The adaptive advantage of integrating motion information across the senses is most prominent when individual motion cues are unreliable. Integration of motion information from the auditory and visual senses is critical for an organism's survival, enabling faster and more accurate responses to our dynamic environment. This response profile parallels behavioral indices of audiovisual integration, in which subjects benefit significantly from audiovisual integration only for the degraded conditions. In all of these regions, the operational profile of audiovisual integration followed the principle of inverse effectiveness, in which audiovisual response suppression for intact stimuli turns into response enhancements for degraded stimuli. Our results suggest audiovisual integration processes at both the sensory and response selection levels. Moreover, we show that the putamen integrates audiovisual signals into more accurate motion discrimination responses. At the neural level, we show audiovisual motion integration bilaterally in the visual motion areas hMT+/V5+ and implicate the posterior superior temporal gyrus/planum temporale in auditory motion processing. Behaviorally, subjects benefited significantly from audiovisual integration primarily for degraded auditory and visual motion signals while obtaining near ceiling performance for “unisensory” signals when these were reliable and intact. Therefore, this 2 × 2 × 2 factorial design manipulated: (1) auditory motion information (signal vs noise), (2) visual motion information (signal vs noise), and (3) reliability of motion signal (intact vs degraded). Subjects discriminated the motion direction of audiovisual stimuli that contained directional motion signal in the auditory, visual, audiovisual, or no modality at two levels of signal reliability. Combining fMRI and psychophysics, this study investigated how the human brain integrates auditory and visual motion into benefits in motion discrimination. This suggests the possibility of auditory information affects tactile perception.For effective interactions with our dynamic environment, it is critical for the brain to integrate motion information from the visual and auditory senses. Consequently, there are differences in judgement between with and without the knocking sound. In short, the participants compared hardness through these conditions, and the correctness of their judgement were used to measure the contribution of auditory and tactile senses toward perceiving hardness. The other condition without auditory information masks the knocking with white noise. In the condition with auditory information, sounds were heard directly, or through a sound system, which consists of the frequency filters and soundproof box. The participants were asked to knock the pair of wood boards, and compare the hardness in two conditions: knock with or without auditory information. To testify this relationship, this research used a comparative judgment on knocking between two wood boards which have different levels of hardness.

The purpose of the present research is to explore the relationship between auditory and tactile senses on hardness perception.

Auditory senses