I wonder about cultural patterns that might result in selection bias in the studies mentioned. > All sixty participants were diagnosed with schizophrenia, and

I wonder about cultural patterns that might result in selection bias in the studies mentioned. > All sixty participants were diagnosed with schizophrenia, and regularly had auditory hallucinations. And later: > ... the Americans’ hallucinations seemed much more aggressive and violent. Perhaps (for example) Americans with non-violent hallucinations tend not to be diagnosed with schizophrenia.