Death Row and Head Trauma A study conducted by Lewis et al. in 1986 looked at 14 juveniles awaiting execution. They found that 57% (8 of the 14) had had a serious brain injury.
Can we conclude that head trauma causes bad behavior later in life? What primary factor is not present here that should be present in both observational studies and controlled experiments?
(Source: Psychiatric, neurological, and psychoeducational characteristics of 15 death row inmates in the United States, American Journal of Psychiatry, vol. 143: 838-845. 1986)