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Image-invariant responses in face-selective regions do not explain the perceptual advantage for familiar face recognition.

Davies-Thompson J, Newling K, Andrews TJ - Cereb. Cortex (2012)

Bottom Line: Here, we used an functional magnetic resonance-adaptation paradigm to investigate image invariance in face-selective regions of the human brain.We found clear evidence for a degree of image-invariant adaptation to facial identity in face-selective regions, such as the fusiform face area.This suggests that the marked differences in the perception of familiar and unfamiliar faces may not depend on differences in the way multiple images are represented in core face-selective regions of the human brain.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, York Neuroimaging Centre, University of York, York YO10 5DD, UK.

ABSTRACT
The ability to recognize familiar faces across different viewing conditions contrasts with the inherent difficulty in the perception of unfamiliar faces across similar image manipulations. It is widely believed that this difference in perception and recognition is based on the neural representation for familiar faces being less sensitive to changes in the image than it is for unfamiliar faces. Here, we used an functional magnetic resonance-adaptation paradigm to investigate image invariance in face-selective regions of the human brain. We found clear evidence for a degree of image-invariant adaptation to facial identity in face-selective regions, such as the fusiform face area. However, contrary to the predictions of models of face processing, comparable levels of image invariance were evident for both familiar and unfamiliar faces. This suggests that the marked differences in the perception of familiar and unfamiliar faces may not depend on differences in the way multiple images are represented in core face-selective regions of the human brain.

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Related in: MedlinePlus

Design and images used in Experiments 2 and 3. (a) Examples of familiar faces used in Experiment 2. (b) Each experiment had 4 conditions in which 1 image, 2 images, 4 images, or 8 images were presented in each stimulus block. In Experiment 2, the images in each block were from the same identity, whereas, in Experiment 3, the images were from different identities. (c) Examples of the 2-image condition in Experiment 2 (left) and Experiment 3 (right).
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fig2: Design and images used in Experiments 2 and 3. (a) Examples of familiar faces used in Experiment 2. (b) Each experiment had 4 conditions in which 1 image, 2 images, 4 images, or 8 images were presented in each stimulus block. In Experiment 2, the images in each block were from the same identity, whereas, in Experiment 3, the images were from different identities. (c) Examples of the 2-image condition in Experiment 2 (left) and Experiment 3 (right).

Mentions: To determine image invariance in face-selective regions, the images from Experiment 1 were incorporated into a block design fMR-adaptation paradigm. Twenty participants took part in Experiment 2 (12 females; mean age, 22). There were 5 image conditions: (1) 1-image of the same identity; (2) 2-images of the same identity; (4) 4-images of the same identity; (8) 8-images of the same identity, and (D) 8-images with different identities. Examples of the stimuli are shown in Figure 2. The faces were either familiar or unfamiliar faces of males and females. Unfamiliar faces were unknown to the participants and were chosen to match familiar faces for their variation in age and appearance. In the same-identity conditions, 8 different familiar identities (4 male, 4 female) and 8 different unfamiliar identities (4 male, 4 female) were used. The different images of the same identity varied in lighting, hairstyle. Images were presented in gray scale and were adjusted to an average brightness level. The mean change in image intensity across images was calculated by taking the average of the absolute differences in gray value at each pixel for successive pairs of images within a block. Table 1 shows that there was a similar mean intensity change in the corresponding familiar and unfamiliar conditions.


Image-invariant responses in face-selective regions do not explain the perceptual advantage for familiar face recognition.

Davies-Thompson J, Newling K, Andrews TJ - Cereb. Cortex (2012)

Design and images used in Experiments 2 and 3. (a) Examples of familiar faces used in Experiment 2. (b) Each experiment had 4 conditions in which 1 image, 2 images, 4 images, or 8 images were presented in each stimulus block. In Experiment 2, the images in each block were from the same identity, whereas, in Experiment 3, the images were from different identities. (c) Examples of the 2-image condition in Experiment 2 (left) and Experiment 3 (right).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3539454&req=5

fig2: Design and images used in Experiments 2 and 3. (a) Examples of familiar faces used in Experiment 2. (b) Each experiment had 4 conditions in which 1 image, 2 images, 4 images, or 8 images were presented in each stimulus block. In Experiment 2, the images in each block were from the same identity, whereas, in Experiment 3, the images were from different identities. (c) Examples of the 2-image condition in Experiment 2 (left) and Experiment 3 (right).
Mentions: To determine image invariance in face-selective regions, the images from Experiment 1 were incorporated into a block design fMR-adaptation paradigm. Twenty participants took part in Experiment 2 (12 females; mean age, 22). There were 5 image conditions: (1) 1-image of the same identity; (2) 2-images of the same identity; (4) 4-images of the same identity; (8) 8-images of the same identity, and (D) 8-images with different identities. Examples of the stimuli are shown in Figure 2. The faces were either familiar or unfamiliar faces of males and females. Unfamiliar faces were unknown to the participants and were chosen to match familiar faces for their variation in age and appearance. In the same-identity conditions, 8 different familiar identities (4 male, 4 female) and 8 different unfamiliar identities (4 male, 4 female) were used. The different images of the same identity varied in lighting, hairstyle. Images were presented in gray scale and were adjusted to an average brightness level. The mean change in image intensity across images was calculated by taking the average of the absolute differences in gray value at each pixel for successive pairs of images within a block. Table 1 shows that there was a similar mean intensity change in the corresponding familiar and unfamiliar conditions.

Bottom Line: Here, we used an functional magnetic resonance-adaptation paradigm to investigate image invariance in face-selective regions of the human brain.We found clear evidence for a degree of image-invariant adaptation to facial identity in face-selective regions, such as the fusiform face area.This suggests that the marked differences in the perception of familiar and unfamiliar faces may not depend on differences in the way multiple images are represented in core face-selective regions of the human brain.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, York Neuroimaging Centre, University of York, York YO10 5DD, UK.

ABSTRACT
The ability to recognize familiar faces across different viewing conditions contrasts with the inherent difficulty in the perception of unfamiliar faces across similar image manipulations. It is widely believed that this difference in perception and recognition is based on the neural representation for familiar faces being less sensitive to changes in the image than it is for unfamiliar faces. Here, we used an functional magnetic resonance-adaptation paradigm to investigate image invariance in face-selective regions of the human brain. We found clear evidence for a degree of image-invariant adaptation to facial identity in face-selective regions, such as the fusiform face area. However, contrary to the predictions of models of face processing, comparable levels of image invariance were evident for both familiar and unfamiliar faces. This suggests that the marked differences in the perception of familiar and unfamiliar faces may not depend on differences in the way multiple images are represented in core face-selective regions of the human brain.

Show MeSH
Related in: MedlinePlus