(Left to right): vchal/shutterstock; Lizzie Wade; ESO/M. Parsa/L. Calçada

Top stories: The seafaring first Americans, hearing voices, and the downside of pampering puppies

Most archaeologists think the first Americans arrived by boat. Now, they’re beginning to prove it

Archaeologists once thought that the earliest people to arrive in the Americas wandered into the continent through a gap in the ice age glaciers covering Canada. But most researchers today think the first inhabitants voyaged by boat out of Beringia—the ancient land now partially submerged under the waters of the Bering Strait—about 16,000 years ago and quickly moved down the Pacific coast, reaching today’s Chile by at least 14,500 years ago. On Mexico’s Cedros Island, researchers are helping fill in the picture of how early coastal people lived and what tools they made.

How your mind protects you against hallucinations

More than 300 years ago, the philosopher René Descartes asked a disturbing question: If our senses can’t always be trusted, how can we separate illusion from reality? We’re able to do so, a new study suggests, because our brain keeps tabs on reality by constantly questioning its own past expectations and beliefs. Hallucinations occur when this internal fact-checking fails, a finding that could point toward better treatments for schizophrenia and other psychiatric disorders.

Coddled puppies make poor guide dogs, as this adorable video shows

As a smooth sea never makes a skillful sailor, so an overprotective mother doesn’t make a successful guide dog. That’s the conclusion of the first study to analyze how mother-puppy interaction influences guide dog training program success. Dogs whose mothers spent the most time licking and grooming them as puppies were almost three times less likely to succeed in a training program for guide dogs for the blind, researchers report this week.

Star hurtling toward massive black hole may seal deal for Einstein’s theory of general relativity

Albert Einstein’s theory of general relativity has passed a multitude of tests over the past century, but physicists remain unsatisfied. That’s because it has never been matched up against a strong gravitational field, like that of a supermassive black hole. Now, a team monitoring a star on its way to a close encounter with the giant black hole at the center of our galaxy says early signs hint that the 102-year-old theory will once again hold up.

CRISPR patent battle in Europe takes a ‘wild’ twist with surprising player

MilliporeSigma, a subsidiary of pharmaceutical giant Merck KGaA of Darmstadt, Germany, has become a new major player in the complicated European patent battles over CRISPR, the revolutionary genome-editing tool. The European Patent Office late last month signaled that it intends to grant a patent to the company, which operates in the United States and Canada, for the use of CRISPR to splice genetic information into eukaryotic cells. Just such a “knock-in” strategy has recently made headlines in a controversial experiment that corrected a disease-causing gene in a human embryo.