Analyzing Human Random Generation: an Approach Based on the Zener Card Test

Zener card test (ZCT) can be assimilated to a random generation task (RGT). The aim was to investigate the properties of the ZCT as an RGT by using a series of validated statistical indicators. The ZCT was administered to 34 students. The Monte Carlo method was used to simulate the expected multinormal distribution and the associated confidence intervals. Several indexes were used to quantify deviations from randomness during the task. The participants were less likely to report repetitions than those expected by pure randomness. In addition, they tended to avoid association of couples of same symbols and had a propensity to increase the distance between symbols. Some of the strategies adopted by participants to avoid repetition or redundancy showed to be under an active process that was sensitive to tiredness. The ZCT can be considered an example of RGT. ZCT has the advantage of using stimuli without an implicit order.