In a study published in the journal Brain Structure and Function, scientists have employed functional magnetic resonance imaging to analyze brain regions involved in attributing social status to faces adorned with decorations and paints.
The study sheds light on the brain mechanisms underlining the interpretation of social markers on the human face, providing new insights into the cultural evolution of humanity.
For at least 150,000 years, humans have culturally modified their bodies by wearing ornamentation and using pigments. These practices have become powerful means of communication, expressing identity, group affiliation, and social status. To pinpoint the brain processes associated with attributing social status from facial adornments, scientists explored the mechanisms at work in the human brain, using fMRI.
Several regions are involved in decoding the social meaning of facial ornaments
The findings of the study, published in the journal Brain Structure and Function, reveal that multiple brain regions are involved in the encoding, evaluation, and categorization of social status from facial ornamentation. The fusiform gyrus, known for its role in face perception, plays a crucial role in this activity, enabling individuals to recognize and process faces as carriers of social information.
The orbitofrontal cortex, associated with social evaluation and decision-making, is also activated when attributing social status. The salience network, responsible for detecting and integrating relevant information, showed significant activity during this task as well.
Another notable finding is the activation of the hippocampus and parahippocampal areas, regions linked to memory and associative abilities. These areas likely facilitate the recall of past experiences and the retrieval of relevant information needed to make social judgments based on face ornamentation.
Left: Based on facial ornamentation, participants had to choose among three options the individual best matching the proposed status.
Right: Lateral and inferior views of brain activations prompted by the attribution of social status. (HG: left hemisphere, HD: right hemisphere, Inf: inferior view).
© Emmanuel Mellet
The inferior frontal gyrus, a region involved in language processing, also exhibited activity when interpreting facial ornaments as carriers of information about social status of individuals. This indicates a closeness between the processes related to language comprehension and those applied to the symbolic interpretation of facial ornamentation.
Complex interactions exist between these regions
By performing an analysis of resting-state functional connectivity, researchers have highlighted complex interactions and coordination among the fusiform gyrus, orbitofrontal cortex, salience network, hippocampus, parahippocampal area, and inferior frontal gyrus. These brain networks collectively contribute to the interpretation and attribution of social status based on facial ornamentation.
The findings of this study represent a substantial advancement in understanding the brain foundations for attributing social status and interpreting symbolic social markers on the human face. Researchers suggest that these connections were likely already in place among Homo populations using red ochre 300,000 years ago and could have reached a degree of integration close to ours around 140,000 years ago in Homo sapiens, who combined the use of ochre for body paintings with the use of shell adornments.
Reference:
Salagnon M, d'Errico F, Rigaud S, Mellet E. Assigning a social status from face adornments: an fMRI study. Brain Struct Funct. Published online March 28, 2024. doi:10.1007/s00429-024-02786-4.