After a limited testing period, OpenAI is opening up its ChatGPT web search tool to all users. The rollout starts with those paying 20 a month for ChatGPT Plus, but OpenAI says it'll show up for everyone, whether they're subscribers or not, in the coming months. While it uses the familiar ChatGPT interface, web search works a little differently. Instead of the bot relying on its training data to come up with answers, it scours the web for relevant and timely information, and then sifts through and summarizes what it's found to generate a coherent response. It means you can type all the queries you would normally plug into Google into ChatGPT instead--from "what time is the Superbowl?" to "what are the best places to visit in Florence?"

Stress can lead to poor decision-making, and people hunting for George Clooney's face could help us understand why. Thackery Brown at Stanford University, California, and his colleagues asked 38 people, with an average age of 23, to navigate looping paths around 12 different virtual towns in a simulated environment. Each town had just a few streets and took about a minute to navigate. The researchers also placed the face of a celebrity – George Clooney, for example – at a point along the route. The team then asked the participants to navigate the simulation again while lying inside a functional magnetic resonance imagine (fMRI) machine.

Facebook has developed software to make people invisible to facial recognition technology. Its'de-identification' program is intended to protect people from'deepfake' style videos in which their faces can be edited onto videos of other people. These convincing clips are becoming so advanced it can be difficult to tell which videos are real and which ones are fake. And there are concerns that, in future, people will be able to make footage of others doing or saying things that they never actually did. But Facebook AI Research now says it has a way of fooling the artificial intelligence used to make these videos while still keeping the original video lifelike.

Among the more modern anxieties of parents today is how virtual assistants will train their children to act. The fear is that kids who habitually order Amazon's Alexa to read them a story or command Google's Assistant to tell them a joke are learning to communicate not as polite, considerate citizens, but as demanding little twerps. This worry has become so widespread that Amazon and Google both announced this week that their voice assistants can now encourage kids to punctuate their requests with "please." The version of Alexa that inhabits the new Echo Dot Kids Edition will thank children for "asking so nicely." Google Assistant's forthcoming Pretty Please feature will remind kids to "say the magic word" before complying with their wishes.

CAMBRIDGE – How can we improve the state of the world? How can we make countries more competitive, growth more sustainable and inclusive, and genders more equal? One way is to have a correct theory of the relationship between actions and outcomes and then to implement actions that achieve our goals. But, in most of the situations we face, we lack such a theory, or if we have one, we are not sure that it is correct. Should we postpone action until we learn about what works? But how will we learn if we do not act?