Assignment 8 - Task Model Due Tuesday 11/5/2002

For this assignment you will have to build a task model of anything. I'll talk about shopping for the assignment example, like we did in class for car buying. Shopping is a task and we are building a model of it. This model should be useful to people who design stores and e-commerce sites, as well as to AI researchers and cognitive psychologists. The model is good when it provides insight into the task, and when it constrains design. There is no set procedure for doing this, but I will try to give you something like a guide.

There are STEPS in the task model. Each step in the task has a REASON for it, some PRECONDITIONS and POSTCONDITIONS. At many steps there are WARNINGS about what can go wrong, and OPPORTUNITIES that we can seize. Sometimes it is useful to provide the user with an explicit MENTAL MODEL or a METAPHOR (shopping cart). People often use their EMOTIONS and their sense of SELF when making decisions instead of optimizing features.

You'll need examples, and by that I mean stories. Stories are something that happened to you or your friends. They have details. They are interesting. Unless you are published in the New Yorker, don't make them up.

Pick your task in one domain, for example shopping for cars (you can't use this one). Build a model of it. Look at your stories. Does the model explain why the stories are interesting? Then pick another domain and see how the model you built applies to it. Expand and generalize. Pick a third domain. Repeat (I feel like a Computer Scientist).

In the end you should have a task model that applies to all three domains, and hopefully the reader of your assignment (more than likely, only me. Often, labor of genius goes unnoticed.) and YOU will have learned something about shopping.

It is perfectly OK to omit tedious details. Remember, we are looking for insight. For example, I know that paying can be done with check, cash or credit, so don't dwell on it unless it somehow affects shopping in interesting ways.

Computer people are relentless optimizers, so now you are thinking to yourself: Why bother with three domains and stories? I'll just think of a nice general model of shopping, and then I'll just plug in three different domains to make Marko happy.

I hate being bored to death. Do it, and I'll know, and I'll make you read it aloud in class.

Work in pairs. It promotes peace and understanding. It makes my job easier. Submit separately.

Finally, only for those of you who just love to take orders: 4-5 pages, 3 stories, 3 domains, 3 paragraphs on what are the insights of your model. And, shut up.

The rest, just do a good job.

Good luck,