My wife and I finally watched the return these New York fab four. Yes, we are a fan of the TV series, so we've been anticipating the big screen version for quite a while. I thought the movie was a pretty good entertainment, and some reviews might be too harsh. I agree with Leila Chudori that the movie was lacking the series' twist and naughty plot. But, in the end, the movie is a 2-hour annex to the series. Not a repetition of the episodes when they were still at their 30s. So, please, it's not The Godfather or Little Women; it has the right to remain cheesy!
The plot revolves around Carrie and Big's relationship. How they decided to get married, then one of them got too obsessed and the other got scared, and how they got through with that. I tried to enjoy the movie by not thinking any economic theories. But still I couldn't help thinking of Becker's 'Economics of Marriage.' You can read Becker's account in his Nobel lecture here; a good summary of his theory (and how the theory evolved between the first JPE article in 1973 and his latter works, especially the 1981 Treatise) here; or in Tim Hartford's popular version here. But note that those pieces look at why do people decide to get married (and how do they choose partners) as opposed to being single. In Carrie and Big's case, the issue is why they want to move to one stable equilibrium (extra-marital cohabitation) to another one (marriage).
One of the movie's subplots is the troubled marriage of Miranda and Steve. The question is, when you have to decide whether you want to keep your marriage or terminate it, do you apply a cost-benefit type of calculation? Maybe. But, in the spirit of the movie, maybe not. It's harder to lose something you've actually had, even though you could 'trade' it with something you'd prefer to have in a counterfactual life. Economists call it the endowment effect, which may suggest, as this article argued, humans are irrational animals.
Or, in Carrie's words to Miranda, "Sorry, Harvard.. this time you need to make decision based on your emotions... not logic..." Ah, I think I'm too carried away with the movie.