AI summary · arXiv: 2303.09728v1 · cs.CV

The Cascaded Forward Algorithm for Neural Network Training

Gongpei Zhao, Tao Wang, Yidong Li, Yi Jin, Congyan Lang, Haibin Ling
Original paper · DOI 10.1016/j.patcog.2024.111292 Submitted to arXiv on 17 Mar. 2023 Published in Pattern Recognition (May 2025) License: NONEXCLUSIVE-DISTRIB 1.0

How to read this summary? Illustrated guide

The essentials

  • The backpropagation algorithm has been widely used in neural networks for the past decade and has played a significant role in the development of deep learning.
  • Backpropagation algorithm limitations include getting stuck in local minima and experiencing vanishing or exploding gradients.
  • Researchers have explored alternative algorithms to address these limitations, such as the Forward-Forward (FF) algorithm.
  • The authors propose a new learning framework called the Cascaded Forward (CaFo) algorithm which does not rely on backpropagation optimization like FF.
  • Unlike FF, the CaFo algorithm directly outputs label distributions at each cascaded block without needing additional negative samples.
  • The CaFo framework allows for independent training of each block, enabling easy deployment into parallel acceleration systems.
  • The proposed CaFo method is evaluated on four public image classification benchmarks and demonstrates a significant improvement in prediction accuracy compared to the baseline approach.
  • Overall, this paper introduces a novel learning framework for neural networks that addresses some of the limitations associated with backpropagation while offering improved efficiency and parallelization capabilities as well as better prediction accuracy in image classification tasks.

Key points written by AI: they may contain errors, check them against the paper.

AI-generated keywords: Backpropagation Cascaded Forward Neural Networks Image Classification Optimization

Read further

  • Comprehensive Summary
  • Layman's Summary
  • Blog article
  • Original abstract
The backpropagation algorithm has been widely used in neural networks for the past decade and has played a significant role in the development of deep learning. However, this algorithm has some limitations such as getting stuck in local minima and experiencing vanishing or exploding gradients. To address these limitations, researchers have explored alternative algorithms to backpropagation. One well-known alternative is the Forward-Forward (FF) algorithm. In this paper, the authors propose a new learning framework called the Cascaded Forward (CaFo) algorithm which does not rely on backpropagation optimization like FF. Unlike FF, the CaFo algorithm directly outputs label distributions at each cascaded block without needing additional negative samples. This leads to a more efficient process during both training and testing. Additionally, each block in the CaFo framework can be trained independently allowing for easy deployment into parallel acceleration systems. The proposed CaFo method is evaluated on four public image classification benchmarks and demonstrates a significant improvement in prediction accuracy compared to the baseline approach. Overall, this paper introduces a novel learning framework for neural networks that addresses some of the limitations associated with backpropagation while offering improved efficiency and parallelization capabilities as well as better prediction accuracy in image classification tasks.

Was this synthesis useful?

Score: 0

Why do we need votes?

Votes are used to determine whether we need to re-run our summarizing tools. If the count reaches -10, our tools can be restarted.

Figures and plots

Ask about a figure by number or use its question button to request visual analysis. Up to two figures and four image panels per question. Values read from plots are approximate; check the original data.

AI assistant instructions?

Tools for this paper

Explain it differently 1 free rewrite left today
Save to a collection Group papers in collections to compare them, chat with them and export them. Continue with Google Create a free account Log in

Advanced tools Premium

For researchers who follow a field closely: citation alerts, journal-club slides, version comparison and Zotero export. Discover Premium

Zotero Zotero guide
Citation alerts Citation alerts guide

Papers around this one

See them on a map

Ranked by how close their title and abstract are to this paper’s. Select some to read them together.

Closest papers

  1. Very close Cites this paper
    Training convolutional neural networks with the Forward–Forward Algorithm
    Riccardo Scodellaro, A. Kulkarni, Frauke Alves et al. · 2023 · Scientific Reports · cited 27 times · Not summarized yet
    Abstract

    Recent successes in image analysis with deep neural networks are achieved almost exclusively with Convolutional Neural Networks (CNNs), typically trained using the backpropagation (BP) algorithm. In a 2022 preprint, Geoffrey Hinton proposed the Forward–Forward (FF) algorithm as a biologically inspired alternative, where positive and negative examples are jointly presented to the network and training is guided by a locally defined goodness function. Here, we extend the FF paradigm to CNNs. We introduce two spatially extended labeling strategies, based on Fourier patterns and morphological transformations, that enable convolutional layers to access label information across all spatial position…

