Happier individuals generate more spontaneous thoughts about friends and value relationships over money.

Spontaneous thoughts are a window into one's mind, as they offer rich information about ongoing psychological processes and value systems. We accessed the contents of these thoughts using a free association paradigm combined with natural language processing techniques to examine how happiness is associated with what people think about and prioritize in daily life. Our analyses revealed that participants (n = 210 from the US/UK) with higher subjective well-being, particularly those with more frequent positive affect, generated thoughts semantically more similar to 'friend,' but not to 'money.' A similar pattern was also found in an independent sample (n = 350 from South Korea), showing consistency of the findings across different cultural contexts. Notably, the semantic similarity of participants' generated thoughts to 'friend' predicted the extent to which participants prioritized social relationships over monetary gains in a realistic dilemma task. By exploring individuals' minds with a computational approach, our work elucidates how the value of social relationships is manifested in spontaneous thought contents and everyday decisions, providing insights into the sources of happiness.