and noted that the emBODY tool has itself been criticised for measurement imprecision.

The strongest empirical challenge comes from psychophysiology. Meta-analytic work by Siegel and colleagues in 2018 found that autonomic markers such as heart rate, blood pressure and electrodermal activity overlap substantially across emotion categories, making it hard to identify distinct physiological fingerprints for individual emotions. Yet participants in the mapping studies produce sharply differentiated maps for anger, sadness and fear. If the physiology is ambiguous but the maps are crisp, then the maps are likely to be shaped substantially by how the brain interprets and labels bodily sensation, not by the sensation alone. Studies in clinical populations point the same way: autistic children have been reported to show less differentiated maps despite no measurable deficit in interoceptive accuracy, and altered maps in schizophrenia have been attributed to impaired associations between bodily sensation and emotional concepts rather than to reduced physiological input.

A further limitation is the scope of the universality claim. The original paper compared West European and East Asian samples, which is a narrow basis for calling the maps culturally universal; later work by Volynets and colleagues extended the comparison, but the samples remain far from representative of the world's cultures, and the cultural-comparison literature in emotion more generally has repeatedly shown that linguistic and conceptual framing matters. There are also ordinary psychometric worries about a task in which participants colour two silhouettes after reading a single word: test-retest reliability, the effect of the order in which emotions are presented, and the fact that the instruction itself tells participants to look for bodily sensations.

Nummenmaa and his collaborators have responded with evidence rather than rhetoric. They note that the original findings replicated with inductions, such as stories and film clips, that never name an emotion or describe a physical response, and that a Swedish-speaking sample, whose language belongs to a different family from Finnish, reproduced the maps. Jung and colleagues reported that individuals with higher interoceptive accuracy draw more intense and more topographically specific maps, which is what one would expect if the maps were partly grounded in real bodily signal. The 2018 study found that feelings rated as highly bodily were associated with greater activation in the insula and somatosensory cortex, regions that encode the intensity and spatial pattern of internal states. Nummenmaa has also argued that the maps need not represent conscious awareness of a specific physiological change; they may summarise net input from skeletomuscular, visceral and autonomic systems. The disagreement is therefore not about whether the maps are reliable and interesting, which most researchers accept, but about what they measure.