Parents grumpy that their 30-year-old children haven't left home may take comfort in the possibility extended time in the nest is making their offspring very, very smart. If birds are a guide, extended parenting helps teach problem-solving skills and adaptive learning.
It makes intuitive sense that humans' extended childhoods are related to our intelligence. Many of the animals with the longest parental care, such as elephants and dolphins, are also among those we consider the smartest, although octopuses put eight holes in the pattern.
Corvid family members Siberian jays and New Caledonian crows stay with their parents long after most other birds would be fending for themselves. The crows have the largest brain size for their bodies among the famously smart corvids and demonstrate a capacity for advanced problem solving that would baffle many humans.
Animal intelligence experts increasingly visit New Caledonia to investigate reports of the local crows' remarkable tool use. In Philosophical Transactions of the Royal Society B, the University of Konstanz's Dr Michael Griesser reports this capacity is not innate. Instead, the young crows require about a year of patient tutelage from their parents to learn the art. During this time the parental crows continue to feed their young, long after other birds would have moved on to a new clutch. The learning process includes letting the young steal precious tools from their parents and unrelated adults to play with.
Griesser and co-authors compared their own observations with those others have made of thousands of bird species, reinforcing their view of the importance of this period.
"Extended parenting has profound consequences for learning and intelligence," Griesser said in a statement. "Learning opportunities arise from the interplay between extended childhood and extended parenting. The safe haven provided by extended parenting is critical for learning opportunities.”
Corvids and humans have the ability for lifelong learning – a flexible kind of intelligence that allows individuals to adapt to changing environments throughout their lifetime,” Dr Natalie Uomini of the Max Planck Institute said, something she attributes to the opportunity to learn while being protected and taught by adults.
New Caledonia crows may be exceptional, but the authors found parallels with Siberian Jays, which live in groups that include a breeding pair, their young and other, sometimes unrelated, juvenile birds. The breeding pair feed and protect their young against predators, but do not do the same for the unrelated birds.
Although these unrelated group members miss out on the most obvious benefits, they get to learn from the older birds, including lessons on how to scare off predators and access food. However, Griesser and Uomini found juveniles that get to stay around their parents learn more and have longer lifespans than those forced to join a family led by an unrelated pair that pays less attention to the new arrivals' education. When the authors challenged birds with a feeding device they would never have encountered, those that had the benefit of extended parenting solved the problem more quickly.