AI at this point, as PreferredChassisFab pointed out, is learned pattern matching. Basically, some X-dimensional matrix of values/responses which gets filled in through a learning phase with human programmers telling the system the appropriate response. The computer then compares future input against this value matrix to determine the correct response. I don't know that I could honestly agree with the "not in our lifetime" statement though. There are people who were alive for the first heavier-than-air flight and then saw us land on the moon, develop computers, the Internet, nuclear fission, fusion, harness those for controlled power, etc. 50 years is a long time for technology; 100 years is an era. With some of the recent studies on the brain, we may approximate it within our lifetime.
Zombies exist, FYI. Just not in humans (that we know of). Ants, flies, and mice all have parasites that cause behavior take overs.