Induction method influence on emotion recognition based on
psychophysiological parameters
Authors: Schmid Ramona , Maria Saat Sophia , Möller Knut , Wagner-Hartl Verena 
Published: February 2023

Recognizing emotions is an essential ability in our daily social
interactions. However, there are individuals who have difficulties
interpreting emotions, such as patients with autism spectrum disorders
(ASD). In order to cope better with everyday life, emotion training can be a
supporting factor for them. However, studies show that emotion training is
not only helpful for patients with ASD, but also in the working environment,
for example in trainings for managers or teams. In recent research, there
are already approaches to use new technologies such as virtual reality to
train emotional and social skills. For the evaluation of these new concepts,
it is important to make the emotional state of a person measurable.
Therefore, a measurement environment has already been developed at
Furtwangen University. This is based on a multidimensional approach
combining subjective and objective psychophysiological measures. Moreover,
the development of facial emotion recognition (FER) systems based on machine
learning techniques are also increasing for measuring a person's emotional
state. Often, they focus on the recognition of Ekman’s basic emotions. To
train and evaluate such FER systems, these basic emotions have to be induced
in an individual. Therefore, a number of methods for emotion induction can
be found in research, e.g. visual stimuli or mental methods. However, in
most studies, only a few selected emotions, such as anger and happiness,
were induced. Thus, there is a lack of studies that examined the induction
of all six basic emotions.For that reason, the aim of the presented
experimental study was to investigate two different methods of emotion
induction for the six basic emotions anger, disgust, fear, happiness,
sadness, surprise, and a neutral category. Overall, 14 women and 10 men (N =
24) aged between 19 and 59 years (M = 29.25, SD = 11.46) participated in the
study. For the first induction method, affective visual stimuli from common
emotional picture databases (EmoPicS, OASIS and IAPS) were used. For the
second induction method, emotions were induced by a so-called
autobiographical recall. Therefore, the participants had to imagine
autobiographical situations that evoked the required emotion in them in the
past. After each different induction of one of the six emotions or the
neutral category, the participants’ emotional state was assessed using the
two dimensions valence and arousal of the Self-Assessment Manikin (SAM).
Furthermore, cardiovascular (ECG) and electrodermal (EDA) activity were
recorded. The results show a significant interaction induction method x
emotional category for both subjective assessments valence and arousal.
Furthermore, based on the results of the psychophysiological responses of
the participants (ECG and EDA), it is shown that the second method to induce
emotions (autobiographical recall) was significantly more arousing than the
first induction method using visual stimuli. To sum it up, the results of
the experimental study show an influence of the induction method that is
evident in both the subjective and the psychophysiological parameters.