You think of something, but it vanishes soon after. Or you meet and shake hands with a new acquaintance, but forget his or her name promptly. Perhaps, you walk into your kitchen, but just cannot recall what you wanted to do.

Exasperating as it is, this type of forgetfulness is usually normal, said Dr Sharon Sha, a professor of neurology at Stanford University.

When people blank on information they just learnt or thoughts they just had, it is typically because the brain did not save them as long-term memories to begin with, she said.

People do not always make memories

When going about your daily life, your brain holds information in a temporary state called working memory, said Dr David Gallo, a professor of psychology at the University of Chicago.

Having a phone conversation while following a dinner recipe, for instance, involves juggling multiple tasks in your working memory at once, he said.

Most people can hold only about four or five thoughts or tasks in their working memories at a time, he said.

But unless those thoughts go through a brain process called encoding, he added, they will not be saved permanently in your long-term memory.

This works like a computer’s “save” function, said Dr Scott Small, director of the Alzheimer’s Disease Research Center at Columbia University. “If you’re taking notes and you close your computer without saving, your notes are gone forever,” he added.

The encoding process involves creating meaningful connections between brain cells and requires ample working memory. So, if you are preoccupied with introducing yourself to someone new or deciding what you will say next, your brain will not encode information like the new name you hear – and you will promptly forget it.

While these lapses may seem frustrating, they are actually essential for day-to-day functioning, said Dr Lynne Reder, a professor emeritus of psychology at Carnegie Mellon University.

If the brain encoded everything you saw, heard, smelled or felt, you would not have any working memory left for things such as walking, talking or listening.

How to remember

Sometimes, it is easy to remember information, Dr Sha said.

If you feel a strong emotion such as fear or trauma in the moment you learn something, for instance, you are more likely to recall it later. This explains why many people remember exactly where they were on Sept 11, she said.

But there are other tricks and tactics, experts say, that can help people purposefully save memories for the long term.

Repeat and recite: Repeating information, especially in new ways, can assist with memory storage, said Dr Ronald Davis, a professor of neuroscience at the University of Florida.

When people hear, see, recite aloud or write down a word, they get several chances to encode that word using different pathways in the brain.

Studies suggest that writing new information by hand – be it on paper or a tablet with a digital stylus – can activate more of the brain than typing can, further strengthening people’s memories. The more times you repeat something, the more likely you are to remember it, Dr Davis said.

Assign meaning: Remembering arbitrary information can be particularly challenging, Dr Reder said. That is why it is sometimes easier to recall names that are connected to certain characteristics or qualities.

You might remember a dog named Rusty if it had rust-coloured fur, for example.

“If you meet someone named Michelle who’s from Florida, you can imagine a Florida beach with a seashell, which sounds like Michelle,” Dr Gallo said. “Now, you can associate that name with a context, visual image and rhyme.”

Sing along: Remembering can come easier when information is set to tunes, Dr Sha said. You might remember an advertisement jingle, for example, even if it is for a product you would never buy.

Neuroscientists are still learning why music helps, but “tagging” memories with tunes might move them into different parts of the brain, making them more likely to stick, she said.

Create a visual or emotional cue: If you are trying to remember to perform a specific task, imagine yourself doing it or thinking about how it will make someone feel, Dr Sha said.

If you need to buy a gift for your daughter, for instance, you can picture yourself purchasing it or imagine how happy she will be when she opens the present.

Prioritise sleep and exercise: It is more challenging to encode new information when you are sleep-deprived, Dr Gallo said, so it is crucial to get enough rest.

Regular activity such as aerobic exercise, weight lifting, stretching or short walks can enhance memory, both in the short term and over time, experts said.

Keeping your heart healthy through exercise helps keep your brain healthy, Dr Gallo said. “This can help you age gracefully and keep your memory functioning optimally at any stage of life.” NYTIMES