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Collect keyboard responses asynchronously in Javascript

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Some of our Mechanical Turk experiments are written in straight-up javascript, which gives you a lot of control and flexibility but at the expense of having to write some pretty basic functionality from scratch.  I recently was in a situation where I wanted to collect separate keyboard responses in different but possibly overlapping time windows: stimuli are coming in fast and on some of them, the subject needs to press the spacebar.  Rather than fix my design so that the response windows would never overlap, I decided to write a function that would collect a one-off keyboard response, asynchronously, meaning that other experiment control code can run behind it. Read the rest of this entry »

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Creating spaghetti plots of eye-tracking data in R

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I’ve been working on consolidating all the different R functions I’ve written over the years for plotting my eye-tracking data and creating just one amazing super-function (based on the ggplot2 package) that can do it all. Here’s a first attempt that anybody with the right kind of dataset should be able to use to create plots like the ones below (generated from fake data. The R code that generates the data is included at the end of the post). If you find this code helpful, please consider acknowledging it via the following URL in your paper/presentation to spread the word:
https://hlplab.wordpress.com/2012/02/27/creating-spaghetti-plots-of-eye-tracking-data-in-r/

Left: Empirical means with error bars indicating standard error for four experimental conditions. Contrast presence is coded in color, adjective type in line type. The first vertical line indicates adjective onset, the second ones indicate mean noun onset in each contrast condition. Right: Smoothed model estimates of proportions in each condition, with ribbons indicating 95% confidence intervals. Data from different subjects is plotted in different panels.

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