What is a Neural Network? Explain Like I’m Five

by Chris Von Wilpert, BBusMan • Last updated November 23, 2023

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What is a neural network?

A neural network is like a digital brain inspired by the way our own noggin works. It's made up of layers upon layers of interconnected nodes or "neurons" that love to play detective and solve mysteries together. Just like a group of detectives piecing together clues to solve a case, these neurons process information, pass it along, and collectively come to a conclusion. They work as a team to recognize patterns, analyze data, and make predictions about anything from identifying handwritten digits to translating content and much more.

Neural network fast facts

  • Convolutional Neural Networks (CNNs) are great at identifying images, working similarly to how our eyes and brain see things.

  • Neural networks have three parts: the input part, which gets data, hidden part, which works on data, and output part, which gives results.

  • Neural networks are layered to handle complicated tasks, like spotting patterns or understanding complex data.

  • Neural networks in machine learning act like a mini-brain, using 'neurons' to learn and make decisions.

  • Tesla's Autopilot uses neural networks to make sense out of what its sensors see, enabling cars to drive and park safely without human intervention.

What is an example of a neural network?

Neural networks, modeled loosely on the human brain, are fascinating components of modern artificial intelligence. A prominent example are the Convolutional Neural Networks (CNNs), widely used in image recognition. Imagine the way your brain instantly recognizes a friend's face. CNNs do something similar, digitally. They have multiple layers, each designed to process and transform data progressively, much like how our own neurons work.

In a CNN, the input layer takes an image and breaks it down into pixels. The hidden layers then act like a series of filters, each extracting specific features like edges, textures, or colors. This is akin to how our brain's neural circuitry processes visual information. The final layer, the output, compiles these features to identify the image — say, distinguishing a cat from a dog. It's a brilliant demonstration of pattern recognition, a fundamental aspect of human cognition, now replicated in digital form.

Deep learning algorithms in CNNs also continuously learn and improve. By adjusting connection weights through processes like gradient descent, these networks can refine their accuracy, much like how we learn from experience. This dynamic ability to learn from data and improve over time is a cornerstone of neural networks, making them not just an imitation of the human brain but a powerful tool for tasks ranging from facial recognition to medical diagnostics.

A basic neural network diagram illustrating the flow from the input layer through hidden layers to the output layer, highlighting the architecture of neural computations. Photograph: GeeksforGeeks.

What are the three layers of a neural network?

Neural networks, inspired by the human brain, consist of three primary layers: the input layer, hidden layer(s), and the output layer. Each plays a crucial role in processing information.

The input layer is the starting point. Think of it as the senses of the neural network, where it receives raw data. In image recognition, for example, this layer takes in the pixel data of an image. The input layer's job is to collect this data without any processing, much like our eyes or ears collect sensory information before our brain makes sense of it.

Then come the hidden layers. These can be one or many, forming the complex web of a neural network's “brain”. Each hidden layer consists of artificial neurons or nodes that perform computations. They extract and process features from the input data, gradually refining it. This is similar to how our brain's neural circuits process sensory information in stages, extracting and interpreting increasingly complex features. The hidden layers are where the magic of pattern recognition, a core capability of neural networks, happens.

Finally, the output layer brings it all together. It takes the processed information from the hidden layers and produces the final result. For instance, in a facial recognition system, the output layer would identify the face. This layer is crucial as it translates complex, processed data into understandable and actionable output, like identifying categories or making decisions. This culmination mimics how our brain integrates processed sensory information to create a coherent understanding or response.

Why do neural networks have so many layers?

Neural networks often have multiple layers to effectively mimic the complexity and depth of the human brain's processing capabilities. Each layer in a neural network captures different levels of abstraction of the data it processes, which is crucial for tasks like pattern recognition, image recognition, or natural language processing.

The first layers, closer to the input, typically detect simple, low-level features like edges or basic textures in images, or individual words in text processing. As data progresses through the network, subsequent layers combine these simple features to detect more complex ones. For example, in image recognition, the initial layers might recognize edges and colors, while deeper layers might identify shapes or specific objects like faces or cars. This layered approach is akin to how our brain processes sensory information, starting from basic perception and moving towards complex understanding.

Moreover, having multiple layers allows deep learning algorithms to learn and model complex, non-linear relationships in data. In real-world scenarios, the relationships between inputs and outputs are rarely straightforward. Deep-learning networks, with their many layers, can approximate these complex functions better than shallow networks. Each additional layer adds a level of depth to the learning capability, allowing the network to capture more subtle nuances in the data.

A digital brain model studded with colorful blocks, symbolizing the complex and multifaceted nature of neural network connections. Photograph: imaginima via Getty Images.

How many layers is a human neural network?

The human neural network, or more precisely, the human brain, is extraordinarily complex and cannot be directly compared to artificial neural networks in terms of layers. The brain consists of approximately 86 billion neurons interconnected in a highly intricate and dynamic network. This network doesn't have distinct 'layers' like an artificial neural network but instead is organized into different regions and structures, each with specific functions.

