# Timeline of machine learning

This page is a timeline of machine learning. Major discoveries, achievements, milestones and other major events in machine learning are included.

## Overview

| Decade | Summary |
| pre- 1950 | Statistical methods are discovered and refined. |
| 1950s | Pioneering machine learning research is conducted using simple algorithms. |
| 1960s | Bayesian methods are introduced for probabilistic inference in machine learning. |
| 1970s | 'AI winter' caused by pessimism about machine learning effectiveness. |
| 1980s | Rediscovery of backpropagation causes a resurgence in machine learning research. |
| 1990s | Work on Machine learning shifts from a knowledge-driven approach to a data-driven approach. Scientists begin creating programs for computers to analyze large amounts of data and draw conclusions – or "learn" – from the results. Support-vector machines (SVMs) and recurrent neural networks (RNNs) become popular. The fields of computational complexity via neural networks and super-Turing computation started. |
| 2000s | Support-Vector Clustering and other kernel methods and unsupervised machine learning methods become widespread. |
| 2010s | Deep learning becomes feasible, which leads to machine learning becoming integral to many widely used software services and applications. Deep learning spurs huge advances in vision and text processing. |
| 2020s | Generative AI leads to revolutionary models, creating a proliferation of foundation models both proprietary and open source, notably enabling products such as ChatGPT (text-based) and Stable Diffusion (image based). Machine learning and AI enter the wider public consciousness. The commercial potential of AI based on machine learning causes large increases in valuations of companies linked to AI. |

