̽��ֱ�� of Cambridge - episodic memory

Being overweight linked to poorer memory

cjb250 — Thu, 25 Feb 2016 17:28:44 +0000

In a preliminary study published in ̽��ֱ��Quarterly Journal of Experimental Psychology, researchers from the Department of Psychology at Cambridge found an association between high body mass index (BMI) and poorer performance on a test of episodic memory.

Although only a small study, its results support existing findings that excess bodyweight may be associated with changes to the structure and function of the brain and its ability to perform certain cognitive tasks optimally. In particular, obesity has been linked with dysfunction of the hippocampus, an area of the brain involved in memory and learning, and of the frontal lobe, the part of the brain involved in decision making, problem solving and emotions, suggesting that it might also affect memory; however, evidence for memory impairment in obesity is currently limited.

Around 60% of UK adults are overweight or obese: this number is predicted to rise to approximately 70% by 2034. Obesity increases the risk of physical health problems, such as diabetes and heart disease, as well as psychological health problems, such as depression and anxiety.

“Understanding what drives our consumption and how we instinctively regulate our eating behaviour is becoming more and more important given the rise of obesity in society,” says Dr Lucy Cheke. “We know that to some extent hunger and satiety are driven by the balance of hormones in our bodies and brains, but psychological factors also play an important role – we tend to eat more when distracted by television or working, and perhaps to ‘comfort eat’ when we are sad, for example.

“Increasingly, we’re beginning to see that memory – especially episodic memory, the kind where you mentally relive a past event – is also important. How vividly we remember a recent meal, for example today’s lunch, can make a difference to how hungry we feel and how much we are likely to reach out for that tasty chocolate bar later on.”

̽��ֱ��researchers tested 50 participants aged 18-35, with body mass indexes (BMIs) ranging from 18 through to 51 – a BMI of 18-25 is considered healthy, 25-30 overweight, and over 30 obese. ̽��ֱ��participants took part in a memory test known as the ‘Treasure-Hunt Task’, where they were asked to hide items around complex scenes (for example, a desert with palm trees) across two ‘days’. They were then asked to remember which items they had hidden, where they had hidden them, and when they were hidden. Overall, the team found an association between higher BMI and poorer performance on the tasks.

̽��ֱ��researchers say that the results could suggest that the structural and functional changes in the brain previously found in those with higher BMI may be accompanied by a reduced ability to form and/or retrieve episodic memories. As the effect was shown in young adults, it adds to growing evidence that the cognitive impairments that accompany obesity may be present early in adult life.

This was a small, preliminary study and so the researchers caution that further research will be necessary to establish whether the results of this study can be generalised to overweight individuals in general, and to episodic memory in everyday life rather than in experimental conditions.

“We're not saying that overweight people are necessarily more forgetful," cautions Dr Cheke, “but if these results are generalizable to memory in everyday life, then it could be that overweight people are less able to vividly relive details of past events – such as their past meals. Research on the role of memory in eating suggests that this might impair their ability to use memory to help regulate consumption.

“In other words, it is possible that becoming overweight may make it harder to keep track of what and how much you have eaten, potentially making you more likely to overeat.”

Dr Cheke believes that this work is an important step in understanding the role of psychological factors in obesity. “ ̽��ֱ��possibility that there may be episodic memory deficits in overweight individuals is of concern, especially given the growing evidence that episodic memory may have a considerable influence on feeding behaviour and appetite regulation,” she says.

Co-author Dr Jon Simons adds: “By recognising and addressing these psychological factors head-on, not only can we come to understand obesity better, but we may enable the creation of interventions that can make a real difference to health and wellbeing.”

̽��ֱ��study was funded by the Medical Research Council and Girton College, ̽��ֱ�� of Cambridge, and the James S McDonnell Foundation.

Reference
Cheke, LG et al. Higher BMI is Associated with Episodic Memory Deficits in Young Adults. ̽��ֱ��Quarterly Journal of Experimental Psychology; 22 Feb 2016. DOI:10.1080/17470218.2015.1099163

Overweight young adults may have poorer episodic memory – the ability to recall past events – than their peers, suggests new research from the ̽��ֱ�� of Cambridge, adding to increasing evidence of a link between memory and overeating.

