An introduction to cognitive load and Miller’s Law

One of the main reasons it’s difficult to make decisions by looking at our options and criteria is because of a cognitive limitation. There’s a bottleneck in our ability to hold information in our short-term memory, which makes it tough to compare all of our options or criteria.

That cognitive limitation is commonly referred to as Miller’s Law. In 1956, the cognitive psychology George A. Miller published a paper about a person’s working memory capacity. According to him, the number of objects we can hold in our short-term memory is seven objects, plus or minus two. In other words, people can only consider up to nine things at a time, and some people struggle with seven or even five. Beyond that, our brain drops things from short-term memory to make room for the new data. Many people try to think of one criterion, one dimension of the problem, and then they switch to another dimension of the problem, and then another, and then they find it very hard to synthesize all this information into one solution.

There are many environmental influences that must be considered, and I will define the nature of influences in the next section. The point I wish to make to start this chapter is that Miller Law’s is real. We can generate ten or twenty options because there are an unlimited amount of options and criteria we can consider. Miller’s Law, however, means there is a limitation on the number of objects we can process in our minds and make a decision. Humans have found ways to bypass this limitation or simplify the decision-making process, but these aren’t comprehensive solutions to the problem. Simplifying or creating shortcuts creates problems, and the very fact that our ability to make calculations is limited creates a lack of self-confidence. It can feel like the deck is stacked against you before you even attempt to play the game.

In every simple decision, the options and criteria – which I will collectively refer to as influences – must be considered. We might be able to consider three options and three criteria (for nine influences total), or two options and four criteria (for eight influences total). When a person is faced with ten options and ten criteria, though, there is no chance for them to be able to make that kind of decision in their head.

The more criteria we use and the more options that we want to consider, the more we find ourselves trying to bypass these mechanisms that help us make the best possible decision. Miller’s Law cannot be beat, though, and the cognitive limit to our decision making ability remains no matter what we try. As a result, we stick to habits or our heuristics instead, and continue to do what we’ve done before. We tend to limit our thinking to either very few criteria, very few options or both. In the end, we minimize our thinking to just a few options and make a choice between them.