Spatial attention and numerical associations in the grip force signal

Numbers, as abstract entities, lack direct sensory experience, yet embodied cognition suggests their grounding in sensorimotor experiences, notably through spatial representation. The Mental Number Line (MNL) hypothesis posits a spatial-numerical association (SNA) where smaller numbers align with the left and larger numbers with the right. While SNAs support the MNL hypothesis, their role in number processing remains debated. Alternative models attribute SNAs to response-related rather than conceptual processes, with inconsistent findings on their link to mathematical proficiency and prevalence among individuals. To address these issues, this thesis employs passive holding force registration, a novel method capturing continuous, high-resolution data without explicit motor responses. In the initial experiments, the thesis validates this novel method for studying lateralized semantics. Experiments demonstrate that spatial attention and semantics influence passive holding force, independent of explicit tasks. Importantly, force fluctuations precede motor responses, suggesting sensitivity to early cognitive processes. Further experiments apply this method to study SNAs in numerical cognition. Shallow and deep semantic tasks elicited MNL-compatible force patterns, with smaller numbers increasing left-hand force and larger numbers increasing right-hand force. These effects emerged early (180 ms) in deeper tasks, aligning with conceptual processing rather than response-related mechanisms. Results indicate SNAs reflect genuine number-space associations, modulated by task demands. This work supports the MNL hypothesis, showing SNAs emerge rapidly during conceptual number processing, reinforcing the embodied cognition view of numerical concepts. Passive holding force registration proves a powerful tool for investigating cognitive processes underlying abstract representations like numbers.