Semantic processing and individual suggestibility modulate motor preparation and perceived distance for looming sounds entering the peripersonal space

Our brain maps the space immediately surrounding the body, the peripersonal space (PPS), to sharpen sensory-motor coordination whenever an object enters it. Within PPS, past research demonstrated how several factors influence motor readiness: from stimulus characteristics, such as body-object distance and stimulus semantics, to personality traits like anxiety. However, most paradigms infer PPS boundaries using tactile and visual stimuli, with auditory cues often playing an ancillary role, rather than directly measuring response modulation to stimuli entering the PPS. Here, we measured anticipatory postural adjustments, as direct physiological indices of motor planning, to examine whether semantic content and individual suggestibility modulate responses to looming sounds stopping within PPS. Thirty-three adults heard affective semantic sounds (positive - applause, negative - dentist drill) or neutral non-semantic (pink noise) sounds halting at five within-PPS distances while we recorded muscle activation timing, distance estimates, affective ratings, and sensory suggestibility. Motor responses were faster as sounds stopped nearer the body but systematically delayed and less precise for semantic sounds compared to non-semantic sounds, with higher suggestibility predicting longer and more variable latencies, particularly for non-semantic sounds. These findings demonstrate that semantic evaluation imposes measurable processing costs that systematically delay motor preparation and increase perceived distance. Individual suggestibility produces freeze-like response patterns that amplify motor uncertainty, specifically when semantic context is absent, revealing distinct cognitive and trait-based mechanisms that jointly regulate defensive behaviour within PPS.