Artificial general intelligence is intended to handle many kinds of intellectual tasks with human-like adaptability, rather than being built for one narrow function. This review examines existing research on why that goal remains difficult, highlighting weaknesses in common sense, reasoning, planning, memory and lifelong learning.

The authors also identify broader engineering challenges: systems may struggle with rare or unexpected situations, produce inaccurate information and require large amounts of computation as their abilities expand. The review suggests that hybrid AI systems, approaches that connect intelligence with interaction in the physical world, and improved reasoning mechanisms could help guide future work.