‘Memories are made of this’ compares different types of memory. There are distinct systems for short term and long term memory. Short term memory is transient. Long term memory, on the other hand, invokes more robust changes to the brain's architecture. Experiments have located specific brain areas for different kinds of memories. Examining the actual mechanisms of memory formation in humans is far harder. Fortunately very similar mechanisms exist in more primitive animals. Kandel's work on habituation and sensitization in sea slugs showed that long term memory required the synthesis of new proteins, whereas short term memory did not. This is consistent with other work done in rodents and humans.