Artificial Intelligence is only tangentially involved with the scientific study of simulating human intelligence. The core issue this movie explores is the relationship between humans and "mechas", robots designed to perform various functions in an increasingly hostile futuristic world.
Monica and Henry Swinton (played by Frances O'Connor and Sam Robards) are mourning the loss of their terminally ill son when they are given the first robot boy designed to reason, show intuition, and love. Monica is utterly confused about her adopted robot son, David, especially with his "it's" sometimes quirky behavior.
In one memorable scene David laughs loudly and abruptly at mealtime, sending the rest of the family into hysterics, until they remember this thing is a machine, not a real kid. Much later, David befriends in interesting character, Gigolo Joe, a mecha who is the ultimate lover. Joe voices some of the movie's most thought provoking lines, to the effect that the humans appreciate what the mechas do but cannot possibly love them.
An extreme example of this tension shows in a "Flesh Fair" where thousands of humans witness the barbaric torture and destruction of mechas, reminiscent of ancient Roman specacles in the Coliseum.
Getting beyond the moral dilemmas and nagging questions for a moment: The special effects were everything you would expect when Steven Spielberg collaborates with the late Stanley Kubrick. Some of the mechas were disturbingly real and at the same time pathetically dilapidated. David's teddy bear, Teddy, arguably the most endearing character, provided a little comic relief.
Overall there is not much of a plot but the character development, thought-provoking questions about men and machines, and stunning effects made it a worthwhile 2 1/2 hours.