Emotion Assessment From Physiological Signals for Adaptation of Game Difficulty

Abstract

Abstract-This paper proposes to maintain player's engagement by adapting game difficulty according to player's emotions assessed from physiological signals. The validity of this approach was first tested by analyzing the questionnaire responses, electroencephalogram (EEG) signals, and peripheral signals of the players playing a Tetris game at three difficulty levels. This analysis confirms that the different difficulty levels correspond to distinguishable emotions, and that, playing several times at the same difficulty level gives rise to boredom. The next step was to train several classifiers to automatically detect the three emotional classes from EEG and peripheral signals in a player-independent framework. By using either type of signals, the emotional classes were successfully recovered, with EEG having a better accuracy than peripheral signals on short periods of time. After the fusion of the two signal categories, the accuracy raised up to 63%.

A survey of affective brain computer interfaces: principles, state-of-the-art, and challenges

“…The number of trials per participant also impacts the performance of aBCIs, especially for participant-dependent models. Determining an acceptable number of [103], the authors report a similar accuracy using either 13 or 19 participants for participant-independent training. This suggests that using around 15 participants might be enough to have an aBCI that can correctly generalize.…”

“…Alternatively, parameters of computer games or e-learning applications could be adjusted to keep users engaged in the interaction, for example by decreasing or increasing difficulty to counteract the detected episodes of frustration or boredom, respectively. [15] Another approach is the manipulation of the game world and mechanics in response to the player's affective state, as demonstrated in 'alpha World of Warcraft', [7] where the avatar shifts its shape according to the degree of relaxation the user experiences. Such reactive games could strengthen the players' association with their avatars, leading to a stronger immersion and an increased sense of presence in the game world.…”

“…We are aware of only two studies which used an interactive situation where the participants were playing games to induce and measure emotions. [27,103] Similarly, two studies [109,110] relied on mental imagery, which is expected to elicit emotional patterns similar to everyday interactions. In all these cases, the experiments were carried out in the lab, and there is thus a strong need to evaluate the performance of aBCI in ecological contexts.…”

Affective Recognition for Multimedia Environments A Review

“…Virtual Reality Scenarios and Games: A number of studies employed games and virtual reality scenes as their stimuli [2], [4], [32], [33], [34], [35]. The average games and VR duration was reported as 226 seconds (±106.44, minimum 120 and maximum 350 seconds).…”

“…The average stimulation duration was reported as 170 seconds (±75.5, minimum 90 and maximum 240 seconds). [26], [28], [29], [33], [34], [40] [25], [29], [30], [31], [35], [36], [37], [38], [39] [25], [30], [32], [34], [35], [36], [37], [38], [39] [25], [30], [34], [37], [38] [29], [30], [35], [37], [38], [39] …”