In an increasingly lucrative market, dozens of companies and startups are selling futuristic-looking headgear that promise to connect to your brain to relieve stress, enhance memory, improve sleep or increase focus, Kaveh reports.

But experts say these products make mostly unsubstantiated claims and in some cases can harm unwary buyers.

"There's a bit of pulling the wool over people's eyes, trying to talk up these products in a way that isn't sincere and transparent," says Karola Kreitmair, a medical ethics expert at the University of Wisconsin.

What's happening: There are two broad categories of wearable brain devices — those that record the user’s brain activity and others that stimulate the brain with electrical currents. These technologies are mainstays in research labs and hospitals — but now they're on Amazon and Kickstarter, too.

• Bellabee, a $159 headband and app, says it can help reduce symptoms of ADHD and PTSD.
• Modius, a $499 headset, claims to curb the appetite and help users lose weight.
• The Brain Stimulator, a $120 device with electrodes that send a current to the brain, says it's based on technology that can help with depression, pain, addiction and memory.

None of the three — a small subset of the growing market — offers research showing that their specific devices do what they claim. None responded to requests for comment.

The big picture: Many companies are imbuing products with an air of medical legitimacy without pointing to serious research. A common pattern: Companies say their products are based on technology that has been shown to be beneficial in some way — but provide no research on their products.

• A study published in Neuron found 41 "neurotechnology" products currently for sale that target either the general public or some particularly vulnerable subset — like children, the elderly, or people with a medical condition.
• Only 33 provided any supporting research, the study found. And just 8 referred to relevant peer-reviewed research.
• Most of the rest made claims about a general technology, or leaned on user testimonials and in-house research that wasn't reviewed by outsiders.

Customers who buy an ineffective device could be in for more than a disappointing waste of money.

• Transcranial direct current stimulation (tDCS), which involves administering a weak electric current to the head, has been tested in labs for depression and anxiety, but the effects of overuse aren't well understood. The method can also cause skin burns and headaches.
• And consumer EEG devices, which record brain activity, can influence user behavior by reinforcing certain "brain states." Scientists question both the accuracy of the device readings, and the scientific basis of drawing any conclusions from them.

The government has done little to police companies selling these devices straight to consumers. "This is a case where industry has run away with something because people are willing to pay money for it — but regulation and validation completely lags behind," Kreitmair, the University of Wisconsin professor, tells Axios.

• Because of how quickly these devices are being developed, the FDA, which regulates medical devices, and the FTC, which protects consumers from false advertising, are ill prepared to reign in companies, says Anna Wexler, a University of Pennsylvania medical ethicist.
• Wexler has proposed convening researchers and industry experts to monitor direct-to-consumer products and work with regulators.
• Other ethics experts — like Judy Illes of the University of British Columbia, a co-author of the Neuron study — say the fledgling industry needs to be pressured to self-regulate.

An FDA spokesperson said the agency doesn't discuss potential investigations, but that the agency has in the past increased scrutiny of certain devices "when necessary to protect patients."

Amid the worst measles outbreak in a century, a sharp and surprising divide has opened between poorer countries that accept the effectiveness of vaccines and high-income nations that are more doubtful about them, according to a new survey.

• Driving the news: Vaccines have around the same acceptance in northern Europe and North America — about 72% support, according to a Gallup survey released today of some 140,000 people in 144 countries. In western Europe the number drops to 59% and in eastern Europe 40%.
• But 92% of those surveyed in east Africa expressed confidence in vaccines and 95% in South Asia.

As Axios wrote yesterday, 1,044 cases of measles have been reported in 28 states this year (see chart above), the most since 1992, when there were 2,126, according to the Centers for Disease Control and Prevention.

The human population will grow to somewhere between 9 billion and 11 billion by the end of the century, depending whom you talk to. And so will the number of farm animals, according to UN figures.

By 2050, the number of cattle around the world is poised to skyrocket to 2.6 billion, an 85% jump from 1.4 billion in 2010.

• The chicken, turkey and duck count will surge by 66%, to 35 billion.
• And the number of sheep and goats will jump 35%, to 2.7 billion.

The dangerous job of content moderation (Casey Newton - Verge)

Buybacks to date exceed 2018 R&D (Dion Rabouin - Axios)

Blackstone CEO seeds new AI center at Oxford (University of Oxford)

The race to create Libra (Tim Bradshaw, Martin Coulter, Hannah Murphy - FT subscription)

Demographics and geopolitics (Nicholas Eberstadt - Foreign Affairs)

Spy agencies, militaries and digital mercenaries are constantly lobbing cyberattacks across national borders, targeting everything from banks, dams and the electrical grid to journalists and activists, Kaveh writes.

The vast majority of attacks go unreported. But a chart from GZERO Media shows a snapshot of the incursions that caused at least $1 million in economic damage and have been made public.

• The numbers show that China and Russia are among the biggest aggressors, and the U.S. is the single biggest target for cyberattacks.
• Our thought bubble: It's extremely unlikely that the U.S. has only launched 9 big cyberattacks, as the chart shows. Instead, it may be that American attacks are less likely to be detected or reported.

Go deeper: The U.S. goes on the cyber offensive