Bidirectional Encoder Representations from Transformers

type: insightlevel: medium

The emergence of BERT

BERT was introduced by Jacob Devlin and his colleagues at Google AI in 2018. It brought about a significant breakthrough in the field of natural language processing (NLP).

Prior to the advent of BERT, traditional NLP models often relied on the RNN (Recurrent Neural Network) or CNN (Convolutional Neural Network) architectures for language processing. However, these models had limitations in understanding context and were dependent on the current word position.

  • Recurrent Neural Networks (RNNs) :

Vanishing gradient problem: When training an RNN on long sequences, information from distant positions in the past can diminish over time. This makes it difficult for RNNs to understand long-range context, especially in lengthy sentences.

Limitation in processing bidirectional context: RNNs typically only consider preceding words in a sequence. Therefore, if a word appearing after another word affects the meaning of that word, the RNN may not grasp this relationship.

Figure 1

  • Convolutional Neural Network (CNN):

    Limitation in understanding long-range context: CNNs often use fixed sliding windows to process input sequences. This means that CNNs may not comprehend distant context and only focus on small local regions within the sequence.

Limitation in processing order-dependent features: CNNs lack the ability to automatically learn order-dependent features of words. This can result in the loss of significant linguistic information, such as part-of-speech dependencies and grammatical structure.

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BERT has surpassed previous models by utilizing the Transformer architecture, a powerful and bidirectional self-attention neural network model. Through the use of Transformers, BERT can consider both preceding and succeeding context, enabling it to capture rich information about semantics and context.

BERT is trained on a large amount of unsupervised data from online sources such as Wikipedia and books. The pre-training process of BERT involves two main tasks: masked language modeling (MLM) and next sentence prediction (NSP). MLM requires the model to predict masked words in a sentence, while NSP evaluates whether two sentences are consecutive in the data.

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After the pre-training phase, BERT can be fine-tuned on specific tasks in NLP. Fine-tuning involves adjusting the weights of BERT on smaller labeled datasets to adapt to each specific task, including text classification, information extraction, machine translation, and many others.

BERT has brought significant improvements in various NLP tasks and has become one of the most important and popular models in the field. The emergence of BERT has opened the door for the development of other powerful deep self-supervised language models and has made a significant contribution to the progress of NLP.

The results achieved by BERT

BERT has achieved significant accomplishments in the field of natural language processing (NLP) and has become one of the most important and popular models in this domain. Here are some noteworthy achievements of BERT:

  • Outstanding performance on multiple tasks: BERT has achieved impressive results on various important NLP tasks. For example, in the General Language Understanding Evaluation (GLUE) competition, BERT achieved the highest scores across all tasks, including sentence classification, predicting sentence relationships, sentiment classification, and many other tasks.

  • Significant improvements in natural language processing: BERT has significantly improved the performance of NLP applications across various tasks, including information extraction, machine translation, sentiment analysis, question answering, and many others. BERT has helped enhance the understanding of semantics and context in these applications.

  • Application in search engines: BERT has been applied by Google in its search engine to improve search results. The use of BERT has helped understand the context and meaning of search queries and provide more accurate and relevant search results aligned with the users' intentions.

  • Development of other powerful self-supervised language models: The success of BERT has inspired further developments and research in creating other powerful deep self-supervised language models. Several variants and improvements of BERT have been proposed, including RoBERTa, ALBERT, ELECTRA, and many others.


  1. BERT Explained: State of the art language model for NLP
  2. BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding