I was at Computer Corporation of America for a few years, until 1988, in the research group. It was quite illustrious in its day, producing very interesting research and prototypes, (concurrency control, extended relational databases, the Adaplex project). We were aware of both the 5th Generation project, and the US "competitor", MCC.
Remember, at the time, Japan was an economic and technical powerhouse, There were concerns about the Japanese buying up valuable real estate in New York. We were worried about the trade imbalance. So 5GP was quite threatening to some.
I remember meeting one of the 5GP researchers who credited MCC for scaring the Japanese into greatly increasing funding for computer science in his country. And one of the other comments here pointed out that the fear worked in the other direction too.
Another commenter here talked about Prolog. One of the lines of research at the time was on "expert systems", and if I remember correctly, Prolog was one of the major languages for research in that area. An expert system was a set of rules for solving a problem in some domain. It was yet another failed attempt at AI, which didn't really work beyond toy problems. (Of course, now, those rules come out of machine learning systems, but the rules are kind of inscrutable.)
At the time, there were a lot of voices pushing the idea that public-private partnerships in the Japanese MITI vein were the future. Economists like Lester Thurow vehemently argued that the US wasn't doing nearly enough in this vein and was going to lose out to Japan as a result.
The history of AI research is sort of messy but around the end of the 1980s you were entering one of the AI winters. As you say, a lot of money had been pumped into expert systems without a lot of commercial success (and some high-profile failures). The Lisp machine market was collapsing. It probably didn't help that a lot of the big computer companies at the time (the Route 128 minicomputer makers) were collectively struggling.
The research arm of CCA disappeared in 1988, at the same time that Symbolics (and other Lisp machine companies) was failing. So I, along with a few Symbolics people, were looking for the next thing to do, as OO databases were becoming a thing. We were brought together by an entrepreneur and formed Object Design, one of the batch of OO database companies of the late 80s/early 90s. Those Symbolics guys were absolutely brilliant.
I remember ObjectStore. Tried to use it, but it didn't work that well for our use case; we were better off doing serialization. Very interesting design, though.
Remember, at the time, Japan was an economic and technical powerhouse, There were concerns about the Japanese buying up valuable real estate in New York. We were worried about the trade imbalance. So 5GP was quite threatening to some.
I remember meeting one of the 5GP researchers who credited MCC for scaring the Japanese into greatly increasing funding for computer science in his country. And one of the other comments here pointed out that the fear worked in the other direction too.
Another commenter here talked about Prolog. One of the lines of research at the time was on "expert systems", and if I remember correctly, Prolog was one of the major languages for research in that area. An expert system was a set of rules for solving a problem in some domain. It was yet another failed attempt at AI, which didn't really work beyond toy problems. (Of course, now, those rules come out of machine learning systems, but the rules are kind of inscrutable.)