Songbirds have a human-like capacity to learn complex vocal patterns, a new study by researchers at the University of Chicago has shown.
"This will help us understand the black box of language better," said biologist Daniel Margoliash.
Psychologist Howard Nusbaum said: "If we're going to make progress understanding how language develops, we need to look at all the evidence, and that includes what we can learn from biology."
Researchers have long studied vocal communication in animals, including birds, whales, porpoises, and non-human primates.
Those patterns provide a way of understanding how human language develops if subjected to the right research program, the researchers said.
"Animals have more intelligence than most people give them credit for. Crows are capable of developing tools, for instance. Jays have a sense of mental time travel. The problem is that we haven't had a way to measure that intelligence," Margoliash said.
The evidence that connects human and animal communication has provided conflicting conclusions. Scientists have not agreed on how communication abilities moved through evolution on their way to the human.
Some studies with non-human primates, the close relatives of humans, suggest that there may be no connections at all.
A new study by Margoliash and Nusbaum shows that starlings are capable of abstract learning of vocal structures.
Margoliash said that a biological feature in starlings, a large well-defined forebrain substantially devoted to vocal learning, could account for their ability to learn complex vocal tasks.
On the other hand, the monkeys that failed to learn the task are not vocal learners.
However, that experiment was in fact helpful, because it suggested such studies could be done, and it led Nusbaum and Margoliash to their work with starlings.
The study appears in the current issue of the journal Trends in Cognitive Sciences.