In the intricate world of animal behavior, the transmission of knowledge from one generation to the next has long been thought to be the primary domain of parents. New research, however, challenges this traditional view, revealing that in some species, the influence of siblings and other unrelated adults can be far more powerful. A groundbreaking study focusing on a common songbird, the great tit, has demonstrated that while parents might introduce a new skill, it is the siblings who predominantly shape and propagate the specific techniques used, fundamentally altering our understanding of social learning in the wild.
Researchers from the University of California, Davis, and the Max Planck Institute of Animal Behavior have shown for the first time in a wild population that juvenile birds with limited parental care rely heavily on their brothers and sisters to acquire vital life skills. The study, published in the journal PLOS Biology, found that while young great tits were more likely to learn a foraging task if their parents knew how, they overwhelmingly adopted the specific method used by their siblings. This dynamic provides a crucial alternative pathway for cultural inheritance, explaining how behaviors can become consistent within families even when direct parental tutelage is brief.
A Novel Experimental Design
To investigate how skills spread through a population, the scientific team developed an innovative experiment centered on custom-designed automated feeding puzzles. They deployed these puzzles across a woodland population of great tits in the United Kingdom, observing 51 breeding pairs and their 229 fledgling offspring over a ten-week period. Each bird was fitted with a tiny microchip, a passive integrated transponder, which allowed the automated system to identify individuals and record every interaction with the puzzle boxes with unprecedented detail, generating tens of thousands of data points.
The Two-Solution Puzzle
The core of the experiment was a puzzle that offered a food reward—a tray of mealworms—to any bird that could solve it. The puzzle was designed with a sliding door that could be pushed either to the left or to the right to reveal the food. This “two-solution” design is a classic method for studying cultural transmission, as it allows researchers to track the spread of a specific, arbitrary behavioral variant. The team trained some parent birds to use only the “slide-left” method and others to use only the “slide-right” method. A control group of parents received no training, allowing the scientists to observe if and how the skill would emerge and propagate without a knowledgeable parent.
The Social Learning Network
By tracking which birds solved the puzzle and which solution method they employed, the researchers mapped the flow of information across the social network. The data revealed a complex interplay of influences, where parents, siblings, and other adults all played a role, but with surprisingly different levels of impact. While the presence of a skilled parent in the family made it more likely that an offspring would eventually solve the puzzle, the parent’s specific technique was not the one most commonly adopted.
Peers and Siblings as Primary Tutors
The study’s most striking finding was the immense influence of non-parental figures, especially siblings. Among the first birds in a family to crack the puzzle, a remarkable 75% learned the skill from an adult that was not their mother or father. This indicates that the young birds were actively observing and learning from the wider community of unrelated, experienced adults. Even more significantly, once one sibling had mastered the puzzle, its technique became the dominant one within the brood. Subsequent learners within the same family group copied their siblings in 94% of cases. This powerful horizontal transmission from sibling to sibling quickly overshadowed the initial vertical transmission from parent to child.
Challenging Parental Influence
The results paint a new picture of cultural inheritance in species with brief periods of parental care. In humans and other animals with extended childhoods, parents have a long and continuous opportunity to impart knowledge. Great tits, however, have a much more compressed schedule. According to lead author Sonja Wild, a postdoctoral researcher with UC Davis and the Max Planck Institute during the study, these birds fledge from the nest knowing almost nothing about survival. They have a very short window of about ten days where they follow their parents, begging for food and learning the basics of how to find it themselves.
During this critical period, the parents are often exhausted from the demands of raising a brood and begin to withdraw their support. This parental pullback creates a strong selective pressure for the fledglings to become self-sufficient as quickly as possible. The study suggests that this pressure drives them to learn from any available source. While a parent might provide the initial spark of knowledge—that the puzzle box contains food—the fledglings spend far more time in close proximity to their siblings, practicing and refining their foraging techniques together. This constant peer interaction makes sibling-to-sibling learning far more efficient and impactful than the limited instruction received from parents.
Implications for Cultural Transmission
This research provides a compelling alternative model for how traditions and behaviors can be passed down through generations. It shows that strong family resemblance in behavior does not automatically mean that parents are the primary teachers. In many species, shared genetics and a shared environment could lead to similarities, but this study elegantly demonstrates that social learning is a key driver. By showing that offspring selectively copy the arbitrary puzzle solutions of their siblings over those of their parents, the researchers confirmed that this was a case of cultural transmission, not just genetic predisposition or independent trial-and-error learning.
The findings help explain the evolution of social learning and how it can adapt to different life histories and parenting styles. In species where parental investment is short-lived, a robust mechanism for peer-to-peer learning may be essential for survival. This reliance on a broader social network for skill acquisition ensures that vital information is not lost if a parent is absent or an ineffective teacher. It diversifies the sources of knowledge and accelerates its spread through the youngest generation, allowing the population as a whole to adapt more quickly to new challenges and opportunities in their environment.