Center for Vision Research, York University, North York, Canada.
PLoS One. 2024 Oct 11;19(10):e0311992. doi: 10.1371/journal.pone.0311992. eCollection 2024.
It is a well-established finding that more informative optic flow (e.g., faster, denser, or presented over a larger portion of the visual field) yields decreased variability in heading judgements. Current models of heading perception further predict faster processing under such circumstances, which has, however, not been supported empirically so far. In this study, we validate a novel continuous psychophysics paradigm by replicating the effect of the speed and density of optic flow on variability in performance, and we investigate how these manipulations affect the temporal dynamics. To this end, we tested 30 participants in a continuous psychophysics paradigm administered in Virtual Reality. We immersed them in a simple virtual environment where they experienced four 90-second blocks of optic flow where their linear heading direction (no simulated rotation) at any given moment was determined by a random walk. We asked them to continuously indicate with a joystick the direction in which they perceived themselves to be moving. In each of the four blocks they experienced a different combination of simulated self-motion speeds (SLOW and FAST) and density of optic flow (SPARSE and DENSE). Using a Cross-Correlogram Analysis, we determined that participants reacted faster and displayed lower variability in their performance in the FAST and DENSE conditions than in the SLOW and SPARSE conditions, respectively. Using a Kalman Filter-based analysis approach, we found a similar pattern, where the fitted perceptual noise parameters were higher for SLOW and SPARSE. While replicating previous results on variability, we show that more informative optic flow can speed up heading judgements, while at the same time validating a continuous psychophysics as an efficient method for studying heading perception.
已有充分的研究发现，更具信息量的光流（例如，更快、更密集或在更大的视野范围内呈现）会降低朝向判断的可变性。目前的朝向感知模型进一步预测在这种情况下会更快地进行处理，但到目前为止，这还没有得到经验证据的支持。在这项研究中，我们通过复制光流速度和密度对性能可变性的影响来验证一种新的连续心理物理学范式，并研究这些操作如何影响时间动态。为此，我们在虚拟现实中使用连续心理物理学范式对 30 名参与者进行了测试。我们将他们沉浸在一个简单的虚拟环境中，在这个环境中，他们经历了四个 90 秒的光流块，在任何给定的时刻，他们的线性朝向方向（没有模拟旋转）由随机游走决定。我们要求他们用操纵杆连续指示他们认为自己正在移动的方向。在四个块中的每一个中，他们体验了不同的模拟自我运动速度（慢和快）和光流密度（稀疏和密集）的组合。使用互相关图分析，我们确定参与者在 FAST 和 DENSE 条件下反应更快，表现出更低的性能可变性，而在 SLOW 和 SPARSE 条件下则相反。使用基于卡尔曼滤波的分析方法，我们发现了类似的模式，其中较慢和稀疏条件下的感知噪声参数拟合更高。虽然复制了关于可变性的先前结果，但我们表明，更具信息量的光流可以加快朝向判断，同时验证了连续心理物理学作为研究朝向感知的有效方法。
