# Opposite effects of interruption frequency on performance in interrupted and uninterrupted multistep task

## TL;DR

This study shows that frequent interruptions in multistep tasks improve performance during interruptions but reduce performance when tasks are uninterrupted.

## Contribution

The study reveals a strategic shift in control mode due to high interruption frequency in multistep tasks.

## Key findings

- High interruption frequency leads to faster and more accurate resumption after interruptions.
- Participants in the highest-frequency group performed worse in uninterrupted tasks.
- Strategic shifts in control mode occur due to frequent interruptions.

## Abstract

We investigated the effects of interruption frequency on interrupted and uninterrupted performance in a serial multistep task. The multistep task consisted of five steps, which were memorized and executed consecutively in predefined order. This task was occasionally interrupted by a letter classification task. After completion of that interruption task, participants needed to resume the multistep task at the correct step. We measured response times and sequence errors (deviations from the prescribed order of steps) at the step after an interruption (resumption performance) and in the corresponding steps of uninterrupted tasks. Interruption frequency varied between subjects and was manipulated twofold as: (1) the percentage of interrupted tasks at all (global frequency: 25% vs. 75%); (2) the number of interruptions per task (local frequency: one or three interruptions), resulting in four different groups. The results revealed faster and more accurate resumption in both 75%-frequency groups compared to the lowest frequency group. However, participants in the highest-frequency group were slower in uninterrupted tasks compared to all other lower frequency groups. These results show that high interruption frequency in multistep tasks induces strategic shifts in participants’ control mode causing better performance during interrupted tasks at the cost of worse performance in uninterrupted tasks.