The cerebral cortex, the brain's outer layer, is crucial for higher-order functions like thought, reasoning, and language. It's divided into four lobes (frontal, parietal, temporal, and occipital), each responsible for different cognitive and sensory activities. Beneath the cortex are other crucial structures like the limbic system (involved in emotions and memories), the thalamus (relaying sensory and motor signals), and the brainstem (controlling basic life functions).

How many neurons are in a neural network?

The number of neurons in a neural network can vary widely depending on the network's complexity and the specific task it's designed for. In artificial neural networks, a neuron refers to a node or unit within the network, often forming part of layers.

In simpler networks, such as those used for basic pattern recognition or linear regression tasks, the number of neurons might range from dozens to a few hundred. These networks might have a single hidden layer or even none (in the case of a perceptron, a type of linear classifier).

For more complex tasks, like image recognition or natural language processing, neural networks can have thousands to millions of neurons. Deep learning networks, especially Convolutional Neural Networks (CNNs) and Recurrent Neural Networks (RNNs), used in image and speech recognition, respectively, often require a large number of neurons to capture the high level of detail and complexity in the data. For instance, a CNN used for image processing might have layers with hundreds or thousands of neurons each to effectively identify patterns and features in image data.

Is ChatGPT a neural network?

Yes, ChatGPT is based on a type of neural network known as a transformer model, which is a specific architecture within deep learning algorithms. Transformer models have revolutionized the field of natural language processing (NLP) due to their effectiveness in handling sequential data, especially text.

A key feature of transformer models like ChatGPT is their use of self-attention mechanisms. These mechanisms allow the model to weigh the importance of different words in a sentence or passage, enabling it to generate more coherent and contextually relevant responses. Unlike traditional neural network architectures that process data sequentially, transformers can process entire sequences of data in parallel, making them more efficient at handling tasks like language translation, question-answering, and text generation.

Where does ChatGPT get its data from?

ChatGPT learns from a huge collection of texts, including books and websites. Think of it like studying: it reads and learns from these sources. The training process is what fine-tunes how ChatGPT thinks. When it gets queries and responds, it adjusts its thinking to get better over time. This is called supervised learning. By doing this, ChatGPT gets good at spotting patterns and subtle details in language. That's how it can create responses that sound like they were written by a human, based on what you ask it.

Is Tesla Autopilot a neural network?

Tesla Autopilot, Tesla's advanced driver-assistance system, uses neural networks as a key component of its technology. The system is designed to provide features like adaptive cruise control, lane centering, and in some cases, self-parking and summoning the car from a parking spot. Neural networks play a crucial role in enabling these functionalities.

The neural networks in Tesla Autopilot are primarily used for processing and interpreting vast amounts of data from the vehicle's sensors, which include cameras, ultrasonics, radar, and more. These networks are used for image recognition tasks, allowing the vehicle to accurately identify and respond to various elements of the driving environment like other vehicles, pedestrians, road signs, and lane markings.

Tesla's approach involves deep learning, a subset of machine learning where neural networks with many layers (deep networks) learn from large amounts of data. The neural networks in Tesla's system are trained on vast datasets compiled from the fleet of Tesla vehicles on the road. This training includes recognizing various driving scenarios and conditions, which helps the system improve over time and work efficiently when presented with real-time data on the road.

An AI's perspective through Tesla’s Autopilot system, with various data points and object recognition cues, showcasing a practical application of neural networks in real-time decision-making. Photograph: Ben Dickson via VentureBeat.

What is the difference between neural networks and algorithms?

Neural networks and algorithms are both tools used in computing, but they work in different ways. Think of an algorithm as a set of instructions for solving a problem or doing a task — like a recipe in a cookbook. It's a step-by-step guide to get a specific result. For example, an algorithm can tell a computer how to sort a list of numbers.

Neural networks, on the other hand, are more like a brain. They're not just following instructions; they're set up to learn from examples. A neural network is made of layers of 'neurons' that work together to understand data, recognize patterns, and make decisions. It's like teaching someone to recognize different types of fruit by showing them lots of examples, rather than giving them a list of rules to follow.

So, the main difference is how they approach problems. Algorithms follow predefined rules, while neural networks learn from data and experiences. Neural networks are especially useful for complex tasks where writing specific rules is difficult —  such as recognizing faces in photos or understanding spoken language.

What is the difference between machine learning and neural networks?

Machine learning and neural networks are closely related but have distinct differences. Think of machine learning as a broad field in computing where machines learn from data. It's like teaching a computer to make predictions or decisions based on examples, without being explicitly programmed for each task. Machine learning uses various techniques, including algorithms like decision trees, support vector machines, and neural networks.

Neural networks, a subset of machine learning, specifically mimic the human brain's structure and function. They consist of layers of interconnected nodes or 'neurons' that process data. These networks are excellent at recognizing patterns and making complex predictions, especially in tasks involving large amounts of data — like image or speech recognition.

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