When somatic attention creates sensation: a new class of bodily experience.

Attention is typically regarded as a modulatory process that amplifies or suppresses existing sensory input. Here we tested whether inward-directed (somatic) attention can instead generate bodily sensations. In a floatation-based sensory deprivation paradigm (restricted environmental stimulation), 100 healthy adults were assigned to three groups: focused somatic attention with a light tactile anchor on a finger or toe (FSA, n = 50), natural somatic attention (NSA, n = 25), or passive somatic awareness (PSA, n = 25). Participants recorded the quality, intensity, and location of any sensations as digital body drawings, which we analyzed quantitatively and with descriptor clustering and contour-based shape analysis. Focused somatic attention produced more frequent, more complex, and more spatially structured sensations than the natural control conditions, though of lower intensity and smaller extent. Most FSA sensations (77%) were referred to sites remote from the anchor, were predominantly ipsilateral, and fell into distinct descriptor families and two geometric forms-compact patches and elongated, pathway-like trajectories spanning multiple joints. These findings demonstrate that somatic attention is not merely modulatory but generative: directed toward minimal, localized tactile input, it can construct coherent referred bodily experiences at unstimulated sites and organize their spatial structure-consistent with a predictive-coding account in which weak bottom-up input tilts the balance toward top-down prediction.