Summary: A new study shows that the brain may be naturally wired to recognize faces. Researchers found that neurons in the brains of one-week-old chicks, which had never seen faces before, responded to face-like patterns of three dots resembling eyes and a mouth.
These findings suggest that the ability to recognize faces is innate, not learned, and could explain why humans see faces in objects like clouds or walls. The results challenge previous theories that face recognition develops solely through experience.
Key Facts:
- Neurons in newborn chicks’ brains respond to face-like patterns, supporting innate face recognition.
- The study suggests that vertebrate brains are predisposed to recognize face-like shapes from birth.
- This innate mechanism may also explain pareidolia, seeing faces in inanimate objects.
Source: University of Trento
Is the brain of animals and humans naturally wired to recognize faces? Is there an innate biological mechanism that explains this ability?
Questions that like these have been fuelling a debate that involves, on the opposite side, those who believe that face recognition is a skill that can be learned through experience and exposure to faces and those who believe that it is innately predisposed in the brain.
A recent study by a research team of the Center for Mind and Brain Sciences (CIMEC) of the University of Trento has given a contribution to the debate.
The team identified, in one-week-old chicks that have never been exposed to faces, a population of neurons that respond to a face-like stimulus composed of three dots that resemble two eyes and a beak (or a mouth).
The animals do not respond to isolated facial features or to dots that are arranged in a disordered manner and that do not recall facial features. The results suggest that face recognition is therefore innate.
The study has been published in PNAS.
About the study.
Numerous behavioural studies suggest that face selectivity may be an innate ability of the brain. Both human newborns and newly hatched chicks who have never seen faces before show spontaneous attraction to face-like stimuli composed of three dark features representing eyes and a mouth (or a beak).
However, the neural mechanism of this innate predisposition was unknown.
Experiments conducted by the research team of UniTrento have shown that baby chicks respond to shapes that resemble schematized faces. The response was identified in a population of neurons in a specific area of the brain. It is called the ‘caudolateral nidopallium’ and is considered an avian equivalent of the mammalian prefrontal cortex.
The study was conducted in the Animal Cognition and Neuroscience (ACN) Laboratory at Cimec, directed by Giorgio Vallortigara, who explains:
“We performed a series of control experiments using schematic faces in which the features were shuffled, displaced, or arranged in all possible combinations. And these neurons seem to respond only to faces. This suggests that this sensitivity to faces is probably innate in the brains of vertebrates.”
Another interesting aspect of the research is the function of this sensitivity, which explains, for example, why sometimes we see faces in the clouds or in spots on the walls, a phenomenon that is known as “pareidolia”.
“This psychological process,” says Vallortigara, “results from a specific brain mechanism. Our brains are naturally wired to respond to this very simple configuration of dots arranged in the right positions. These are stimuli that do not exist in nature.
“There are no schematic faces in the world, but these platonic faces are the simplest way for brains to represent something that looks like a face. So, a newborn baby or a newborn chick will be attracted by these stimuli consisting of three dark spots arranged in an inverted triangle and thus will be able to learn, over time, the specific characteristics of the mother’s face and distinguish them from those of a stranger.
“These neurons act as a kind of face detector, a mechanism that facilitates learning about a particular category of stimuli, which is important from the point of view of social life.”
New scenarios for theories on learning.
The study suggests that learning would not be possible if it were not supported by predisposed innate mechanisms. According to the authors of the study, learning from experience, through trials and errors, would take too long and with high risk of making mistakes.
Funding: The research has received European funding through Professor Vallortigara’s ERC Advanced grant Spanumbra.
About this facial recognition and neuroscience research news
Author: Alessandra Saletti
Source: University of Trento
Contact: Alessandra Saletti – University of Trento
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Innate face-selectivity in the brain of young domestic chicks” by Giorgio Vallortigara et al. PNAS
Abstract
Innate face-selectivity in the brain of young domestic chicks
Shortly after birth, both naïve animals and newborn babies exhibit a spontaneous attraction to faces and face-like stimuli.
While neurons selectively responding to faces have been found in the inferotemporal cortex of adult primates, face-selective domains in the brains of young monkeys seem to develop only later in life after exposure to faces.
This has fueled a debate on the role of experience in the development of face-detector mechanisms, since face preferences are well documented in naïve animals, such as domestic chicks reared without exposure to faces.
Here, we demonstrate that neurons in a higher-order processing brain area of one-week-old face-naïve domestic chicks selectively respond to a face-like configuration.
Our single-cell recordings show that these neurons do not respond to alternative configurations or isolated facial features. Moreover, the population activity of face-selective neurons accurately encoded the face-like stimulus as a unique category.
Thus, our findings show that face selectivity is present in the brains of very young animals without preexisting experience.
