# Studying the Impact of Mood on Identifying Smartphone Users

## TL;DR

This study investigates whether mood affects smartphone user identification accuracy, finding that excluding mood-related samples worsens performance, and mood-related behavioral changes do exist but do not necessarily impact biometric identification.

## Contribution

The paper challenges the assumption that mood negatively influences mobile biometric performance by showing that removing mood-influenced samples reduces accuracy, and identifies behavioral changes linked to mood.

## Key findings

- Performance decreases when mood-related samples are removed.
- Behavioral patterns such as locking, audio, and location habits vary with mood.
- Mood does not significantly impact biometric identification accuracy.

## Abstract

This paper explores the identification of smartphone users when certain samples collected while the subject felt happy, upset or stressed were absent or present. We employ data from 19 subjects using the StudentLife dataset, a dataset collected by researchers at Dartmouth College that was originally collected to correlate behaviors characterized by smartphone usage patterns with changes in stress and academic performance. Although many previous works on behavioral biometrics have implied that mood is a source of intra-person variation which may impact biometric performance, our results contradict this assumption. Our findings show that performance worsens when removing samples that were generated when subjects may be happy, upset, or stressed. Thus, there is no indication that mood negatively impacts performance. However, we do find that changes existing in smartphone usage patterns may correlate with mood, including changes in locking, audio, location, calling, homescreen, and e-mail habits. Thus, we show that while mood is a source of intra-person variation, it may be an inaccurate assumption that biometric systems (particularly, mobile biometrics) are likely influenced by mood.