Birds are perhaps the most admired of creatures in the animal kingdom. Their beautiful plumage dazzles the eye, and their ability to fly evokes a sense of awe. They have been the subject of innumerable poems and have appeared in the art of virtually every culture since the earliest cave paintings of ancient humans.
Yet, their cognitive ability is not usually the trait we most admire. We use the term “birdbrain” pejoratively to describe a stupid or shallow person. Even scientists have labeled birds’ brains as “primitive,” a categorization they are now reconsidering. Birds in fact are much smarter than was once assumed. Many species are even able to use tools and perform sophisticated problem-solving tasks. Studies of the neurology of birds at the Imperial College of London have revealed that their brains are wired in ways very similar to those of human beings — in ways that suggest very high levels of cognition.
One of the most striking similarities between humans and birds is their ability to make song. There are a few other animals that can create complex musical phrases — dolphins and whales are other examples — but the ability is rare. Our human proclivity to “sing like a bird” is especially odd since none of our living primate relatives possess the ability.
In evolutionary terms, the ancestors of modern birds and humans diverged more than 310 million years ago. Yet, there appears to be a genetic link that explains the similarity. Andreas Pfenning and his team at the Massachusetts Institute of Technology compared the genes of three vocalizing birds — parakeets, humming birds, and zebra finches — to those of humans and other primates. Specifically, they looked at brain-cell transcriptomes, which indicate how genes are expressed within cells. They found that there were 55 genes that showed similar patterns of activity in birds and humans, but these genes were either not active or not present in nonhuman primates. It seems likely that these genes remained, in effect, dormant in our ancestors until evolutionary pressures demanded their re-emergence millions of years later.
Although songs vary by region, every species of bird sings in its own signature style with a unique tempo and pitch. Marsh wrens always sing in a fast-paced, almost harried tempo, and white-throated sparrows sing a laid-back, slow song. Birds sing in a pitch range similar to that of human singers, each bird species taking some part of our typical four-part harmony. Cedar waxwings, for example, sing in the range of the high soprano, while ravens sing in low bass. The complexities of their songs vary widely, from the canyon wren’s run up and down the diatonic scale, to the English sparrow’s single-note chirp.
Remarkably, birds and humans also seem to have similar tastes in music, deferring to the same harmonic choices. For example, the hermit thrush, a songbird native to North America, sings almost exclusively in “harmonic series,” a pattern of notes that is especially pleasing to the human ear and is often used in popular music songwriting. The bird does, however, have the ability to sing in other patterns. It simply chooses this pattern over other possibilities most of the time, just like Burt Bacharach. Other vocalizing birds also prefer consonant notes, which sound melodic and pleasing to the ear, over less pleasant dissonant notes — even chickens cluck in consonant notes. This has all been confirmed scientifically, but a few minutes outdoors will confirm the same — bird songs sound lovely to the human ear.
Scientists think that the ability to sing and the ability to speak are directly related, both in birds and in humans. Although human language is more complex, ornithologists have discovered that birds employ syntax and grammar in ways that parallel human speech. Kentaro Abe of Kyoto University found that Bengal finches respond predictably when recorded tweets and chirps are played back in a specific order, but not when the sounds were jumbled randomly. He also demonstrated that birds from different geographical areas have unique languages and dialects. Birds of the same species from other regions do, however, learn over time to “speak” in similar ways when they are placed among “foreign” birds, such as in a zoo. Recently, a British scientist developed a computer program to help ornithologists decode bird languages.
Musical ability and verbal ability seem to be related in humans, too. Reyna Gordon of Vanderbilt University demonstrated that natural musical ability in small children is linked to the ability to absorb English grammar. Her study focused on 25 six-year-olds, none of whom had received formal education in grammar. She administered a series of aptitude tests both in music, which focused primarily on the ability to replicate rhythm and pitch, and in language, which focused on the ability to recognize correct grammar in simple sentences.
The scores on the tests were predictable: Kids who scored well on music tests also scored well on grammar tests, and vice versa. Educators believe that simple musical tests, such as having a toddler clap along to a rhythm or sing a simple song in the correct pitch, could be used to help identify young students with language difficulties for early intervention, even before preschool. The study also suggests that students are likely to benefit from early musical education, which has been further confirmed by numerous studies revealing the academic benefits of musical training.
In a study published in the Journal of Music Therapy, educators at Florida State University gave children a boost in their later writing abilities with a program called “Early Intervention and Exceptional Student Education.” Developmentally normal prekindergarten students were given music lessons, twice a week, for seven and a half weeks, for a total of 15 sessions. Compared with control groups, these children showed superior print recognition skills and more advanced writing skills when they finished kindergarten.
When something is wrong with language processing in the brain, birds may help us to understand the problem. Although bird brains are much smaller than our own, they nonetheless are very similar. Areas critical for high-level cognition, including language processing and problem solving, are wired in remarkably similar ways. Birds’ brains provide a better blueprint of human brain wiring than do those of more closely related primate species, and the development of musical ability may be the common element that explains why that has happened, despite millions of years of evolutionary separation. As neuro-ornithologists study bird brains more, they will likely find out a lot more about us, too.
The effect of environmental pollution on the human brain finds its correlate in birds’ brains, as well. Birds who live in areas contaminated with mercury sing simpler songs compared to members of their species living in less polluted areas, suggesting reduced cognitive ability. Similarly, infants whose mothers were exposed to high levels of mercury show significantly impaired cognitive development, especially in the area of language acquisition. Alzheimer’s disease victims have very high levels of mercury in their brains, as well.
Scientists are only beginning to realize what we can learn about ourselves from this class of animals that otherwise seems so different. There are many questions yet to be answered: How is it that an evolutionarily divergent species’ brain developed in such similar ways? Will it someday be possible to converse with birds, at least on some rudimentary level? Can studies of birds’ brains help us solve neurologically based speech impediments? We’re only beginning to investigate these questions. In the meantime, we can still find inspiration from these charming kindred spirits who sit in the trees.
This article was originally published in the Summer 2015 issue of Brain World Magazine.