Two studies on audio signaling thru birdsong songs and mating states:Birdsong study pecks theory that music is uniquely human
(Medical Xpress)—A bird listening to birdsong may experience some of the same emotions as a human listening to music, suggests a new study on white-throated sparrows, published in Frontiers of Evolutionary Neuroscience.
“We found that:
- the same neural reward system is activated in female birds in the breeding state that are listening to male birdsong…For male birds listening to another male’s song, it was a different story: They had an amygdala response that looks similar to that of people when they hear discordant, unpleasant music.
The study, co-authored by Emory neuroscientist Donna Maney, is the first to compare neural responses of listeners in the long-standing debate over whether birdsong is music.
“Scientists since the time of Darwin have wondered whether birdsong and music may serve similar purposes, or have the same evolutionary precursors…But most attempts to compare the two have focused on the qualities of the sound themselves, such as melody and rhythm.”
“Birdsong is a signal…And the definition of a signal is that it elicits a response in the receiver. Previous studies hadn’t approached the question from that angle, and it’s an important one.”
During the non-breeding season, both sexes of sparrows use song to establish and maintain dominance in relationshipsDuring the breeding season, however, a male singing to a female is almost certainly courting her, while a male singing to another male is challenging an interloper.
For the females in the breeding state every region of the mesolimbic reward pathway that has been reported to respond to music in humans, and that has a clear avian counterpart, responded to the male birdsongFemales in the non-breeding state, however, did not show a heightened response.
And the testosterone-treated males listening to another male sing showed an amygdala response, which may correlate to the amygdala response typical of humans listening to the kind of music used in the scary scenes of horror movies.
“The neural response to birdsong appears to depend on social context, which can be the case with humans as well…Both birdsong and music elicit responses not only in brain regions associated directly with reward, but also in interconnected regions that are thought to regulate emotion. That suggests that they both may activate evolutionarily ancient mechanisms that are necessary for reproduction and survival.”
A major limitation of the study…is that many of the regions that respond to music in humans are cortical, and they do not have clear counterparts in birds.
Is that song sexy or just so-so?
A songbird study conducted by Emory University sheds new light on this question, showing that a change in hormone levels may alter the way we perceive social cues by altering a system of brain nuclei, common to all vertebrates, called the “social behavior network.”
“Social behaviors such as courtship, parenting and aggression depend primarily on two factors: a social signal to trigger the behavior, and a hormonal milieu that facilitates or permits it….Our results demonstrate a possible neural mechanism by which hormones may alter the processing of these signals and affect social decision-making.”
Across most of the network,
song-specific neural responses were higher in the “breeding” females than the “non-breeding” ones. But the effects of estrogen were not identical in every regionIf every node in the network just responded more in the presence of estrogen, then we’d conclude that estrogen acts as an on-off switchBut what we’re seeing is more complicated than that. Some activity goes up with estrogen, and some goes down. We are seeing how estrogen changes the big picture as the brain processes social information.”
The findings suggest that the perceived meaning of a stimulus may be related to the activity in the entire social behavior network, rather than a single region of the brain. “The same neural mechanism may be operating in humans,”
“In women, preferences for male faces, voices, body odors and behavior change over the course of the menstrual cycle as estrogen levels rise and fall. Our work with these songbirds shows a possible neural basis for those changes.”