A new analysis supports the previously overlooked “brain lag” hypothesis—the idea that, in some primate lineages, the evolution of larger body size preceded the evolution of larger brain size—while also building on that hypothesis by suggesting that some lineages’ brain sizes then continued to grow beyond an expected baseline. Robin Dunbar of the University of Oxford presents these findings in the open access journal PLOS One on July 1, 2026.

AI-generated impersonations of political figures are judged by members of the public to be more authentic, relevant, and coherent than the speakers’ actual debate responses, according to a new study published July 1, 2026 in the open-access journal PLOS One by Steffen Herbold of the University of Passau, Germany, and colleagues.

Sleep is a fundamental aspect of human health that plays a crucial role in cognitive function, academic performance, and social interactions. A study published July 1, 2026 in PLOS One by Yao Zhao at Temple University, USA, and colleagues suggests that wearable devices can provide accurate, longitudinal sleep data to facilitate analyses of changing sleep patterns over time.

When moms were slower to vocally respond to their 1-yr-old baby’s vocalizations, the child was more likely to have been diagnosed with a psychiatric disorder by age 7, in a new study published July 1, 2026 in the open access journal PLOS One by Bethany Stanley of the University of Glasgow, UK, and colleagues.

Gentle purchase incentives can lead customers to choose groceries with higher animal husbandry standards more often. A recent study at the University of Bonn at least suggests this. The researchers used two different animal welfare label posters as “nudges.” Each poster itself changed the consumer behavior of participants shopping in a virtual supermarket. The share of products with higher animal welfare standards in the shopping cart was highest when both posters were combined. Further studies have yet to clarify the extent to which the results can be transferred to real shopping situations. The study has been published in the Journal of Behavioral and Experimental Economics.