Fig 1.
The procedure of experiment 1.
(A) Participants started with the learning phase during which they were presented with three faces together with their identities. The faces were presented sequentially in random order for 20 seconds each. (B) Following the learning phase, participants completed a test assessing whether they had learned to correctly assign labels to faces. In this test they were asked to choose which of two labels corresponded to a particular face. (C) The main task was a matching task during which EEG was recorded. Each trial started with a fixation cross followed by a short presentation of a face. After 1300ms of a delay period a label was displayed and stayed on the screen until the participant responded. The photographs are for illustration purposes, they were not the faces used in the task. The individuals from the photographs have given written informed consent (as outlined in PLOS consent form) to publish these photographs.
Fig 2.
Three types of trials used to analyze the data from both experiments.
In matching trials face and label corresponded with one another. In non-matching trials they did not correspond. There are two ways to categorize non-matches. One way (non-matching 1) is to take the first stimulus as a reference and to determine how the second stimulus is mismatching. This allows one to assess the influence of expectations induced by different stimuli (you, friend, stranger) on RTs. The other way (non-matching 2) is to take the second stimulus as a reference and to determine whether the first stimulus was mismatching. This allows one to assess the influence of different stimuli presented second (you, friend, stranger) on the participant’s RTs.
Fig 3.
(A) A single trial from experiment 1 illustrating the procedure. (B) Reaction times separately for (from left to right) matching, non-matching 1 (NM1), and non-matching 2 (NM2) trials (see Fig 2 for explanation of how NM1 and NM2 were derived) for self (green), friend (purple), and stranger (black). (C) Event-related potentials following presentation of the face, including the time course of the N2 (between 240 and 340ms) and the late frontal positivity (450-750ms) at electrode AFz (left panel), and corresponding average of all conditions voltage topographies and voltage topographies of the difference between the self-condition and the friend/stranger conditions (right panel). (D) Average of all conditions topographies and grand-averaged stimulus-locked waveforms of the central-parietal P3 for self, friend, and stranger at electrode CPz, separately for matching trials and two types of mismatching trials (NM1 and NM2). The individual from the photograph has given written informed consent (as outlined in PLOS consent form) to publish this photograph.
Fig 4.
(A) A single trial from experiment 2 illustrating the procedure. (B) Reaction times separately for (from left to right) matching, non-matching 1 (NM1), and non-matching 2 (NM2) trials (see Fig 2 for explanation of how NM1 and NM2 were derived) for self (green), friend (purple), and stranger (black). (C) The time course of the frontal P3 (350-450ms) following presentation of a label at electrode FCz (left panel), and corresponding average of all conditions voltage topographies and voltage topographies of the difference between the self-condition and the friend/stranger conditions (right panel). (D) Average of all conditions topographies and grand-averaged stimulus-locked waveforms of the central-parietal P3 after presentation of the face for self, friend, and stranger at electrode CPz, separately for matching trials and two types of mismatching trials (NM1 and NM2). The individual from the photograph has given written informed consent (as outlined in PLOS consent form) to publish this photograph.