Tactile and Visual Spatial Frequency Perception Follows Optimal Integration but Is Not Affected by Spatial Proximity

Spatial frequency is a fundamental feature in both visual and somatosensory perception, yet how these modalities integrate spatial frequency information remains unclear. This study investigates whether visuotactile spatial frequency perception follows the principles of Maximum Likelihood Estimation (MLE) and whether spatial proximity influences multisensory integration, using virtual reality (VR) and high-precision 3D-printed tactile stimuli. Experiment 1 found that the visuotactile integration of spatial frequency cues follows the MLE rule. However, Experiment 2 revealed that this integration is not affected by spatial proximity. These findings provide additional insights into the feature dependency of multisensory integration between vision and touch and highlight the potential for independent processing before integration, offering new perspectives on the mechanisms of spatial frequency processing in both visual and tactile modalities.