Ecological indirect perception

I want to follow on from Sabrina's important posts about information, and why psychology should be about information for the forseeable future. Sabrina's taxonomy includes information beyond what ecological psychologists talk about, information that needs to be investigated to find out exactly what kind of behaviour it can support. (This is what Gibson did for perception, and it paid off in spades.) 

I'm particularly interested in the information in pictures and mirrors; surfaces that present information about being surfaces and about being something else. This post is me thinking out loud about the implications; these are by no means my final thoughts on the matter, it's me taking the taxonomy for a spin and seeing where I end up. Feedback welcome!

Mirrors are Literally Windows to Another World

The other day, psychologist Tom Hartley tweeted "Your reflection is always half the size of the real thing - no matter how far from mirror. Hard to believe but true." and linked to this post in which someone demonstrates this effect. I had never quite thought about it, but realised it was of course always true: the mirror is at half the distance specified in the reflection. Then I read this post linked from the original, which reviewed an article by Lawson et al (2007) describing how people misjudge the size of objects on mirrors - specifically, they think the projection is larger than it actually is. This got me thinking about some work by Gibson on slant perception (Gibson, 1950) and then I realised that this really is an interesting topic. So I'm taking a break from the brain this week to blog about some optics instead.