Figure 8
From: Similar contrast sensitivity functions measured using psychophysics and optokinetic nystagmus
(a) Schematic psychometric functions based on responses to rightward (blue) and leftward (red) motion, or responses over all stimuli (dashed-line). A bias towards responding to the right will lead to more correct responses for rightward than leftward stimuli, even with stimuli that are sufficiently low contrast to be effectively invisible. This behaviour is captured by the γ parameter of a Weibull function. The difference in γ, across data collected with left and right stimuli, quantifies bias as a value between −1 (strong bias to leftwards response) and +1 (strong bias to rightwards response) with 0 corresponding to unbiased behaviour. (b) Estimated bias (Δγ) for OKN and report. Grey and coloured symbols are levels of bias that either were or were not significantly greater than 0. The fit is based on a linear regression (inversely weighted by the confidence intervals on the bias estimates; weights determine symbol size) and shows a significant correlation of response bias across OKN and report.
