It’s Fright Night!

Lucy Lewis | 31 OCT 2018

Halloween is the time for all things scary, and the best thing for scaring people is to put on a good horror movie, preferably something with creepy dark figures appearing suddenly after a long, tense build up. But what is it about these films that gets us so freaked out?

Fear is an integral part of our survival mechanisms, it is a part of the ‘fight or flight’ response to prepare us for combating or escaping from a potential threat. Deep down, you know the demons from Insidious aren’t real, and the clown from It isn’t going to appear behind the sofa, and yet we jump at their appearance on screen, hide behind pillows when the music goes tense and even continue thinking about them once the film is finished.

Halloween

Scene from ‘A Nightmare on Elm Street’ (1984).

This is because horror movies tap in to this innate survival mechanism by presenting us with a situation/character that looks like a threat. When we see something potentially threatening, this activates a structure in the brain known as the amygdala, which associates this threat with something to be fearful of (Adolphs 2013). The amygdala acts as a messenger to inform several other areas of the brain that there is a threat present, thus resulting in multiple physiological changes, including the release of adrenaline (Steimer, 2002) which causes the typical bodily functions we experience during fear, e.g. increased heart rate.

Even though we know the movie isn’t real, the amygdala takes over our logical reasoning to produce these responses, a phenomenon known as the “amygdala hijack” (Goleman, 1995).  This is when the amygdala stimulates these physiological changes to prepare us against this fearful threat before the prefrontal cortex of the brain, responsible for executive functions, can assess the situation and regulate our reactions accordingly (Steimer, 2002).

In fact, studies looking into fear conditioning, which is when associations are made between a neutral stimulus like a clicking sound and an aversive stimulus like an electric shock (Gilmartin et al 2015), have shown that inactivation of the medial prefrontal cortex results in a deficit in the ability to disconnect this association, suggesting that the prefrontal cortex is necessary for the extinction of a fear memory (Marek et al, 2013).

Halloween2

A schematic diagram of the fear pathway, adapted from a VideoBlocks image.

You’ve probably noticed that you can also remember something that scared you so much better than even remembering what you had for breakfast. Forming memories of the events that cause us to feel fear is important for our survival mechanisms, because it helps us to avoid threats in the future. Evidence suggests that the stress hormones that are released following exposure to fearful events contribute to the consolidation of memories, for example Okuda et al (2004) gave rats an injection of corticosterone (the major stress hormone for rodents) immediately following one training session of a task requiring the animals to remember objects presented to them in an arena. They showed that, 24 hours later, the animals that received this injection showed significantly greater recognition of these objects than controls, suggesting that this stress hormone increased their ability to remember the objects around them. Therefore, the scarier the film, the more we remember it.

So, don’t worry if you are a big scaredy-cat when it comes to horror films, it’s actually natural! It’s just your brains response to a threatening situation, and you can’t control it no matter how hard you try. But if you are planning a film night full of ghosts and ghouls this Halloween, go and get yourself a big pillow to hide behind and prepare for that good old amygdala to get into action!

Edited By Lauren Revie & Sophie Waldron

References:

  • Adolphs, R. 2013. The Biology of Fear. Current Biology, 23:R79-R93.
  • Gilmartin, M. R., Balderston, N. L., Helmstetter, F. J. 2015. Prefrontal cortical regulation of fear learning. Trends in Neuroscience, 37:455-464.
  • Goleman, D. 1995. Emotional Intelligence: Why It Can Matter More Than IQ. New York: Bantam Books.
  • Marek, R., Strobel, C., Bredy, T. W., Sah, P. 2013. The amygdala and medial prefrontal cortex: partners in the fear circuit. Journal of Physiology, 591: 2381-2391.
  • McIntyre, C. K. and Roozendaal, B. 2007. Adrenal Stress Hormones and Enhanced Memory for Emotionally Arousing Experiences. In: Bermudez-Rattoni, F. Neural Plasticity and Memory: From Genes to Brain Imaging. Boca Raton (FL):CRC Press/Taylor & Francis, Chapter 13.
  • Okuda, S., Roozendaal, B., McGaugh, J. L. 2004. Glucocorticoid effects on object recognition memory require training-associated emotional arousal. Proceedings of the National Academy of Science, USA, 101:853-858.
  • Steimer, T. 2002. The biology of fear- and anxiety-related behaviors. Dialogues in Clinical Neuroscience, 4:231-249.
  • VideoBlocks, AeMaster still photo from: 3D Brain Rotation with alpha. https://www.videoblocks.com/video/3d-brain-rotation-with-alpha-4u23dfufgik3slexf

Learning to make healthier food choices

Sophie Waldron | 3 MAY 2018

If you haven’t already, read Sophie’s first article ‘Learn, eat, repeat: how food advertising works’!

You are sitting down at a desk and a huge burger comes floating towards you. It gets bigger and bigger as it advances, faster and faster. Luckily, you know what you have to do. Don’t press anything on your computer, and the burger will go away.

