Why do movie characters wear college shirts to bed?

Here's another leftover from last weekend's plane movie viewing. 

I could have made this the latest entry in my Tiresome Tropes series -- you know, the one that has barely any entries at all -- but I don't know that this really rises to the level of a trope. It's just something I've noticed, and I'm sure you've noticed, that warrants an explanation.

My last viewing on my flight from Melbourne to Dubai was The Friend, the movie where Naomi Watts has to deal with a Great Dane bequeathed to her following the suicide of her friend and former lover (Bill Murray), which was not, unfortunately, anywhere near as potent for me as the similarly titled Our Friend, the Gabriela Cowperthwaite-directed film that was my surprise #1 of 2021. There should be no reason it would be -- movies with similar titles have no likelihood of being anything like each other in quality or otherwise, it goes without saying -- but this also had the pedigree of writer-directors David Siegel and Scott McGehee, who directed one of my top 25 of last decade, What Maisie Knew. Alas, despite all this spuriously reasoned potential for success, I could go no higher than 3.5 stars on The Friend. 

Although it was going to be cutting it tight to finish the movie before we landed -- and I of course pride myself on not starting a movie I can't finish on the plane -- I did take a minute to go back earlier in the movie and get this screenshot. This was the best of about three I got, but the others were not very flattering to Ms. Watts, whom I noticed in this film is starting to show signs of aging, but is doing so gracefully at least, without any apparent signs of plastic surgery:

Anyway, they all illustrate today's topic: For some reason, screenwriters think that people disproportionately wear merchandise from a college or university when they go to bed.

Why is this?

I'm actually going to ask Google in a minute to see what AI slop will come up on the topic. But first, a few ideas.

1) It is a good character shorthand. The quality of the university you use for their nighttime garments indicates their intellectual prowess or lack thereof, though I suppose it would take a real familiarity with instituations of higher learning for most viewers to be able to discern a specific commentary the screenwriter is making from the choice of shirt. Like, I can't think of a university you would use if you wanted to show that a character is not intelligent, at least in a way the majority of viewers would immediately get. Of course, wearing a shirt from a college doesn't necessarily mean you went there -- it could be you have a son or daughter there, or you just visited on a road trip -- but that could also be its own form of commentary. If a known dummy who is a wannabe intellectual wears a Harvard shirt to bed, I suppose that tells you something.

2) It is good shorthand for the region of the world this takes place. Many movies don't work to belabor their geographical location, but they like having a quick signifier like this that will do some of that work. That doesn't really work in The Friend, though, as the movie takes place in Manhattan but UC Berkeley is of course in the San Francisco area.

Okay let's see what Google Slop has to say about it:

Movie characters wear college shirts to bed for narrative effect: they signify youth, innocence, rebellion, or a connection to a specific institution and character archetype, providing a visual shorthand to quickly convey information about their personality and background without needing extensive dialogue or exposition. This practice also draws on real-life behavior, as the wearing of old, comfortable clothes for sleeping was once common and continues to be a casual, relatable behavior. 

Well dang, that's pretty good, and not as much Slop as I would have predicted. And it hits on my points as well.

I didn't consider the comfort angle, though I suppose that's just because I was trying to find something more objective. Certainly we're talking adults here, and their college shirt would most likely be something they'd had for a long time, making it old and comfortable.

Even with a solid narrative foundation for the choice, it interests me how often it is used. So often, in fact, that I would say it verges on cliche -- or, a trope, as mentioned earlier. 

A concert t-shirt would have many similar functions, and I'd say is the next mostly likely option in this situation to a college shirt. I'd argue you can actually say more about a character through a t-shirt with a rock band on it than you can with a t-shirt with a college on it.

Then again, maybe the concert tee is a prized possession that is better for daytime use.