A Guide to Understanding Artificial Intelligence, Machine Learning, Neural Networks & Deep Learning
Introduction
Artificial intelligence is rapidly transforming how organizations across industries process information, make decisions, and solve complex problems. AI encompasses a broad spectrum of technologies from traditional rule-based systems to advanced machine learning, neural networks, and deep learning. Each AI type is designed to enable machines to perform tasks that once required human intelligence. Unlike conventional programming, which relies on rigid, hand-coded instructions, modern AI systems learn from data, adapt to new circumstances, and continuously improve over time. This article explores the key distinctions between these technologies, examining how they relate to one another, how they are built and trained, and where they are most effectively applied—with particular attention to their growing role in finance and other data-intensive fields.
To provide a structured foundation for understanding these technologies, this article progresses from broad to more specific topics including:
Together, these topics offer a comprehensive framework for understanding not only what these technologies are, but how they work, where they excel, and how to deploy them responsibly.
Artificial Intelligence vs. Traditional Programming
AI systems are designed to learn from data, adapt to new scenarios and circumstances, and improve over time. This makes them especially effective for dynamic, data-rich challenges in which patterns continuously evolve. In contrast, traditional programming is fundamentally a rule-based framework. Programmers develop specific instructions or rules that computers execute without variation. Such systems are highly effective for straightforward, predictable tasks in which the logic is clearly defined and does not change.(1)
The following table provides a structured comparison of rule-based and AI-based systems across critical dimensions:
How AI-Based Systems Improve Over Time
A key strength of AI systems lies in their capacity to adapt and improve continuously. This improvement occurs through a continuous cycle of four processes:(2)
1) Data Ingestion
AI systems continuously collect and process new inputs, such as customer transactions, repayment records, spending behaviors, and market movements. This continuous stream keeps the system aligned with the latest trends. For example, in fraud detection, unusual transaction clusters or activity in new geographies can be detected in near real time.
2) Retraining
AI models are periodically retrained using newly collected data, updating internal parameters, and reducing reliance on outdated historical patterns. In credit risk scoring, this means the model can recognize new repayment trends even as borrower behavior shifts due to economic changes or new regulations.
3) Performance Monitoring
Robust AI systems incorporate feedback loops to compare predictions with actual outcomes. If performance drifts due to new fraud tactics, changing borrower demographics, or other factors, the system flags the issue for further adjustment. These adjustments help maintain outcome quality and minimize undetected errors.
4) Iterative Learning
Through repeated cycles of data ingestion, retraining, and monitoring, AI models achieve greater accuracy and nuance. Over time, they can detect new or hidden patterns, such as fraud rings using multiple accounts or subtle repayment trends that indicate financial health or distress.
The AI Hierarchy: How AI, ML, NN & DL Relate to Each Other
A common point of confusion is treating artificial intelligence, machine learning, neural networks, and deep learning as interchangeable terms. They are not interchangeable, they represent nested subsets of one another, each building on the foundation of the layer above it. Think of them as nesting dolls. Or think of them with Deep Learning is a house, on a street called Neural Networks, in a neighborhood called Machine Learning, in a city called Artificial Intelligence.
Artificial Intelligence (AI)
AI is the outermost layer and represents the overarching goal of creating machines capable of performing tasks that typically require human intelligence. It covers everything from simple "if-then" logic and expert systems to complex robotics and natural language processing. This layer includes both rule-based systems that follow explicit instructions and systems that learn.
Machine Learning (ML)
Machine learning is a subset of AI focused specifically on algorithms that improve through experience. Rather than being told how to solve a problem, ML systems use statistical techniques to find patterns in data and make predictions. Its defining characteristic is adaptability and the ability to learn without being explicitly programmed for every outcome.
Neural Networks (NN)
Neural networks are a specific approach to implementing machine learning, inspired by the structure of the human brain. Rather than relying on purely statistical formulas, they use layers of interconnected nodes (neurons) to process information. This architecture allows them to handle more complex, non-linear relationships in data that simpler ML algorithms often struggle with.
Deep Learning (DL)
Deep learning is the innermost layer and is specialized form of neural networks in which the "deep" refers to the number of layers through which data is transformed. These additional layers enable deep learning models to automatically discover the features they need to focus on without human labeling. Deep learning is the powerhouse behind modern breakthroughs such as ChatGPT and self-driving cars.
