Short of sleep? Your memory could be playing serious tricks on you.
Short of sleep? Your memory could be playing serious tricks on you.
We all know that lack of sleep affects our memory, along with other cognitive abilities.
Sitting in the office, sleep deprived, it’s difficult to remember your own name, let along the ever-lengthening to-do list.
But now new research shows that not getting enough sleep increases the chances your mind will actually create false memories.
The study, published in Psychological Science, allowed one group of participants to get a full nights’ sleep, while another had to stay up all night (Frenda et al., 2014).
In the morning they were given a series of photos that were supposed to show a crime being committed.
Next, both groups were given some eyewitness statements about the crime.
Like many witness statements in real-life crimes, the details were different to those shown in the photographs.
For example, in one instance the photo showed a thief putting a wallet in his jacket, but in the witness statement it said he put it in his pants (that’s ‘trousers’ for British people, not his underwear!).
Afterwards, they were asked what they had seen in the original photographs.
The results showed that those who’d missed out on their sleep were the most likely to regurgitate the false eyewitness statements they’d just read, rather than remembering the ‘true’ crime-scene photos they’d been shown moments beforehand.
The lack of sleep had messed with their heads to the extent that all the evidence — right and wrong — had got mixed up.
One of the study’s authors, Kimberly Fenn, said:
“People who repeatedly get low amounts of sleep every night could be more prone in the long run to develop these forms of memory distortion.
It’s not just a full night of sleep deprivation that puts them at risk.”
Indeed, a preliminary study they carried out found that getting just five hours sleep was enough to cause people to start manufacturing false memories.
The physical changes in the motor cortex that result from learning and sleep.
The physical changes in the motor cortex that result from learning and sleep.
Sleep after learning encourages brain cells to make connections with other brain cells, research shows for the first time.
The connections, called dendritic spines, enable the flow of information across the synapses.
The findings, published in the prestigious journal Science, are the first to show physical changes in the motor cortex resulting from learning and sleep (Yang et al., 2014).
One of the study’s authors, Wen-Biao Gan, PhD, said:
“We’ve known for a long time that sleep plays an important role in learning and memory. If you don’t sleep well you won’t learn well.
But what’s the underlying physical mechanism responsible for this phenomenon?
Here we’ve shown how sleep helps neurons form very specific connections on dendritic branches that may facilitate long-term memory.
We also show how different types of learning form synapses on different branches of the same neurons, suggesting that learning causes very specific structural changes in the brain.”
The results come from studies in mice, which were genetically engineered with a fluorescent protein in their neurons.
With the use of a laser-scanning microscope, the fluorescent protein allowed the scientists to track and image the dendritic spines before and after they learnt a new skill; in this case balancing on a spinning rod.
Some of the mice were allowed to sleep after they had learned to balance on the rod, others were not.
In the brains of those that had slept, there was more growth of dendritic spines.
In addition, the type of task the mice learnt –whether they ran forward or backward across the rod — affected where the dendritic spines grew.
Gan continued:
“Now we know that when we learn something new, a neuron will grow new connections on a specific branch.
Imagine a tree that grows leaves (spines) on one branch but not another branch. When we learn something new, it’s like we’re sprouting leaves on a specific branch.”
It fights the stress hormone which damages the brain’s ability to learn and remember.
It fights the stress hormone which damages the brain’s ability to learn and remember.
It’s a smile.
New research from researchers at Loma Linda University has found that older people with diabetes who were shown a funny video scored better on a memory test. (Bains et al., 2014).
The reason seems to be that cortisol — the ‘stress hormone’ — damages the brain’s ability to learn and remember.
It does this by affective certain neurons in the brain.
Humour and laughter, though, are well-known relievers of stress.
One of the study’s authors, Dr. Lee Berk said:
“It’s simple, the less stress you have the better your memory.
Humor reduces detrimental stress hormones like cortisol that decrease memory hippocampal neurons, lowers your blood pressure, and increases blood flow and your mood state.
The act of laughter — or simply enjoying some humor — increases the release of endorphins and dopamine in the brain, which provides a sense of pleasure and reward.
These positive and beneficial neurochemical changes, in turn, make the immune system function better.
There are even changes in brain wave activity towards what’s called the “gamma wave band frequency,” which also amp up memory and recall.
So, indeed, laughter is turning out to be not only a good medicine, but also a memory enhancer adding to our quality of life.”
