# Continuous Hand-Arm Vibrations Do Not Interfere with Cognitive Processing

## TL;DR

This study finds that hand-arm vibrations from machines do not significantly affect human cognitive performance or attention during tasks.

## Contribution

The study provides empirical evidence that hand-arm vibrations do not interfere with cognitive processing in human-machine interactions.

## Key findings

- Hand-arm vibrations did not affect response times or error rates in cognitive tasks.
- Vibration comfort and discomfort correlated with task performance in one experiment.
- Vibrations did not modulate the congruency effect in attention tasks.

## Abstract

When humans engage in closely coupled human-machine interactions, they often experience hand-arm vibrations, which are a byproduct of the running machine. Yet, in closely coupled human-machine interactions, it is important to ensure that human attention and cognition remains sufficiently high to avoid accidents and to achieve a good performance. The aim of the present study was to examine whether hand-arm vibrations impact on cognitive processing. In two studies, we investigated the impact of constant or random vibration compared to a baseline condition without vibration on selective attention. In detail, we assessed overall performance (RT and error rates) and the congruency effect in a flanker task (Experiment 1) and a temporal flanker task (Experiment 2). In Experiment 2, we additionally explored experienced vibration comfort and discomfort, two constructs often considered in ergonomics. In both experiments hand-arm vibrations neither affected mean response times nor proportion of correct responses. Additionally, hand-arm vibrations did not modulate the congruency effect. Experiment 2 revealed that vibration comfort and discomfort seem to correlate with task-performance. We conclude that hand-arm vibrations in general do not impact on cognitive processing, but it seems important to consider which vibration is selected to achieve optimal performance depending on user experience.