Researchers also found that the genetic effects that allow people to recognize faces are linked to a highly specific mechanism in the brain, unrelated to other brain processes such as the ability to recognize words or abstract art.
The study consisted of 164 identical twins, who share all of their genes, and 125 non-identical same-sex twins, who share 50% of their genes. All the participants took the Cambridge Face Memory Test, which measures ability to learn six faces and then recognize them in novel poses and lighting.
Scientists examined the similarity between scores for both types of twin pairs. The correlation for identical twin pairs was 0.70, whereas the correlation for non-identical twins was less than half that, at 0.29. This difference suggests that the similarity in identical twin pairs is due to their shared genes, rather than shared family environment.
"We are excited about this finding because the brain mechanisms carrying out face recognition are fairly well understood, meaning that the high heritability of face recognition could provide a good opportunity to connect genes to brain mechanisms and then to behavior," said Dr Brad Duchaine from UCL's Institute of Cognitive Neuroscience.
The study also investigated whether these brain processes were specific to recognizing faces, or more general recognition processes. Twins and a large cohort of non-twins did the Cambridge Face Memory Test and two other tests; one which required recognizing previously learned words and the other required recognizing previously learned abstract art. The results showed that these abilities were only weakly related to face recognition ability.
Citation: Wilmer et al., 'Human face recognition ability is specific and highly heritable', PNAS, February 2010; doi: 10.1073/pnas.0913053107