This isn’t some dystopian reality where burgers are our new overlords. It’s a computer task that can help people make healthier food choices. In the task, which people can also engage with on their smartphones as an app, participants have to prevent a learnt response to unhealthy food items.

People are first trained to press certain computer keys every time certain images of healthy and unhealthy food come on screen. Then in a subsequent phase participants have to press keys to every picture on screen except to pictures of unhealthy food. Helpfully, a prompt comes with pictures of healthy food, warning people not to respond.

This task may seem simple, but it is designed to help people mentally tackle automatically activated learnt responses to obtain unhealthy food. We live in what scientists call an ‘obesogenic’ environment, where high calorie food is abundant and pushed on us through advertising. Research has shown that learnt associations between pictures (such as a brand logo) and tasty food can make us reach for that food even when we are full (Watson et al., 2014)! In such a world we learn to respond to the attractively colored logo-dripping packets of fast food and eat them, rather than thinking carefully about which foods benefit us. Inhibiting learnt key press responses to food might give us the cognitive skills to think twice about automatically reaching for a chocolate bar.

The unhealthy food inhibition task was designed by Lawrence and her team in 2015. They investigated whether preventing an automatic key press response to unhealthy food pictures would reduce consumption of unhealthy foods in people’s everyday lives. It was found that the task reduced self-reported snacking for up to 6 weeks. This holds many possibilities. If people can make healthier choices based on one lab session, it is likely that they can be healthier for much longer if they could carry on with the task on a regular basis as part of a smartphone app.

Another avenue for treating overeating is mindfulness. Mindfulness practice cultivates experiencing the present external and internal environment, including sensory influx and the thoughts and feelings we have. Mindfulness eating practice focuses on the experiential qualities of food, taste, texture, and our feelings of satiety. There has been evidence that incorporating mindfulness eating into one’s life reduces self reported measures of binge and emotional eating (Alberts et al 2012), consumption of sweets (Mason et al., 2015), and BMI (Tapper et al., 2009).

Currently the mechanism by which mindfulness eating leads to healthier food consumption is unknown. Mindfulness has been found to decrease self-reported body image concern in healthy women with disordered eating (Alberts et al 2012), which may lead these women to eat healthier. However there is a problem that runs through this research: self-report.

Self-report is practical, experimenters could not follow around participants every day for 6 weeks prior to testing and write down exactly what they ate, so instead they ask them to keep a food diary. However self-report studies give an indirect measurement of the dimension experimenters are focusing on, and thus conflate actual changes in behaviour with changes in reporting about a certain behaviour. For example in the study on body image and mindfulness eating, it could be that reduced body image concern actually results in healthier and more natural eating. Yet it also could be that women eat the same but interpret this eating as healthier because of their more positive self-image. Self-report cannot distinguish these possibilities.

Another way in which mindfulness eating may trigger healthier choices is by increasing the flexibility of learning about reward and punishment. It has been claimed that obesity might be due to an inflexibility in this kind of learning, as once people have learned that a food is tasty (and thus rewarding) they may eat too much of it despite the undesirable consequences overeating brings, such as feeling too full or being overweight. In other words, they fail to change their overeating behaviour even when it leads to something unpleasant, a punishment. Janessen and colleagues (2018) found that time invested in mindfulness eating correlated positively with good performance on a task where participants had to quickly learn that a previously rewarded item was now punished, and vice versa. This hints that mindfulness eating could arm people with the cognitive flexibility required to overcome compulsive automatic eating patterns.

Further research will have to look at the long-term health consequences of mindfulness eating practice, and apps that train us to inhibit automatically reaching for unhealthy food. Yet studies so far are promising! Both these tools, and others, will be essential in catching up with the explosion of accessible high calorie food and food advertisement in the modern world.

Interested in the science of obesity and how we can tackle it? A recent BBC documentary ‘The Truth About Obesity‘ covers some strategies, including a study looking at the effectiveness of using apps to train better eating behaviours, filmed at CUBRIC

Interested in the effect of mindfulness on the brain? Check out our previous article: ‘The Neuroscience of Mindfulness: What Happens When We Mediate?’

Edited by Jonathan Fagg

References:

  • Alberts, H. J. E. M., Thewissen, R. & Raes, L. (2012). Dealing with problematic eating behaviour. The effects of a mindfulness-based intervention on eating behaviour, food cravings, dichotomous thinking and body image concern. Appetite 58, 847–851.
  • Janssen, L. K., Duif, I., Loon, I., dv Vries, J. H. M., Speckens, A. E. M., Cools, R & Aarts, E. (2018). Greater mindful eating practice is associated with better reversal learning. Scientific Reports, 5702.
  • Lawrence, N. S., O’Sullivan, J., Parslow, D., Javaid, M., Adams, R. C., Chambers, C. D., Kos, K., Verbruggen, F. (2015). Training response inhibition to food is associated with weight loss and reduced energy intake. Appetite, 17-28.
  • Mason, A. E. et al. (2015). Effects of a mindfulness-based intervention on mindful eating, sweets consumption, and fasting glucose levels in obese adults: data from the SHINE randomized controlled trial. J. Behav. Med. 1–13.
  • Tapper, K. et al. (2009). Exploratory randomised controlled trial of a mindfulness-based weight loss intervention for women. Appetite 52, 396–404.
  • Watson, P., Wiers, R. W., Hommel, B., & Wit, S. (2014). Working for food you don’t desire. Cues interfere with goal-directed food-seeking. Appetite, 139 -148.

