Playing Parrots Produce ‘Contagious Laughter’
The kea parrot, Nestor notabilis, produces a laughter-like “play call” when they are playing. Researchers used recorded play calls from captive kea to test how they affected wild kea and found both juveniles and adults respond to the recorded play call — by playing!
by GrrlScientist for Forbes | @GrrlScientist
Kea, Nestor notabilis, are large parrots that live in alpine and forested areas on New Zealand’s South Island. They have olive-green plumage with a red rump and a long, thin decurved charcoal grey beak. The upper surface of their wings have sapphire blue on the leading edge of their dark grey flight feathers whilst the underwings are brilliant orangeish-red splashed with narrow lemon yellow stripes across the dark grey primaries. Immature birds can be distinguished from adults by their yellow ceres at the base of their upper mandible and their yellow lower mandible.
Keas are omnivores, eating a variety of plant leaves, fruits and seeds, as well as insects, and even preying upon other birds and consuming mammal carrion. They are social, living in groups of roughly a dozen individuals. As you might expect from a long-lived social animal, Kea are highly intelligent and curious, and they have many complex behaviors. One such behavior is play, which is often accompanied by a high-pitched warbling call that sounds (to my ears) rather like laughter.
This call may indicate to nearby kea that the individual producing the call is playing instead of fighting. But kea also produce this “play call” when they are playing alone, which suggests that the call alone may affect the mood of the individual producing it, as well as the moods of any nearby kea that may hear it. Based on these observations, the researchers wondered whether this “play call” is acting as a positive emotional contagion towards other kea, quite like contagious laughter in humans.
Yes, kea “laughter” is contagious
After analysing the entire vocal repertoire of captive kea living in Austria, the team of researchers identified the kea “play call” and played a recording of it to flocks of wild kea living in New Zealand. They compared the wild parrots’ play call responses to their responses to a recording of a “standardized tone” (2 kHz) and to a recording of a local songbird, the South Island robin, Petroica australis, which were used as control sounds.
After hearing the recording of the captive kea’s play call, the wild kea that were already playing ended up playing longer and more energetically, or they started playing with other non-playing members of the flock (as you can see in the brief video below). This was seen in both adults and juveniles.
“We were able to use a playback of these calls to show that it animates kea that were not playing to do so,” lead author Raoul Schwing, who studies comparative cognition at the Messerli Research Institute in Austria, said in a press release.
“The fact that at least some of these birds started playing spontaneously when no other birds had been playing suggests that, similar to human laughter, it had an emotional effect on the birds that heard it, putting them in a playful state,” added Dr. Schwing.
Interestingly, hearing the play call did not act as an invitation to join in play that was already underway, but instead, it inspired birds to start “playing with other non-playing birds, or in the case of solitary play, with an object or by performing aerial acrobatics,” the researchers noted in their paper (ref).
“This specific call induced playfulness, supporting the hypothesis that play vocalizations can act as a positive emotional contagion,” Dr. Schwing said.
Other animals, such as chimpanzees, wolves and rats, also show signs of emotionally contagious vocalizations, but the kea is the first bird known to exhibit this sort of behavior. Further, kea are unusual because play between adults of the opposite sex occurred spontaneously under the same circumstances as play in juveniles. (However, in my experience, cognitive scientists will find many more parrot species, as well as corvids, that show signs of play and “contagious laughter” — if they only look for it.)
“[L]aughter in human beings has a very similar effect because hearing people laugh boosts our own emotion and makes things seem funnier,” affirmed Dr. Schwing.
“If animals can laugh, we are not so different from them.”
Raoul Schwing, Ximena J. Nelson, Amelia Wein, and Stuart Parsons (2017). Positive emotional contagion in a New Zealand parrot, Current Biology 27(6):R213–R214, published online on 20 March 2017 ahead of print. doi:10.1016/j.cub.2017.02.020
Clark, C.M.H. (1970). Observations on population, movements and food of the kea, Nestor notabilis, Notornis 17: 105–114. (PDF)
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Originally published at Forbes on 24 March 2017.