Recognition of Intensive Valence and Arousal Affective States via Facial Electromyographic Activity in Young and Senior Adults

PLoS One. 2016 Jan 13;11(1):e0146691. doi: 10.1371/journal.pone.0146691. eCollection 2016.

Abstract

Background: Research suggests that interaction between humans and digital environments characterizes a form of companionship in addition to technical convenience. To this effect, humans have attempted to design computer systems able to demonstrably empathize with the human affective experience. Facial electromyography (EMG) is one such technique enabling machines to access to human affective states. Numerous studies have investigated the effects of valence emotions on facial EMG activity captured over the corrugator supercilii (frowning muscle) and zygomaticus major (smiling muscle). The arousal emotion, specifically, has not received much research attention, however. In the present study, we sought to identify intensive valence and arousal affective states via facial EMG activity.

Methods: Ten blocks of affective pictures were separated into five categories: neutral valence/low arousal (0VLA), positive valence/high arousal (PVHA), negative valence/high arousal (NVHA), positive valence/low arousal (PVLA), and negative valence/low arousal (NVLA), and the ability of each to elicit corresponding valence and arousal affective states was investigated at length. One hundred and thirteen participants were subjected to these stimuli and provided facial EMG. A set of 16 features based on the amplitude, frequency, predictability, and variability of signals was defined and classified using a support vector machine (SVM).

Results: We observed highly accurate classification rates based on the combined corrugator and zygomaticus EMG, ranging from 75.69% to 100.00% for the baseline and five affective states (0VLA, PVHA, PVLA, NVHA, and NVLA) in all individuals. There were significant differences in classification rate accuracy between senior and young adults, but there was no significant difference between female and male participants.

Conclusion: Our research provides robust evidences for recognition of intensive valence and arousal affective states in young and senior adults. These findings contribute to the successful future application of facial EMG for identifying user affective states in human machine interaction (HMI) or companion robotic systems (CRS).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Arousal / physiology*
  • Electromyography / methods*
  • Emotions / physiology*
  • Face / physiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Photic Stimulation
  • Signal Processing, Computer-Assisted
  • Young Adult

Grants and funding

This research was supported by grants from the Transregional Collaborative Research Center (DFG-Project SFB TRR62) “Companion-Technology for Cognitive Technical System” funded by the German Research Foundation (DFG) and doctoral scholarships by the China Scholarship Council (CSC) for Jun-Wen Tan and Hang Li. The authors thank the Brazilian Government for the financial support. In particular the agencies FAPEMIG (Research Foundation of the state of Minas Gerais), CNPq (National Council of Technological and Scientific Development) and CAPES Foundation for the Coordination and Improvement of Higher Level or Education Personnel). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.