Why we forget and how to improve your memory

Many of us worry about forgetfulness: from misplacing keys, losing our train of thought, or wondering “Why do I keep forgetting everything?”

If you’ve ever felt that way, you’re not alone.

In this episode of Let’s Talk Health, cognitive neuroscientist Professor Matthew Mundy unpacks what memory really is, why it changes over time, and what we can do to strengthen it.

What is memory?

People often search for a simple memory definition, but memory is far more complex than just “remembering things.” Professor Mundy explains that memory is the brain’s ability to retain information for future use, whether that’s recalling something important or improving how we interact with the world.

He describes two major types of memory:

1. Declarative memory

   These are the memories we’re consciously aware of: what you had for breakfast, where you travelled last year, or the capital of France.

2. Non-declarative memory

   These are the skills and habits we perform automatically, like riding a bike or playing the piano.

Professor Mundy puts it simply:

“Memory is about improving how we interact with the world around us… we can do that consciously or subconsciously.”

Understanding these systems helps explain why some memories fade while others stay with us for life.

Common causes of forgetfulness and poor memory

Forgetfulness is incredibly common, and most of the time it’s linked to everyday factors rather than anything serious. There are several key contributors.

1. Age-related changes

   Different parts of the brain age at different rates. Procedural memories (like skills) are stored in older, more stable regions of the brain, which is why they often last longer than episodic memories (like events).

2. Sleep

   Sleep plays a major role in improving memory and concentration. A poor night’s sleep disrupts the brain’s ability to encode and retrieve information.

   “If we don’t get a good night’s sleep, the architecture of your brain isn’t functioning in the way it could and you’re more likely to forget things.”

3. Stress

   Stress chemicals can block memory formation. Whether it’s chronic stress or a moment of acute pressure, both can interfere with how memories are stored and recalled.

4. Lifestyle and distraction

   Modern life demands a lot from our short-term memory. Professor Mundy notes that we can only hold around 6 to 8 items in short-term memory at once. When we exceed that, things “fall out.”

   This is why multitasking often leads to mistakes or forgetfulness and the brain feels overloaded.

How to better memory

Improving memory isn’t about quick fixes; it’s about supporting the brain through healthy habits and smart strategies. Professor Matthew Mundy shares several evidence-based ways to strengthen memory at any age.

1. Prioritise sleep

   Sleep is where memory consolidation happens. Getting consistent, good-quality sleep is one of the most effective ways to improve memory and concentration.

2. Support your brain as you age

   Professor Mundy emphasises the importance of staying mentally and physically active.

   Cognitive exercises like crosswords, sudoku and brain-training apps can help reinforce neural connections and slow age-related decline.

3. Learn to ‘chunk’ information

   Chunking is a powerful memory technique. Instead of trying to remember eight separate digits, we naturally group them into two blocks of four.

   You can use chunking for shopping lists, study notes, or anything that feels overwhelming.

4. Stay physically active

   Movement increases blood flow to the brain and supports cognitive health. Even light daily activity can make a difference.

5. Manage stress

   Mindfulness, breathing exercises, and time in nature can help reduce stress and improve memory performance.

Nutrition and food supplements for memory

Diet plays a role in brain health. Foods rich in antioxidants, omega-3s and B-vitamins support cognitive function. Some people also explore food supplements for memory, such as:

• Omega-3 fish oil
• B-complex vitamins
• Herbal supplements like ginkgo biloba

Why memory changes across life

1. Early childhood: Memory is “fuzzy” before language develops because language gives structure to thought.
2. School years: Learning creates more mental “hooks” to attach new information to.
3. Adulthood: Memory stabilises, then gradually declines as brain structures age.

How to better and strengthen memory

Though it isn’t possible to increase the brain’s memory capacity, it is possible to use memory more effectively. Techniques like chunking reduce mental load and make information easier to recall.

Sleep plays a critical role in strengthening memory, particularly long-term memory. During sleep, the brain reinforces the connections between neurons that store information learned during the day.

Stress can significantly interfere with memory formation and recall. Managing stress through relaxation and mindfulness creates better conditions for memory to function effectively.

Listen to the full conversation with Matthew Mundy to dive deeper into how memory works, and what you can do to support yours.