The canonical study about Einstellung was Luchin's water jug problem,
which was featured in Die Hard III:
Subjects in Luchin's studies (who did this in the 1940s, and presumably hadn't seen Die Hard) first solved several easy problems that got them into the mindset of adding smaller amounts together to fill a larger jug. So , they put a 1 gallon + a 2 gallon jug to fill a 4 gallon jug with 3 gallons of water. The test was something like trying to fill a 5 gallon jug with 4 gallons, given only a 1 gallon and a 2 gallon. This is the crux of insight-based problems solving, and related to the 'thinking outside the box' problem
What does this have to do with the Chronicle crossword?
The States of Matter is a theme puzzle and also a rebus puzzle. This means that you need to fit multiple letters, or even an entire word, in a single box. many times, when solving a rebus puzzle, a solver only realizes it after they are having a hard time answering the long answers--the first case of Einstellung. You get accustomed to the rule of 1-letter =1-box, and it takes a while to challenge that assumption. But most avid puzzle-solvers are probably able to detect this after a while. But this theme is especially tricky, because the across and down rebuses are different. For example, we have
4A: Shade similar to sapphire. (_ _ _ _ _)
4D: Lake Mead feeder. (_ _ _ _ _ _)
When I hit this clue, I actually knew the answer to the down clue--the Colorado River. This didn't fit in the space allowed, so I moved on. Similarly, for 4A, I was stymied because there are many bluegreen colors, but nothing stood out. Once I had completed some fill, I saw that 4D was (_ RIVER), and before long worked out that 4A was (_BLUE), and realized there was a rebus theme at work, but then I really got stuck. Was colorado blue a color?
A bit more solving and I got into a similar situation with 9A/D:
9A: Alternative to plastic wrap
9D: Cocktail made with sloe gin
After trying out some ideas (sloe gin fizz couldn't be right), and getting some more hints about the theme (Tin foil? Aluminum foil?), I figured out 9D ended with SLAMMER. But was an Aluminum or Tin slammers anything? I got on the right track by thinking about the periodic table abbreviation for Tin, which is SN. Looking back to the title (states of matter), I realized we have abbreviations for both states and elements, and then was able to escape the Einstellung, and get AL = Aluminum/Alabama; CO=Cobalt/Colorado, and so on.
The process here also involved the role of analogy in problem solving, which I'll probably save for another blog.
Anyway, a nice theme puzzle by Jacob Stulberg that makes the solver think 'outside the box'.