Short answer: for all practical purposes, yes, it can and it does. For each specific example, there is no way to tell for sure (afaik) if the example was in th

Short answer: for all practical purposes, yes, it can and it does. For each specific example, there is no way to tell for sure (afaik) if the example was in the training set. But you can easily run some experiments yourself, inventing your own words which would not likely be in the training set, especially when taken together. I have done this, and GPT4 will frequently make inferences on par with the "optimystic" one. For example I just tried "surfrandma" and it said "It appears to be a combination of the words "surf" and "grandma", but without additional context, it's challenging to provide a precise meaning."