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Cognition and Motivated Behaviour Lab

Department of Psychology

How does cognition influence our consumption?

Am I Hungry?

How do we know when we’re hungry? How do we decide we have had enough to eat?  These are simple questions, but the answers are surprisingly complex. Physiologically, hunger and satiety are driven by the balance of a number of hormones in our bodies and brains. Some, like the “satiety hormone” leptin, give information about the amount of energy that is currently stored in fat around the body and act to reduce hunger. Others, like the “hunger hormone” ghrelin, are released when the stomach becomes empty, and work to increase our appetite.

However, 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. Recent research suggests that a surprising psychological process may also play a role. Memory – especially episodic memory, the kind where you mentally relive a past event - is also an important component in consumption regulation. How vividly we remember a recent meal, for example today’s lunch, makes a huge difference to how hungry we feel and how much we are likely to reach out for this tasty chocolate bar later on. In fact, just the act of thinking about what we last ate can be enough to reduce subsequent snacking by up to a third.

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 our societies. Currently around 60% of UK adults are overweight or obese: this number is predicted to rise to approximately 70% by 2034.