Shopping and Such

Thursday morning I went back to CHI and attended a couple of paper sessions including one on Fitts' Law. This is a basic logarithmic relation modeling human movement (e.g., arm movement as registered by mouse coordinates) stating that time to movement (T) is proportional to the distance to target (D, sometimes also given as A, the amplitude of the required movement) and target width (W).

There seems to be some debate on whether Fitts' Law can be used to predict eye movement. Some say yes from empirical observations. Others say no from (I think) what we know from saccadic programming: the brain programs the eye with faster rotations (larger amplitude) when covering larger distances making movement time constant. If that's so, I don't see how that relates to target size...indeed, even though Fitts' Law has been discussed by CHI researchers for 25+ years (and Fitts himself had done some eye tracking), I suppose one would really need to examine eye position accuracy to somehow relate eye targetting error to eye rotation speed to target distance. I'm really not sure whether anyone's done so...at this year's CHI paper session on Fitts' Law, prediction error had just been introduced—apparently it's not been considered before in this context.

After that thought-provoking paper session, we went walking around Florence, with the intent on spending the afternoon shopping (well, that was my intention, anyway). I basically picked a city square we hadn't been to before, Piazza Santa Croce as it happened, and off we went. Turns out there wasn't much there in this piazza. I think we eventually headed back through the Ufizzi to the Piazza della Repubblica. I think we may have had a snack there since that seemed to one of our preferred places for lunch. There are several good outside cafes there, including Cafe Concerto Paszkowski, Cafe Giubbe Rosse, and Cafe Gilli. Although we went in to a couple of leather places, and looked at some of the things offered by the street vendors ("Rrrrrolex"!), we found nothing, and eventually went for dinner to a restaurant right by The Michael Collins where we ended up for a couple of Guinnesses once again.