  2. Very close
    Scalable Forward-Forward Algorithm
    Andrii Krutsylo · 2025 · arXiv.org · preprint, not peer reviewed · cited 1 time · Not summarized yet
    Abstract

    We propose a scalable Forward-Forward (FF) algorithm that eliminates the need for backpropagation by training each layer separately. Unlike backpropagation, FF avoids backward gradients and can be more modular and memory efficient, making it appealing for large networks. We extend FF to modern convolutional architectures, such as MobileNetV3 and ResNet18, by introducing a new way to compute losses for convolutional layers. Experiments show that our method achieves performance comparable to standard backpropagation. Furthermore, when we divide the network into blocks, such as the residual blocks in ResNet, and apply backpropagation only within each block, but not across blocks, our hybrid des…

  3. Very close Cites this paper
    Exploring the Feasibility of Forward Forward Algorithm in Neural Networks
    Suraj R Gautham, S. Nair, Suresh Jamadagni et al. · 2024 · 2024 International Conference on Advances in Modern Age Technologies for Health and Engineering Science (AMATHE) · cited 1 time · Not summarized yet
    Abstract

    This research explores the Forward-Forward Algorithm, proposed as an alternative to Backpropagation, in the context of Convolutional and Recurrent Neural Networks for multiclass classification. The authors' investigation aims to evaluate the algorithm's efficiency, advantages, and disadvantages for real-world applications. Results offer insights into the untapped potential and nuances of this approach, guiding researchers in optimizing neural network performance and potentially advancing a more human-like approach in Deep Learning.

  4. Close Cites this paper
    Mono-Forward: Revisiting Forward-Forward through Objective-Locality Decomposition
    J. Gong, Bruce Li, Waleed Abdulla · 2025 · cited 5 times · Not summarized yet
    Abstract

    Backpropagation remains the dominant algorithm for training deep neural networks, but it incurs substantial memory overhead and relies on global error propagation, which is often regarded as biologically implausible. The Forward-Forward (FF) algorithm is an appealing local-learning alternative to backpropagation, yet it still lags behind backpropagation in accuracy. A central unresolved question is whether this gap arises from FF's locality or from the positive-negative double-pass goodness objective used to train each layer. In this work, we revisit FF under the supervised setting through a decomposition that separates these two design choices. Our analysis suggests that FF's performance li…

  5. Close Cites this paper
    HCL-FF: Hierarchical and Contrastive Learning for Forward-Forward Algorithm
    Jie Yao, Hong-En Chen, C.-C. Jay Kuo · 2026 · Computer Vision and Pattern Recognition · cited 2 times · Not summarized yet
    Abstract

    Deep neural networks trained with backpropagation have achieved outstanding performance in vision tasks but remain biologically implausible, computationally demanding, and difficult to interpret. The Forward-Forward (FF) algorithm offers a promising alternative by training each layer independently through local goodness objectives. However, its purely local optimization lacks hierarchical coordination across layers, and the decoupling of goodness from features leaves the representations unconstrained and semantically ambiguous. We propose a Hierarchical and Contrastive Learning FF framework (HCL-FF) to address these limitations. HCL-FF introduces (1) a coarse-to-fine hierarchical learning st…

  6. Close
    NoProp: Training Neural Networks without Back-propagation or Forward-propagation
    Qinyu Li, Yee Whye Teh, Razvan Pascanu · 2025 · Machine Learning · cited 11 times · AI summary available
    Abstract

    The canonical deep learning approach for learning requires computing a gradient term at each layer by back-propagating the error signal from the output towards each learnable parameter. Given the stacked structure of neural networks, where each layer builds on the representation of the layer below, this approach leads to hierarchical representations. More abstract features live on the top layers of the model, while features on lower layers are expected to be less abstract. In contrast to this, we introduce a new learning method named NoProp, which does not rely on either forward or backwards propagation. Instead, NoProp takes inspiration from diffusion and flow matching methods, where each l…

  7. Close Cited by this paper
    The Predictive Forward-Forward Algorithm
    Alexander G. Ororbia, Ankur A. Mali · 2023 · Annual Meeting of the Cognitive Science Society · cited 55 times · Not summarized yet
    Abstract

    We propose the predictive forward-forward (PFF) algorithm for conducting credit assignment in neural systems. Specifically, we design a novel, dynamic recurrent neural system that learns a directed generative circuit jointly and simultaneously with a representation circuit. Notably, the system integrates learnable lateral competition, noise injection, and elements of predictive coding, an emerging and viable neurobiological process theory of cortical function, with the forward-forward (FF) adaptation scheme. Furthermore, PFF efficiently learns to propagate learning signals and updates synapses with forward passes only, eliminating key structural and computational constraints imposed by backp…

