I am in the middle of Cooper's book "About Face" now, which basically established Goal-Oriented Design, so this take on Activity-Centered Design versus Human-Centered Design was pretty interesting.
On user research:
Most items in the world have been designed without the benefit of user studies and the methods of Human-Centered Design. Yet they do quite well. Moreover, these include some of the most successful objects of our modern, technological worlds.
On activities vs tasks:
Do note the emphasis on the word “activity” as opposed to “task.” There is a subtle difference. I use the terms in a hierarchical fashion. At the highest levels are activities, which are comprised of tasks, which themselves are comprised of actions, and actions are made up of operations. [...] For example, mobile phones that combine appointment books, diaries and calendars, note-taking facilities, text messaging, and cameras -- can do a good job of supporting communication activities. This one single device integrates several tasks: looking up numbers, dialing, talking, note taking, checking one’s diary or calendar, and exchanging photographs, text messages, and emails. One activity, many tasks.
On difference between HCD and ACD:
Activity-Centered Design (ACD) is actually very much like Human-Centered Design (HCD). Many of the best attributes of HCD carry over. But there are several differences, first and foremost being that of attitude. Attitude? Yes, the mindset of the designer.
The activities, after all, are human activities, so they reflect the possible range of actions, of conditions under which people are able to function, and the constraints of real people. A deep understanding of people is still a part of ACD. But ACD is more: it also requires a deep understanding of the technology, of the tools, and of the reasons for the activities.
On listening to users too much:
One basic philosophy of HCD is to listen to users, to take their complaints and critiques seriously. Yes, listening to customers is always wise, but acceding to their requests can lead to overly complex designs. Several major software companies, proud of their human-centered philosophy, suffer from this problem. Their software gets more complex and less understandable with each revision. Activity-Centered philosophy tends to guard against this error because the focus is upon the Activity, not the Human. As a result, there is a cohesive, well-articulated design model. If a user suggestion fails to fit within this design model, it should be discarded. Alas, all too many companies, proud of listening to their users, would put it in.