A critical point us that every Deep Learning model is a Neural Network, every Neural Network is a form of ML and all ML is a form of AI—but not vice versa. The hierarchy flows only inward.(3)
Artificial Intelligence
Artificial intelligence (AI) refers to the development of computer systems capable of performing tasks that typically require human intelligence, such as understanding language, recognizing patterns, solving problems, and making decisions. AI involves training algorithms and particularly machine learning models on large datasets so they can identify patterns and make predictions or generate outputs without being explicitly programmed for every scenario. Modern AI encompasses a range of techniques, from traditional rule-based systems to deep learning neural networks that power today's most advanced applications, including voice assistants, image recognition, recommendation engines, and large language models like the one generating this response. Rather than replacing human thinking entirely, AI is best understood as a tool that augments human capability, automating repetitive or complex tasks while enabling new possibilities across fields like healthcare, education, science, and business.
Type of Artificial Intelligence
Machine Learning
Machine learning is a form of artificial intelligence in which systems automatically create rules by learning from data rather than relying on explicitly programmed instructions. As new data is introduced, the model continuously adapts and improves its performance. ML problems fall into two broad categories: regression (predicting continuous values, such as future sales) and classification (predicting categorical outcomes, such as whether a loan will default).
Machine Learning focuses on training models to identify patterns in data, typically relying on manual feature extraction defined by humans. It is well suited for small to medium-sized datasets, runs efficiently on standard CPUs, trains quickly, and produces interpretable results. Common applications include spam detection and credit scoring. (4)
Machine learning relies on several foundational concepts. Data is the raw input and numbers, text, images, audio, or sensor readings. A model is the core system that identifies patterns and produces predictions. Algorithms provide instructions that guide how models are built and refined. Training is the process of exposing algorithms to data so the model can learn, while validation fine-tunes parameters and prevents overfitting. Testing uses unseen data to assess real-world performance.
Types of Machine Learning
Machine Learning Architecture & Structure
Machine learning systems are built on a layered architecture that moves data through a series of computational stages. At the foundation lies the data pipeline where raw inputs are collected, cleaned, and transformed into numerical representations that algorithms can process. Above this sits the model layer, where the actual learning takes place. Most modern ML models are structured as networks of interconnected nodes (neurons) organized into layers: an input layer that receives data, one or more hidden layers that extract increasingly abstract features, and an output layer that produces predictions or classifications. The depth of these hidden layers is what distinguishes "deep learning" from shallower, classical approaches.
The core technology powering modern machine learning is the artificial neural network, inspired loosely by the brain's biological structure. During training, data flows forward through the network (the "forward pass"), generating a prediction. That prediction is then compared to the known correct answer using a loss function, which quantifies the error. Through a process called backpropagation, the error signal flows backward through the network, and an optimization algorithm most commonly stochastic gradient descent that nudges each connection weight slightly in the direction that reduces the error. Repeat this across millions of examples and the model gradually learns. Specialized architectures have emerged for different domains including convolutional neural networks (CNNs) for image data, recurrent networks (RNNs) and transformers for sequential or language data, and graph neural networks for relational data.
Structurally, ML systems exist within a broader engineering ecosystem. A trained model is rarely the end product, and it must be deployed, monitored, and maintained within an MLOps pipeline that manages versioning, retraining, and performance tracking. Hardware plays a critical role: GPUs and purpose-built chips like TPUs accelerate the matrix math that underpins neural network computation. At the highest level, large systems often combine multiple models and an ensemble, a retrieval system, or a mixture of specialized experts and coordinated to manage complex, real-world tasks. The result is less than a single algorithm and more an interconnected stack of data engineering, statistical modeling, and software infrastructure working in concert.
Neural Networks
Neural networks are inspired by the structure and behavior of the human brain, though far simpler. The human brain contains approximately 86 billion neurons connected by trillions of synapses. A neural network is a simplified mathematical model that mimics some of these principles, using numerical signals and structured layers of artificial neurons. Traditional computer programs rely on strict, rule-based logic. Fraudsters can study fixed rules and deliberately alter their behavior to bypass detection. Neural networks address this by learning patterns automatically from large volumes of data rather than following rigid instructions.(5)
Types of Neural Networks
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Neural Network Architecture & Structure
A neural network consists of three primary types of layers. The input layer receives raw data, one or more hidden layers use weighted connections to extract patterns, and the output layer generates the final prediction, such as a class label, probability score, or numerical value. The fundamental unit is the neuron. Each neuron multiplies its inputs by learned weights, adds a bias for flexibility, and passes the result through an activation function that determines whether the signal propagates forward. Collectively, neurons act as gatekeepers that evaluate inputs against learned rules.
