Article Figures & Data
Figures
- Figure 1.
Schematic illustration of the task structure. Each trial consisted of a stream of stimuli presented foveally either with a fixed (regular condition) or jittered (irregular condition) SOA. Notice that the intervals surrounding the targets were exactly the same for the regular and irregular condition. The targets were visual gratings (Gabors) tilted 45° clockwise or counter-clockwise and presented at seven contrast levels to yield a range of performance levels spanning from near chance to near perfect. Participants were asked to respond to the orientation of the target (i.e., left or right) whenever a target was presented. Target presentation was always indicated by a change in the placeholder color to prevent responses to standard stimuli.
- Figure 2.
Behavioral consequences of rhythmic temporal expectation. a, Psychometric functions describing performance on regular (red line) and irregular (gray line) temporal expectation conditions as a function of target contrast. Bar plots show the average values of slope and threshold in the regular and irregular conditions. b, Scatterplots showing the effect of temporal expectation on slope and threshold values for each participant. Blue dots indicate the group average. Points below the identity line indicate a gain effect of temporal expectation. c, Average reaction times for correct responses from the regular and irregular conditions as a function of target contrast. Error bars indicate SEM.
- Figure 3.
Comparison between behavioral results and diffusion-model predictions. a, Fitted diffusion model to psychometric and chronometric functions at the target contrasts. All three free parameters were fitted separately for the regular (red) and irregular (gray) conditions using maximum-likelihood estimation. b, Hierarchical model comparing tests between nested models to determine which of the three model parameters (the accumulation rate k, the decision-bound A, and the residual time constant tR) could explain the observed difference between regular and irregular conditions significantly better than a null model for which the three parameters had fixed values across the two conditions. c, Comparison of changes in threshold predicted by each model with the behavioral data. *p < 0.05; ns, nonsignificant effect.