The study’s lead author, Dr. Gurinder Singh Bains added:
“Our research findings offer potential clinical and rehabilitative benefits that can be applied to wellness programs for the elderly.
The cognitive components — learning ability and delayed recall — become more challenging as we age and are essential to older adults for an improved quality of life: mind, body, and spirit.
Although older adults have age-related memory deficits, complimentary, enjoyable, and beneficial humor therapies need to be implemented for these individuals.”
Brain regions are synchronized as neurons fire at a common frequency.
Brain regions are synchronized as neurons fire at a common frequency.
“Nothing is more memorable than a smell.
One scent can be unexpected, momentary and fleeting, yet conjure up a childhood summer beside a lake in the mountains; another, a moonlit beach; a third, a family dinner of pot roast and sweet potatoes during a myrtle-mad August in a Midwestern town.” ~ Diane Ackerman
Or, in the somewhat less poetic language of science: areas of the brain that are central to long-term memory and the sense of smell are coupled together by brain waves oscillating at 20-40 hertz.
The findings, published in the journal Nature, come from the Kavli Institute for Systems Neuroscience in Norway, where they have been using mice to explore the strong connections between smell and memory (Igarashi et al., 2014).
In their research, the experimenters first had to simulate the laying down of a smell-related memory, like the association we might have between cut grass and a summer long-ago.
So, the mice were taught that certain smells led them to rewards of food.
Then, they needed to see what happened in the mice’s brains when they retrieved the memory.
This is analogous to the moment when the cut grass smell hits our noses and we are instantly transported back a decade.
Kei Igarashi, the study’s lead author explained the results:
“Immediately after the rat is exposed to the smell there is a burst in activity of 20 Hz waves in a specific connection between an area in the entorhinal cortex, lateral entorhinal cortex (LEC), and an area in the hippocampus, distal CA1 (dCA1), while a similar strong response was not observed in other connections.”
The entorhinal cortex is important in linking spatial memory to smell — the mice had to remember where the reward was — and the hippocampus plays an important role in turning short-term memories into long-term memories, as well as spatial navigation.
Synchronising the brain
Not only does the study explore how smell and memory are linked, it is also one of a wave of new studies investigating how different parts of the brain synchronise with each other to create functional networks.
Edvard Moser, director of the Kavli Institute for Systems Neuroscience, explains:
“This is not the first time we observe that the brain uses synchronised wave activity to establish network connections.
Both during encoding and retrieval of declarative memories there is an interaction between these areas mediated through gamma and theta oscillations.
Together, the evidence is now piling up and pointing in the direction of cortical oscillations as a general mechanism for mediating interactions among functionally specialized neurons in distributed brain circuits.”
It’s a lot to think about when you are smelling a rose; but it’s all happening in that moment when you pick up a rose, breathe in, and are taken back in time.
New technique holds promise for those experiencing disturbing emotional flashbacks.
New technique holds promise for those experiencing disturbing emotional flashbacks.
A better way to deal with recurring negative memories is to focus on the context and not the emotion, according to a new study published in Social Cognitive and Affective Neuroscience (Denkova et al., 2014).
For example, if you were thinking about a funeral you attended, you might focus on what you were wearing or who was there, instead of how you were feeling at the time.
Professor Florin Dolcos, one of the study’s authors, thinks this approach could provide a promising alternative to other ways of regulating the emotions, like suppression and reappraisal.
Dolcos explained:
“Sometimes we dwell on how sad, embarrassed, or hurt we felt during an event, and that makes us feel worse and worse.
This is what happens in clinical depression — ruminating on the negative aspects of a memory.
But we found that instead of thinking about your emotions during a negative memory, looking away from the worst emotions and thinking about the context, like a friend who was there, what the weather was like, or anything else non-emotional that was part of the memory, will rather effortlessly take your mind away from the unwanted emotions associated with that memory.
Once you immerse yourself in other details, your mind will wander to something else entirely, and you won’t be focused on the negative emotions as much.”
The researchers reached this conclusion by asking participants to share both positive and negative memories.
A few weeks later these memories were triggered while sometimes focusing on felt emotions and other times on the context of the event.
Brain scans during recall showed that…
“…when participants were focused on the context of the event, brain regions involved in basic emotion processing were working together with emotion control regions in order to, in the end, reduce the emotional impact of these memories.”
We don’t yet know if this strategy will work in the long-term, which is very important for those suffering from depression, but it’s easy to do and unlikely to cause any harm.
