Hi there,

I've always known that "art is good for you," in the big arm-waving sense that it just seems like it must be true, but that's not really proof, is it? This week, though, I've found a nice concrete manifestation of that truth. It's a paper showing that people who read fiction can be changed to become kinder, more forgiving versions of themselves. What I've always hoped to be true turns out to actually be true! That's my #1 story this week.

Before I tell you about that, though, I've got some news about dogs, some news about effective leadership, and some news about teens and marijuana (spoiler alert: teens shouldn't consume it).

We start this week, though, with a paper about the biomechanics of envenomation. It turns out that little stinger the bee left behind in your arm after it flew away is a wonder of fluid dynamics.

It turns out bees' stingers have a super-strange mechanism for pumping venom into their victims. It involves a weird double-plunger system that I've never seen before.

Most venomous animals (e.g. spiders, scorpions, snakes) squeeze a muscle around a venom reservoir, forcing venom out in one squirt. The honey bee stinger works as a self-contained, tiny pump with two pistons running in opposite directions inside a single chamber. Each piston is a soft, flexible valve that inflates like a parachute on the downstroke to push venom out, then collapses on the upstroke so it doesn't suck the venom back. Meanwhile, venom continually enters the chamber. This design lets the stinger refill and pump at the same time, which means venom flows continuously.

People have been describing bee stinger anatomy for more than a century, but nobody had actually watched the pump work. The authors say this is unique – that no other (known) biological systems use this mechanism to pump continuously, and they also say no human-made pumps work this way. Maybe that will change now that we've seen how brilliant these little bees' behinds are!

It’s a sad reality: big dogs don’t live as long as smaller dogs do.

But why?

It’s not only a mystery why that should be, it’s also counterintuitive. After all, across mammals, the bigger ones (e.g. elephants, whales) tend to live much longer than the smaller ones (e.g. mice).

A new study, based on genetic data from 864 dogs, offers an answer. “Jumping genes” – bits of DNA that have copied and pasted themselves all over the place in the genome – are more prevalent in big dogs than small ones. It seems that as breeders have selected for large body size, that’s been one of the genetic traits that’s been incidentally chosen. But  those duplicated genes start to wreak havoc on the body as the animal gets older.

Elephants, whales, and other large mammals didn’t get bigger via jumping genes. Their evolution was much longer and slower, and the mechanisms by which they got big are different.

This is a very early first step, but the hope is that one day this research will help those dogs live much longer than they currently do.

If you've ever worked with a team, you'll probably remember a time where everyone had converged on some plan of action, but you had a better idea. Those moments are tricky. Do you stick your neck out, thereby providing your bosses with more options, or do you shut your mouth to ensure you don't get fired?

If the goal of management is to get the best ideas out of the team (and I acknowledge that's not always the case!), they need to create a workplace that encourages people to speak up. A new paper suggests that the way to do that is to make sure people feel safe and supported.

The paper consists of two experiments. In the first, 113 online workers imagined sitting on a three-person marketing task-force and being the lone person who preferred one target market (public elementary schools) over the other (parents of kids aged 4 to 13). Half first recalled a supportive team experience in which they comfortably asked for help and got it. The other half recalled a typical team discussion about how to work together. They wrote out their argument, and other people, who didn't know the conditions, rated those arguments independently.

Participants who were primed to feel more secure wrote longer explanations (~33%), and what they wrote landed better. They scored around 8% higher on task focus, 6% higher on elaboration, and 5% higher on persuasiveness.

In other words, people did a better job advocating for their opinions when they felt safe.

A new study on the use of marijuana by teens comes to two important conclusions: (1) marijuana hurts cognitive development, and (2) smart teens are at greater risk of becoming users.

Teens get smarter as they get older – their cognitive performance improves. But the study of ~11,000 U.S. youth shows that those who start using cannabis (about 2,200 of the kids) gained their cognitive abilities more slowly than their abstaining peers. As a result, kids who used cannabis were scoring significantly worse than non-users by ages 15 to 17 on most tests, including working memory, processing speed, inhibitory control, language, and visual processing.

The study also found that kids who were scoring better on cognition before they became teens (ages 9–10) were more likely to start taking cannabis than kids who performed worse. That suggests it may be the quicker-developing kids who are most likely to try cannabis, and then they lose their edge. The authors suggest the difference may reflect earlier maturation rather than innate intelligence, but the effect is the same.

I'm not sure how to convince a teenager to avoid marijuana, but if the teen in question is a smart one, maybe they'll be motivated by wanting to stay ahead of the curve. After all, if they're a bright kid, their increased risk is all the more reason to talk to them about this in the first place.

A new study shows how a fiction writer can foster empathy in their readers, but also shows that once that empathy is brought out of a reader, it spills out into their real-world relationships. In other words, a well-written book makes the reader a better person.

In a first experiment, readers met a fictional repairman who carelessly let an 85-year-old woman's puppy escape from her house. In some versions, he apologized to the woman aloud. In other versions the regrets only happened inside his head: "The repairman thought to himself, I wish I didn't leave the door open." The readers who got the inner thoughts were more willing to forgive him. That literary technique is called “internal focalization.”

In a second experiment, new participants went through the same procedure, but were then asked to think of a time someone close to them had severely wronged them. They described it and said whether the person had apologized and what it would take to forgive. They then rated whether they had fully forgiven the person. Like before, those who read the repairman's inner thoughts version forgave him more than the “out-loud” version. Those who forgave the fictional repairman more tended also to forgive the real-life offender more.

If you think about it, the likelihood a person was willing to find forgiveness just came down to what they'd read lately. This is a perfect example of why the arts are so important. (It's also a perfect reminder that I should read more fiction!)

Last Week's Trivial Answer

Last week's question was "What is the Title of the Book for which Charles Darwin is Best Known?" The correct answer was "On the Origin of Species."

Thanks for reading! -Dan