Why Do Ideas Get More Creative Across Time? An Executive Interpretation of the Serial Order Effect in Divergent Thinking Tasks

The serial order effect the tendency for later responses to a divergent thinking task to be better than earlier ones is one of the oldest and most robust findings in modern creativity work. But why do ideas get better? Using new methods that afford a fine-grained look at temporal trajectories, we contrasted two explanations: the classic spreading activation account and a new account based on executive and strategic aspects of creative thought. After completing measures of fluid intelligence and personality, a sample of young adults (n = 133) completed a 10-min unusual uses task. Each response was time-stamped and then rated for creativity by three raters. Multilevel structural equation models estimated the trajectories of creativity and fluency across time and tested if intelligence moderated the effects of time. As in past work, creativity increased sharply with time and flattened slightly by the task's end, and fluency was highest in the task's first minute and then dropped sharply. Intelligence, however, moderated the serial order effect as intelligence increased the serial order effect diminished. Taken together, the findings are more consistent with a view that emphasizes executive processes, particularly processes involved in the strategic retrieval and manipulation of knowledge, than the simple spreading of activation to increasingly remote concepts.