[lutusp]

> Why would it be unethical if people voluntarily agree to participate?

12-year-olds? The study we're discussing examines the behavior of minors. Minors cannot give the kind of consent you're suggesting.

Also, the sort of strictly designed experiments that might turn psychology into a science, are extremely expensive and not likely to be funded. The reason? Research standards in psychology are so abysmally low that a well-designed study would be so expensive by comparison that the granting agencies would refuse to fund it.