Ethan Millard is joined by Rebecca Cressman, midday host at FM100.3.

Ethan comes from a family of big heads. They have big heads. A few of them have ridiculously big heads. It's a family trait. His parents always said "big head, big brains".

Is that true? Is your brain big because your head is big? And does that make you smarter?

Of course a larger brain would require more space in a larger skull, but a large head could also be caused by thicker bone or a lot of musculature. Our heads are full of muscles. That can make your head look bigger.

Researchers at the University of Tennessee did a study and found that human skulls are larger than they were in 1825. Our heads have grown 1/3 inch taller and have about a tennis ball worth of extra brain space.

Some scientists believe that our modern lifestyle has done this. Humans enjoy more calories and less strenuous work today than in 1825.

Another theory is that because of modern medicine, more large headed babies are born. In 1825, a lot of large heads would have failed to birth.

But what about the question of whether or not a bigger brain means your smarter?

The Stanford Neurosciences Institute says the science linking brain size and intelligence is weak. There are animals with bigger brains than humans. The average human brain is 3lbs, give or take. An elephant brain is 11lbs and a sperm whale brain is a whopping 18lbs.

Humans do have abnormally large brains compared to their actual body size, but intelligence is based on a lot of factors. Nutrition and stimulation during development is a well known factor of intelligence.

Different parts of the brain can vary in size from person to person and scientists believe that can also play a role in how a person thinks.

One problem with researching brain size and intelligence is that the research tends to use IQ tests.  These don't measure important human elements such as creativity and social intelligence.  IQ tests also can't predict how successful a person will be in their life. 

Stuff Your Dad Knows is hosted by Ethan Millard.  What do you do when your children hit you up with crazy questions?  Do you know the answer?  Do you just pretend?  Kids are smart, so this podcast empowers parents to answer those tough questions and stay at the top of the family food chain.  If you want to be more efficient, just listen to the podcast with your children present.  Then you don't have to be the information middle man.  Family harmony is our goal!

If you want to ask a question, use #stuffyourdadknows and Ethan will answer it for you!  Follow him @EthanMillardKSL on Twitter.