Three experiments studied the effects of voluntary and involuntary focus of attention on recognition memory for pictures. Experiments 1 and 3 tested the conceptual-masking hypothesis, which holds that a visual event will automatically disrupt processing of a previously glimpsed picture if that event is new and meaningful. Memory for 112-ms pictures was tested under conditions where the to-be-ignored 1.5-s interstimulus interval contained a blank field; a repeating picture; a new picture; a new, nonsense picture; or a new, inverted picture each time. The blank field, repeating picture, and new, nonsense picture did not disrupt memory as much as a new, meaningful picture, supporting the conceptual-masking hypothesis. Experiment 2 studied voluntary attentional control of encoding by instructing subjects to focus attention on the brief pictures, all pictures, or the long pictures in a sequence. Recognition memory for pictures of both durations showed a striking ability of observers to process pictures selectively. The possible role of these effects in visual scanning are discussed.