Search for a ball that has undergone hidden motion rapidly improves during the second year of life ("Dev. Psychol.," 2000; 36:394-401). In three experiments we investigated whether the poor performance of younger toddlers was due to attentional failure by highlighting the major cue for the hidden object. We observed only slight improvement in search behaviour. We performed two other experiments that tested the depth of understanding of 3-year-olds in this task and found that their performance was robust to changes in the apparatus and experimental procedures. Overall, the results point to a rapidly developing ability in the second year of life to either reason about space or select the correct motor response in search tasks. (Contains 4 figures and 2 tables.)