Intuitive number evaluation is not affected by information processing load

Numbers play a major role in decisions about vital life issues. This study compared the relative advantage of analytical vs. intuitive numerical processing in numerical average evaluations, while varying information load, complexity of the task and the information presentation formats. Thinking manipulation was based on Dehaene’s [5] model, which postulates two pathways for the numerical processing. The complexity level of the task was manipulated by varying the number of items to be averaged. The information presentation format were simultaneous vs. sequential. When few numbers were presented, analytical evaluations were more accurate. When task complexity increased and a sequential presentation was used, intuitive evaluations were more accurate. The results challenge the common position that analytical thinking is always advantageous in numerical evaluations, suggesting instead that the relative efficiency of each thinking mode is mediated by task’s factors. The cognitive mechanisms that might underlie our results are discussed.