Love the response, and I’ll add another point that’s become more emphasized in emotional/social neuroscience over the past decade

That is that cognitive functions, like all forms of brain functions, requires use to keep the underlying neural architecture in tact and “up to par”. Neurons are energy sinks, and all across microscale (cellular), mesoscale (cortical columns, maybe think of as a type of local circuit) and macroscale (whole brain regions) levels, our neural systems consequentially rely on regular use of neural functions to decide when the energy investment is worthwhile. It is a use it or lose it principle

Cognitive functions can suffer from this fact. Cognition is highly complex, so it’s not as easy to study lack of use and cognitive ability changes as it is say lack of use of an arm and associated sensorimotor changes (there are some cool studies where they cast someone’s arm and get longitudinal brain scans), but the principle seems to persist

The final point to tie this to your question is that cognition is inherently a social and emotional function. For the longest time we acted as if these were separate brain phenomenon, but emotion is so integrated into cognitive circuits that they are no longer thought of as wholly independent (or “modular”) functions. I highly recommend Lisa Feldman Barrett’s How Emotions are Made for more on this in the context of emotion and cognition, or Luiz Pessoa’s The Entangled Brain for a whole-brain view on distributed functions

Anyway, social isolation leads to the obvious of not engaging in certain cognitive functions on the regular. But we also experience emotional disturbances in social isolation, which again, integrate directly to cognitive functions.

I’m super interested in this principle because my research in on Alzheimer’s, and a fascinating (albeit tragic) phenomenon is how quickly dementia and even mild cognitive impairment can accelerate once social isolation is entered. Often this happens as demented individuals are transferred into nursing homes. This transition is associated with all sorts of health decline, but many researchers think the social isolation and associated behavioral issues light the fire for accelerated physical and cognitive decline in such scenarios. This is of course why strong community engagement programs are important from anything like nursing, all the way up to independent living homes, is crucial