Start talking to Ellie Pavlick about her work — looking for evidence of understanding within large language models (LLMs) — and she might sound as if she’s poking fun at it. The phrase “hand-wavy” is a favorite, and if she mentions “meaning” or “reasoning,” it’ll often come with conspicuous air quotes. This is just Pavlick’s way of keeping herself honest....

Milk is more than just a food for babies. Breast milk has evolved to deliver thousands of diverse molecules including growth factors, hormones and antibodies, as well as microbes. Elizabeth Johnson, a molecular nutritionist at Cornell University, studies the effects of infants’ diet on the gut microbiome. These studies could hold clues to hard questions...

Anne Salomon’s first week as a graduate student in 2001 was not what she had anticipated. While other new students headed to introductory lectures, Salomon was whisked away by van and then motorboat to Tatoosh Island, which sits just offshore of the northwestern tip of Washington’s Olympic Peninsula. Among the tide pools of this isolated island, Salomon...

String theory captured the hearts and minds of many physicists decades ago because of a beautiful simplicity. Zoom in far enough on a patch of space, the theory says, and you won’t see a menagerie of particles or jittery quantum fields. There will only be identical strands of energy, vibrating and merging and separating. By the late 1980s, physicists...

The central objects of study in topology are spaces called manifolds, which look flat when you zoom in on them. The surface of a sphere, for instance, is a two-dimensional manifold. Topologists understand such two-dimensional manifolds very well. And they have developed tools that let them make sense of three-dimensional manifolds and those with five...

In 2022, researchers at the Bee Sensory and Behavioral Ecology Lab at Queen Mary University of London observed bumblebees doing something remarkable: The diminutive, fuzzy creatures were engaging in activity that could only be described as play. Given small wooden balls, the bees pushed them around and rotated them. The behavior had no obvious connection...