I did some science projects with hamsters as a kid...
the first project was 5th grade... I proved hamsters could learn using a maze and a skinner box.
the skinner box was basically one big room and two little rooms with hammy-operable doors leading into them (my mom and I made it out of plywood and used dollhouse doors). I put something good smelling on top of the T where the inside walls met (so that they couldn't use their sense of smell to figure out which door was the correct one) and taped a little paper circle to one door and a paper triangle to the other. the circle door was the correct one because I figured circles looked more like seeds
at first, the door on the right was always the circle door and the one where they got a treat as soon as they went through it. once they always beelined for that door when placed in the box, I started switching the shapes between each run (I did 10 tries per hammy per night), so the circle would be on the right door, then the left, then the right, etc. once they mastered that, I started placing the shapes totally at random so there was no pattern for them to follow and they HAD to decide based on shape.
in 7th grade, I did another experiment using hamsters and the skinner box - this time to see if they could see colors. I only had time to test one color, so I picked the one most likely to be visible if they only had partial color vision - blue. I used a piece of blue construction paper to make the colored circle, then my mom xeroxed it in a bunch of different shades of gray. we used a light meter to figure out which shade of gray matched the blue exactly so that they couldn't tell the difference because of one being brighter than the other.
I ran the tests the same as the first time - starting always on the right, then alternating, then no pattern; doing 10 tests per hammy per day.
the results were that all but one hamster aced the tests by the end and therefore, could see blue. the one that couldn't see blue and failed miserably, only getting a treat when it got lucky, was an albino (which was expected to be fully color-blind)... I'm glad I happened to have an albino baby at the time (I bred hamsters for myself), since that ended up working well as a control to verify that a color-blind hamster wouldn't be able to tell the two circles apart.