Limits...
Familiar Face Detection in 180 ms.

Visconti di Oleggio Castello M, Gobbini MI - PLoS ONE (2015)

Bottom Line: We investigated the effect of personal familiarity on the earliest stages of face processing by using a saccadic-choice task to measure how fast familiar face detection can happen.By contrast, accuracy of saccades to unfamiliar faces with familiar faces as distractors did not exceed chance.Saccades to faces with object distractors were even faster (110 to 120 ms) and equivalent for familiar and unfamiliar faces, indicating that familiarity does not affect ultra-rapid saccades.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire, United States of America.

ABSTRACT
The visual system is tuned for rapid detection of faces, with the fastest choice saccade to a face at 100 ms. Familiar faces have a more robust representation than do unfamiliar faces, and are detected faster in the absence of awareness and with reduced attentional resources. Faces of family and close friends become familiar over a protracted period involving learning the unique visual appearance, including a view-invariant representation, as well as person knowledge. We investigated the effect of personal familiarity on the earliest stages of face processing by using a saccadic-choice task to measure how fast familiar face detection can happen. Subjects made correct and reliable saccades to familiar faces when unfamiliar faces were distractors at 180 ms--very rapid saccades that are 30 to 70 ms earlier than the earliest evoked potential modulated by familiarity. By contrast, accuracy of saccades to unfamiliar faces with familiar faces as distractors did not exceed chance. Saccades to faces with object distractors were even faster (110 to 120 ms) and equivalent for familiar and unfamiliar faces, indicating that familiarity does not affect ultra-rapid saccades. We propose that detectors of diagnostic facial features for familiar faces develop in visual cortices through learning and allow rapid detection that precedes explicit recognition of identity.

No MeSH data available.


Related in: MedlinePlus

Example of the paradigm (A) with stimuli used in the experiment (B).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4549263&req=5

pone.0136548.g001: Example of the paradigm (A) with stimuli used in the experiment (B).

Mentions: For each subject we took pictures of the faces of three friends with three different head orientations (frontal view with direct gaze, and head turned approximately 40 degrees to the left and to the right with averted gaze). Thus, nine pictures (three identities with three head orientations) were used as familiar-face stimuli for each subject. We used three different images for each identity (familiar and unfamiliar) in three different orientations to prevent idiosyncratic responses to a single image. The choice of the image for target and distracter was random in order to minimize expectations of identity. Pictures of students taken at a different institution, the University of Vermont, with the same setting for the familiar faces served as unknown controls. Unknown-face stimuli depicted individuals with the same head and gaze orientation as the familiar stimuli (see Fig 1 for an example). For object stimuli, we took pictures of three objects (a boot, a cup, and an abacus) in three different orientations around their main axis. Thus, each category (Unknown Faces, Familiar Faces, Objects) had three different stimulus identities in three orientations. We matched all stimuli in average luminance (expressed in pixel intensity ranging from 0 to 255) and contrast, set to 128 and 40 respectively using the function lumMatch in the SHINE toolbox [4,28]. Stimuli were shown on a CRT screen set at a resolution of 800x600 pixels and an 85Hz refresh rate, at a distance of 50cm. The center of each image was 8.6 degrees from the fixation cross, and each stimulus subtended 14x14 degrees [4]. The average width and height of the objects and faces were 7.93 (SD: 1.75) and 10.47 (SD: 1.04) degrees respectively. The background was set to an average gray (128 mean pixel intensity).


Familiar Face Detection in 180 ms.

Visconti di Oleggio Castello M, Gobbini MI - PLoS ONE (2015)

Example of the paradigm (A) with stimuli used in the experiment (B).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4549263&req=5

pone.0136548.g001: Example of the paradigm (A) with stimuli used in the experiment (B).
Mentions: For each subject we took pictures of the faces of three friends with three different head orientations (frontal view with direct gaze, and head turned approximately 40 degrees to the left and to the right with averted gaze). Thus, nine pictures (three identities with three head orientations) were used as familiar-face stimuli for each subject. We used three different images for each identity (familiar and unfamiliar) in three different orientations to prevent idiosyncratic responses to a single image. The choice of the image for target and distracter was random in order to minimize expectations of identity. Pictures of students taken at a different institution, the University of Vermont, with the same setting for the familiar faces served as unknown controls. Unknown-face stimuli depicted individuals with the same head and gaze orientation as the familiar stimuli (see Fig 1 for an example). For object stimuli, we took pictures of three objects (a boot, a cup, and an abacus) in three different orientations around their main axis. Thus, each category (Unknown Faces, Familiar Faces, Objects) had three different stimulus identities in three orientations. We matched all stimuli in average luminance (expressed in pixel intensity ranging from 0 to 255) and contrast, set to 128 and 40 respectively using the function lumMatch in the SHINE toolbox [4,28]. Stimuli were shown on a CRT screen set at a resolution of 800x600 pixels and an 85Hz refresh rate, at a distance of 50cm. The center of each image was 8.6 degrees from the fixation cross, and each stimulus subtended 14x14 degrees [4]. The average width and height of the objects and faces were 7.93 (SD: 1.75) and 10.47 (SD: 1.04) degrees respectively. The background was set to an average gray (128 mean pixel intensity).

Bottom Line: We investigated the effect of personal familiarity on the earliest stages of face processing by using a saccadic-choice task to measure how fast familiar face detection can happen.By contrast, accuracy of saccades to unfamiliar faces with familiar faces as distractors did not exceed chance.Saccades to faces with object distractors were even faster (110 to 120 ms) and equivalent for familiar and unfamiliar faces, indicating that familiarity does not affect ultra-rapid saccades.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire, United States of America.

ABSTRACT
The visual system is tuned for rapid detection of faces, with the fastest choice saccade to a face at 100 ms. Familiar faces have a more robust representation than do unfamiliar faces, and are detected faster in the absence of awareness and with reduced attentional resources. Faces of family and close friends become familiar over a protracted period involving learning the unique visual appearance, including a view-invariant representation, as well as person knowledge. We investigated the effect of personal familiarity on the earliest stages of face processing by using a saccadic-choice task to measure how fast familiar face detection can happen. Subjects made correct and reliable saccades to familiar faces when unfamiliar faces were distractors at 180 ms--very rapid saccades that are 30 to 70 ms earlier than the earliest evoked potential modulated by familiarity. By contrast, accuracy of saccades to unfamiliar faces with familiar faces as distractors did not exceed chance. Saccades to faces with object distractors were even faster (110 to 120 ms) and equivalent for familiar and unfamiliar faces, indicating that familiarity does not affect ultra-rapid saccades. We propose that detectors of diagnostic facial features for familiar faces develop in visual cortices through learning and allow rapid detection that precedes explicit recognition of identity.

No MeSH data available.


Related in: MedlinePlus