What if an individual holds a value that is at variance with "the dominant behaviours and beliefs of... [his]...society or... group"?

I think it is probably impossible to hold a value that no one has held before; or a value that is at least not a variant of some previously held value. So, in that sense it seems reasonable to say that values are culturally constructed. That is to say I think we are limited to a certain range of culturally embedded values from which to choose, but "the dominant behaviors and beliefs of a society or a group" cannot determine that we will chose those particular behaviors and beliefs.

Values are the dominant behaviours and beliefs of a society or a group" and that values have nothing to do with individuals.

If there are behaviours and beliefs that dominate a society or group, it seems likely that there are also minority behaviours and beliefs. Presumably, these form a sub-group within which they are in turn dominant. Thus 'wages for housework' might be a subgroup within the larger feminist group which is in turn a sub-group of society at large.

However, it seems to me that a sub-sub-group can onlybegin with an individual having a new, or modified behaviour or belief, and recruiting converts. Such people used to be called 'prophets', but social science has no room for such as this, and so is forced to resort to random magic to explain how dominant values change and develop.

It's as silly a position to take, as if a physicist were to claim that the properties of materials have nothing to do with the atoms that compose them.

You may want to consider how norms arise. If what we value is based on desire what we want, then how we act must be based on our ability to act in such a manner so we can obtain what we want. What we ought to do to obtain what we want involves our associations with others. Norms arise in society's because each of us has wants and there has to be rules, to prevent mayhem. We follow normative rules so that we can get what we value.

Values relate to people's beliefs. For example, the belief that being charitable is more desirable than being greedy. A belief is personal, hence others can believe the converse: that being greedy is more desirable.

What can be socially constructed, however, is environmental pressure which pushes more persons to comply to a belief which might increase their social fitness, evade persecution and so on.

Thank you for all the responses. I have read them all and don't really have too much to add at the moment but the replies have given me something to digest, think about and try to get my head around.