Do animals with bigger brains remember more things?

Scientists don’t have an answer to this question yet. Some people have hypothesized that there is a link between the brain size of different species of animals and memory ability (and also other abilities, like tool use or social play).

While we can’t yet answer this question, we do know a few things about the role of brain size.

First, the brain is like a piece of paper that has been wadded up into a ball — it has lots of folds and ridges. Can you imagine how a small piece of paper could be crumpled loosely into a paper ball that is the same size (volume) as a larger piece of paper that has been really crumpled and squished together? This can also happen with brains! Two different types of animals can have brains with a similar volume. But that doesn’t mean the two brains are made from the same amount of brain tissue — if one animal’s brain has lots of folds and ridges, it will be made of more brain tissue than another animal whose brain is smooth with few folds. It’s the amount of brain tissue that matters.

Second, bigger animals have bigger brains. But this doesn’t mean that the brains of bigger animals can always do more things than the brains of smaller animals. Instead, what is important is the size of the brain in relation to the size of the body.

Birds and mammals do have relatively larger brains (relative to their body sizes) than other vertebrate animals. A lot of ongoing research is trying to understand why these animals evolved to have these larger brains and what it may mean for these animals’ abilities, including their memories.

Third, it’s important to remember that while many parts of the brain are typically working together, there are different parts of the brain that help with different abilities. Some animals have relatively large olfactory cortices (the parts of the brain that process smell) because scent is the sense they use most often. Others have relatively smaller olfactory cortices but larger visual cortices (this is true of human brains). So it’s not just the overall relative size that matters but also which portions of the brain are especially large or especially small.