Program running versus problem solving: mental task effect on tonic heart rate.

It was hypothesized that mental tasks that involve program running (RUN tasks) would cause a greater tonic heart rate (HR) increase than tasks that require the search for problem solutions (EDIT tasks). Three experiments using verbal, numeric, and graphic material were run to compare tasks matched for difficulty but differing in qualitative demands (RUN vs. EDIT tasks). As predicted, filling in missing letters in words caused a larger HR increase than finding words that were logical continuations of a series of words (Experiment 1) and performing arithmetic operations caused a greater HR increase than logical completion of a series of digits (Experiment 2). In Experiment 3, two of three tasks that demanded counting of graphic elements caused a larger HR increase than a task that required logical completion of a series of graphic elements. Experiments 1 and 2 also showed that RUN tasks evoked greater phasic HR acceleration than EDIT tasks.