A slime mold that does not have a brain uses its body to detect mechanical signals in its environment and performs calculations similar to what we call “thinking” to decide in which direction to grow based on that information. You can also solve mazes, learn new things, and predict events.
Research led by Harvard University has verified that some organisms are capable of “thinking” without having a brain or nervous system. This is the case of the slime mold Physarum polycephalum, a unicellular organism that is able to choose where to grow based on data it collects from the environment. It does this by detecting mechanical signals.
The incredible abilities of this simple organism also include the ability to learn new behaviors, anticipate certain situations, and even find their way out of mazes. According to a press release, the new study differs from previous research carried out with the Physarum mold because the organism was not stimulated through chemical signals or food that could condition its behavior.
How is it possible that an organism lacking a brain and conformed by such a simple structure can carry out actions that relate to thinking? It is worth remembering that slime mold is endowed with a single cell: it grows based on a tubular structure and a series of branches. It does not have any organ or area of its body that can resemble a brain, nor does it have a nervous system.
Feel the environment
According to the new study, published in the journal Advanced Materials, the secret of this amoeba-like organism is detection of mechanical signals that it picks up from its surroundings. Using this data, you can move your watery cytoplasm in two directions throughout your entire body. However, the main question is to discover how you make your decisions and what are the processes involved.
While previous research had proven that this slime mold can react to stimuli given to it, such as substances to feed it, scientists now sought to verify whether this representative of protointelligent life was capable of making decisions based solely on in physical signals that come from their environment.
The researchers verified this by applying a series of small disk-shaped structures to the growing organism in the Petri dish. The purpose was to determine if and how these signals from their close environment were modifying the slime mold’s chosen growth pattern.
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To the surprise of specialists, the single-celled organism was able to physically “feel” the disks and make decisions based on various patterns, rather than being guided solely by signal intensity. In other words, it decided not only according to the magnitude of each disk, which would mark a greater intensity of the physical or mechanical signal, but also according to other parameters, such as the way the disks were grouped.
Consequently, this brainless creature can calculate which way to grow based on the relative stress patterns you detect in your environment: It does not simply grow into the largest or heaviest object you can feel.
Understanding how this simple organism manages to perform calculations of this type is crucial to learn more about the fundamentals of cognition and how mechanical signals can determine the behavior of living things.
Mechanosensation Mediates Long-Range Spatial Decision-Making in an Aneural Organism. Nirosha J. Murugan, Daniel H. Kaltman, Paul H. Jin, Melanie Chien, Ramses Martinez, Cuong Q. Nguyen, Anna Kane, Richard Novak, Donald E. Ingber and Michael Levin. Advanced Materials (2021).DOI:https://doi.org/10.1002/adma.202008161
Video and podcast: edited by Pablo Javier Piacente based on elements and sources free of copyright. Video Image Credit: Emilian Robert, viviane6276, AJS1, and 3D Animation Production Company on Pixabay. Nirosha Murugan, Levin Laboratory, Tufts University and Harvard University Wyss Institute. Uday Mittal on Unsplash.
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Photo: Physarum polycephalum slime mold growing in a Petri dish. Credit: Nirosha Murugan, Levin Laboratory, Tufts University and Harvard University Wyss Institute.