Day-to-day living is one of the greatest challenges for those with Alzheimer’s.
Day-to-day living is one of the greatest challenges for those with Alzheimer’s.
Two recent studies provide evidence of the protective effects of Vitamin E against both mild to moderate Alzheimer’s disease and age-related memory problems.
In the first, 613 patients across 14 centres for veterans in the US who had mild to moderate Alzheimer’s were involved in an experiment to test Vitamin E (Dysken et al., 2014).
Some were randomly assigned to receive Vitamin E and their results were compared with comparison groups.
One of the trial’s co-investigators, Dr. Mary Sano, explained the effects on functional decline, the increasing problems Alzheimer’s sufferers have with day-to-day living:
“This trial showed that vitamin E delays progression of functional decline by 19% per year, which translates into 6.2 months benefit over placebo.”
The study’s authors think that vitamin E can be recommended as standard clinical practice.
This is an encouraging result given that there are few other useful drugs for mild to moderate dementia.
A second study carried out in Finland also provided support for the use of Vitamin E to fight age-related memory problems.
The study, published in the journal Experimental Gerontology, examined 140 people over 65 who did not have any memory problems at the start of the study (Mangialasche et al., 2013).
They were followed up over the next eight years and the researchers found that higher levels of vitamin E in the blood seemed to protect against memory disorders.
The interesting thing about the study was that it looked at different types of vitamin E: there are 8 naturally occurring forms, all of which have antioxidant properties.
Levels of all of these naturally occurring forms were associated with a protective effect against memory problems.
The fact that vitamin E is widely available and relatively inexpensive makes these findings even more practical.
Researchers at the University of Basel have now found that green tea extract can improve working memory (Schmidt et al., 2014).
Working memory is vital to holding pieces of visual, verbal or other information in your mind while you manipulate them.
Better working memory has been linked to improved learning, attention and other vital outcomes.
Synaptic functioning
In their study, participants were given a drink which sometimes contained green tea extract and were then asked to complete a series of tests of their working memory.
Either way the drink looked and tasted the same, whether or not it contained green tea extract.
Meanwhile, their brains were scanned to see how the green tea affected synaptic functioning.
What the researchers found was that not only did participants do better on the tests after ingesting the green tea, but that it enhanced the connections between the frontal and parietal regions of the brain.
The findings are interesting especially for older adults, as a series of studies have suggested green tea may be beneficial in this area:
“…consumption of green tea improved memory and attention in subjects with mild cognitive impairments and that the consumption of flavonoid-rich foods such as green tea reduced beta-amyloid-mediated cognitive impairments.
[…]
Furthermore, higher consumption of green tea has also been associated with a lower prevalence of cognitive impairments in older adults.” (Schmidt et al., 2014).
Why we remember and why we forget: it’s context, fading emotions, deep processing, the ‘Google effect’, the reminiscence bump and way more…
Why we remember and why we forget: it’s context, fading emotions, deep processing, the ‘Google effect’, the reminiscence bump and way more…
Many people say they have bad memories, but the majority are wrong.
The way memory works can be unexpected, frustrating, wonderful, and even quirky — but not necessarily ‘bad’.
For most of us the problem isn’t with our memories, it’s with understanding how memory works.
Here are ten interesting quirks of memory which provide a better insight into what makes us remember — or forget.
1. Context is king
What we can remember partly depends on the situation and mental state we are in at the time.
This is because our memories work by association.
The context itself can refer to all kinds of things: some things are easier to remember in a certain place, others when we experience specific smells, others when we are in particular emotional states.
One striking study which demonstrates this had deep sea divers learning lists of words either 15ft underwater or on dry land (Godden & Baddeley, 1975).
It turned out that when they learned words underwater, they remembered 32% of them when tested underwater, but only 21% when tested on the beach.
Of course our memories are far more complex than lists of words: many will have all kinds of contextual hooks, but the study neatly makes the point that for memory, context is very important.
2. Google remembers for you
If you’ve ever worried about the effect the internet is having on your mind, then this aspect of memory would seem to fuel those worries.
The ‘Google effect’ is the finding that we tend to forget things which we know we can look up on the internet.
In a study by Sparrow et al. (2011) participants were manipulated into thinking they could either retrieve items they were supposed to recall from a computer, or that the items had been irrevocably deleted.
The results showed that people’s memory was worse for things they thought they could look up.
Crucially, though, despite the fact that people’s memory was worse when they could access the information, they were better at knowing where to find it.
