y’know that thing where people give theirunborn baby some music to listen to, hoping to make them smarter or something? turns out, birds do a similar thing, but withactual science to back them up. they sing to their babies while they’restill inside their eggs — what’s known as incubation calling. and there’s a lot we still don’t knowabout how these calls work, because they seem to do different things for different species. but we are learning! and a study published this week in sciencesuggests that some incubation calls can even
affect how australian zebra finch embryosgrow up. mother birds seem to pass on chemical signalsto their developing offspring before laying eggs. but incubation calls could be a way to tweakthe babies’ development inside the eggs, before they hatch. australian zebra finches, for example, makea special incubation call when their eggs are just about to hatch — starting about5 days before — but only when it’s 26 degrees celsius or warmer. these birds nest year-round, so the scientiststhink it’s a way for parents to give their kids a heads-up that it’s hot outside.
here’s the weird thing, though: the parents’incubation calls made the babies develop differently. as an experiment, the researchers artificiallyincubated a bunch of eggs that they got from nests in the wild, and during that final 5day window, they played some sounds. some of the eggs listened to incubation calls,while others, as a control, just heard normal mom-and-dad conversation chirps. and the embryos who heard the incubation callsgrew up to be smaller. now, you’d think that smaller birds wouldhave a harder time surviving, but the scientists think it might be an adaptation for warmerweather. smaller animals have more skin relative totheir mass, so they can lose more body heat
than larger animals. that way, they stay cooler in hot weather. also, growing really fast in warmer temperatureshas been linked to oxidative stress — which is the buildup of unstable oxygen free radicalsthat can cause damage. so if the finches stay small, it could savethem from biological problems, which would explain why the birds developed this alternativegrowth plan — and why it can be triggered by an incubation call. but as far as the mechanism itself, like howexactly a song could affect how an embryo develops, that we do not know.
enough about bird behaviors, though, becausea new study published in pnas talks about people behaviors! specifically, about the parts of our brainthat activate when we help other people, which psychologists call prosocial behaviors. the researchers had volunteers play a learninggame, while getting their brain scanned by an fmri machine. they wanted to study why different peoplemight be better or worse at learning to help others, and how it might be connected to empathy,or your ability to understand someone else’s feelings. their game was based on a psychological conceptcalled reinforcement learning, which is basically
when something — like a human or a robot— looks at a situation and tries to pick the option that gives it the most reward. as you get predictions right or wrong, youlearn how to choose the option that leads to the rewards. in this study, the team tested how 31 peoplelearned to get points for themselves, someone else — who was an actor pretending to beanother participant in the study — and for nobody, as a control. here’s how the game worked: people had to choose between two symbols,both letters from an abstract symbols font.
one symbol had a 75% chance of getting points,and one had a 25% chance of getting points. the subjects had to learn which shape waswhich through trial and error. over multiple rounds, they gained points,and were told that more points would earn them more money — though they were all paidthe same amount in the end. the researchers used fmri to record brainactivity while the subjects were making decisions, and used computer models to find patternsacross all the experimental trials. unsurprisingly, people learned fastest whenthey were competing for themselves. but they had participants take an empathytest, and people who were more empathetic tended to learn almost as quickly when theywere playing for someone else — the prosocial behavior.
so what was going on inside their brains? well, in all the learning tests, there wasactivity in the ventral striatum , which is part of the reward pathways in your brain. a connected region called the subgenual anteriorcingulate cortex, was specifically activated when people were playing for someone else. other studies have linked this region to prosocialand moral behaviors, social emotions, and trust. so this research seems to reinforce some ofwhat scientists do know. but the scientists want to learn more abouthow we learn empathy and prosocial behaviors, and how the two are connected.
that way, we can better understand the brainsof people who struggle with these traits — and get a deeper grasp of how our brains workin general. thanks for watching this episode of scishownews, brought to you by our president of space morgan and big try hard. morgan completed the bicycle trip across theu.s. raising money for youtube channels he loves. thank you, morgan! you can catch up his journey at bigtryhard.com. if you want to help support this show, justgo to patreon.com/scishow. and don’t forget to go to youtube.com/scishowand subscribe!
