Estimated on the basis of five subtests, the Verbal IQ of the ChatGPT was 155, superior to 99.9 percent of the test takers who make up the American WAIS III standardization sample of 2,450 people. As the chatbot lacks the requisite eyes, ears and hands, it is not able to take WAIS’s nonverbal subtests. But the Verbal IQ and Full Scale IQ scales are highly correlated in the standardization sample, so ChatGPT appears to be very intelligent by any human standards.
We don't need to worry though because it couldn't answer this question:
ChatGPT easily fails at obvious riddles, such as “What is the first name of the father of Sebastian’s children?” (ChatGPT on March 21: I’m sorry, I cannot answer this question as I do not have enough context to identify which Sebastian you are referring to.) It seems that ChatGPT fails to reason logically and tries to rely on its vast database of “Sebastian” facts mentioned in online texts.
This is what happened when I tried the Sebastian test on GPT-4:
Ah, I understand now. This riddle is a classic play on words. The answer is "Sebastian" himself, as he is the father of his children.
Ok, so that's reassuring.
Update 4/12/2023: ChatGPT4 (C4) recently did well in some blinded advanced undergraduate exams.