Modeling causal inference in vestibular-visual heading perception

描述(申请人提供)：航向由前庭信号和跨视网膜的图像运动模式(光流图)指示。当前庭提示和光流相结合时，航向精度会提高。只有当两个线索是由同一原因产生的，即观察者在世界固定环境中的运动时，这种多感官整合才是有益的。然而，光流具有内在的模糊性，这对航向感知构成了一个关键的挑战：光流指示观察者的运动以及世界上物体的运动。利用定量的人类心理物理学和数学模型，我在这里测试了这样一个假设，即大脑执行一个决策过程，推断与前庭和视流线索相关的原因。根据这个被称为“因果推理”的决策过程，如果推断出两个线索是由共同的原因产生的，那么这两个线索是整合的。因此，因果推理预测，多感官航向知觉将取决于视觉和视觉航向信息之间冲突的程度以及这些线索的可靠性。此外，我将在因果推理框架内考察运动物体对航向知觉的影响，该框架预测运动物体对航向知觉的影响将随着世界上物体运动速度的增加而减小。所有实验都将使用一个带有大视场立体投影系统和两个可选强制选择方法的6自由度运动平台。我将开发因果推理过程的数学模型，并使用贝叶斯模型比较技术严格地将这些模型的预测与实验数据进行比较。这项研究的发现对于理解基本的知觉前庭-视觉相互作用以及在基础和临床空间定向心理物理学领域开辟新的方向具有重要意义。

DESCRIPTION (provided by applicant): Heading direction is indicated by vestibular signals and patterns of image motion across the retina (optic flow). Heading precision improves when vestibular cues and optic flow are integrated. Such multisensory integration will be beneficial only if the two cues are produced by the same cause, that is, movement of the observer in a world-fixed environment. However, optic flow possesses an inherent ambiguity which poses a crucial challenge to heading perception: optic flow indicates the combined movement of the observer as well as movement of objects in the world. Using quantitative human psychophysics and mathematical modeling, here I test the hypothesis that the brain implements a decision process that infers the causes associated with vestibular and optic flow cues. According to this decision process, termed "causal inference", the two cues are integrated if it is inferred that a common cause produced them. Causal inference thus predicts that the multisensory heading percept will depend on the magnitude of the conflict between visual and optic flow heading information as well as the reliability of these cues. In addition, I will investigate the influenceof moving objects on heading perception within the causal inference framework, which predicts that the influence of moving objects on heading perception will decrease as the velocity of object motion in the world increases. A 6 degrees-of- freedom motion platform with attached large field-of-view stereo projection system and two-alternative-forced- choice methodology will be used for all experiments. I will develop mathematical models of the causal inference process and will rigorously compare the predictions of these models with the experimental data using Bayesian model comparison techniques. Findings of this research are important for understanding basic perceptual vestibular-visual interactions and opening new directions in the fields of basic and clinical spatial orientation psychophysics.