Neural networks excel at learning complex, nonlinear patterns from noisy or imperfect data, generalizing to unseen cases, and working across diverse industries and all without requiring manual feature engineering. The trade-offs are real, though: they demand large datasets and significant compute, can overfit training data, and often behave as black boxes that are difficult to interpret.
Forward Propagation
Forward propagation is how a network generates a prediction. Data enters the input layer and flows forward at each hidden layer, neurons apply weights, add a bias, and pass results through an activation function. Early layers detect simple features; deeper layers combine these into increasingly abstract concepts. The final output emerges from the output layer. Critically, no learning happens in forward propagation is purely the prediction phase.
Backpropagation
Backpropagation is where learning actually occurs. After the forward pass produces a prediction, a loss function measures the error and how far off the prediction was from the correct answer. The network then runs a backward pass, using the chain rule of calculus to trace how much each weight contributed to that error. Weights with greater responsibility for the error are adjusted more, guided by an optimization method like gradient descent.
This forward-then-backward cycle repeats across many training iterations, progressively reducing error and refining the network's internal weights until it can make reliable predictions on new, unseen data.
Neural Networks Applications in Finance
Neural networks have become a transformative force in finance and accounting, moving well beyond research environments to become central tools investment firms, insurance companies and for banks in such things as loan approval. They enable organizations to manage risk by identifying and mitigating potential exposures before they materialize, optimize portfolios through data-driven allocation that balances returns against risk, and detect fraud by recognizing sophisticated patterns that traditional rule-based systems would miss.
What makes neural networks particularly valuable in these settings is their ability to recognize trends and anomalies in complex financial data, process enormous volumes of transactions at scale, adapt dynamically to shifting market conditions, and deliver precise predictions and classifications that support better decision-making across the organization.
Deep Learning
Deep learning is a subset of machine learning and a branch of artificial intelligence in which computer systems learn to recognize patterns, generate content, and make decisions by training on massive amounts of data. Rather than being explicitly programmed with rules, deep learning models use multilayered neural networks to automatically develop their own internal representations through exposure to examples, extracting complex features without manual intervention and a process that has unlocked capabilities that once seemed far beyond the reach of machines.
These models typically require exceptionally large datasets and significant computational power, often in the form of GPUs. While they train more slowly and function as less-interpretable black boxes, they frequently achieve higher accuracy than traditional approaches. This makes deep learning particularly effective in applications such as image recognition, fraud detection, and language translation.(6)
Types of Deep Learning
Among the many forms deep learning takes, two have risen to prominence in recent years are Generative AI and Large Language Models (LLMs). Both represent major leaps in what AI can do. not just analyzing the world, but actively creating within it.
Generative AI
Generative AI refers to deep learning models capable of producing entirely new content, such as, text, images, audio, video, code. It also includes learning patterns from existing data rather than simply classifying or predicting. One technical approach underpin modern generative models are Generative Adversarial Networks (GANs). With GANs two competing models refine output until generated content becomes indistinguishable from reality. Another model are Transformers, the architecture behind large language models like ChatGPT that excel at text generation, summarization, and question answering. For image generation specifically, diffusion models have become particularly influential, training on the process of gradually adding and removing noise from pictures. This approach is used by tools like Midjourney, DALL·E, and Stable Diffusion to produce photorealistic or artistic imagery from a simple text prompt. Generative AI has transformed creative industries, enabling designers, filmmakers, musicians, and marketers to prototype and produce at a scale and speed previously impossible, while also raising pressing questions about authenticity, copyright, and the spread of synthetic media. (7)
Generative AI Architecture and Structure
Generative AI is built on transformer-based neural networks, which use a self-attention mechanism to process and relate information across entire sequences simultaneously, while enabling models like LLMs to generate coherent text, and complementary architectures like diffusion models and GANs to produce images and other media. Training happens in two phases including large-scale pre-training on vast datasets using massive GPU clusters, followed by fine-tuning with techniques like RLHF to align model behavior with human preferences. In practice, these foundation models sit within broader systems layered with retrieval, tool use, memory, and safety components, converting inputs into numerical embeddings, processing them through billions of parameters, and decoding outputs token by token. This process at sufficient scale, gives rise to emergent capabilities like reasoning, creativity, and code generation.
