# readme.md

Please cite our paper if you use or modify this code.
Burlingham, C.S. & Heeger, D.J. (2020). Heading perception depends on time-varying evolution of optic flow. PNAS.

## Usage
/stimulus/
• run OFexpt_EM.m to run the envelope motion experiment. You will need to install MGL first: https://gru.stanford.edu/doku.php/mgl/download
• run OFexpt_PM_Last.m to run the non-varying phase motion (last) experiment.
• The code for every other experiment in the paper are included in this directory as well (including control experiments).

/analysis/choiceData/
• run OFAnalysis.m to fit a psychometric function to choice data and extract heading bias and variability. 
• To recreate figs 4 and S1-3 run this function within a directory containing data (.mat) files, which are automatically outputted by MGL.
• run OFAnalysis_controlExpts.m on data from the control experiments to recreate figs S5 and S7. 

/analysis/eyeData/
• run wsEyeAnal.m within a directory containing .mat (MGL choice data) and .edf (EyeLink gaze data) files to reproduce eye movement analyses detailed in the supplementary appendix.

/Rieger&Lawton/
• run myRiegerLawton.m to recreate fig S6 in the SI.
• myRiegerLawton.m estimates heading from the optic flow fields conveyed by the stimuli in our experiment, using the method of Rieger & Lawton (1985).