Biological Bases of Intelligence

Your next lesson will play in 10 seconds
  • 0:19 Genetic Factors
  • 1:15 Environmental Factors
  • 2:22 The Flynn Effect
Create An Account
To Start This Course Today
Used by over 10 million students worldwide
Create An Account
Try it free for 5 days
Lesson Transcript
Instructor: Polly Peterson
Have you ever wondered if your intelligence is entirely due to genetics or if it's shaped by the environment surrounding you? In this lesson, you'll learn about the factors that affect and influence a person's intelligence.

Do we inherit intelligence from our parents? What are the origins of intelligence? Is there any truth to the claim that genes determine it, or is intelligence solely the result of environmental factors? Many studies suggest that intelligence is influenced by both genetic and environmental factors.

We do know that people who share genes tend to have similar mental capabilities. Identical twins have near-identical genetic codes, and they often score nearly the same on intelligence tests. Biological children and their parents, who are likewise genetically similar, are more likely to have similar IQs than adopted children and their parents.

Measurable physiological factors also support biological and possibly genetic influences that affect intelligence. For one thing, larger brain size is loosely correlated with greater intelligence. So are the brain's glucose metabolic rate, or the speed at which it makes energy, and the speed of brain waves. But none of these things are solely responsible for intelligence.

Still, research shows that we aren't born with a biologically predetermined amount of intelligence that remains fixed for our whole lives. Environmental influences have been shown to impact test results. Both fluid intelligence, or the ability to learn new ways of doing things, and crystallized intelligence, or the stockpile of knowledge we've accumulated throughout our whole lives, have been shown to change over time.

The environments in which we live influence our intelligence. Twins raised in the same environment have IQs that are more similar than twins raised in different homes. Other studies suggest that peer groups, the people you associate with, can impact intelligence. For these reasons, education generally tends to improve intelligence, but poverty seems to harm it.

To unlock this lesson you must be a Member.
Create your account

Unlock Your Education

See for yourself why 10 million people use

Become a member and start learning now.
Become a Member

Already a member? Log In

Earning College Credit

Did you know… We have over 49 college courses that prepare you to earn credit by exam that is accepted by over 2,000 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Click "next lesson" whenever you finish a lesson and quiz. Got It
You now have full access to our lessons and courses. Watch the lesson now or keep exploring. Got It
You're 25% of the way through this course! Keep going at this rate,and you'll be done before you know it.
The first step is always the hardest! Congrats on finishing your first lesson.
Way to go! If you watch at least 30 minutes of lessons each day you'll master your goals before you know it.
Congratulations on earning a badge for watching 10 videos but you've only scratched the surface. Keep it up!
You've just watched 20 videos and earned a badge for your accomplishment!
You've just earned a badge for watching 50 different lessons. Keep it up, you're making great progress!
You just watched your 100th video lesson. You have earned a badge for this achievement!
Congratulations! You just finished watching your 200th lesson and earned a badge!
Congratulations! You just finished watching your 300th lesson and earned a badge!
You are a superstar! You have earned the prestigious 500 video lessons watched badge.
Incredible. You have just entered the exclusive club and earned the 1000 videos watched badge.
You have earned a badge for watching 20 minutes of lessons.
You have earned a badge for watching 50 minutes of lessons.
You have earned a badge for watching 100 minutes of lessons.
You have earned a badge for watching 250 minutes of lessons.
You have earned a badge for watching 500 minutes of lessons.
You have earned a badge for watching 1000 minutes of lessons.