Spatial biases in size perception

In this study we replicated an old finding demonstrating that participants underestimate the size of an object in their dominant hand compared to the size of an object in their non-dominant hand (McPherson & Renfrew, 1953). Moreover, we showed that this handedness-related bias in size comparisons seems confined to the haptic modality, and that it is not related to differences in strength between the dominant and the non-dominant hand. Identification of the specific differences in sensory inputs provided by the dominant and non-dominant hands and/or the size expectations that underlie the handedness-related bias in size judgments remains a challenge for the future; at present different priors for specific tasks find some indirect support. In more general terms, our findings show that haptic size perception is malleable by bodily dispositions, such as handedness, and therefore the impact of handedness on haptic size judgments represents an example for embodied perception in the haptic modality. We have submitted the results of our study for publication in the journal "Attention, Perception, & Psychophysics", and we hope that our study will be published in 2026.