Thirza Dado

PhD Candidate at the Neural Coding Lab who studies how the world is represented by the brain using synthesized reality.

Map is not the territory; limitations of decoding

2023, 12 July

The treachery of images The Treachery of Images, 1929, by Rene Magritte challenges us to recognize the limitations of representations. The painting emphasizes that we must be aware of the separation between the image and the actual object, and that we should not fall into the trap of simplistic interpretations.

Neural decoding is a fascinating avenue of exploration in the realm of cognitive neuroscience. It involves the intricate process of translating neuronal activity into meaningful representations, which could take the form of visualizations, language or sounds (to name a few), allowing us to interpret and make sense of the information encoded in the brain. But let’s not get too caught up in the euphoria of possibilities. Behind the promising facade of this pioneering field, there are a series of limitations and prejudices that may arise within the decoding process, reminding us that “the map is not the territory” (– Alfred Korzybski) we seek to explore.

Models are abstractions of reality

When light enters the eyes, it sets off a domino effect of electrical impulses in the visual system that specifically encodes the visual information from the surrounding world. The objective of decoding is then to model the reverse transformation from the neural responses back to the real-world concepts they represent. Let's start by acknowledging the fundamental fact that models, no matter how sophisticated and refined they may be, are always a simplification of reality. While these models can provide valuable insights, we must remember that they merely constitute an attempt to approximate a complex system using assumptions and measured parameters.

When we forget that the map is not the territory, we can fall prey to reduction and oversimplification where complex human experiences can be reduced to simplistic, predictable patterns, leading to stereotypical ideas.

Let’s explore this concept through an example:

Imagine researchers developing a model to decode facial expressions from brain activity. They gather data from a homogeneous group of participants, with the majority belonging to a specific ethnic group. The model learns to recognize patterns that correlate with different facial expressions, such as joy, sadness, and anger. However, due to the model being trained on a dominant ethnic group, it may inadvertently exhibit bias and incorrectly interpret facial expressions in other ethnic groups. This can lead to false predictions and misinterpretations of emotions in minority individuals. The model may overlook subtle nuances and cultural differences in facial expressions, resulting in misunderstandings or even stigmatization of minorities.

When we forget that the map is not the territory, we can fall prey to reduction and oversimplification where complex human experiences can be reduced to simplistic, predictable patterns, leading to stereotypical ideas. If we blindly rely on the decoding model without maintaining critical thinking and acknowledging its limitations, we can make erroneous interpretations and incorrect predictions. This could not only result in scientific inaccuracies but also have practical consequences, for example, in the context of healthcare or neurotechnology.

Abstraction can be powerful

But there is another side to the coin since “a model which took account of all the variegation of reality would be of no more use than a map at the scale of one to one” (– Joan Robinson). Acknowledging the limitations of models does not mean we should strive for a perfect depiction of reality. In fact, it is practically impossible to capture every detail and variation of reality within a model. Such a model would be incredibly complex and unwieldy, causing more confusion than enlightenment. Hence, generalization is a powerful tool.

Models serve as a foundation for further exploration and discovery.

By simplifying the complexity of reality and identifying overarching principles, models provide a structured approach to grasp the world around us. They enable us to generate insights and make predictions about broader populations and situations, offering valuable guidance in navigating the intricacies of reality. Just as a map allows us to understand and navigate an area, decoding models provide us with a framework to study the brain. They allow us to capture the essential elements and understand key relationships. While they cannot capture the full complexity of reality, they offer us valuable guidance. It is important to strike a balance between representation and reality. We should be aware of the limitations of models and generalizations, while also recognizing that they can help us better understand the world.

Moreover, models serve as a foundation for further exploration and discovery, operating within an iterative cycle of hypotheses, experiments, and revisions. This iterative process allows us to formulate specific questions, design new experiments, and expand our knowledge.

Our mental model is also an abstraction of reality

The notion that representations are simplifications of reality goes even further. It follows the core of our own mental model and the way we perceive the world. Our neural representation of the world is, in fact, an abstraction of the real world. We can never have direct access to the full richness of reality but can only catch glimpses through our senses and cognitive processes. Our brains constantly construct and interpret an internal representation of the world based on this limited information colored by our subjective beliefs, expectations, and biases. That said, it is not only important to be critical of the limitations of decoding models themselves but also of our own mental model that influences the interpretation of the results. This recognition invites us to humility and continuous reflection on the intricate nature of our own thinking.

Conclusion

The promise of neural decoding is enticing. The idea that we can decipher thoughts and intentions purely by observing neural activity raises hope for the treatment of neurological disorders, the restoration of sensory and motor skills, and even the possibility of mind-reading. However, let us not forget that we are still at the beginning of this complex field of research. Else, it can lead to distorted results and misleading interpretations. While we have made progress in decoding sensory inputs, comprehending abstract concepts, subjective experiences, and higher cognitive functions remains largely beyond our reach. The human mind is an elusive entity, and current technologies and methods still have a long way to go before they can capture the full spectrum of our inner lives.

So let us, amidst the excitement about the possibilities of neural decoding, maintain humility. We must be aware of the limitations and biases inherent in this field. In a world craving quick answers and immediate gratification, it is crucial to approach our research with patience and methodical diligence.

That’s all!

2023

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2022

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