The effect of the color red on encoding and retrieval of declarative knowledge

• Red color during knowledge encoding or retrieval impairs learning outcomes.
• Repeated color exposure affected both sexes differently.
• For girls, single color exposure impaired knowledge test performance.
• For boys, repeated color exposure showed a negative effect.
• Descriptive analyses showed a similar trend for measures of cognitive load.

Studies on color psychology have demonstrated that the color red impairs cognitive performance in achievement situations. This study extends this line of research to the context of learning. One hundred and ninety students of a secondary school were instructed to memorize a short text (encoding phase). Subsequently, they were administered a knowledge test and a measure of cognitive load (retrieval phase). The experimental design manipulated the color (red versus gray) of the stimulus material during the encoding and the retrieval phase. For boys, repeated color exposure affected test performance more strongly than color presentation during a single phase. In contrast, for girls, a single color manipulation impaired knowledge retrieval, whereas repeated exposure to red had no effect. Descriptive analyses identified similar effects for cognitive load.