Given that you can look most stuff up on the internet, doesn’t that mean we’ll eventually forget almost everything?
Lead author of the study, Betsy Sparrow, doesn’t see this as the beginning of the end, rather a ‘reorganisation of the way we remember things’:
“Our brains rely on the Internet for memory in much the same way they rely on the memory of a friend, family member or co-worker. We remember less through knowing information itself than by knowing where the information can be found.”
So it’s not a step backwards, but an evolution in how memory works.
3. Negative emotions fade faster
This is a simple — and wonderful — quirk of how memory works.
It’s the fact that, on average, negative emotions are forgotten quicker than positive.
A typical study asks people to write about things that have happened to them over a period of months.
Then they are asked to recall these events up to five years later.
A curious thing happens for most (non-depressed) people: the negative things are forgotten at a higher rate than the positive.
Psychologists aren’t exactly sure why this happens, but it seems to be part of our natural psychological immune system which helps protect against life’s inevitable knocks.
4. Deep processing
This is a very obvious and intuitive quirk of memory, but nonetheless continually ignored by generations of students and others who are trying to learn.
It’s the fact that the deeper a fact or memory is processed, the greater the chance of it being recalled later.
A classic study had people trying to memorise a list of words (Craik & Tulving, 1975).
Some were told to focus on surface details, like the sound of the words or how they were written. Another group, though, had to process the meaning.
You’ll be unsurprised to learn that those who thought about the meaning of the words did the best on a subsequent test.
And yet, students and other learners continue to revise by rote or by just focusing on surface details.
Looking for deeper connections is the way to more strongly fix memories in the mind.
5. Memory distortion
When a memory is ‘misattributed’ some original true aspect of a memory becomes distorted through time, space or circumstances.
Some examples that have been studied in the lab are:
Misattributing the source of memories. In one study participants with ‘normal’ memories regularly made the mistake of thinking they had acquired a trivial fact from a newspaper, when actually the experimenters had supplied it (Schacter, Harbluk, & McLachlan, 1984).
Misattributing a face to the wrong context. Studies have shown that memories can become blended together, so that faces and circumstances are merged.
Memory expert Daniel Schacter suggests that misattributions may actually be useful to us (Schacter, 1999).
The ability to extract, abstract and generalise our experience enables us to apply lessons we’ve learnt in one domain to another.
6. The Zeigarnik effect
The Zeigarnik effect is named after a Russian psychologist, Bluma Zeigarnik, who noticed an odd thing while sitting in a restaurant in Vienna.
The waiters seemed only to remember orders which were in the process of being served. When completed, the orders evaporated from their memory.
Zeigarnik went back to the lab to test out a theory about what was going on.
She asked participants to do twenty or so simple little tasks in the lab, like solving puzzles and stringing beads (Zeigarnik, 1927). Except some of the time they were interrupted half way through the task.
Afterwards she asked them which activities they remembered doing.
People were about twice as likely to remember the tasks during which they’d been interrupted than those they completed.
The Zeigarnik effect, therefore, is that incomplete tasks are remembered better than completed ones.
It’s pretty easy to see why that might be a useful quirk of memory.
7. Childhood amnesia
Most adults can’t remember much, if anything, from before the age of three.
A new study of childhood memory reveals that childhood amnesia sets in at around the age of seven (Bauer & Larkina, 2013).
The results showed that between 5 and 7 years-of-age, the children could remember between 63% and 72% of the events they’d first recalled at the age of three.
However, by the age of 8 or 9, the children only remembered about 35% of the events.
When children are young the hippocampus–a part of the brain crucial to memory–is still undergoing neurogenesis: new neurons are constantly being produced.
Until this process is complete we find it hard to lay down long-term autobiographical memories.
8. The reminiscence bump
While we may remember little from before around the age of seven, the teenage and early adult years are a completely different matter.
Between about 10 and 30-years-old, most adults experience some of the biggest moments in their lives, all in relatively quick succession.
There’s education, puberty, falling in love, deciding on a career, getting married, having a first child and so on.
While life’s later years can be full of happiness and fulfilment, it’s in these two decades when most people experience the largest changes to their identities, goals and life circumstances.
Naturally, then, people tend to remember this period most intensely — that is the ‘reminiscence bump’, named after the bump on the graph of people’s retrieval of autobiographical memories (in red below).
9. The consistency bias
New experiences don’t fall on a blank slate; we don’t merely record the things we see around us.
