Big Brains, Small Brains!

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Updated on May 20, 2013

Grade Level: 9th - 12th; Type: Neuroscience/Biology


To investigate existing research and determine whether brain size is correlated with intellectual ability.

Research Questions:

  • What is brain size?
  • How is brain size measured?
  • What does it mean when brain size is measured "directly?"
  • How do neuroscientists make connections between brain size and intelligent behaviors?
  • Obtain a copy of the research conducted by neuroscientist Dr. Sandra Witelson at McMaster University (see bibliography below) and review the data presented.
  • What questions do you have related to this study?
  • What do you conclude from the Witelson study?
  • Why did Dr. Witelson caution us as to the use of MRI scans?
  • How do you react to the statement, “It remains to be determined what the contributions of nature and nurture are to this cerebral size relationship with intelligence"? What is the message?

Can we really develop our brain as we do our muscles? Is there a similarity between this critical organ and other systems of our body? Does a large brain indicate intellectual superiority? How are our brains physically measured?

Brain size is an important aspect of animal anatomy and evolution. In recent years, over 50 studies have been conducted on this subject in an attempt to explain and make sense of variations in brain size. The question of the degree to which we can link size and intellectual performance has yielded controversial outcomes. What has the research at Mc Master University proved? What did the research entail? What is the significance of their findings? Where do we go from here?

In this project, students will research what the current data indicate and identify what they see as the implications of this research. They will also raise questions that they view as worthy of future research efforts.


  • Texts, studies and articles onthe relationship between brain size and intellectual ability
  • Tape recorder/player
  • Computer disc
  • Art supplies for illustrations (if provided).

Experimental Procedure

  1. For this science project, you are asked to take on the role of a reporter for your local newspaper. Your job is to review the current research on brain size and its relationship to intelligence. You are being asked to focus on the McMaster University study.
  2. It is important that you keep the account simple so that your audience understands what has been been discovered.
  3. You may incorporate diagrams as well as pictures of the MRI equipment.
  4. You may also want to interview neuroscientists at a local hospital about how they view the research.
  5. For your science fair projectdisplay, include your dictionary of terms and concepts, your answers to the research questions, your newspaper article, and any photos, notes, or other material you gathered from the interviews. Do not forget your bibliography.
  6. Based on your article, you are asked to include what you would further explore based on what you've learned. Any questions or ideas?

Terms/Concepts: Brain;Cortex; Neo cortex; Frontal lobes; Grey matter; White matter; Intelligence; Aptitude; Intelligence quotient; General intelligence factor; Nervous system; Neurons; Age and gender differences; Genetic factors; Whole brain size; Cranial capacity craniometry; Evolution; Behavioral complexity; Neuroplasticity; Neuroimaging; Brain injury; Brain tumor; Learning disability; MRI scans


Dr. Muriel Gerhard (Ed.D.) is a retired educator with fifty seven years of experience in all aspects of public education. She has been a teacher, principal, administrator, college professor, researcher, grants writer, change agent and science editor. She is the author of several books on education used as college texts. These include the best selling Effective Teaching Strategies with the Behavioral Outcomes Approach and The Behavioral Outcomes Handbook for Teachers and Administrators. Presently she is a consultant in science education and curriculum development, a marriage and family therapist, a newspaper columnist and an author. Her latest book, recently published, is a memoir of sixty vignettes entitled "Now That I`m Dead, I Decided to Write this Book".

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