I'm pretty sure they're referring to scientists on Earth.

Edit: Though I agree that alien scientists of Tri-Solaris probably lead more depressing lives than their counterparts on earth

I don't know if this series is yet considered far enough in the past that we don't have to worry about spoiler warnings (I feel like the house rules about this apply differently to books than to movies), but I will just say that one of the most fascinating and mind-bending considerations in the book is the idea that some civilizations progress linearly and some progress exponentially, and how mind bending it is to have to plan ahead for exponential advances.

Hmm, fair enough - I checked Wikipedia. My mind completely erased the "sophon" bit or whatever it was called, it just got erased again. Not a fan of that particular fairy dust.

I thought they were referring to the inability of the aliens to make an accurate calendar.