Cat tree

In August, I’ll be moving into a new apartment, with a larger bedroom and two roommates—plus Nibbler and Kallie.  The cat tree I have for them (the top half is shown here, brand new) is 2 years old, and not in very good shape: the covering on the top perch has disintegrated, the sisal rope at the base (used often as a scratching post) is coming off, one of the lower perches is broken (my fault).  Closer inspection has revealed just how cheaply it was made: particle board, cardboard tubes, poor quality covering.

Thus, considering the larger space they (and I) will have in August, I’ve started thinking about building a replacement (possibly for August, maybe a little later).  I’ll update this post as I come up with new ideas, perhaps with some pictures as the thing actually takes shape.

Core ideas:

  • TWO top perches.  Both cats think the top perch is the best place to be, and once one cat gets onto the top, the other is entirely out of luck: attempts to fight up to the top fail.  The two perches need to be sufficiently far apart that one cat cannot monopolize both.
  • Raised edges on the top perches.  Kallie, in particular, likes to sleep on the top, but I think it’s a little difficult for her to be really comfortable there because of the risk of falling off.  Nibbler might like to sleep there, but is just too big to do anything than sit there, awake.
  • A large, heavy base.  Once in a while some rambunctious activity results in the current cat tree toppling, crashing into either a bookcase, my dresser, or my laundry basket.  The current base is too small, and too light.
  • Soft, but tough carpeting.  It needs to be easy to clean/vacuum, and I don’t want it to turn into a disintegrating mess after a year or two.

Optional ideas:

  • Box at the bottom.  The current cat tree has a raised box, with a hole on top and hole at the corner (so the cat can go through it).  It’s too small for an adult cat, though; Kallie sometimes dives in after a toy, but it’s too small even for her to lie comfortably in; forget about Nibbler.  Both cats (Nibbler especially) enjoy their “cat tube” (see below), and I think would similarly enjoy a proper-sized enclosed space.  Having openings at two ends (or maybe top and side, like the current one?) would be good as well.
  • Adjustable perch heights.  This depends on how, exactly, I go about attaching it, but is something to keep in mind.


More ideas to come.

Economic modelling of behaviour

One of the big problems faced in economics, particularly in macroeconomics, is the bugbear of uncertainty. Actually, that’s not right: it’s one of the problems we try *not* to face. Typically, at most, we handle uncertainty by deciding upon a set of events, and assigning a probability to each, then assume that an agent in our model knows the events and probabilities of each.

Prima facie, that seems wrong: typically real people don’t know the probability of an event. The defence of the assumption, however, goes something like this: people aren’t stupid, therefore as they see reality unfolding and see uncertainty resolving itself, they will adjust their behaviour. Since we’re often modelling long-term repetitions of the same set of events, even if people initially guess the wrong probabilities, by observing the events that occur, they will update their beliefs on the probabilities, converging to the true probabilities.

This seems wrong to me, still: casual observation yields examples every day where people make the same mistake, again and again, and don’t update their beliefs–or update them wrongly. For example, flip a coin 100 times.  Straight, non-human-interpreted probability says that there is a better-than-even chance of seeing a string of 7 of the same side of the coin in a row somewhere in that 100 flip sequence, and more than a 10% chance of seeing 13 in a row. Or take a pair of dice rolled 100 times: there’s a 15 percent chance that the same total will be rolled 4 times in a row somewhere in the 100 roll sequence. But we humans aren’t very good at dealing with probabilities: when we see 7 heads in a row, we start thinking the coin must be biased, or the dice must be loaded.

Continue reading Economic modelling of behaviour