  8. Close Cited by this paper Used in depth by this paper A method it uses
    The Forward-Forward Algorithm: Some Preliminary Investigations
    Geoffrey E. Hinton · 2022 · arXiv.org · preprint, not peer reviewed · cited 498 times · Not summarized yet
    Abstract

    The aim of this paper is to introduce a new learning procedure for neural networks and to demonstrate that it works well enough on a few small problems to be worth further investigation. The Forward-Forward algorithm replaces the forward and backward passes of backpropagation by two forward passes, one with positive (i.e. real) data and the other with negative data which could be generated by the network itself. Each layer has its own objective function which is simply to have high goodness for positive data and low goodness for negative data. The sum of the squared activities in a layer can be used as the goodness but there are many other possibilities, including minus the sum of the square…

Prior work it builds on

  1. Related
    Biologically Motivated Algorithms for Propagating Local Target Representations
    Alexander G. Ororbia, Ankur A. Mali · 2018 · AAAI Conference on Artificial Intelligence · cited 108 times · Not summarized yet
    Abstract

    Finding biologically plausible alternatives to back-propagation of errors is a fundamentally important challenge in artificial neural network research. In this paper, we propose a learning algorithm called error-driven Local Representation Alignment (LRA-E), which has strong connections to predictive coding, a theory that offers a mechanistic way of describing neurocomputational machinery. In addition, we propose an improved variant of Difference Target Propagation, another procedure that comes from the same family of algorithms as LRA-E. We compare our procedures to several other biologicallymotivated algorithms, including two feedback alignment algorithms and Equilibrium Propagation. In tw…

  2. Related*
    Overfitting and neural networks: conjugate gradient and backpropagation
    S. Lawrence, C. Lee Giles · 2000 · Proceedings of the IEEE-INNS-ENNS International Joint Conference on Neural Networks. IJCNN 2000. Neural Computing: New C · cited 321 times · Not summarized yet
  3. Related
    Batch Normalization: Accelerating Deep Network Training by Reducing Internal Covariate Shift
    S. Ioffe, C. Szegedy · 2015 · International Conference on Machine Learning · cited 48,613 times · Not summarized yet
    Abstract

    Training Deep Neural Networks is complicated by the fact that the distribution of each layer's inputs changes during training, as the parameters of the previous layers change. This slows down the training by requiring lower learning rates and careful parameter initialization, and makes it notoriously hard to train models with saturating nonlinearities. We refer to this phenomenon as internal covariate shift, and address the problem by normalizing layer inputs. Our method draws its strength from making normalization a part of the model architecture and performing the normalization for each training mini-batch. Batch Normalization allows us to use much higher learning rates and be less careful…

  4. Related Used in depth by this paper A method it uses
    Matching Networks for One Shot Learning
    O. Vinyals, C. Blundell, T. Lillicrap et al. · 2016 · Neural Information Processing Systems · cited 8,864 times · Not summarized yet
    Abstract

    Learning from a few examples remains a key challenge in machine learning. Despite recent advances in important domains such as vision and language, the standard supervised deep learning paradigm does not offer a satisfactory solution for learning new concepts rapidly from little data. In this work, we employ ideas from metric learning based on deep neural features and from recent advances that augment neural networks with external memories. Our framework learns a network that maps a small labelled support set and an unlabelled example to its label, obviating the need for fine-tuning to adapt to new class types. We then define one-shot learning problems on vision (using Omniglot, ImageNet) an…

  5. Related
    The neural coding framework for learning generative models
    Alexander G. Ororbia, Daniel Kifer · 2020 · Nature Communications · cited 86 times · Not summarized yet
    Abstract

    Neural generative models can be used to learn complex probability distributions from data, to sample from them, and to produce probability density estimates. We propose a computational framework for developing neural generative models inspired by the theory of predictive processing in the brain. According to predictive processing theory, the neurons in the brain form a hierarchy in which neurons in one level form expectations about sensory inputs from another level. These neurons update their local models based on differences between their expectations and the observed signals. In a similar way, artificial neurons in our generative models predict what neighboring neurons will do, and adjust …

Papers that cite it

  1. Close Uses this paper in depth
    Forward Learning of Graph Neural Networks
    Namyong Park, Xing Wang, Antoine Simoulin et al. · 2024 · International Conference on Learning Representations · cited 4 times · Not summarized yet
    Abstract

