Validation of a force transducer-embedded platform as an alternative to handles in weight perception research.

The recording and interpretation of lifting force data - such as load and grip forces - are central to studying weight perception. Typically, such data are collected using force transducer-embedded handles placed on top of objects. While effective, these handles may be impractical or undesirable for certain experimental paradigms. A potential alternative is a force transducer-embedded platform, but validation is needed to determine whether it captures force data with the same consistency and interpretability as the handle-based method, particularly given the potential for data loss around lift-off. In two experiments, we compared these methods by having participants lift light and heavy objects off a platform either directly or via handles to assess the convergent validity of experimental outcomes and the concurrent validity of the recorded data. Our findings indicate that the experimental outcomes and data from both methods were highly comparable, but only for the heavy objects. However, for the light object, platform-recorded force data showed lower agreement with handle-based measures, and several anticipated sensorimotor effects were not observed in the platform data. These discrepancies resulted in differences in experimental outcomes, particularly in the detection of switch effects, highlighting the platform's limitations for capturing lighter-weight interactions. Therefore, we suggest that while handles remain preferable for capturing rich force data, the platform method broadens methodological options and presents a viable and valid alternative.