A study by UC Berkeley researchers discovered that zebra finches can quickly memorize the individual sounds of up to 50 other birds of their kind.
The experiment began in December 2018 and found that zebra finches have the ability to identify each other from a crowd based on a peer’s distinct sound or call. The study used a “memory ladder” designed by campus postdoctoral fellow William Wood to train the finches and test their memory, according to campus professor and study co-author Frederic Theunissen.
“The amazing auditory memory of zebra finches shows that birds’ brains are highly adapted for sophisticated social communication,” Theunissen said in an email.
UC Berkeley postdoctoral fellow Julie Elie’s work studying call perceptions among birds, which was published two years ago, influenced this study. Her work was one of the first studies in identifying distinct zebra finch calls and how the birds use this information to recognize others, Theunissen added.
The zebra finches can understand each other by making auditory memories, which are stable for up to one month, to detect an individual voice, according to Theunissen.
“These are what we call high-level auditory memories, I like to use the terms: memories for auditory objects, in the sense that animals are not remembering particular sounds but a set of particular features in these sounds that carry a particular meaning,” Theunissen said in the email. “Here the features are aspects of the sounds that are unique for each individual and the meaning is the identity of the vocalizer.”
According to Theunissen, zebra finches have “mastered” the ability to recognize a source and meaning of a peer’s call, both of which require complex mapping skills. This sound-to-meaning mapping process is quick and takes a few exposures for the birds to pick up.
Furthermore, this ability for finches to learn sounds is similar to the cognitive ability of young children while learning words, according to Theunissen. It’s similar to how humans can tell which person is talking by the sound of the person’s voice, a Berkeley news article adds.
“The memory capacity was high,” Theunissen said in the email. “Humans of course can remember many words but I am not sure that we (humans) have been tested with a voice recognition involving this many novel speakers (learned this quickly).”
Moving forward, the researchers are interested in continuing their current approaches to further explore the evolution of language, and the birds’ vocal communication abilities, according to Theunissen.