Duration of mood effects following a Japanese version of the mood induction task.

Researchers have employed a variety of methodologies to induce positive and negative mood states in study participants to investigate the influence that mood has on psychological, physiological, and cognitive processes both in health and illness. Here, we investigated the effectiveness and the duration of mood effects following the mood induction task (MIT), a protocol that combines mood-inducing sentences, auditory stimuli, and autobiographical memory recall in a cohort of healthy Japanese adult individuals. In Study 1, we translated and augmented the mood-inducing sentences originally proposed by Velten in 1968 and verified that people perceived the translations as being largely congruent with the valence of the original sentences. In Study 2, we developed a Japanese version of the mood induction task (J-MIT) and examined its effectiveness using an online implementation. Results based on data collected immediately after induction showed that the J-MIT was able to modulate the mood in the intended direction. However, mood effects were not observed during the subsequent performance of a cognitive task, the Tower of London task, suggesting that the effects did not persist long enough. Overall, the current results show that mood induction procedures such as the J-MIT can alter the mood of study participants in the short term; however, at the same time, they highlight the need to further examine how mood effects evolve and persist through time to better understand how mood induction protocols can be used to study affective processes more effectively.