Visual dissociation: an illusory conjunction of pictures and forms.

Undergraduates viewed rapidly presented series of color photographs (9/s) and were required to indicate which photograph appeared within a black outline rectangle (the "frame"). Experiment 1 demonstrated that subjects were often confident and wrong, reporting the immediately preceding or following picture in the sequence. Experiment 2 showed that migration of the frame to other pictures cannot be attributed to spatial separation, because the same effect occurred when a small frame was presented in the center of the picture itself. Experiment 3 ruled out masking of the "framed" picture as the cause of the illusion by showing that the framed picture is indeed identified on those trials where the frame appears to be elsewhere. Experiment 4 showed that when simpler, more familiar stimuli (numbers) were presented, a more rapid presentation rate (18/s) was required to obtain the effect. It is proposed that the illusion reflects the action of integrative processes in a very short-term buffer and that it may provide a new tool with which to study the integration of features within scenes.