Unit 6: Robotic Control 2 – Representation

This unit covered one chapter and dealt with the question of how do robots store information about their environment.

Table of Contents

Reading – Chapter 12: What’s in your Head?

This unit was primarily about representation or working memory. It was a discussion based upon the stored information which is used by an object to plan and problem solve in its environment. Representation can refer to information about self, the environment, other objects, goals, actions, and tasks. Representations are very useful and can be in many different forms but they do have a cost. There is an initial cost for building a representation, a cost to maintain the information and a cost to update the information.

Food For Thought 12-1

Do you think animals use internal models? What about insects?

I do believe that animals maintain internal models. They are able to recognize people and environments and are able to problem solve and remember solutions to those problems. I think one of the best examples that animals have internal models is that of mice in a maze. If I am properly reading an article entitled Spatial learning by mice in three dimensions correctly, mice are able to remember the solution to a maze and can even remember exactly which paths have been visited without needing to revisit dead ends. “Mice learn to retrieve food from the ends of the arms without omitting any arms or re-visiting depleted ones… This suggests intact three-dimensional spatial representations in mice over short timescales”. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4451476/

My instinct is that most insects do not use internal models or representations. This belief is based on my opinion that insects are simpler creatures, that cannot afford the processing to store and maintain a model of the world when they can use other signals and techniques to achieve their goals. For example I believe that ants will follow pheromone trails instead of maintaining a map of their environment for pathfinding. However, I have never before actually stopped to think about whether insects have “memory” before now. But that still leaves some important questions, such as how do Bee’s get back to their beehive? It seems like insects will need to be able to form some memories about landmarks at least to be able to navigate their environment. So this seems to indicate that insects will need some internal models to build spatial representations. Looking at the Wikipedia article for Insect Cognition at: https://en.wikipedia.org/wiki/Insect_cognition it seems that insects are indeed able to build memories and can make use of spatial information to form memories about locations.

Food For Thought 12-2

Why might you not want to store and use internal models?

I think it will depend on the task you are trying to achieve. It does not make sense for a 3D printer to have a memory or map of the room that it is in, because it doesn’t need to move or navigate through that space, it is a stationary device. So, you will only want to use internal models if they are appropriate or relevant to the task at hand. Further there is a cost to building, storing and maintaining internal models, so if you are facing limitation in sensors, processing power or storage space you will need to find ways to solve the problem within those constraints. Often because of the cost of an internal model it might be more effective to find a solution that does not need an internal model to function.

Instructor’s Notebook

The instructor’s notebook indicates that there are no exercises for this unit.


This was a very short unit again, and I am beginning to get excited for the final project.

Shawn Ritter

November 20th, 2021

Featured Image: Photo by Markus Spiske: https://www.pexels.com/photo/person-holding-film-strip-4201333/

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