[dredmorbius]

Given the difficulties of random blinding, and the long-term (decades-long) duration of the research, studying that aspect (with the same post hoc brain morphology analysis) might help assess causality.

There was some exclusion of other factors in the study per TFA.

[nephihaha]

The island of Saint Helena only started getting TV relatively recently, so some studies have been done on children there to compare effects.

[dredmorbius]

Since 1995, per Wikipedia, citing Wireless South Atlantic press release and St. Helena Broadcasting Corporation Ltd. sources:

<https://en.wikipedia.org/wiki/Communications_in_Saint_Helena...>

Total population (2021): 4,439. <https://en.wikipedia.org/wiki/Saint_Helena>

Additional areas: South Africa and Tanzania saw television introduced relatively recently, 1975 and 1994 respectively. Those would be larger populations, though confounded by other factors (poverty, racism, higher early-adult mortality due to HIV/AIDS).

<https://en.wikipedia.org/wiki/Geographical_usage_of_televisi...>

That could be interesting.

[nephihaha]

A lot of these places have gradual introduction as well. There were parts of the UK without a proper TV signal well into the 1980s.

Mid 1990s is earlier than I thought. Places like Tristan da Cunha and Pitcairn Island may be even later.

[dredmorbius]

I'd thought of some other remote island locations as well, though most have quite small populations. That would make large-scale studies challenging.

Slightly orthogonal: Simon Winchester's book Outposts details many of these, including aspects of their cultures, though I don't recall if he dwelt long on the specifics of television or its lack.

<https://bioeconometrician.github.io/outposts/> (Review)

Several of those islands have significant military and/or communications roles for the UK, and as such may have better-than-expected comms links.

[nephihaha]

Ascension Island and the Falkland Islands seem to have reasonable broadcasting because they have major military bases on them. Diego Garcia would be the same. The Falklands have a substantial civilian population, but Ascension has almost no one who can be classed as a kind of native. (Tristan Da Cunha and Saint Helena both do.)

Somewhere like Bermuda or certain smaller Caribbean Islands will have had decent service due to being tax havens (Cayman Islands, Virgin Islands) or major tourist destinations (St. Barts, Bahamas, Barbados). (Jamaica, Cuba, Trinidad & Tobago, and Hispaniola all have large populations.)

I was in Nepal in the early 1990s and there was a surprisingly limited service within Kathmandu (mostly satellite), and none up in the hills. I imagine that has changed a lot since then. I am friendly with a Nepali family here and they watch a lot of Hindi soaps and Bollywood, because they can understand the language. I'm sure Nepal is swamped with "global" content now and is no better for it.

[dredmorbius]

There are a few other instances which come to mind.

The spread of cable television within the US had distinct limits through the 1980s and 1990s, with much of country (by area, though not population) excluded. Satellite TV had its heyday, and regions in which it was popular (often as the only alternative to very limited over-the-air terrestrial broadcast) were referred to as "Birdland", after the dishes pointed at orbiting "birds", or satellites.

Which is a long way of saying that looking at the proliferation of cable and penetration of satellite TV might allow for some differentiation within US populations.

Back in my uni days, an example which came up was of inverse relationship between fertility and television reception within remote mountain regions in Southeast Asia (Thailand if memory serves, which it does poorly). I'm not finding that reference though there's more recent research of a similar nature:

Diffusion Processes and Fertility Transition: Selected Perspectives, Chapter 7 "Mass Media and Fertility Change" <https://www.ncbi.nlm.nih.gov/books/NBK223858/> (2001).

The general inference being that late-night TV viewing and sex were substitute activities.