It’s taken me ages to realise that there’s a difference, but it seems:

The constructivist school came first and is characterised by PCT.  Meaning is ascribed internally within an actor as a consequence of their own experiences.  An individual can, however, change their view of the world as a consequence of their interactions with others.  Meaning is therefore developed within a social group as a consequence of influence and negotiation.

Then constructionism came along and is characterised by development of meaning directly from the interactions of actors.  Meaning is collective and developed directly from social interations.  This school would seem, therefore, to assume that an individual can’t understand their world in isolation form others, which seems somewhat odd.  After all, with this view, what would be the point of skiddling?

Constructs span both, it’s just a question of how they are developed and reorganised…

But, if we’re talking about value theory and judgement among a group of stakeholders, then both have to be considered.  This suggests that interpretation of artefacts has to be considered from a fundamentally different perspective if we’re considering an individual or that individual’s function within a group.  We must decide if we assume knwoldge to be generated first by individuals and then shaped by individuals’ interactions, or if comes solely from the interactions of individuals.  Or maybe it’s bits of both…

It’s interesting that the learning theory has only recently hooked onto the social aspects of learning (Laurillard) – i.e. the construcitivist view – and all the reflective learning (reflective design theory; schon’s double loop learning, etc.) are firmly grounded in the constructionist view.

Does this mean that SNA hasn’t yet been meaningfully looked at from the point of view of knowledge generation, or am I missing something???  Having said that, the Tipping Point stuff assumes, through the action of “salesmen,” a constructivist stance.  Although, from memory, it ever acknowledges this.  I may have to read it again…