Uncontrolled Thoughts in the Dark? Effects of Lighting Conditions and Fear of the Dark on Thinking Processes

Abstract

Although darkness alters physical reactivity, perceptions, and behavior, no previous research has investigated its impact on primary and secondary process thinking. This study examined the effect of lighting on young adults’ thinking contents, related to their fear of the dark. Seventy-eight participants (41 females, 21.44 ± 2.15 years of age on average) wrote stories in a well-lit or semidark room and completed the Intensity of Fear of the Dark Questionnaire. Stories were analyzed via the Regressive Imagery Dictionary. Results showed that individuals with high levels of fear of the dark produce longer stories with higher relative frequency of primary content words in the semidark condition than in the well-lit condition, while others produce similar stories in both conditions. In addition, fearful individuals used significantly less secondary content words relative to primary content words in the semidark condition than in the well-lit condition. Results have been discussed from a regulatory perspective.