Scientists explain the reason why you forget what you were looking for when you enter a room

Have you ever walked into a room only to forget why you went there in the first place? According to cognitive neuroscience, there's a clear reason why this happens, and it has everything to do with how the brain processes space and memory. Christian Jarrett, a cognitive neuroscientist and science writer, explained the phenomenon in his column for BBC Science Focus. He says this mental hiccup is known as the "doorway effect," a term used to describe the experience of forgetting your original intention after entering a new room. Jarrett wrote, "Fear not, you’re far from the only one to have had this rather unsettling experience."

The concept is rooted in the brain’s tendency to compartmentalize activities and information based on environmental context. As Jarrett explained, when you pass through a doorway, your brain essentially resets its understanding of the environment. The doorway acts as a psychological boundary that separates one context from another. Research conducted at the University of Queensland further found that moving through doorways between identical rooms did not significantly impact memory. This suggests that a change in context is critical. However, when participants were distracted with a secondary task while crossing into an identical room, their memory was affected. 

Jarrett noted this supports the idea that forgetfulness is more likely when the brain is already managing multiple tasks. It has also been studied by psychologists at the University of Notre Dame, as per Well and Good. In one experiment, researchers used a virtual reality setup to show that participants' memory of items was diminished after they passed through a doorway. Professor Gabriel Radvansky, who conducted the study, explained that our minds naturally break continuous experiences into smaller mental units called event models. When we transition to a new event, a process called "event updating" occurs. The brain removes information from the prior event and shifts focus, often causing us to forget what we were just doing.

He also noted that the same information can be stored in more than one event model. For example, if you are in the bedroom and head to the kitchen to get a glass of water, that goal might be stored in both memory contexts. Your brain has to choose between competing versions of the same memory, which can lead to temporary forgetting. Passing through a doorway is one example of what Radvansky calls an "event boundary." Similar lapses can occur when switching computer windows, changing spaces, or when someone enters or leaves the room. Radvansky said, "It means that our brains are parsing up the world in a perfectly normal and adaptive way." Clearing out previous information allows us to better focus on what matters now.

Without this, our attention might stay locked on things no longer relevant. Still, when it does happen, it can be frustrating. To help avoid it, Radvansky recommends carrying a physical reminder of your goal between spaces. For instance, if you are heading to the garage for a screwdriver, bring a screw with you. If you do forget, there's a simple way to jog your memory. He said, "One of the best things that you can do is go back to the room where you originally established your goal or learned something." That space may offer visual cues to help trigger your memory. If walking back feels like too much effort, even mentally picturing the original room or recalling what you were doing can often bring the goal back into focus.