Schlagwort: Perception of Faces

How do We Perceive Faces?
Is Face Detection Innate?

Functional Specialisation

The recognition of faces is “crucial to social interactions” (Duchaine and Yovel 2008), and several scientific studies indicate that a “number of separate processes,” some of which are “specialized for faces,” are involved in this recognition. Cognitive experiments have shown that “faces are represented in a more holistic manner than other objects.” This is supported by neuropsychological studies that have identified a “number of regions in the central visual pathway” which are preferentially activated when we see a shape resembling a face. Different strategies that process various types of information are applied within these areas. The shape of individual facial features, the spacing between inner facial features, and the global structure of the face are all processed separately (i.e., holistic information; Maurer et al., 2002; Piepers and Robbins, 2012). Some of these areas even consist “entirely of face-selective neurons,” and damage or failure within them can lead to face recognition deficits such as “prosopagnosia.”

Neural Specialisation

The exact localization of brain areas involved in face recognition has been a subject of debate within the scientific community. While the fusiform face area (FFA) has historically been considered “the most selective face area” (Rossion 2015), lesion studies suggest that the “lateral part of the right inferior occipital cortex,” also known as the occipital face area, may actually be more critical. This region is noted for having the “largest overlap of lesions causing prosopagnosia” (Bouvier & Engel 2006) and is also where electrical stimulation can induce transient prosopagnosia (Jonas et al. 2012). However, it is important to note that these “labeled clusters” may be arranged differently across individual brains.

In 1986, Bruce and Young developed an information processing model of face recognition that distinguishes “several different components in the complex skill of facial processing” (McCarthy and Warrington 1990). This model includes a “range of dissociations in face processing skills” that operate in parallel after the initial common step of visual analysis. The model differentiates “directed visual processing,” or “face detection,” which involves the ability to perceive that a certain visual stimulus is a face, from components such as “facial speech analysis,” which includes expression analysis and lip reading, and “face recognition,” the “capacity to recognize whether a face is familiar” (Simoni and Di Giorgio 2019).

In this post, I intend to focus on face detection; the other parallel processes will be explored in more detail in subsequent articles. Therefore, I will briefly examine its mechanisms and investigate whether it is innate by considering the distinction between “inborn predispositions and developmental changes” (Simoni and Di Giorgio 2015) throughout the developmental process. Several studies conducted in a research lab in Padova have detected a preference for “up-down asymmetry” in newborns. This preference was observed not only with “face-like stimuli” but also with “real faces in which the geometry of the face was disrupted.” Additionally, it was found that newborns tend to look longer at congruent patterns. Congruency, defined as “the presence of a corresponding relationship between the shape and orientation of the contour and the spatial disposition of the inner features,” is particularly prevalent in facial shapes.

To conclude, the preference for faces at birth might be explained by a “collection of preferred structural and configural properties.” However, the question of how and when faces become special stimuli and begin to be processed differently from other objects remains unresolved. The “presence of some domain-relevant biases at birth” appears to be sufficient to guide the “gradual and progressive structural and functional specialization” that develops later in childhood, influenced by the experiences an infant has in its species-specific environment.

Sources:

Duchaine, B., and G. Yovel. „Face Perception and Processing in Early Infancy: Inborn Predispositions and Developmental Changes.“ In The Senses: A Comprehensive Reference, Vol. 2. Academic Press, 2008. https://www.sciencedirect.com/science/article/abs/pii/B9780123708809003340.

Roisson, B. „Brain Mapping.“ In Reference Module in Neuroscience and Biobehavioral Psychology: An Encyclopedic Reference, Vol. 2. Academic Press, 2015. https://www.sciencedirect.com/science/article/abs/pii/B9780123970251000373.

McCarthy, Rosaleen A., and Elizabeth K. Warrington. Cognitive Neuropsychology: A Clinical Introduction. Academic Press, 1990. https://www.sciencedirect.com/science/article/abs/pii/B9780124818453500060.

Simon, Francesca, and Elisa di Giorgio. „Face Perception and Processing in Early Infancy: Inborn Predispositions and Developmental Changes.“ Frontiers in Psychology, Section Perception Science, Vol. 6 (2015). https://www.frontiersin.org/articles/10.3389/fpsyg.2015.00969/full.

Images:

Shamash, Philip. “Image for ‘Instinct and Learning: Two Sides of the Same Coin.’” Sainsbury Wellcome Centre Blog. September 10, 2020. https://www.sainsburywellcome.org/web/blog/instinct-and-learning-two-sides-same-coin.

„Fusiform Face Area and Face Recognition.“ Wikipedia. Accessed August 23, 2024. https://en.wikipedia.org/wiki/Prosopagnosia#/media/File:Fusiform_face_area_face_recognition.jpg.

„Diagram Illustrating a Functional Model for Face Processing.“ ResearchGate. Accessed August 23, 2024. https://www.researchgate.net/figure/A-two-dimensional-box-and-arrow-diagram-for-illustrating-a-functional-model-for-face_fig2_221917426.