## Timeline

| Year | Event type | Caption | Event |
| 1763 | Discovery | The Underpinnings of Bayes' Theorem | Thomas Bayes's work An Essay Towards Solving a Problem in the Doctrine of Chances is published two years after his death, having been amended and edited by a friend of Bayes, Richard Price. The essay presents work which underpins Bayes theorem. |
| 1805 | Discovery | Least Square | Adrien-Marie Legendre describes the "méthode des moindres carrés", known in English as the least squares method. The least squares method is used widely in data fitting. |
| 1812 | | Bayes' Theorem | Pierre-Simon Laplace publishes Théorie Analytique des Probabilités, in which he expands upon the work of Bayes and defines what is now known as Bayes' Theorem. |
| 1843 | Visionary | Visionary Pioneer | Ada Lovelace Lovelace's most significant relationship was with Charles Babbage, the inventor of the Analytical Engine, which is considered the first conceptual blueprint for a modern computer. Lovelace's vision extended beyond Babbage's own understanding of his machine. She saw the Analytical Engine as more than a calculator; she believed it could process and manipulate any form of symbolic data, such as music or text. This early vision of machines processing more than just numbers laid the groundwork for the development of symbolic AI and machine learning. Her contributions included what is now considered the first algorithm designed to be executed by a machine, making her the world's first computer programmer. Lovelace's understanding of the computational potential of machines continues to influence modern technologies like artificial intelligence. |
| 1913 | Discovery | Markov Chains | Andrey Markov first describes techniques he used to analyse a poem. The techniques later become known as Markov chains. |
| 1943 | Discovery | Artificial Neuron | Warren McCulloch and Walter Pitts develop a mathematical model that imitates the functioning of a biological neuron, the artificial neuron which is considered to be the first neural model invented. |
| 1950 | | Turing's Learning Machine | Alan Turing proposes a 'learning machine' that could learn and become artificially intelligent. Turing's specific proposal foreshadows genetic algorithms. |
| 1951 | | First Neural Network Machine | Marvin Minsky and Dean Edmonds build the first neural network machine, able to learn, the SNARC. |
| 1952 | | Machines Playing Checkers | Arthur Samuel joins IBM's Poughkeepsie Laboratory and begins working on some of the first machine learning programs, first creating programs that play checkers. |
| 1957 | Discovery | Perceptron | Frank Rosenblatt invents the perceptron while working at the Cornell Aeronautical Laboratory. The invention of the perceptron generated a great deal of excitement and was widely covered in the media. |
| 1963 | Achievement | Machines Playing Tic-Tac-Toe | Donald Michie creates a 'machine' consisting of 304 match boxes and beads, which uses reinforcement learning to play Tic-tac-toe (also known as noughts and crosses). |
| 1967 | | Nearest Neighbor | The nearest neighbour algorithm was created, which is the start of basic pattern recognition. The algorithm was used to map routes. |
| 1969 | | Limitations of Neural Networks | Marvin Minsky and Seymour Papert publish their book Perceptrons, describing some of the limitations of perceptrons and neural networks. The interpretation that the book shows that neural networks are fundamentally limited is seen as a hindrance for research into neural networks. |
| 1970 | | Automatic Differentiation (Backpropagation) | Seppo Linnainmaa publishes the general method for automatic differentiation (AD) of discrete connected networks of nested differentiable functions. This corresponds to the modern version of backpropagation, but is not yet named as such. |
| 1976 | Discovery | Transfer Learning | Stevo Bozinovski and Ante Fulgosi introduced transfer learning method in neural networks training. |
| 1979 | | Stanford Cart | Students at Stanford University develop a cart that can navigate and avoid obstacles in a room. |
| 1979 | Discovery | Neocognitron | Kunihiko Fukushima first publishes his work on the neocognitron, a type of artificial neural network (ANN). Neocognition later inspires convolutional neural networks (CNNs). |
| 1981 | Achievement | Learning to recognize 40 patterns | Stevo Bozinovski showed an experiment of neural network supervised learning for recognition of 40 linearly dependent patters: 26 letters, 10 numbers, and 4 special symbols from a computer terminal. |
| 1981 | | Explanation Based Learning | Gerald Dejong introduces Explanation Based Learning, where a computer algorithm analyses data and creates a general rule it can follow and discard unimportant data. |
| 1982 | Discovery | Recurrent Neural Network | John Hopfield popularizes Hopfield networks, a type of recurrent neural network that can serve as content-addressable memory systems. |
| 1982 | Discovery | Self Learning | Stevo Bozinovski develops a self-learning paradigm in which an agent does not use an external reinforcement. Instead, the agent learns using internal state evaluations, represented by emotions. He introduces the Crossbar Adaptive Array (CAA) architecture capable of self-learning. |
| 1982 | Achievement | Delayed reinforcement learning | Stevo Bozinovski solved the challenge of reinforcement learning with delayed rewards. Using the Crossbar Adaptive Array (CAA) he presented solutions of two tasks: 1) learning path in a graph 2) balancing an inverted pendulum. |
| 1985 | | NETtalk | A program that learns to pronounce words the same way a baby does, is developed by Terry Sejnowski. |
