Text-based and memory-based metrics of cognitive coupling.

The present study was an investigation of the relation between cognitive coupling, a correlation between text difficulty and reading time, and other measures of mind wandering during reading. To measure cognitive coupling, we manipulated the text difficulty of individual sentences. Because mind wandering may shift attention away from the text, we predicted a cognitive coupling interaction, that is, that the effect of difficulty on processing time should be less when readers are off task.