There has been a bit of a chorus of interest1 in what I actually do for a living. Because I'm one of the handful of people (and the only woman) to work on my current study species, I can't tell you exactly what I work on with without giving the game away. However, I can give you a broad overview of my research interests.
I work in the area of animal behaviour, and — more specifically — on how animals make sense of events in the world around them. If you think about it, every species (including humans2) lives in a swirling mass of events and stimuli, but only a tiny proportion of this information is relevant to the animal. An animal paying equal attention to everything would be drowned in information, and waste a lot of time and energy in responding to things that wouldn't provide any actual benefit. On the other hand, without extracting patterns and meaning from the order of events you would be doomed to respond to important events passively, without any ability to predict when, where or how things might happen. Most animals fall somewhere between those two extremes in their responses, but humans are particularly good at extracting patterns and meaning — so much so that we sometimes see meaning where there is none. Ironically, this is what makes being a scientist both possible and very difficult.
One aspect of this idea that I'm particularly interested in is how animals deal with information about the physical world. Even very young human children expect certain standards of behaviour from objects. Objects cannot pass through solid barriers, or suddenly jump from one place to another, and babies show surprise and interest when they see these laws of physics being violated. This allows us to behave in a very flexible way, because we can apply this general knowledge to completely new situations. Is this something that is a human speciality, or do other animals share some of these more abstract concepts about physics and the physical world? Of course, you can't just ask non-human animals what they know about the world3, so you have to devise cunning experiments in which animals reveal their answers to your questions in their choices and responses. I can tell you that this is a lot harder than it sounds. I'm fond of posing questions about mechanisms — how do animals deal with information? — but biology being what it is, you also have to consider why a behaviour has evolved (functional questions), as well as thinking about how the behaviour develops as the animal grows up, and also when it appeared in the evolution of that species.
There are lots of potential ramifications of this area of research, but one that hovers in the background is whether there is some kind of mental discontinuity between human and non-human animals. Do animals have the same kind of abilities (just less of them), or did humans travel at some point over a set of railway points, and go off on a completely different track of their own?
So that — in a nutshell — is what I do, more or less. I'll leave it as an exercise for the reader to work out where Lego fits in...
1 Well, OK — a trio.
2 I'm the kind of biologist who regards humans as big, rather ugly primates: embarrassingly under-endowed in the sharp teeth and claws department, but quite nifty at making acceptable claw and teeth substitutes. And inordinately fond of digital watches (with apologies to Douglas Adams).
3 To be more precise, you can ask whatever questions you like, but you'll be waiting a long time for an answer.