Figure 1.

Task design. During encoding (top), subjects were presented with adjectives and had to vividly imagine, depending on the cue, a scene (such as a garbage dump for “SCENE-dirty”) or an object (such as an amplifier for “OBJECT-loud”) described by the adjective. Scene and object trials were randomly intermixed, and each trial contained a rating period, in which the success of the mental imagery was evaluated on a five-point scale. Encoding trials alternated with an active baseline task (arrows task). The unscanned surprise memory test (bottom) consisted of an item recognition part (old/new judgments on adjectives) followed by a source memory test, asking subjects to indicate the type of imagery (object or scene) they had engaged in during encoding (including confidence ratings).