What is the butterfly effect?
The butterfly effect is a term used in chaos
theory to describe how small changes to a seemingly unrelated thing or condition (also known as an initial condition) can affect large, complex systems. The term comes from the suggestion that the flapping of a butterfly's wings in South America could affect the weather in Texas, meaning that the tiniest influence on one part of a system can have a huge effect on another part.
Origins in Weather Prediction
The concept of the butterfly effect is attributed to Edward Norton Lorenz, a mathematician and meteorologist
, who was one of the first proponents
of chaos theory. Lorenz was running global climate models on his computer one day and, hoping to save himself some time, ran one model from the middle rather than the beginning. The two weather predictions, one based on the entire process, including initial conditions, and another based on a portion of the data, starting with the process already part way completed, diverged drastically. Lorenz, along with most scientists of his time, had expected the computer models to be identical regardless of where they started. Instead, tiny, unpredictable variations caused the two models to differ.
Intrigued by the results, Lorenz began creating a mathematical explanation that would show the sensitive dependence of large, complex systems like the weather. Sensitive dependence means that the development of the system depends on a wide number of factors. To simplify his findings, Lorenz coined the butterfly explanation that has since become so widely known.
In human behavior, it may be possible for small initial changes to render behavior unpredictable. For example, someone who has committed suicide are often left wondering what could have caused the death. They might agonize over the myriad small details they did not see, but which could have predicted the suicide. The butterfly effect might suggest that a huge range of experiences, dispositions
, and genetic, physical, and emotional factors were too many to account for in the person's actions.