Study title

We present two psychophysics experiments investigating the impact of visual self-motion cues on visual spatiotemporal summation. The first experiment is a 4AFC target detection task where participants give the location of a target that appeared in one of four known locations, against a moving background. Each target is composed of two small probes which are separated by four diagonal pixels. Probes always appear for one frame (8.33ms). The probes are either presented concurrently (at the same time) or are separated by one of six interstimulus-intervals (ISIs) of 0 to 100ms. The two probes are aligned radially, such that the second probe is either inward (closer to the centre of the screen) or outward than the first probe. The background is an array of ~1000 dots which move in an expanding or contracting pattern to simulate forwards or backwards self-motion. The main manipulation is the relationship between the alignment of the probes (inward or outward) and the background motion (expanding or contracting). The relationship can either be congruent (both in same direction) or incongruent. Staircases adjust the target luminance for each condition to identify the threshold where participants have 75% accuracy. A second study has the same design but with targets appearing in three of the four known locations and participants identifying the location which did NOT contain a target. Finally a flow-parsing study was conducted to validate that our background stimulus was eliciting self-motion cues. In this study participants saw a single moving target in one of four locations and indicated whether it was moving inwards or outwards. A staircase procedure adjusted the target speed to identify the speed where participant gave an ‘inward’ response 50% of the time. This project is still ongoing with further data to collect.Every time we move, the image of the world at the back of the eye changes. Despite this, our perception is of an unchanging world. How does...