Have you ever watched one of the many TV shows set during the apocalypse - a dystopian future where life as we know it is over and people are only focussed on survival? If it's not zombies, it's viruses or natural disasters. One thing that seems to be a quintessential part of these series is survivors searching for food and resources. Is that why people stockpile food when things go bad?

What is stockpiling? Quite simply it's when people accumulate a substantial number of goods, for example food or water. According to psychologist Judy Rosenberg, stockpiling perishable goods like eggs and milk is a positive sign that people believe a crisis will be over soon. When people stockpile tinned goods, it can be a sign that people fear that the crisis will endure.

But why do we do it? Consumer psychologist Paul Marsden puts it down to three factors that relate to retail therapy. Firstly, 'autonomy' - the idea the people feel the need to be in control. Secondly, ‘relatedness' - panic shopping helps people to feel connected to the community or other shoppers who are doing the same.

Lastly, 'competence' - people want to feel like they are 'smart shoppers' and doing the right thing. Sander Van der Lindon, an assistant professor of social psychology at Cambridge University, said that a phenomenon known as 'fear contagion' can take hold. People's decision making is hampered when stressed, so they follow the actions of other people. If they are panic buying, you will too.

So, can you stop people from stockpiling? Well, supermarkets can ration the amount of products consumers purchase, and governments can try to reassure people that there is no need to panic. However, it seems that it goes against our basic psychology to try and stop people from panic buying.

So, the next time a virus, natural disaster or zombie apocalypse starts, remember that panic buying is probably a given, thanks to our need for retail therapy to manage our emotional state.