Our closest living cousins, the chimpanzee apes, have a better short term memory than human apes.

Chimpanzees demonstrate their superior short term memory in this YouTube video.

It's really amazing to watch. The humans don't even come close.

Why do chimpanzee apes have a better short term memory than human apes?

Natural selection selects for advantages that keep a creature alive. Advantages accumulate and spread throughout a population.

But what happens when an evolved trait no longer becomes necessary? For example when one lineage of fishes winds up in a cave in total darkness. Then seeing becomes useless. If a mutation makes eyesight worse, that fish still survives because it can't see anyway. Since better eyesight is not selected for by natural selection, mutations that make eyesight worse accumulate, and eventually this lineage of fish becomes completely blind.

Perhaps our ancient pre-human ancestors needed a strong short term memory to survive, and so this advantage was selected for. Our ancient ape ancestors who had a better memory were more likely to survive long enough to reproduce and their genes were passed on to the next generation.

But then something happened that made an excellent short term memory less important. According to this BBC News article a scientist said "These studies tell us that elaborate short-term memory skills may have had a much more salient function in early humans than is present in modern humans, perhaps due to our increasing reliance on language-based memory skills."

Our increasing reliance on language-based memory skills meant that a superior short-term memory became less necessary and so this advantage was not selected for, just like better eyesight was not selected for a lineage of fish that lived in completely dark caves.

Some more information from the same BBC News article:

The shortest time duration, 210 milliseconds, did not leave enough time for the subjects to explore the screen by eye movement - something we do all the time when we read.

This is evidence, the researchers believe, that young chimps have a photographic memory which allows them to memorise a complex scene or pattern at a glance. This is sometimes present in human children but declines with age, they say.

"Young chimpanzees have a better memory than human adults," Dr Matsuzawa told BBC News.

"We are still underestimating the intellectual capability of chimpanzees, our evolutionary neighbours."

Dr Lisa Parr, who works with chimps at the Yerkes Primate Center at Emory University in Atlanta, US, described the research as "ground-breaking".

She said the importance of these primates for understanding the skills necessary for the evolution of modern humans was unparalleled.

"They are our closest living relatives and thus are in a unique position to inform us about our evolutionary heritage," said Dr Parr.

How are you Christian creationists doing? Are you keeping up with this? Do you better understand why everyone laughs at you when you deny our evolutionary relationship with the chimpanzee apes? Ready to join the 21st century yet? I didn't think so.

Another better video about the same thing:

Man Vs Chimp - memory test