The belief that some people are born gifted and others are fated to be mediocre is deeply rooted in our culture. But the influence of genes on learning is not straightforward. Writing in eLife, Mets and Brainard1 describe how learning can be enhanced in songbirds by tailoring tutoring strategies to match the genetic biases of individuals. The authors’ study suggests that there are not necessarily ‘high-quality’ or ‘low-quality’ gene sets when it comes to learning — instead, certain sets of genes are better or worse fits for particular learning environments.
A polygenic score is an estimate of an individual’s propensity to display a given trait, taking into account all of his or her genes. These scores have been viewed by some as a way to assess a baby’s genetic potential to develop complex disorders such as schizophrenia2. They have also been used to assess educational success, and can currently explain about 13% of the variation in the number of years of schooling that individuals in a population will complete3. But we are a long way from a genomic analysis that could direct specific educational investments or predict which children would benefit the most. Working this out in humans is dauntingly hard, because we cannot experimentally control genes and environments simultaneously.
However, interactions between genetics and learning are not unique to humans. Young songbirds acquire their vocal repertoire by imitating songs produced by adults. For birds, as for humans, learning is a social and cultural process — as in spoken language, vocal learning across generations produces local cultures of song dialects. Accurate learning is crucial for birds because those that do not acquire the local dialect are less likely to attract mates4.
Experimental systems have been established that allow researchers to control both the genetics and the learning environment of songbirds from an early age, yielding insights into how the two interact. These systems have revealed, for example, that when birds are raised away from their parents and ‘tutored’ by song playbacks, the tempo of their songs is strongly influenced by their genetics5. By contrast, the influence of genetics on tempo is much weaker when a bird is raised by an adult tutor that actively guides the youngster6. Thus, a picture has emerged of an interplay between genetics and learning experience.
Mets and Brainard set out to pin down this relationship in more detail, using a population of Bengalese finches (Lonchura striata domestica) that had varied song-learning abilities. First, they compared how well finches tutored by their own parents learnt a song, compared with birds whose eggs had been moved into that nest before hatching. When birds were tutored by their own fathers, they generally learnt better than did fostered birds, suggesting that a match in genetic propensity for learning is key to how well birds learn songs.
The authors found that cross-fostered birds learnt well if their adoptive tutor had a song that was similar in tempo to their own. This result indicates that an interaction between genes and experience explains much of the variation in learning outcomes. It seems that certain birds are genetically tuned to learn and produce slow songs, whereas others are wired for fast songs. Giving a ‘slow’ bird a fast tutor does him or her no favours; the same is true in reverse (Fig. 1).
To rule out the possibility that the results reflected a difference in how fathers behaved towards their own offspring as opposed to their fostered tutees, Mets and Brainard reran the experiment using a computer-based tutoring system. As shown previously, when all birds were tutored with a standard synthetic song, there was a strong genetic variability in learning propensity. The authors demonstrated that those genetically predisposed to acquire a song with a tempo similar to that of the synthetic song learnt much better than ‘faster’ and ‘slower’ birds. Varying the tempo to match the tempo characteristic of the bird’s biological father improved learning.
It might be imagined that the most brilliant birds would be able to learn at any tempo, whereas others would learn well only when tutored at a slow tempo. But Mets and Brainards’ results demonstrate that this is not the case. Most remarkably, birds that were genetically tuned to sing slowly were not inherently worse learners. In fact, they often learnt better than the fast birds once the tutoring tempo ‘resonated’ with them.
The authors’ results indicate that, if we can work out how to match genetic predisposition and ‘tutoring’ style among humans, we might be able to enhance learning for children. Indeed, some observational results in humans suggest that there is an interaction between the polygenic score for education of a child and that of their mother7 — high polygenic scores for both mother and child are associated with higher educational achievement than is a high score for the child or the mother alone. Of course, in extreme cases, some children (and birds) might be inherently worse learners, no matter to whom they are matched.
It is difficult to be a child in today’s super-competitive world. Mets and Brainard’s results raise the possibility that even a modest mismatch between tutoring pace and genetics can hamper learning. Of course, we do not yet have a good way to discover how interactions between a person’s genes and their environment will affect learning8,9. But it is imperative to ensure that human genetics studies of learning are sufficiently nuanced, and acknowledge the huge effect of the environment — including the possibility that a child might be in the wrong learning environment for their genes.
Nature 575, 290-291 (2019)