| 1986 | Application | Backpropagation | Seppo Linnainmaa's reverse mode of automatic differentiation (first applied to neural networks by Paul Werbos) is used in experiments by David Rumelhart, Geoff Hinton and Ronald J. Williams to learn internal representations. |
| 1988 | Discovery | Universal approximation theorem | Kurt Hornik [de] proves that standard multilayer feedforward networks are capable of approximating any Borel measurable function from one finite dimensional space to another to any desired degree of accuracy, provided sufficiently many hidden units are available. |
| 1989 | Discovery | Reinforcement Learning | Christopher Watkins develops Q-learning, which greatly improves the practicality and feasibility of reinforcement learning. |
| 1989 | Commercialization | Commercialization of Machine Learning on Personal Computers | Axcelis, Inc. releases Evolver, the first software package to commercialize the use of genetic algorithms on personal computers. |
| 1992 | Achievement | Machines Playing Backgammon | Gerald Tesauro develops TD-Gammon, a computer backgammon program that uses an artificial neural network trained using temporal-difference learning (hence the 'TD' in the name). TD-Gammon is able to rival, but not consistently surpass, the abilities of top human backgammon players. |
| 1995 | Discovery | Random Forest Algorithm | Tin Kam Ho publishes a paper describing random decision forests. |
| 1995 | Discovery | Support-Vector Machines | Corinna Cortes and Vladimir Vapnik publish their work on support-vector machines. |
| 1997 | Achievement | IBM Deep Blue Beats Kasparov | IBM's Deep Blue beats the world champion at chess. |
| 1997 | Discovery | LSTM | Sepp Hochreiter and Jürgen Schmidhuber invent long short-term memory (LSTM) recurrent neural networks, greatly improving the efficiency and practicality of recurrent neural networks. |
| 1998 | | MNIST database | A team led by Yann LeCun releases the MNIST database, a dataset comprising a mix of handwritten digits from American Census Bureau employees and American high school students. The MNIST database has since become a benchmark for evaluating handwriting recognition. |
| 2002 | Project | Torch Machine Learning Library | Torch, a software library for machine learning, is first released. |
| 2006 | | The Netflix Prize | The Netflix Prize competition is launched by Netflix. The aim of the competition was to use machine learning to beat Netflix's own recommendation software's accuracy in predicting a user's rating for a film given their ratings for previous films by at least 10%. The prize was won in 2009. |
| 2009 | Achievement | ImageNet | ImageNet is created. ImageNet is a large visual database envisioned by Fei-Fei Li from Stanford University, who realized that the best machine learning algorithms wouldn't work well if the data didn't reflect the real world. For many, ImageNet was the catalyst for the AI boom of the 21st century. |
| 2010 | Project | Kaggle Competition | Kaggle, a website that serves as a platform for machine learning competitions, is launched. |
| 2011 | Achievement | Beating Humans in Jeopardy | Using a combination of machine learning, natural language processing and information retrieval techniques, IBM's Watson beats two human champions in a Jeopardy! competition. |
| 2012 | Achievement | Recognizing Cats on YouTube | The Google Brain team, led by Andrew Ng and Jeff Dean, create a neural network that learns to recognize cats by watching unlabeled images taken from frames of YouTube videos. |
| 2012 | Discovery | Visual Recognition | The AlexNet paper and algorithm achieves breakthrough results in image recognition in the ImageNet benchmark. This popularizes deep neural networks. |
| 2013 | Discovery | Word Embeddings | A widely cited paper nicknamed word2vec revolutionizes the processing of text in machine learnings. It shows how each word can be converted into a sequence of numbers (word embeddings), the use of these vectors revolutionized text processing in machine learning. |
| 2014 | Achievement | Leap in Face Recognition | Facebook researchers publish their work on DeepFace, a system that uses neural networks that identifies faces with 97.35% accuracy. The results are an improvement of more than 27% over previous systems and rivals human performance. |
| 2014 | | Sibyl | Researchers from Google detail their work on Sibyl, a proprietary platform for massively parallel machine learning used internally by Google to make predictions about user behavior and provide recommendations. |
| 2016 | Achievement | Beating Humans in Go | Google's AlphaGo program becomes the first Computer Go program to beat an unhandicapped professional human player using a combination of machine learning and tree search techniques. Later improved as AlphaGo Zero and then in 2017 generalized to Chess and more two-player games with AlphaZero. |
| 2017 | Discovery | Transformer | A team at Google Brain invent the transformer architecture, which allows for faster parallel training of neural networks on sequential data like text. |
| 2018 | Achievement | Protein Structure Prediction | AlphaFold 1 (2018) placed first in the overall rankings of the 13th Critical Assessment of Techniques for Protein Structure Prediction (CASP) in December 2018. |
| 2021 | Achievement | Protein Structure Prediction | AlphaFold 2 (2021), A team that used AlphaFold 2 (2020) repeated the placement in the CASP competition in November 2020. The team achieved a level of accuracy much higher than any other group. It scored above 90 for around two-thirds of the proteins in CASP's global distance test (GDT), a test that measures the degree to which a computational program predicted structure is similar to the lab experiment determined structure, with 100 being a complete match, within the distance cutoff used for calculating GDT. |