Affordances and Prospects

Stan Ruecker today successfully defended a thesis on theorizing rich propospect affordances for interpretively-tagged text collections. Two things that are very interesting about the thesis are:

1. He traces the literature on affordances (that show up without a lot of background in UI discussions like Norman) to JJ Gibson and environmental psychology.

2. He proposes prospects (visualizations that have a meaningful representation of all items in a collection) as useful way to interface with medium sized text collections like Orlando.

Affordances: The discussion on affordances raised an interesting issue about intention. Gibson argues that affordances are in the phenomenon not in the intention of the user. This nicely bypasses problems about intention. However, user testing typically involves some sense of the intentions of the user – you test how well an interface meets needs (intentions) of users. How does affordance (which focuses on opportunities for action as a relationship between user/object) avoid (if at all) intentionality? How is the study of affordance different from functional user testing? One answer is that affordances go beyond what a phenomenon was intended to do. This would seem to be the case with logical (xml) markup – which provides more affordances than just the ones imagined by the encoder. Markup can end up providing affordances not intended just as many technologies (phone, internet) end up being great for things their creators didn’t intend them for. This needs to be worked out.

Prospects: A prospect is a type of visualization – one which tries to represent every item in the scope. This brings us first to the lack of a good sense of why visualizations are intuitively accessible as opposed to other types of overview or narrative interface. What is it about a picture that is worth a thousand words? Second, we have the issue of visualizations of the whole (overviews) and prospects. Are prospects a type of overview – namely those that include something on every item or are they another way of thinking about visual overviews? What does seem true is that we expect of an overview that it will represent the whole whether through representing every item or some other technique. This is important – prospects, visualizations, and overviews help us answer different questions than focal interfaces like a search system. They help us ask “what is this about?”, “what can I look for?”, “what can I expect?” rather than “where is?”. Ruecker summarizes the difference as one between browsing interfaces and searching interfaces.

Prospects look very promising for interfaces to heavily marked up documents where the markup is itself part of the information which can only be grasped if you have a sense of the encoding structure – the ontology applied through the DTD to the practice of tagging the text. To use XML (semantic web …) a user needs some sense of the scope of the tagging especially when there is an excess of tagging (more tagging than is needed to format the display of the content – ie. tagging that can’t be shown easily in rendering the page.)