Learn, eat, repeat: how food advertising works

Sophie Waldron | 23 APR 2018

You woke up late and ate breakfast late. Thing is, now it’s noon and you are hungry again. How can you be hungry when you only ate an hour ago?

When interacting with our environment, we form associations between items that occur together. This occurs with food, for example if we always eat lunch at 12pm, we will associate that time with food.

What is more, feelings and responses associated with one item can be linked to another by association. The feeling of hunger that is linked to food can become associated with 12pm, so that the time seems to be making you hungry independent of whether you are about to eat or not!

This kind of learning by association is Pavlovian conditioning, discovered by the Russian doctor Ivan Pavlov (hence the name)! He was attempting to study dog’s digestion by measuring their saliva, when he discovered that they would salivate not only to food, but to other stimuli associated with food, such as the experimenter’s footsteps.

Pavlovian conditioning is a gift to advertisers. It provides an avenue to create thoughts or feelings towards a product by associating it with other relevant things. It’s what Coca-Cola are trying to do by sponsoring sporting events – they are hoping that by associating Coke with sports, people will think of it as healthy. Predominantly advertisers attempt to create good feeling towards their products by associating them with stuff their audience likes. They sell Walker’s crisps by associating them with football, new chocolate bars by associating them with old chocolate bars, and even try to sell Pepsi by linking it to Kendall Jenner and social justice movements!

…perhaps think twice about that last one!

It is likely that these associations take charge of our preferences from an early age. We live in an environment teeming with food advertising! A recent study asked 4-6 year old children which of two identical food items they would rather eat, one in plain packaging and one in packaging with a fast food logo. Children overwhelmingly chose the packet with the logo on, despite no differences to how the food inside looks or smells (Robinson et al 2010).

This likely reflects the fact that because of associations between the logo and other pleasant things, established by advertising, children see the food inside as inherently better. The age of the children points to how associations like these form early on in life, and likely determine food choices for many years to come. This learning could contribute to why changing eating behaviour is so hard, as learnt associations have to be revised.

How do these associations influence our behaviour? Pavlovian conditioning only describes the formation of associations between two items, so we must invoke another form of learning if we are to understand how advertising can change which foods we act to obtain. This is instrumental learning, which describes how if a behaviour leads to something pleasant (like tasty food) it is likely to be repeated. My mum used to employ this tactic to stop me being naughty as a child. If I didn’t throw a tantrum the whole way round the supermarket, I got a chocolate cookie.

Pavlovian and instrumental learning interact to influence our actions. Specifically, Pavlovian associations can override and shape learnt behaviours. Watson and colleagues (2014) demonstrated this using a laboratory based computer task. Participants first learned instrumentally that pressing one key got them a piece of chocolate, and another key delivered popcorn. They also learned associations between chocolate and a striped pattern and popcorn and a checked pattern.

Participants then ate lots of chocolate or popcorn. This wasn’t just for fun, the idea was that if a participant eats lots of chocolate they will want to eat it less in future, so not act to obtain it. This was true, participants who had gorged on chocolate pressed on the key associated with chocolate less in the next round of the experiment. These participants were then presented with one of the pictures Pavlovian-associated with chocolate. Experimenters found that even if a participant did not usually want to act to obtain chocolate, when presented with an image associated with chocolate they would press the key to get it!

Think about this in a real world setting. This means that even if we are completely full and don’t want to eat, if we see an advert for pizza on the TV we may quickly find ourselves on the deliveroo website. Furthermore our behaviour may be swayed even by seeing things which are not food, but which are associated with food through advertising. Seeing Gary Lineker’s face might make us reach for a packet of crisps even if we don’t really fancy them. This means that food adverts can control not only what we like to eat, but also tip us towards eating when we do not want to.

Association formation surrounding food is not specific to advertisement. When we interact with an environment in which food is only presented in certain situations, associations (both Pavlovian and instrumental) will form. Going back to the kitchen in the house you grew up in can make you crave cherished childhood foods – fish fingers and smiley faces anyone? It also works the other way round, how often has a certain flavour evoked in you a memory.

This fundamental mechanism just transfers particularly well to advertising. Associations can make us like certain foods in the first place, and also control when and how often we eat them.

Related article: Learning to make healthier food choices.

Edited by Jonathan Fagg

References:

  • Robinson, T. N., Borzekowski, D. L. G., Matheson, D. M., & Kraemer, H. C. (2007). Effects of fast food branding on young children’s taste preferences. Archives of Pediatrics & Adolescent Medicine, 161(8), 792e797.
  • Watson, P., Wiers, R. W., Hommel, B., & Wit, S. (2014). Working for food you dont desire. Cues interfere with goal-directed food-seeking. Appetite, 0195-6663.