Instead everything we do, have done to us, think or experience, is affected by past thoughts and things that have already happened to us.
One strong psychological drive humans have is to be consistent.
This, then, can lead to a consistency bias: we have a tendency to reconstruct the past to make it more compatible with our current world-view.
For example, as people get older, on average, they get politically more conservative.
Despite this people report always having had roughly the same views (Markus, 1986).
10. The recall effect
Many memories which have the scent of authenticity may turn out to be misremembered, if not totally fictitious events, if only we could check.
But, does the long passage of time warp the memory, or is there some more active process that causes the change?
In one experiment participants had memories laid down in a carefully controlled way to test this out (St. Jacques & Schacter, 2013).
The results showed that people’s memories were both enhanced and distorted by the process of recall. This shows that merely recalling a memory is enough to strengthen it.
This is one aspect of the fact that memory is an active, reconstructive process; recalling something is not a neutral act, it strengthens that memory in comparison to the others.
A good memory
Hopefully these ‘quirks’ of memory help to underline the fact that some of what we think of as the disadvantages of memory are really strengths.
As the great psychologist William James said:
“If we remembered everything we should on most occasions be as ill off as if we remembered nothing.”
“I hear, and I forget; I see, and I remember” –Chinese proverb
“I hear, and I forget; I see, and I remember” –Chinese proverb
Our memory for things we’ve seen or touched is much better than for what we’ve heard, a new study reveals.
The study had people listening to a variety of sounds, shown pictures and given things to touch (Begelo & Poremba, 2014).
The researchers found that it was the things people heard that they were most likely to forget, more than things they had seen or touched.
This study provides a fascinating insight into how memory works.
Lead author James Bigelow explains:
“We tend to think that the parts of our brain wired for memory are integrated. But our findings indicate our brain may use separate pathways to process information. Even more, our study suggests the brain may process auditory information differently than visual and tactile information, and alternative strategies — such as increased mental repetition — may be needed when trying to improve memory.”
In the study people were exposed to all sorts of everyday sounds, sights and tactile experiences.
They watched basketball games, heard dogs barking and touched a coffee mug that was hidden from view.
Whether it was an hour later or a week later, people’s recall was similar for things they’d seen or touched, but significantly worse for those they’d heard.
Previous studies have found that hearing sounds and words together can aid memory
Studies on chimpanzees and monkeys also show that their auditory memory is worse than tactile or visual memory.
Here are graphs showing how humans, chimps and monkeys forget depending on whether the source is auditory or visual:
This suggests that our poorer memory for things we’ve heard has its root in the evolution of the primate brain.
Can you remember anything from before the age of three?
Can you remember anything from before the age of three?
Most adults can’t remember much, if anything, from before the age of three.
It’s what Sigmund Freud first termed ‘childhood amnesia’.
But it wasn’t always this way: there must have been a time in childhood when memories from before the age of 3 could be recalled.
A new study of childhood memory reveals that childhood amnesia sets in at around the age of seven (Bauer & Larkina, 2013).
For their study, the researchers began interviewing a group of children at the age of three, asking them what they could remember.
They were then followed up at the ages of 5, 6, 7, 8, and 9 to see what they could remember from before.
The results showed that between 5 and 7 years-of-age, the children could remember between 63% and 72% of the events they’d first recalled at the age of three.
However, by the age of 8 or 9, the children only remembered about 35% of the events.
Their memories had, though, undergone an interesting transformation.
At the age of 5 or 6, children remembered more events, but their narratives of these events were hazy.
When older, though, despite remembering fewer events, what they did recall had greater detail.
Psychologists theorise that childhood amnesia occurs because the brain is still learning to encode long-term memories. The neural architecture that underlies this ability needs time to develop.
Childhood memory expert, Professor Patricia Bauer, explained:
“You have to learn to use a calendar and understand the days of the week and the seasons. You need to encode information about the physical location of the event. And you need development of a sense of self, an understanding that your perspective is different from that of someone else.”
When children are young the hippocampus–a part of the brain crucial to memory–is still undergoing neurogenesis: new neurons are constantly being produced.
This has the effect of clearing out old memories to prepare the way for new learning. This is vital for a growing child, but not so important for a young adult.
It isn’t until we gain the ability to lay down long-term memories reliably that we can begin to build a strong self-identity.
Bauer continues:
“Knowing how autobiographical memory develops is critically important to understanding ourselves as psychic beings. Remembering yourself in the past is how you know who you are today.”
