>Whether someone with an IQ of 80 (of any age) can give informed
>consent is an open question (to me). The degree to which anyone
>can appreciate and assess "negative consequences" is presumably a
>function of the "negative consequences" to which they have been
>exposed in life.
And indeed, everyone, no matter how "intelligent" is going to have blind spots. I think this phrase, informed consent, is too vague to be of much use.
The other issue you allude to is the extent to which experience shapes our perceptions. Someone with a sufficiently traumatic past is going to see danger where it doesn't exist. Is this intelligent?