Generative AI Applications in Finance
Generative AI is transforming finance and accounting by automating time-consuming tasks, enhancing decision-making, and improving accuracy across a range of functions. In financial reporting, AI models can draft earnings summaries, generate variance analyses, and produce regulatory filings with minimal human input, dramatically reducing the hours spent on routine documentation. In accounting, generative AI assists with anomaly detection in transaction data, automated reconciliation, and audit preparation by synthesizing large volumes of ledger data into coherent, actionable insights. Beyond back-office operations, financial institutions are leveraging these tools for personalized client communications, dynamic risk assessments, scenario modeling, and real-time forecasting capabilities that once required entire teams of analysts. As the technology matures, its integration with ERP systems and financial data platforms is enabling a shift from reactive reporting to proactive, AI-driven financial strategy.
Large Language Models (LLMs)
Large language models (LLMs) are a specific and enormously impactful category of deep learning model trained to understand and generate human language. Google researchers in 2017, utilized Transformer architecture to help LLMs learn by processing enormous amounts of text from the internet, books, and other sources, developing a nuanced grasp of grammar, facts, reasoning, and tone. Models like GPT-4, Claude, and Gemini contain billions or even trillions of parameters, and what makes them particularly remarkable is their emergent ability. At sufficient scale and size, they develop capabilities their creators did not explicitly train for, such as basic arithmetic, logical inference, and step-by-step problem solving. While all LLMs are a form of generative AI, not all generative AI is an LLM. For example, a model predicting time-series patterns like revenue, for instance, is generative AI for structured data but was not trained on language.(8)
Modern LLM-based agents can perform a remarkably broad range of useful action including searching and indexing documents to answer targeted queries, classifying emails and tickets, clustering similar statements or customer behaviors, generating code, emails, and summaries, extracting structured information from unstructured files, and rewriting or condensing long documents into concise briefings. LLMs are now embedded in search engines, productivity software, customer service platforms, and scientific research tools, making them one of the most widely deployed technologies in history. Together with generative AI more broadly, they represent not just an evolution in deep learning, but a fundamental shift in how humans interact with machines.
LLM Architecture and Structure
Large language models are built on the transformer architecture, which uses a self-attention mechanism to weigh relationships between all words in a sequence simultaneously, enabling the model to capture long-range linguistic dependencies far more effectively than older sequential approaches. These models contain billions of learned numerical weights called parameters, trained in two phases: first, pre-training on vast text corpora by predicting the next token in a sequence, then fine-tuning using techniques like RLHF to align the model's behavior with human preferences. Input text is broken into tokens, converted into high-dimensional vectors called embeddings, and passed through stacked layers of attention heads and feed-forward networks to build contextual representations. At inference time, the model generates text one token at a time, sampling from a probability distribution with its knowledge distributed implicitly across its weights rather than stored in any retrievable form/ This explains both their impressive generalization and their tendency to hallucinate.
LLM Applications in Finance
Large language models are transforming finance and accounting by automating time-consuming tasks and augmenting human decision-making across a wide range of functions. In financial analysis, LLMs can rapidly parse earnings reports, SEC filings, and market news to generate summaries, flag risks, and surface investment insights that would take analysts hours to compile manually. In accounting, they are being deployed to automate invoice processing, expense categorization, and reconciliation, significantly reducing manual data entry and error rates. LLMs also power intelligent chatbots for customer-facing banking services, helping users with account inquiries, loan applications, and financial planning guidance. Compliance and audit functions benefit as well, with models capable of scanning large volumes of contracts and transactions to detect anomalies, flag regulatory violations, or ensure adherence to standards like GAAP or IFRS. Additionally, LLMs are being used for financial forecasting support, credit risk assessment, and generating narrative explanations for complex financial models bridging the gap between raw data and actionable business intelligence.
The Distinction Between Generative AI vs. LLM
Generative AI is a broad category of artificial intelligence models designed to create new content, encompassing a wide range of modalities from text and images to audio and video. Large language models, or LLMs, represent a specialized subset of generative AI that are trained on massive amounts of text data, enabling them to understand and produce human-like language with remarkable fluency. While all LLMs are a form of generative AI applied to language, not all generative AI systems are LLMs, as the broader category also includes image generators like DALL-E and Midjourney, as well as time-series generators used in fields such as finance and healthcare. This distinction is important because each type of generative model relies on different architectures, training data, and techniques suited to its specific output format. Understanding where LLMs fit within the larger generative AI landscape helps clarify both their impressive capabilities and their inherent limitations as tools built primarily around language.
