I have been struggling with similar thoughts specifically concerning
interactions on e-commerce sites. I too felt that I needed to de-construct
the magnitude/complexity/motivational issues in ways that could be
operationalised and tested more effectively. So I came up with a graphical
model of the interplay of factors going on inside the customer's head, as
they progressed through their shopping journey.
So, how does this help me generate and test hypotheses about customer tasks?
Firstly, it teases apart predispositional factors - at its simplest level
this could be 'I love/hate shopping online' or, more subtely 'Amazon messed
me around on my last order (which in fact they have!) so I'd really rather
not put myself through all that again'. These, I suggest, resolve into a
single, and at least to some extent measureable, variable, purchase inertia
(the customer's inherent task-resistence). Then purchase impetus kicks in -
what makes them want to embark upon the task. I suggest this is determined
by the perceived need (I want a digital camera), the trigger (my mate's
asked me to take photo's at his wedding next week), and the shopping tactics
(I'll buy it at my local camera store but will have a quick look online
first). If the purchase impetus exceeds the purchase inertia, purchase
momentum results and the task commences. If the task is to be completed,
this purchase momentum must be sufficient to overcome all the hassles us
interaction designers have put in the way of task completion (okay, only
joking - well, sort of!).
Now we get into the specifics of task analysis. Consumer psychology seems
pretty well sorted on the interplay between constructed preferences (what am
I looking for and why) and the consideration set (what products am I
selecting for consideration and screening using my constructed preferences).
The only issue here is what comes out at the end of this decision-making
process. Obviously, if successful it results in product choice. But choice
is not the same as purchase and I suggest that purchase motivation (how keen
am I on my chosen product) and purchase justification play a key intervening
role in turning choice into action. The issue of purchase justification is
an interesting one. It is obviously an internal construction within the
customer's mind but research suggests that it is strongly influenced by
information presented to them. I've done a couple of jobs for clients
looking at how to customise purchase justifications depending upon the
journey taken by the customer and their interests/needs that can be inferred
from this. An interesting example of a 'purchase' justification engine was
the online manifesto published by the UK Labour Party during the 2005
General Election - they asked about your circumstances (family, level of
income, gender) and customised their manifesto promises accordingly (see http://www.cx-i.com/online_politics/persuadePers.aspx).
As may be evident, this model is work-in-progress and there is still some
way to go before it is fully resolved (e.g. what exactly is the difference
between purchase momentum and purchase motivation - intuitively they seem to
be somewhat different things but I can't see how to operationalise that
difference). The model is also designed to be specific to online shopping
but I feel there are a number of aspects of it that may be generalisable to
other areas of interaction design.
My conclusion, however, in relation to your original post is that digging
deeper than simply number and complexity of tasks can lead to a richer and
more subtle set of hypotheses.