    Graph neural networks (GNNs) have achieved remarkable success across a wide range of applications, such as recommendation, drug discovery, and question answering. Behind the success of GNNs lies the backpropagation (BP) algorithm, which is the de facto standard for training deep neural networks (NNs). However, despite its effectiveness, BP imposes several constraints, which are not only biologically implausible, but also limit the scalability, parallelism, and flexibility in learning NNs. Examples of such constraints include storage of neural activities computed in the forward pass for use in the subsequent backward pass, and the dependence of parameter updates on non-local signals. To addre…

  2. Close Uses this paper in depth
    Stochastic Forward-Forward Learning through Representational Dimensionality Compression
    Zhichao Zhu, Yang Qi, Hengyuan Ma et al. · 2025 · Neural Information Processing Systems · cited 5 times · Not summarized yet
    Abstract

    The Forward-Forward (FF) learning algorithm provides a bottom-up alternative to backpropagation (BP) for training neural networks, relying on a layer-wise"goodness"function with well-designed negative samples for contrastive learning. Existing goodness functions are typically defined as the sum of squared postsynaptic activations, neglecting correlated variability between neurons. In this work, we propose a novel goodness function termed dimensionality compression that uses the effective dimensionality (ED) of fluctuating neural responses to incorporate second-order statistical structure. Our objective minimizes ED for noisy copies of individual inputs while maximizing it across the sample d…

  3. Close
    Reformulating the Forward-Forward Algorithm with Layer-wise Similarity-based Objectives
    J. Gong, Raymond Luo, Emma Wang et al. · 2026 · IEEE International Joint Conference on Neural Network · Not summarized yet
    Abstract

    Backpropagation underpins the success of artificial neural networks, yet it has critical limitations such as backward locking and global error propagation. The Forward-Forward algorithm has been proposed as a more biologically plausible method that replaces the backward pass with an additional forward pass. Nevertheless, the Forward-Forward algorithm significantly trails backpropagation in accuracy, and its optimal form requires multiple forward passes at inference time, resulting in low inference efficiency. In this work, the Forward-Forward algorithm is reformulated within a similarity-learning paradigm. The proposed algorithm is named Forward-forward Algorithm Unified with Similarity-base…

  4. Close
    Block-local learning with probabilistic latent representations
    D. Kappel, Khaleelulla Khan Nazeer, Cabrel Teguemne Fokam et al. · 2023 · arXiv.org · preprint, not peer reviewed · cited 8 times · Not summarized yet
    Abstract

    The ubiquitous backpropagation algorithm requires sequential updates through the network introducing a locking problem. In addition, back-propagation relies on the transpose of forward weight matrices to compute updates, introducing a weight transport problem across the network. Locking and weight transport are problems because they prevent efficient parallelization and horizontal scaling of the training process. We propose a new method to address both these problems and scale up the training of large models. Our method works by dividing a deep neural network into blocks and introduces a feedback network that propagates the information from the targets backwards to provide auxiliary local lo…

  5. Close
    Energy-Efficient Supervised Learning With a Binary Stochastic Forward-Forward Algorithm
    Risi Jaiswal, Supriyo Datta, Joseph G. Makin · 2025 · IEEE Transactions on Artificial Intelligence · cited 1 time · Not summarized yet
    Abstract

    Reducing energy consumption has become a pressing need for modern machine learning, which has achieved many of its most impressive results by scaling to larger and more energy-consumptive neural networks. Unfortunately, the main algorithm for training such networks, backpropagation, poses significant challenges for custom hardware accelerators, due to both its serial dependencies and the memory footprint needed to store forward activations for the backward pass. Alternatives to backprop, although less effective, do exist; here the main computational bottleneck becomes matrix multiplication. In this article, we derive forward-forward (FF) algorithms for binary, stochastic units. Binarization …

How are these papers found?

We compare the title and abstract of this paper with those of every paper summarized on this site, and with the papers Semantic Scholar recommends, those it cites and those citing it (for a much-cited paper, its most recent citations and, from OpenAlex, the most cited ones). Among the prior work and the follow-ups, the papers that use each other in depth, a method it uses and the much-cited follow-ups come a little higher. The levels (very close, close, related) come from the similarity of the texts, not from a judgment of quality; * marks a paper without an abstract, compared by its title. The sentence under a paper is written by an AI from the two abstracts: check it in the papers. A paper marked not relevant by three readers leaves the list.

Updated on 5 November 2026.

The illustrated guide to the papers around a paper

The previous summary was created more than a year ago and can be re-run (if necessary) by clicking on the Run button below.

Disclaimer: The AI-based summarization tool and virtual assistant provided on this website may not always provide accurate and complete summaries or responses. We encourage you to carefully review and evaluate the generated content to ensure its quality and relevance to your needs.