AI Hallucinations
AI hallucinations arise from a combination of technical and structural limitations inherent in how these systems are built and deployed. At their core, models are constrained by gaps in their training data and a tendency to overgeneralize from limited examples, leading them to produce outputs that sound plausible but are factually incorrect. This problem is compounded by ambiguous or poorly constructed prompts that give the model insufficient guidance, as well as reliance on static or outdated knowledge that fails to reflect current realities.(9) The consequences of these failures extend well beyond isolated errors in high-stakes domains like financial services, hallucinations can trigger incorrect loan approvals and elevated default rates, while indirectly eroding customer trust, attracting regulatory fines, and causing lasting reputational damage that compounds far beyond the original mistake.
Safeguards to reduce the impact of hallucinations include:
The cost of hallucinations extends beyond immediate errors. Direct costs may include incorrect loan approvals and increased default rates, while indirect costs often manifest as loss of customer trust, regulatory fines, and reputational damage. These consequences can compound over time, far outweighing the initial mistake.
Humans and AI
AI delivers the greatest value in financial contexts when managing large volumes of structured data, offering consistency, accuracy, and speed in tasks like drafting investor memos, generating loan communications, and performing statistical bias checks. The most effective model is a human-in-the-loop framework where AI manages repetitive, data-intensive work while humans refine outputs, validate results for fairness and compliance, and maintain oversight for legal and reputational protection. This collaboration acts as a force multiplier—freeing analysts to focus on advisory roles and enabling deeper, more informed client consultations.(10)
However, human contribution remains essential, as qualities like empathy, ethical reasoning, relationship management, and strategic thinking cannot be replicated by machines. Human oversight ensures that AI-generated content aligns with laws, ethical standards, and company values, while actively monitoring for bias and compliance risks. The most successful
financial strategies intentionally integrate both human expertise and AI capability, combining scale and precision with judgment, cultural awareness, and trust-building communication to strengthen client confidence and drive better outcomes.
Conclusion
The landscape of artificial intelligence spanning machine learning, neural networks, deep learning, and large language models and generative AI represents one of the most significant technological shifts of our time. As these technologies grow more sophisticated, their value lies not in replacing human judgment but in amplifying it. From supervised and reinforcement learning models that adapt to evolving financial data, to neural networks that detect subtle fraud patterns invisible to rule-based systems, AI offers unprecedented analytical power. Yet this power comes with responsibilities such as ensuring data quality, guarding against hallucinations, maintaining transparency, and upholding ethical standards. Organizations that succeed will be those that thoughtfully integrate AI capabilities with human expertise and leveraging the speed and precision of machines while preserving the ethical reasoning, and contextual understanding that only people can provide. Please feel free to reach out to me if you have any comments on the contents or subject matter.
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Question 1 (strategic / architecture) The article mentions continuous improvement pipelines (data ingestion, retraining, monitoring), but doesn’t go deep into modern architectures. 👉 How would this approach integrate with current systems based on LLMs + RAG (Retrieval-Augmented Generation), where “learning” doesn’t always require retraining the model but rather updating the context? This significantly changes how we understand the model lifecycle. Question 2 (practical / business) The value of AI in finance is strongly emphasized, but: 👉 How would you recommend deciding between using interpretable classical models (e.g., regression, decision trees) vs more complex models (deep learning or LLMs), especially in regulated environments where explainability is critical? There’s a real tension here between performance and compliance that would be worth exploring further.
The article does a very good job of organizing the “mental map” of AI, especially with the hierarchical analogy (AI → ML → NN → DL), which remains one of the biggest sources of confusion even among technical profiles. One of its strongest points is that it doesn’t stay at an academic level, but effectively connects concepts to real-world use cases in finance—something many introductory articles fail to achieve. It’s also great to see the inclusion of topics like hallucinations and human-in-the-loop, which are no longer optional but critical in production environments. That said, there is a slight “traditional” bias in how Machine Learning vs Deep Learning is presented. Today, in many real-world scenarios (especially with tabular data in finance), models like Gradient Boosting still compete with or outperform deep learning. This could have been better nuanced to avoid reinforcing the idea that “deep learning = always better.”