Effects of visual perception of gravity on tongue posture

Visual perception of gravity change may impact tongue posture during speech production. Previous studies [Chander et al., 2019, Behav. Sci., 9(11)] report anticipatory visual disturbances induce compensatory postural behavior in the human body and [Philips et al., 2022, Theor. Iss. Ergon. Sci., 23(1)] showed the magnitude of postural response is dependent on velocity and direction of movement. Prior research [Assländer et al., 2023, Sci. Rep., 13(1), 2594] investigated the visual component impact on body posture balance in virtual-reality. Building on [Shamei et al., 2023, Sci. Rep. 13(1), 8231] investigation of postural adaptation in microgravity, the current study investigates postural behavior during spoken production of elongated vowels through a gravitational virtual-reality environment. Ultrasound imaging measured the impact of tongue posture for vowel production in an immersive virtual-reality rollercoaster through gravitationally stable, rising, and falling conditions. Acoustic analyses compared the production of elongated vowels [i, e, o, u, ɑ] across conditions. The falling condition is predicted to have the highest F1 followed by the leveled, and raising conditions. F1 will be reported by comparing the tongue height across conditions. Implications for postural adaptation in virtual-reality conditions will be discussed.