Online validation of combined mood induction procedures

Abstract

Film clips, music, and self-referential statements (termed Velten, after their originator) have been successfully used to temporarily induce sadness and happiness. However, there is little research on the effectiveness of these procedures combined, particularly in internet-based settings, and whether Velten statements contribute to alter mood beyond the effect of simple instructions to close one's eyes and enter the targeted mood. In Study 1 (N = 106) we examined the effectiveness 80 Velten statements (positive, negative, neutral-self, neutral-facts) to create brief and effective sets that might be used in future research. In Study 2 (N = 445) we examined the effect size of 8-min combined mood induction procedures, which presented video clips in the first half and music excerpts with Velten statements or closed eyes instructions in the second half. Participants answered questionnaires on social desirability, joviality, and sadness before being randomly assigned to 1 of 7 groups varying in Valence (positive, negative, neutral) and Velten (closed eyes control, self-referential Velten, and, in the case of neutral condition, factual statements). Subsequently, participants completed the joviality and sadness scales a second time. Compared to the neutral conditions, the positive mood inductions increased joviality (Hedges G = 1.35, 95% CI [1.07, 1.63]), whereas the negative mood inductions increased sadness (Hedges G = 1.28, 95% CI [1.01, 1.55]). We did not observe any significant difference between Velten and closed eyes instructions in inducing joviality or sadness, nor did we observe any significant difference between neutral Velten statements referring to self and facts. Although social desirability bias was associated with reports of greater joviality and lower sadness, it could not account for the effects of the positive and negative mood induction procedures. We conclude that these combined mood induction procedures can be used in online research to study happy and sad mood.

Fig 1. Illustration of joviality change scores across mood induction procedures.

A raincloud plot showing the distributions of change scores in Joviality from pre to post-induction grouped by induction condition. The small dots below each raincloud show the observed scores of that condition (jittered). The lower and upper hinge on the boxplots represent the first and third quartile with the median in between, whereas the whisker lines extend to the most extreme values but no further than 1.5 × the interquartile range from the hinge. The raincloud shapes illustrate the distribution of observations based on Kernel density probability functions computed for each condition (scaled to have equal heights across conditions). To highlight “no change” from pre- to post induction, 0 is indicated with a vertical line.

Fig 2. Illustration of sadness change scores across mood induction procedures.

A raincloud plot showing the distributions of change scores in Sadness from pre to post-induction grouped by induction condition. The small dots below each raincloud show the observed scores of that condition (jittered). The lower and upper hinge on the boxplots represent the first and third quartile with the median in between, whereas the whisker lines extend to the most extreme values but no further than 1.5 × the interquartile range from the hinge. The raincloud shapes illustrate the distribution of observations based on Kernel density probability functions computed for each condition (scaled to have equal heights across conditions). To highlight “no change” from pre- to post induction, 0 is indicated with a vertical line.