The influence of stimulus uncertainty and experimental instructions on visual selection

The looking behavior of adults and children was recorded while they viewed pairs of stimuli differing in stimulus uncertainty. Ss in one experimental group were encouraged to identify the stimuli and indicate whether they had been seen in a previous phase of the experiment. For the remaining Ss, instructions minimized the importance of the stimuli to the experiment. Results indicate that, when stimulus uncertainty was influential, the relationship between stimulus uncertainty and looking time was monotonically increasing. However, stimulus uncertainty was an effective determinant of looking behavior only when Ss were motivated to identify the stimuli. The behavior of adults and children did not differ.