Fig. 1: Schematic design of the protocol.

The experiment consisted of an encoding phase, an immediate recognition phase (IR), and a delayed recognition phase (DR), with a total of 10 runs. a The encoding phase consisted of two runs. In each run, 160 stimuli (80 houses and 80 faces) were pseudo-randomly presented for 1000ms with a 1500ms inter-stimulus interval. The second encoding run (encoding repetition) was identical to the first, except for the order of stimulus presentation. Prior to the encoding phase, participants were instructed to memorize the stimuli in order to recognize them in a subsequent recognition test. b The IR phase directly followed the encoding phase. In the IR phase, the stimuli consisted of the 160 stimuli from the encoding phase intermixed with an additional 80 distractors: 40 houses and 40 faces. The trials were equally divided over 4 runs during the IR phase. In the IR, the 1500ms  presentation of a stimulus was followed by a 3000ms response screen, which displayed the question “Was this picture presented in the encoding phase?” with four boxes below referring to four response alternatives: “definitely not”, “probably not”, “probably yes”, “definitely yes”. c The DR phase was conducted two days after the first session (48 h). The procedure of the DR was identical to that of the IR, except for the stimulus presentation order and the distracter stimuli, i.e. 80 new distractors were presented in the DR.