Good to know
By Elva Arulchelvan, Trinity College Dublin
As a researcher investigating how electric brain stimulation
can improve people’s powers of recollection, I’m often asked how memory
works—and what we can do to use it more effectively. Happily, decades of
research have given us some clear answers to both questions.
Memory essentially operates in three stages, with
different brain
regions contributing to each one.
Sensory
memory, which can last only milliseconds, registers raw information such as
sights, sounds, and smells. These are first processed by the brain’s five primary sensory
cortices (visual cortex for sights, auditory cortex for sounds, and so
on).
Working
(short-term) memory holds and manipulates a small amount of
information over several seconds or more. Think of this as your brain’s mental
workspace: the system that lets you do mental arithmetic, follow instructions,
and comprehend what you’re reading. So it mainly involves the prefrontal
cortex—the front part of your brain that supports attention, decision-making,
and reasoning.
Finally, long-term memory stores
information more permanently, from minutes to a lifetime. This includes both
“explicit” memories (facts and life events) and “implicit” ones (skills,
habits, and emotional associations).
For long-term memories, the hippocampus and temporal lobes—located
deep within the brain, around the sides of your head near your
temples—contribute largely to memories involving facts or life events, while
the amygdala (near
the hippocampus), cerebellum (at
the back of the brain), and basal ganglia (deep
in the brain) process emotional or procedural memories.
Working memory often acts as a conscious gateway to
long-term memory—but it
has its limits. In 1956, the American psychologist George Miller proposed
that we can only hold about seven “chunks” of
information in our working memory at any time.
While the exact number
is debated to this day, the principle holds: working memory is limited. And
that limitation can shape how effectively we learn and remember things.
But you can also get your memory working more effectively.
Here are five easy steps for improving both your working and long-term memory.
1. Put your phone away
Smartphones reduce your working memory capacity. Even just
having a phone nearby—no matter if it’s face down and on silent—can
reduce performance on memory and reasoning tasks.
The reason is that part of your brain is still subtly
monitoring it. Even resisting the urge to check notifications consumes mental
resources—which is why researchers
sometimes call smartphones a “brain drain.” The solution is simple:
put your phone in another room when you need to focus. Out of sight really does
free up mental capacity.
2. Stop your mind racing
Stress and anxiety can take up
valuable mental space.
When you’re worrying about something or are distracted by racing thoughts, part
of your working memory is already in use.
Relaxation
training and mindfulness
practices can improve both working memory and academic performance,
probably by reducing stress levels. And if meditation feels intimidating, try
breathing techniques such as “cyclic sighing.”
Inhale deeply through your nose, take a second, shorter inhale, then slowly
exhale through your mouth. Repeating this for five minutes can calm the nervous
system and create better conditions for learning.
3. Get chunking
Everyone can expand their working memory using the technique
of chunking—grouping information into meaningful units. In fact, you probably
already do it to remember some phone numbers or lists of words—breaking long
sequences into bite-size chunks that your brain can recall as a mini-group.
The same principles apply if you’re delivering a
presentation, to help your audience remember your key points more effectively.
Chunking would involve grouping ten case studies, say, into three or four
themes, each with a short headline and single key takeaway.
Repeat this structure on each slide: one idea, a few
supporting details, then move on. By organizing information into meaningful
patterns, you reduce cognitive load and make it more memorable.
4. Become a retriever
In the 19th century, German psychologist Hermann Ebbinghaus
demonstrated how quickly we forget information after learning it. Within about
30 minutes, we lose roughly half of what we have learned, with much more fading
over the next day. Ebbinghaus called this the forgetting curve.
The light blue line on the chart below illustrates this.
However, there is a way of ensuring that more sinks in when
you are trying to learn a lot of information in a short period of time: retrieval practice.
When preparing to give a talk or studying for an exam,
rather than simply rereading your notes, keep testing how much you remember.
Use flash cards, answer practice questions, or try explaining the material out
loud without notes.
Memory works through associations. Each time you
successfully retrieve information, you link the material to new prompts,
examples, and contexts. This builds more cues to
accessing the information and strengthens each memory pathway.
Often when we “forget,” the memory isn’t gone—we just lack the right retrieval
cue.
5. Give yourself a break
Research shows that memory is more effective when study
or practice sessions are spread out, rather than massed together. If you
are studying for an exam, build solid blocks of downtime into your revision
schedule. The dark blue line on the chart above illustrates how spacing out
your practice sessions can help you remember more information over time by
adjusting Ebbinghaus’s forgetting curve.
One study suggests leaving gaps between each revision
session that equate to 10-20%
of the time left until your exam or presentation. So, if your deadline
is five days away and you do hours of revision a day, you should still take
between a half and a full day off in between sessions. In other words, don’t
overdo it—you probably won’t see the rewards!
If you only remember one thing from this article about
improving memory, make it this. Memory isn’t just about intelligence; it’s
about strategy. Small changes in how you study or work can make a real
difference in how well, and how long, you remember crucial information.
Adapted from an article originally published in The Conversation.
