Responses to the number line task.

<p>Mean response locations with standard error of the mean are shown, separated by fast (top) and slow (bottom) responses, as well as by type of stimuli—non-symbolic (dots) in blue and symbolic (red) in red. The fitted regression lines for each case are taken from a multiple regression analysis of response location that included linear and logarithmic regressors. Non-linear compression—positive for dots and negative for words—is only observed in fast responses (see details in text, and in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0120423#pone.0120423.g002" target="_blank">Fig. 2</a>).