Chimpanzees have a sense of fairness that was previously seen as uniquely human, finds a study by Emory's Yerkes National Primate Research Center and Georgia State University. The researchers played the Ultimatum Game with the chimpanzees to determine how sensitive the animals are to the reward distribution between two individuals if both need to agree on the outcome.
The findings, published by the Proceedings of the National Academy of Sciences (PNAS), suggest a long evolutionary history of the human aversion to inequity, as well as a shared preference for fair outcomes by the common ancestor of humans and apes.
“We used the Ultimatum Game because it is the gold standard to determine the human sense of fairness," says lead author Darby Proctor, a post-doctoral fellow at Yerkes. "In the game, one individual needs to propose a reward division to another individual and then have that individual accept the proposition before both can obtain the rewards. Humans typically offer generous portions, such as 50 percent of the reward, to their partners, and that’s exactly what we recorded in our study with chimpanzees.”
"Until our study," adds co-author Frans de Waal, "the behavioral economics community assumed the Ultimatum Game could not be played with animals, or that animals would choose only the most selfish option while playing. We've concluded that chimpanzees not only get very close to the human sense of fairness, but the animals may actually have exactly the same preferences as our own species."
For purposes of direct comparison, the study was also conducted separately with human children.
We love “The Two-Way” post on NPR.org today, pondering the age-old question of why people find pandas so cute. “The Two-Way” reviews previous articles on the question, including a 2005 one by the Washington Post, and the findings of Emory psychologist Stephan Hamann that “cute” pictures cause increased activity in the brain’s middle orbital cortex:
“Some evidence,” the Post noted, “suggests the brain activity there is greater when the stimulus is ‘neotenous,’ which is to say it has juvenile characteristics – a button nose, big eyes, a large wobbly head, chubby extremities or pudgy cheeks.”
In other words, we’re programmed to be suckers for babies.
Written for a general audience, the book describes how life traces – tracks, burrows and other impressions – relate to the natural history and behaviors of plants and animals of the beaches and maritime forests of Georgia’s barrier islands.
Ghost crabs and birds, feral hogs and alligators all leave signs of their activities in the environment. Many of these signs go unnoticed by most of us, simply because we don’t know how to read them.
“In many instances, you won’t see the animals that made these traces,” Martin says. “That’s one of the fantastic aspects of this book: You can use it as a manual for interpreting the natural world around you.”
Martin will give a public talk about the book on the evening of Saturday, January 26, for Atlanta Science Tavern. Click here for details.
"Art offers scientists a chance to see the systems they work on in a new light,” says Emory biologist Nicole Gerardo. Her lab studies evolution by observing interactions between microbes and other organisms such as aphids and fungus-growing ants.
Gerardo teamed up with Diane Kempler, a lecturer in visual arts, to teach a ceramics course called “Clay and Science: A Symbiotic Relationship.”
The students created pieces that explored everything from the interactions of lichen, bark and trees to the relationship between reading and the brain. You can see these works and others in the video above.
Sometimes he sounds like music to her ears. Other times, not so much.
By Carol Clark
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, and in people listening to music that they like,” says Sarah Earp, who led the research as an undergraduate at Emory University.
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,” Earp notes. “But most attempts to compare the two have focused on the qualities of the sound themselves, such as melody and rhythm.”
Earp’s curiosity was sparked while an honors student at Emory, majoring in both neuroscience and music. She took “The Musical Brain” course developed by Paul Lennard, director of Emory’s Neuroscience and Behavioral Biology program.
“During one class, the guest speaker was a composer and he said that he thought that birdsong is like music, but Dr. Lennard thought it was not,” Earp recalls. “It turned into this huge debate, and each of them seemed to define music differently. I thought it was interesting that you could take one question and have two conflicting answers that are both right, in a way, depending on your perspective and how you approach the question.”
Perhaps your brain would enjoy some music while reading this. Here's a sample of Earp's favorite: "Firebird."
As a senior last year, Earp received a grant from the Scholars Program for Interdisciplinary Neuroscience Research (SPINR), and a position in the lab of Maney, who uses songbirds as a model to study the neural basis of complex learned behavior.
When Earp proposed using the lab’s data to investigate the birdsong-music debate, Maney thought it was a great idea. “Birdsong is a signal,” Maney says. “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.”
Earp reviewed studies that mapped human neural responses to music through brain imaging.
She also analyzed data from the Maney lab on white-throated sparrows. The lab maps brain responses in the birds by measuring Egr-1, part of a major biochemical pathway activated in cells that are responding to a stimulus.
The study used Egr-1 as a marker to map and quantify neural responses in the mesolimbic reward system in male and female white-throated sparrows listening to a male bird’s song. Some of the listening birds had been treated with hormones, to push them into the breeding state, while the control group had low levels of estradiol and testosterone.
During the non-breeding season, both sexes of sparrows use song to establish and maintain dominance in relationships. During 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.
Justin Bieber, watch your back: A male white-throated sparrow belts out a tune.
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 birdsong. Females 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,” Earp says. “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, Earp adds, is that many of the regions that respond to music in humans are cortical, and they do not have clear counterparts in birds.
“Perhaps techniques will someday be developed to image neural responses in baleen whales, whose songs are both musical and learned, and whose brain anatomy is more easily compared with humans,” she says.
Earp, who played the viola in the Emory orchestra and graduated last May, is now a medical student at the Cleveland Clinic.
So what music makes her brain light up? “Stravinsky’s ‘Firebird’ suite,” Earp says.
