Participants. Twenty one participants completed the experiment (13 females, 8 males; 19 right-handed; age range 18-25 years, M = 20.6). Participants were undergraduate students from the University of Waterloo (UW), with normal or corrected-to-normal vision, who took part in the study for course credit. The study received full ethics clearance from the UW Research Ethics Board and all participants signed informed written consent. This work was carried out in accordance with the Code of Ethics of the World Medical Association (Declaration of Helsinki).
Stimuli. Greyscale photographs of 8 individuals (four men, four women) with neutral expression were taken from George et al. (2001). Each face was photographed against a black background with the …show more content…
Participants were instructed to focus on a central fixation cross at all times (see Figure 1). Before each trial, the fixation cross (1° x 1°) was presented for 1200 ms, and then became a fixation trigger that participants must have focused on for 300 ms to activate the next trial. For each trial, an individual face was presented for 150 ms randomly in one of 9 possible locations aligned vertically across the screen. Each face centre was positioned from –6° (below fixation) to +6° (above fixation) visual angle vertically. The centres of each adjacent face position were separated by 1.5° of visual angle vertically. Following stimulus presentation, participants were required to discriminate whether the target face had a direct or an averted gaze as quickly and as accurately as possible, using a two-button press with their index and middle fingers of their dominant hand. Responses were made using the b and m keys of a standard keyboard, which were counterbalanced across participants. The next trial started 1000 ms after the end of stimulus presentation, regardless of whether a response was made or not. Before the experimental session, 9 practice trials (one for each possible stimulus location) were presented to familiarize participants with the stimuli and …show more content…
Preliminary analyses revealed no significant differences between left- and right-averted gaze targets across eccentricities, and no significant effects of participant gender or stimulus gender on gaze discrimination were found. Mean RT data were computed using only correct responses. For each subject, RTs that were below 150 ms (0.1% of the total data) or exceeded 2.5 standard deviations (9.3% of the total data) from the mean of each gaze condition per eccentricity were discarded. All trials in which more than one fixation was made (i.e., when participants moved their eyes away from the centred fixation) were eliminated (2.9%). RTs exceeding 1000 ms were recorded as a miss (7.2%). Miss rates did not vary significantly across gaze conditions or eccentricities. Error rates were calculated as the number of false alarms (e.g., pressing the AG button when a DG face was presented, or vice versa) that were made out of the total amount of responses that could have been made for each individual eccentricity. As this was a two-button press, forced choice task, a 50% error rate to a particular condition was chance level performance. Response rates were also calculated as the overall percentage of responses to each gaze condition regardless of whether participants were correct or not, indicating a possible response bias to press one button over the
Stimuli. Greyscale photographs of 8 individuals (four men, four women) with neutral expression were taken from George et al. (2001). Each face was photographed against a black background with the …show more content…
Participants were instructed to focus on a central fixation cross at all times (see Figure 1). Before each trial, the fixation cross (1° x 1°) was presented for 1200 ms, and then became a fixation trigger that participants must have focused on for 300 ms to activate the next trial. For each trial, an individual face was presented for 150 ms randomly in one of 9 possible locations aligned vertically across the screen. Each face centre was positioned from –6° (below fixation) to +6° (above fixation) visual angle vertically. The centres of each adjacent face position were separated by 1.5° of visual angle vertically. Following stimulus presentation, participants were required to discriminate whether the target face had a direct or an averted gaze as quickly and as accurately as possible, using a two-button press with their index and middle fingers of their dominant hand. Responses were made using the b and m keys of a standard keyboard, which were counterbalanced across participants. The next trial started 1000 ms after the end of stimulus presentation, regardless of whether a response was made or not. Before the experimental session, 9 practice trials (one for each possible stimulus location) were presented to familiarize participants with the stimuli and …show more content…
Preliminary analyses revealed no significant differences between left- and right-averted gaze targets across eccentricities, and no significant effects of participant gender or stimulus gender on gaze discrimination were found. Mean RT data were computed using only correct responses. For each subject, RTs that were below 150 ms (0.1% of the total data) or exceeded 2.5 standard deviations (9.3% of the total data) from the mean of each gaze condition per eccentricity were discarded. All trials in which more than one fixation was made (i.e., when participants moved their eyes away from the centred fixation) were eliminated (2.9%). RTs exceeding 1000 ms were recorded as a miss (7.2%). Miss rates did not vary significantly across gaze conditions or eccentricities. Error rates were calculated as the number of false alarms (e.g., pressing the AG button when a DG face was presented, or vice versa) that were made out of the total amount of responses that could have been made for each individual eccentricity. As this was a two-button press, forced choice task, a 50% error rate to a particular condition was chance level performance. Response rates were also calculated as the overall percentage of responses to each gaze condition regardless of whether participants were correct or not, indicating a possible response bias to press one button over the