Researchers from Tenon Hospital in Paris reported to the American Urological Association that dogs can be trained to detect the odor of chemicals released into urine by prostate cancer. The researchers first trained a Belgian Malinois to identify urine samples from patients with prostate cancer and to differentiate them from urine samples from healthy subjects. They then determined whether the dog could select a urine sample from a prostate cancer victim when four urine samples from healthy people were present. The dog was correct in 63 out 66 tests—more accurate than the prostate-specific antigen (PSA) test now used to detect prostate cancer. The researchers currently are training other dogs.

Questions:

Do you think the dog's success rate was coincidental? Why or why not?

Do you see any weakness in the experiment?

If you were testing the ability of this dog to detect urine from victims of prostate cancer, would you do anything differently?