Imagine this. You’ve bought a new house. It’s everything you’ve ever dreamed of and you can’t wait to decorate and furnish it. You come across a copy of the Ikea catalogue, which you casually flick through whilst having your breakfast. The sleek and affordable designs catch your eye and so you immediately make the trip to the nearest Ikea store. It’s 10am when you arrive and you happily weave your shopping trolley through the model kitchens, bedrooms and bathrooms, around the aisles of quirky lampshades, bathroom accessories and contemporary artwork, finally reaching the mighty warehouse, stacked high with boxes of DIY flat-pack units.
Three hours have passed and you arrive at the checkout. You place your items on the conveyer belt for the shop assistant to scan through the till. You move closer to the front of the queue and greet them with a sigh and an awkward smile of embarrassment, as you hand over £3.50 for a solitary vanilla-scented candle and a pack of Daim bars!
So what happened? Why didn’t you buy anything else? Chances are you experienced Decision Fatigue. Scientists have coined this phrase to describe the exhausting process of making decisions, which we are all susceptible to in many aspects of normal life but particularly as consumers where willpower is key.
Experiments have demonstrated the link between Decision Fatigue and willpower in various ways. In one study (Vohs et al., 2008), subjects were asked to repeatedly choose one item from random pairs of inexpensive objects, ranging from chewing gum to tennis balls. They were also told their decision would influence which item they could keep and take home at the end of the day. Let’s call this group the deciders. Another group of subjects (we can call these the non-deciders) were simply asked to write down what they thought about each item (i.e. they didn’t have to make any decisions) and were told that the experimenters would choose an item for them to keep and take home.
Immediately after, both deciders and non-deciders, were asked to hold their hand in ice-cold water, as a measure of willpower. The results showed that deciders pulled their hands out of the water much faster than non-deciders. Essentially, those subjects who were forced to make several decisions in the first part of the experiment, gave up much quicker than those who didn’t have to decide on anything.
As a consumer the same tends to happen, whether you are shopping in a store, choosing food in a restaurant or browsing the Internet for holidays. To make any decision you need to place some value on each option and imagine the possible futures that would arise from selecting A over B. For example, if you were browsing for shower curtains in Ikea, you brain would be hard at work, pondering and analysing what the outcome would be if you chose shower curtain A over shower curtain B. Would it be long enough to fit over the bathtub? Is the material thick enough to prevent water spraying on the floor? Does the pattern match the bathroom tiles? Thought after thought. Question after question.
It’s the Prefrontal Cortex (at the front of your brain) that has the job of decision-making by processing this kind of information. You won’t be aware that this is happening, but it is, and if you spent a couple of hours looking at all the products in a large shop like Ikea your Prefrontal Cortex can go into overdrive (perhaps this explains why you often hear people complaining of headaches whilst shopping!). Your poor brain becomes exhausted, your willpower plummets and you could give up completely (explaining why the deciders in the experiment pulled their hands out of the icy water quicker than the non-deciders). Or, like the Ikea shopper, when willpower drops you could simply default to an easier decision such as the most pleasant smelling candle or which chocolates would best satisfy a sugar craving.
In fact, it’s no surprise that our fictional Ikea shopper sought out chocolates after their 3-hour shopping trip. It’s well known that willpower is reduced when blood sugar levels fall (Galliot and Baumeister, 2007). Indeed, have you ever wondered why there are 
restaurants or cafés in stores (and if the boss is clever enough, located right in the middle of them)? It gives hungry consumers, who have become tired of making decisions, the chance to re-fuel and boost their blood sugar, before continuing with their intensive shopping/decision-making trip.
So, perhaps the answer is to first have a hearty meal and then break the decision-making into small chunks interspersed with regular snack breaks to give your Prefrontal Cortex time to rest and re-fuel. That way your Prefrontal Cortex may be more able to effectively compute information and make clearer decisions. Otherwise, as time goes on, Decision Fatigue is still likely to kick in, your willpower could decline and your prefrontal cortex might only have enough energy to make the easiest decision it can – to do nothing at all.
Post by: Tarah Patel
REFERENCES:
Galliot M and Baumeister R, Pers Soc Psychol Rev. 2007 Nov; 11(4):303-27.
Vohs K et al., Journal of Personality and Social Psychology, 2008, Vol. 94, No. 5, 883– 898.