How vividly we remember a recent meal, for example today’s lunch, can make a difference to how hungry we feel

Lucy Cheke

Franck Mahon

Too many croissants yesterday... (cropped)

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Clever crows and dancing duets

bjb42 — Thu, 01 May 2008 00:00:00 +0000

Nicky Clayton has always been fascinated by birds – by their glamour and elegance, their movement and rituals, their melodies and labours. This abiding passion has taken her from studying birdsong in zebra finches to observing complex feats of cognition in members of the corvid (crow) family, which includes scrub-jays, British jays, ravens and crows. Moving from the ̽��ֱ�� of California Davis to Cambridge’s Department of Experimental Psychology in 2000 with her colony of scrub-jays, she embarked on a series of experiments with colleague Professor Tony Dickinson that was to break new ground in comparative cognition. Their inventive experiments have shown that birds hide (or cache) food, remember where to recover it from at a later date, and even steal it from each other. Not only this, but by remembering past events (such as whether or not they would find breakfast in a certain room in the morning), the birds could take action for their future (by moving breakfast into the empty room the night before).

̽��ֱ��widely held view had been that animals can learn things through experience but not through memory; this ability to mentally travel back through time – so-called episodic memory – was thought to be something unique to the human race. For the first time ever, these experiments showed that humans are not alone in being able to remember a past experience in terms of what happened, where and when.

Nicky Clayton’s research has already branched out to cognitive studies comparing corvids with great apes through a collaborative project with her husband, Dr Nathan Emery (Queen Mary, ̽��ֱ�� of London). She is now also embarking on similar studies in young children with Dr Jim Russell in the Department of Experimental Psychology. These incredibly productive collaborations hold great promise for our future understanding of the workings of the brain in animals and humans.

What would others be surprised to learn about you?

A large part of my life is spent dancing – ballet, jazz, and particularly Latin dance like salsa and tango. Of course birds dance too: I have a favourite video clip that I show my students of the dance of the Swallow-tailed Manakin – it’s the avian equivalent of tango, and not surprisingly therefore they are found in Argentina! Two males perform a duet, a fabulous, showy double-act in which they display their beautiful plumage and synchronised movements. ̽��ֱ��males spend 90% of their time for nine months of the year dancing – a pretty intense avian dance school. This example encapsulates why I love dance: the elegance of movement, the colours, form, intensity and dedication – it strikes the core of my soul.

Who or what inspires you?

What inspires me is the curiosity and creativity of science, and the social and serendipitous meetings between people that lead on to discoveries. My academic hero is the late Bill Thorpe, Professor of Animal Ethology and founder of Cambridge’s Sub-Department of Animal Behaviour. He was an incredibly wise man and in many ways ahead of his time: he suggested that because bird brains are structurally different from the classic mammalian structure people shouldn’t assume that they are creatures of instinct. We now know of course that birds have quite impressive cognitive abilities.

Have you ever had a Eureka moment?

I suppose when Tony Dickinson and I first met – at the International Comparative Psychology meeting in Montreal in 1996 – and he said animals don’t need episodic memory. That got us talking and we began asking questions in a way that nobody else had been doing before. Out of that developed a wonderfully fruitful collaboration, with the result that four years later I moved here and we have been collaborating ever since.

What’s the best piece of advice you’ve ever been given?

Lord Krebs of Wytham, whom I worked with in Oxford, always emphasised the importance of balance in your life. His maxim was ‘healthy minds need healthy bodies’.

If you could wake up tomorrow with a new skill, what would it be?

I’d like to be able to dance flamenco. And I’d like to be reincarnated as a scrub-jay – imagine what it must be like to experience being part of this clever family of birds and find out what they really are thinking!

What motivates you to go to work each day?

That’s really easy: I love what I do. I love my days spent in research, in teaching undergraduates and graduates, in running a wonderfully supportive family-style lab, and last but by no means least, these long-term collaborations with my two best friends – Nathan, who is my husband and soulmate, and dear Tony. And I love releasing steam by dancing tango and salsa.

What is your favourite research tool?

My eyes and ears. For so much of the work I do what’s essential is detailed observation – looking and listening. It’s also important for dancing – being a good observer and a good listener helps you to copy the nuances of the rhythms.

Nicky Clayton, Professor of Comparative Cognition in the Department of Experimental Psychology, has thrown the doors wide open on animal cognition. Where once the idea would have been dismissed that animals can re-experience the past and plan for the future, her imaginative studies have shown this inherent cleverness in crows.

What inspires me is the curiosity and creativity of science, and the social and serendipitous meetings between people that lead on to discoveries.

Professor Nicola Clayton

Philip Mynott

Nicola Clayton

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