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Transformers in AI

  • Writer: Aastha Thakker
    Aastha Thakker
  • Oct 30, 2025
  • 5 min read

If you’ve seen Transformers, you know how ordinary machines turn into powerful Autobots. In AI, something remarkably similar happened in 2017, a revolutionary architecture called Transformers reshaped the entire landscape.


Unlike the Autobots though, these digital transformers don’t battle Decepticons, they battle something far more complex: the chaos of human language, the nuances of context, and the challenge of understanding meaning across vast spans of information. And they’re winning.


The result? The AI revolution you’re living through right now.


Life Before Transformers


You’re having a conversation, but you can only remember the last three things the other person said. Everything else? Gone. That’s exactly how AI worked before transformers.


The old guard, RNNs (Recurrent Neural Networks) and LSTMs (Long Short-Term Memory networks), processed language like reading a book through a keyhole, one word at a time, constantly forgetting what came before:


Google Translate in 2016 had 60% accuracy and felt robotic. Machine-generated text was obviously artificial. AI couldn’t write a coherent paragraph, let alone have a meaningful conversation or solve complex reasoning problems.




The 2017 Revolution: “Attention Is All You Need”



In June 2017, eight researchers from Google Brain published a paper with perhaps the most confident title in AI history: “Attention Is All You Need”.


The breakthrough? Instead of processing text sequentially like reading a book word by word, transformers could simultaneously analyze every word in relation to every other word.




How Transformers Actually Work


The Attention Mechanism:


“The bank can refuse to lend money because it is not profitable.”


  • Traditional models: Process word by word, might get confused about what “it” refers to

  • Transformers: Simultaneously analyze all relationships:

  • “it” ↔ “bank” (high attention score)

  • “it” ↔ “money” (low attention score)

  • “profitable” ↔ “bank” (high attention score)

The model learns that “it” refers to “the bank” through attention patterns, not just word proximity.

Self-Attention:

Self-attention is like hosting a town hall meeting where every word gets to vote on how much attention every other word deserves. Each word simultaneously asks three crucial questions:

  1. Query (Q): “What am I looking for in this context?”

  2. Key (K): “What unique information do I represent?”

  3. Value (V): “What meaning do I contribute to the overall understanding?”

The mathematical beauty lies in computing attention scores between all word pairs, but the intuition is elegantly simple: words that should influence each other will naturally have higher attention scores.



Multi-Head Attention:


Why stop at one attention mechanism? Multi-head attention runs 8–16 parallel attention processes, each specializing in different aspects:


  • Head 1: Focuses on grammatical relationships

  • Head 2: Captures semantic meaning

  • Head 3: Identifies syntactic patterns

  • Head 4: Tracks long-range dependencies

It’s like having multiple expert reviewers simultaneously analyzing different aspects of the same text, then combining their insights for a richer understanding.


Positional Encoding:


Since transformers process all words simultaneously, they need to learn that “The cat sat on the mat” is different from “The mat sat on the cat.” Positional encoding adds unique mathematical “fingerprints” to each word based on its position, using sine and cosine functions that help the model understand sequence order without sacrificing parallel processing.

The Transformer Family Tree: From BERT to GPT and More

BERT: The Master Reader (2018)

Full Name: Bidirectional Encoder Representations from Transformers

Superpower: Understanding context by reading in both directions


BERT revolutionized reading comprehension by processing text bidirectionally like a human who can glance ahead while reading to better understand the current sentence.


Game-changing moment: When Google integrated BERT into search in 2019, search result relevance improved by 10% — the biggest improvement in five years. Suddenly, searches like “2019 brazil traveler to usa need a visa” returned accurate results instead of generic visa information.


Real-world applications:


  • Sentiment analysis (“This movie is not bad” = positive)

  • Question answering systems

  • Document classification

  • Named entity recognition

GPT: The Master Writer (2018–2024)

Full Name: Generative Pre-trained Transformer

Superpower: Generating human-like text by predicting what comes next


The GPT family works like the world’s most sophisticated autocomplete, but instead of just predicting the next word, it understands context, style, tone, and intent across thousands of words.


