Myth 08 · Myths
The left-brained accountant and the right-brained artist
Quizzes sort people into logical left-brain or creative right-brain types, but a scan study of about 1,000 people found no sign that individuals favor one side of the brain overall.
- Nielsen and colleagues, PLOS ONE
- University of Utah, United States
- 2013
- 3 min read
On this page
Before you readWhat would you do?
Your company wants to use an AI quiz that labels each new hire as "left-brain analytical" or "right-brain creative" and assigns jobs from that. What is the best advice?
Pick an answer now. The file tells you whether you were right.
01The file in one minute
1The real finding
Split-brain research showed some functions lean to one side, such as language to the left in most people.
2The stretch
Pop psychology turned this into personality types: logical left-brained people and creative right-brained people.
3The evidence
A 2013 study of about 1,000 brain scans found no sign that people favor one side overall.
4The lesson for AI
Tools that sort people into neat types can look scientific. Ask what evidence the categories rest on.
02Timeline
1960s
Roger Sperry and colleagues study split-brain patients.
1970s onward
Popular books turn the findings into left-brain and right-brain personality types.
1981
Sperry shares the Nobel Prize in Physiology or Medicine.
2013
A University of Utah scan study of about 1,000 people finds no dominant side.
03The myth
In the 1960s, Roger Sperry and his colleagues studied patients whose brain halves had been separated by surgery to treat severe epilepsy. They found that the two halves can specialise: in most people, language depends more on the left side, and some spatial and face-processing tasks lean more on the right. Sperry shared the 1981 Nobel Prize in Physiology or Medicine for this work.
Popular books and quizzes stretched these findings into personality types. Logical, organised people were said to be "left-brained", creative and intuitive people "right-brained", and some training courses promised to help you use your weaker side.
In 2013 a team at the University of Utah, led by Jared Nielsen, looked at brain scans from about 1,000 people aged 7 to 29. They found the expected local specialisation for some functions, but no evidence that some people are overall "left-brained" and others "right-brained".
04What the evidence says
Specialisation is real for particular functions. But almost every real task, from doing sums to painting, uses networks on both sides that talk to each other constantly through a thick bundle of fibres. Creativity and logic each draw on many areas spread across both halves.
The type labels persist because they are simple and flattering, and because people remember the times a label seemed to fit. They can also do harm if a child decides they are "not a maths person" because of a quiz.
The AI angle: AI tools that score people and sort them into neat types can look scientific while resting on weak evidence. Ask what the categories are based on before you let one decide anything about you or your staff.
The idea behind this caseLesson: What is AI, really? →
05How to spot the next one
- Separate the real finding (some functions lean to one side) from the stretched claim (people have a dominant side).
- Be careful with quizzes and tools that put people into fixed types, especially for hiring or school choices.
- Remember that skills grow with practice, whatever a label says.
- Ask any tool that sorts people what evidence shows the categories predict anything.
07 — Sources
- An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging · PLOS ONE · 2013-08-14
- Roger W. Sperry, Facts · NobelPrize.org · 1981