Intraindividual Fluctuation in Optimism Under Daily Life Circumstances: A Longitudinal Study

Area of Science:

• Psychology
• Mental Health Research
• Cross-Cultural Psychology

Background:

• Optimism traditionally viewed as a stable trait.
• Emerging evidence suggests optimism can fluctuate within individuals.
• Limited understanding of state optimism's characteristics and cultural variations.

Purpose of the Study:

• Develop and validate a Japanese version of the State Optimism Measure (J-SOM).
• Investigate the nature of intraindividual fluctuations in state optimism.
• Examine the relationship between state optimism, trait optimism, and mental health indicators.

Main Methods:

• Two online longitudinal surveys (weekly and monthly) with university students (N=196).
• Administered the Japanese State Optimism Measure (J-SOM) and other mental health assessments.
• Analyzed factor validity, internal consistency, and correlations between state/trait optimism and mood/happiness.

Main Results:

• The J-SOM demonstrated high factor validity and internal consistency.
• State optimism showed significant correlations with depressive mood and subjective happiness.
• Intraindividual changes in state optimism were linked to mood and daily life quality changes, unlike trait optimism.

Conclusions:

• The validated J-SOM accurately measures state optimism in a Japanese context.
• State optimism exhibits significant intraindividual variability over weeks.
• Fluctuations in state optimism, not trait optimism, are associated with daily psychological well-being.