Evolution timeline:

  • GPT-1 (2018): Proof of concept with 117M parameters

  • GPT-2 (2019): 1.5B parameters, so good OpenAI initially withheld the full model

  • GPT-3 (2020): 175B parameters, demonstrated emergent abilities nobody expected

  • GPT-4 (2023): Multimodal capabilities, enhanced reasoning, and the foundation for ChatGPT

  • GPT-5 (August 2025): The latest breakthrough, unified reasoning and multimodal capabilities in one model

The scaling revelation: Each generation didn’t just get bigger, it got qualitatively smarter, suggesting that intelligence might be an emergent property of scale.

GPT-5

Glimpse at what GPT-5 could bring:

  1. Built-in thinking that puts expert-level intelligence in everyone’s hands

  2. Smoother multimodal switching and better context retention fully realized

  3. Better at following tool instructions and executing long chains of tool calls

  4. Produces high-quality code and generates front-end UI with minimal prompting

T5: The Universal Translator (2019)

Full Name: Text-to-Text Transfer Transformer Philosophy: Every NLP problem is a text generation problem

T5 treats everything as translation: summarization becomes translating long text to short text, sentiment analysis becomes translating text to “positive” or “negative,” and question answering becomes translating questions plus context to answers.


Vision Transformers: Beyond Language (2020)


The Vision Transformer (ViT) paper proved that transformers aren’t just for text. By treating image patches like words in a sentence, ViTs achieved state-of-the-art results in computer vision, challenging the dominance of convolutional neural networks.


The insight: Attention mechanisms are universal — they can find patterns in any sequential or structured data.


Transformers: Real-World Applications


  1. Language Models Everywhere:

  2. ChatGPT & GPT-4: Conversational AI that feels genuinely helpful

  3. Google Search: BERT powers better understanding of search queries

  4. Google Translate: Now supports over 110 languages with near-human quality (blog.google)

  5. GitHub Copilot: AI pair programming that writes code from natural language descriptions (GitHub)

  6. Grammarly: Real-time writing assistance powered by transformer-based language models (Grammarly)

2. Multi-Modal Revolution:


  • DALL·E 2/3: Text-to-image generation, 4M+ images daily. (link)

  • CLIP: Links text & images with 97.3% ImageNet accuracy. (link)

  • Whisper: Speech recognition across 99 languages (<2% error). (link)

  • GPT-5: Handles text + images + videos (up to 256 frames).

  • Midjourney: 15M+ users, creating 2M+ images daily.

3. Scientific Breakthroughs

  • AlphaFold: Predicting protein structures that could revolutionize drug discovery

  • AlphaCode: Solving competitive programming problems at human expert level

  • Scientific literature analysis: Automatically extracting insights from millions of research papers

  • Drug discovery: Identifying potential compounds and predicting molecular properties

The Reality Check: Transformers Aren’t Perfect


  1. Computational Appetite: Transformers are resource-intensive. The attention mechanism scales quadratically with sequence length, double the input length, quadruple the computation required.

  2. Hallucination Problem: Confident but Wrong. Transformers are pattern-matching machines, not knowledge databases. They can generate convincing but completely fabricated information with unwavering confidence. Examples: Citing non-existent research papers with believable titles, Creating fake historical facts that sound plausible, Inventing biographical details about real people.

  3. Bias and Fairness: Since transformers learn from human-generated data, they inherit and sometimes amplify human biases like gender stereotypes, racial bias, cultural biases etc. The influential paper “On the Dangers of Stochastic Parrots” by Bender et al. highlighted these critical concerns about bias amplification and environmental costs.

  4. Security Vulnerability: Transformers introduce new attack vectors like prompt injection, model extraction, backdoor attacks that trigger specific behaviors, privacy etc.

Transformers are your gateway to understanding not just current AI, but the foundation for everything that’s coming next. Every major AI breakthrough in the past five years has transformer DNA in it.

Essential Resources for Your Transformer Journey


See you all next Thursday! And a quick reminder — think twice before handing your images to Gemini or any AI tool. Your photos hold more about you than you realize, so don’t give away privacy for convenience.



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