Face inversion effect
[7][8] There seems to be something different about inverted faces that requires them to also involve these mid-level and high-level scene and object processing mechanisms.
[9] The most supported explanation for why faces take longer to recognise when they are inverted is the configural information hypothesis.
This causes a delay since it takes longer to form a representation of a face with only local information.
[10] Faces are processed in separate areas of the brain to other stimuli, such as scenes or non-facial objects.
For example, the fusiform face area (FFA) is a face-selective region in the brain that is only used for facial processing.
This suggests that there is something special about inverted compared to upright faces that requires them to involve object and scene processing regions.
[13] First-order relational information consists of the spatial relationships between different features of the face.
Instead, independent features are put together piece-by-piece to form a representation of the object (a face) and allow the viewer to recognise what it is.
[10] Although the configural processing hypothesis is a popular explanation for the face inversion effect, there have been some challenges to this theory.
Perceptual learning is a common alternative explanation to the configural processing hypothesis for the face inversion effect.
It follows that highly efficient mechanisms have been able to develop to the quick detection and identification of upright faces.
[20] The face-scheme incompatibility model has been proposed in order to explain some of the missing elements of the configural information hypothesis.
[21] This makes the face-scheme incompatibility model similar to the perceptual learning theory, because both consider the role of experience important in the quick recognition of faces.
[20][21] Instead of just one explanation for the face inversion effect, it is more likely that aspects of different theories apply.
[17] The ability to quickly detect and recognise faces was important in early human life, and is still useful today.
[22][23] Highly efficient facial recognition mechanisms have therefore developed to support this ability.
[26] When those with prosopagnosia view faces, the fusiform gyrus (a facial recognition area of the brain) activates differently to how it would in someone without the condition.
[12] Individuals with prosopagnosia can be unaffected or even benefit from face inversion in facial recognition tasks.
[12] Like those with prosopagnosia, individuals with autism spectrum disorder (ASD) do not use a configural processing mechanism to form a holistic representation of a face.
[32] However, there is some evidence that the development of a holistic facial recognition mechanism in those with ASD is simply delayed, rather than missing.
