Why Do We Forget Thoughts? Brain Limitations Behind Memory Loss Explained

Forgetting what we were just thinking about is a common experience. Whether it’s walking into a room and forgetting why we’re there or starting to talk and losing track of the thought, our brains seem to slip up every now and then. This everyday phenomenon is intimately tied to how the brain processes and juggles information, with much of the cause attributed to the limitations of working memory.

How memory works

To understand why we forget, it’s essential to understand memory itself. According to Susanne Jaeggi, a professor of psychology at Northeastern University, memory is not a single process, but rather involves several components. It can be broadly divided into long-term memory and working memory. Long-term memory holds experiences, skills, and knowledge, while working memory temporarily stores thoughts, allowing us to process information in real time.

What is working memory?

Earl K. Miller, a professor of neuroscience at MIT, describes working memory as a sketchpad where our conscious thoughts reside. It is very limited, holding only four to seven pieces of information at a time. The brain is constantly moving from one thought to another, and this constant shifting makes it easy for some thoughts to slip through the cracks.

Why do we forget?

The main reason we forget is that working memory is not designed to multitask. It is forced to juggle multiple ideas, often dropping one if its attention is diverted. Miller explains that this juggling is even more likely to fail when we are tired or under the influence of alcohol. Furthermore, age plays a role in how efficiently working memory functions, with its peak performance in our 20s before declining later in life.

Retrieving forgotten thoughts

An effective way to retrieve a forgotten thought is to recreate the environment in which it occurred. Jaeggi suggests returning to the scene or retracing your steps, as this can provide the brain with the context it needs to remember what was lost. This technique helps because the brain often relies on environmental cues to trigger memory retrieval. In short, understanding how working memory works can help us be more aware of its limitations and take steps to prevent unnecessary forgetfulness.