Head Motion Elicited by Viewing Affective Pictures as Measured by a New LED-Based Technique

Postural control in emotional states: An effect of biofeedback

BACKGROUND

Emotional states in the short term and affective impairments, such as anxiety and depression in the long run, can have a significant impact on postural control. Individuals with these conditions often struggle with maintaining balance during emotionally charged situations, which can increase their risk of falls and injuries. Biofeedback has been proposed as a potential intervention to improve postural control during emotional induction.

RESEARCH QUESTION

How do emotional stimuli affect postural control performance in the presence of real-time postural feedback?

METHODS

Forty-two participants took part in the study. The visual stimuli used in the experiment to induce emotions of various valence in the subjects were video clips, containing a series of pictures (24 positive, 24 neutral and 24 negative pictures). During the experiment, participants were required to maintain balance standing on a force platform while watching the videos on a computer screen. For each subject, three sessions of 480 s were generated, each of which included two conditions: with and without biofeedback (a target on the screen indicating the subject's position relative to the center of pressure (CoP).

RESULTS

The No Feedback condition provoked a higher medial-lateral and anterior-posterior sway, but lower velocity of CoP than the Feedback condition. We did not find any effect of the valence of emotional videos on indicators of postural control in No Feedback condition. However, both negative and positive videos provoked a lower velocity of CoP in comparison to neutral videos in the Feedback condition.

SIGNIFICANCE

Changes observed in postural control during the Feedback condition in the presence of emotional stimuli (both negative and positive) could be explained by the shift in attention from the task of maintaining posture to the emotional videos. The results of this study have important implications for clinicians involved in postural training and rehabilitation.

What emotion dimensions can affect working memory performance in healthy adults? A review

Due to the critical roles of emotion and working memory in our daily activities, a great deal of attention has been given to how emotion influences working memory performance. Although the association between emotion and working memory is relatively well established, whether mood enhances or impairs working memory performance remains controversial. The present review provides a relatively representative overview of the research on the effect of different dimensions of emotion on working memory among healthy adults spanning a 30-year period. The findings show that the valence, arousal and motivational dimensions of emotion could all exert an impact on working memory performance. The impact of emotion on working memory might be modulated by task relevance, emotion type, working memory paradigms and individual differences. The vast majority of the studies regarding the effect of emotion on working memory performance focused on the impact of negatively valenced affect and yielded highly contradictory findings. The impacts of arousal and motivation on working memory have been less explored, and inconsistent findings have also been reported. Possible explanations are discussed. Considerable research on the effect of certain dimensions of emotion on working memory has suffered from a lack of control of other emotional dimensions, and different aspects of working memory have been investigated by various paradigms. Directions for further studies should include the exploration of specific dimensions of emotion on different aspects of working memory, with the other dimensions being well controlled.

Head movement differs for positive and negative emotions in video recordings of sitting individuals

Individuals tend to approach positive stimuli and avoid negative stimuli. Furthermore, emotions influence whether individuals freeze or move more. These two kinds of motivated behavior refer to the approach/avoidance behavior and behavioral freezing/activation. Previous studies examined (e.g., using forced platforms) whether individuals' behavior depends on stimulus' valence; however, the results were mixed. Thus, we aimed to test whether emotions' effects on spontaneous whole-body behavior of standing individuals also occur in the seated position. We used a computer vision method to measure the head sway in video recordings that offers ease of use, replicability, and unobtrusiveness for the seated research participant. We analyzed behavior recorded in the laboratory during emotion manipulations across five studies totaling 932 participants. We observed that individuals leaned more forward and moved more when watching positive stimuli than when watching negative stimuli. However, individuals did not behave differently when watching positive or negative stimuli than in the neutral condition. Our results indicate that head movements extracted from seated individuals' video recordings can be useful in detecting robust differences in emotional behavior (positive vs. negative emotions).

Does Social Content Influence the Subjective Evaluation of Affective Pictures?

This study explored the effect of the perceived social content of affective pictures on the subjective evaluation of affective valence and arousal. For this purpose, we established three categories of social content (pictures without people, with one person and with two or more people). A sample of 161 subjects rated 200 pictures varying in affective valence (unpleasant, neutral, and pleasant), arousal and social content. Results of two-factor analysis of variance, F(4, 157) = 71.7, p < .001, ηp2 = .31, showed that perceived social content influenced the ratings of affective valence, specially for unpleasant pictures, with the greatest social content (two or more people) leading subjects to rate unpleasant pictures with the lowest ratings (all pairwise comparisons' p < .001). Regarding arousal, F(4, 157) = 64.0, p < .001, ηp2 = .29), the higher the social content, the higher the arousal ratings, but only for pleasant (all pairwise comparisons' p < .007) and unpleasant (all pairwise comparisons' p < .001) pictures. Overall, this study demonstrated an effect of the perceived social content on the subjective evaluation of affective valence and arousal of emotional stimuli.