Ch 18 Case Study: 10 Twins Found Strangely Alike
Jim Lewis didnât learn he had a twin until he was 5, and it never sank in. Jim Springer learned he had a twin when he was a little older, but thought his twin was dead. When the two men were 39, researchers at the University of Minnesota Twin Study Group, who had been studying twins, reunited them.
The two âJimsâ are famous because they have so many similarities. It amazed the scientists that they even weighed exactly the same, had the same first name, and were both 6 feet tall (1.8 meters).
In addition to their similar physical traits
Both had a dog named Toy.
Each had been married twice.
Each oneâs first wifeâs name was Linda.
Each onesâ second wifeâs was named Betty.
Both had a son named James Allen.
Both smoked Salem cigarettes.
Both drank Miller Lite.
Both had worked as sheriffs, part time.
Both had recurring migraines.
Both bit their nails.
Many of their mannerisms and speech patterns.
Do some reading on genetic control of behavior and answer the questions below.
1. Why are these two men an ideal set of twins in which to study behavior?
2. Do you think the evidence shows that the behaviors listed in the case are 100% genetic?
3. Do you know any identical twins? Are they alike or different? List 4 things about them that are alike and 4 that are different.
4. Can you see any problems that might arise from studying twins raised apart? List 3.