You might think that knowledge and memory go hand in hand, and you're mostly correct. However, in some cases, knowledge can actually hurt one's ability to remember.

Now that doesn't quite mean a person's memory can be so filled up with knowledge that there isn't room for more. It does mean our knowledge can make us too quick to dismiss details that we don't consider important. And so we don't remember them.

Let's look at an example.

Say you're testing your friend's memory, and you start off showing them a picture of one cat. You also tell them that cat has beta cells in its body.

Next, you have your friend look through a series of photos of various animals and ask which animals also have beta cells. Your friend guesses all the cats. 

Now you show your friend a photo of a dog. Did you show them that dog already? They might not remember because they were too busy thinking about beta cells to pay attention to the details of each photo.

Once your friend recognized whether a creature was a cat or not a cat, they went on to the next picture. Their knowledge led them to ignore the details in each picture. Most likely, they would have had trouble remembering whether any particular cat or dog had been presented.

But who wouldn't recognize immediately whether an animal were a cat or not a cat?

Young children might not, for example. Because they don't immediately recognize a cat from a dog from a bear, they study each photograph closely to come to a careful decision as to whether it looks like the creature in the original photograph. Hence, on a surprise memory test like this one, young children actually perform better than adults, despite the fact that adults typically have much better memories than young children.

Read more

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• Smell the past
• Emotional hangover

Source

• ScienceDaily - Children can have a better memory than adults (at least sometimes)