Second AI Winter
1988–1993 · 3 milestones
Expert systems proved brittle and expensive. The AI bubble burst again, but foundational work on learning algorithms continued quietly.
Milestones
The Second AI Winter Begins
The expert systems bubble burst. LISP machine companies collapsed. The DARPA Strategic Computing Initiative was cut. Japan's Fifth Generation project was failing. Expert systems proved brittle, expensive to maintain, and unable to learn. The AI industry lost billions.
LeNet: Convolutional Neural Networks
Yann LeCun demonstrated that convolutional neural networks (CNNs) could be trained with backpropagation to recognize handwritten digits. The refined LeNet-5 (1998) achieved 99%+ accuracy on MNIST and was deployed by banks to read checks — running in ATMs for years.
TD-Gammon: Reinforcement Learning Plays Backgammon
Gerald Tesauro created TD-Gammon, a neural network that learned to play backgammon at expert level through self-play using temporal difference reinforcement learning. It discovered novel strategies that surprised human experts.
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Frequently asked questions
When was the Second AI Winter era of AI?+
The Second AI Winter era of artificial intelligence spans 1988 to 1993.
What defined the Second AI Winter era?+
Expert systems proved brittle and expensive. The AI bubble burst again, but foundational work on learning algorithms continued quietly.
What are the key milestones of the Second AI Winter era?+
This era includes 3 milestones, among the most impactful: The Second AI Winter Begins (1988), LeNet: Convolutional Neural Networks (1989), and TD-Gammon: Reinforcement Learning Plays Backgammon (1992).