Evolving Reward-Agnostic Domain-Adapted Learning in Neuromodulated Neural Networks

Core Concepts

Biological intelligence can learn efficiently from diverse non-reward information by exploiting assumptions about task domains, a capability that is poorly accounted for by mainstream AI learning algorithms. This study demonstrates how such Domain-Adapted Learning (DAL) can evolve from reward-driven learning through the integration of non-reward information into the learning process using neuromodulation.

Abstract

The paper proposes a theory explaining how biological evolution can produce DAL abilities that are more efficient than reward-driven learning. The key idea is that reward-driven learning (RDL) provides a consistent learning process that evolution can then consolidate into more efficient DAL by gradually integrating non-reward information into the learning process. The authors set up a computational model where a population of neural networks (NNs) learns a navigation task. The NNs use Reinforcement Learning (RL) as an approximation of RDL, and a neuromodulation (NM) mechanism to integrate non-reward information into the learning process. The evolutionary dynamics observed in the model support the proposed theory. Initially, RL alone drives learning progress. Over generations, NM-based learning abilities gradually emerge and become the dominant learning mechanism, eliminating reliance on reward information altogether. The evolved DAL agents show a 300-fold increase in learning speed compared to pure RL agents, learning exclusively from non-reward information using local NM-based weight updates. The authors analyze the learning process of the evolved agents, observing a transition from random trial-and-error to focused experimentation for gathering task-relevant information. They discuss the implications of their findings for understanding biological intelligence and developing more efficient AI learning algorithms.

Stats

The agents in the main experiment achieve a mean reward of over 0.9 within 10 trials, compared to the pure RL agent taking over 3000 trials to reach a mean reward of about 0.7. The evolved DAL agent obtains a mean reward of 0.5 at the end of the first trial.

Quotes

"Advanced biological intelligence learns efficiently from an information-rich stream of stimulus information, even when feedback on behaviour quality is sparse or absent." "Reward plays a special role, but we are not constrained to learning from reward alone. This versatility allows us to learn efficiently and robustly even when reward signals are scarce." "The central quality measure driving the RL process is (cumulative discounted) reward. All association of stimuli (observations) to responses (actions) is controlled by this quantity. In RL the dependence on reward coincides with the requirement of an explicit scalar quality measure for backpropagation: loss signals for connection weight updates are calculated from the scalar reward signal."

Key Insights Distilled From

Breaching the Bottleneck: Evolutionary Transition from Reward-Driven Learning to Reward-Agnostic Domain-Adapted Learning in Neuromodulated Neural Nets

by Solvi Arnold... at arxiv.org 04-22-2024

https://arxiv.org/pdf/2404.12631.pdf

Deeper Inquiries

How can the insights from the evolution of DAL be applied to develop more efficient and flexible learning algorithms for real-world AI systems?

The insights gained from the evolution of Domain-Adapted Learning (DAL) can be instrumental in enhancing the efficiency and flexibility of learning algorithms in real-world AI systems. By understanding how biological intelligence circumvents the reward bottleneck and leverages non-reward information for learning, we can design AI systems that are less reliant on explicit reward signals. This can lead to more adaptive and versatile learning processes that can efficiently learn from diverse types of information, even in the absence of abundant reward feedback. One practical application of these insights is in the development of AI algorithms that can learn from limited real-world experience more effectively. By pre-evolving DAL abilities in AI systems specific to their deployment domain, we can enable them to learn efficiently and adaptively from new information without being heavily dependent on explicit reward structures. This can lead to faster learning speeds, improved performance, and increased autonomy in AI systems, allowing them to make decisions and adapt to new situations more effectively. Furthermore, incorporating neuromodulation-based learning mechanisms, as observed in the evolution of DAL, can help AI systems overcome information bottlenecks and learn from a wider range of inputs. By integrating neuromodulatory update mechanisms into learning algorithms, we can create AI systems that are more flexible, adaptive, and capable of learning from diverse sources of information, similar to how biological systems learn efficiently from non-reward stimuli. In essence, applying the insights from the evolution of DAL can lead to the development of AI systems that are more efficient, flexible, and autonomous in their learning processes, ultimately enhancing their performance and adaptability in real-world scenarios.

What are the potential limitations or downsides of relying too heavily on domain-specific assumptions in the learning process, and how can these be mitigated?

While domain-specific assumptions can enhance learning efficiency and adaptability in AI systems, relying too heavily on these assumptions can also pose certain limitations and downsides. One potential limitation is the risk of overfitting to specific task domains, which can hinder the generalization of learning to new or unseen environments. If an AI system is too specialized to a particular domain, it may struggle to adapt to novel situations or tasks outside its predefined scope. Another downside of relying heavily on domain-specific assumptions is the potential lack of flexibility and robustness in the learning process. If an AI system is too rigid in its assumptions about the task domain, it may not be able to effectively learn from unexpected or diverse sources of information, limiting its adaptability and performance in dynamic environments. To mitigate these limitations, it is essential to strike a balance between domain-specific assumptions and generalizability in AI learning algorithms. One approach is to incorporate mechanisms for meta-learning or transfer learning, allowing AI systems to leverage knowledge and experiences from one task domain to another. By promoting transferability of learning across different domains, AI systems can become more versatile and adaptable to a wider range of scenarios. Additionally, implementing techniques such as regularization, ensemble learning, and continual learning can help prevent overfitting to specific task domains and promote robustness in the face of uncertainty or variability in the environment. By diversifying the learning process and incorporating mechanisms for adaptation and generalization, AI systems can mitigate the potential downsides of relying too heavily on domain-specific assumptions.

Could the evolutionary transition from RDL to DAL observed in this study provide insights into the development of cognitive abilities and the emergence of flexible intelligence in biological systems?

The evolutionary transition from Reward-Driven Learning (RDL) to Domain-Adapted Learning (DAL) observed in this study offers valuable insights into the development of cognitive abilities and the emergence of flexible intelligence in biological systems. By understanding how biological evolution may have facilitated the evolution of DAL through the integration of non-reward information into the learning process, we can gain a deeper understanding of the mechanisms underlying cognitive flexibility and adaptability in living organisms. The transition from RDL to DAL in the evolutionary process highlights the importance of gradually integrating non-reward information into the learning process to overcome information bottlenecks and enhance learning efficiency. This evolutionary pathway mirrors the way biological systems have evolved to learn from diverse stimuli and adapt to different task domains, showcasing the flexibility and versatility of cognitive abilities in living organisms. Furthermore, the concept of DAL and its evolutionary development shed light on how biological systems leverage implicit assumptions about task domains to learn efficiently and robustly, even in the absence of explicit reward signals. This adaptive learning process, driven by the gradual accumulation of biases induced by non-reward information, provides a model for understanding how cognitive abilities evolve to handle complex and varied environments. Overall, the evolutionary transition from RDL to DAL offers insights into the development of cognitive abilities and the emergence of flexible intelligence in biological systems by showcasing the adaptive mechanisms that enable organisms to learn, adapt, and thrive in diverse and changing environments. These insights can inform the design of AI systems and cognitive models that aim to replicate the flexibility and adaptability observed in biological intelligence.