Saltwater Aquarium Blog

FISH ARE CAPABLE OF HUMAN-LIKE LOGIC

This is a copy of an article that was published in the Aquarium Fish International.  I submitted it for publication in the Aquabits section of their magazine.  It is the first article that I ever had published, and is based on an article/news item written by Robin Lloyd.  Even though it’s a low sodium article (freshwater) I found it fascinating that fish are able to use a type of logic called Transitive Inference.  The original article is below: 

Researchers at Stanford University have shown that African cichlids are capable of using logical reasoning at level similar to 4- or 5-year old humans to determine social pecking orders.  As many aquarists already know, cichlids often spar to establish hierarchical dominance and delineate territories.  Stanford researchers allowed five fish to establish a hierarchy (labeled A, B, C, D, E).  The A fish defeated B, B defeated C, C defeated D and D defeated E.  “Bystander” fish were allowed to watch the selected interactions from the center of the tank, in a transparent, protected enclosure.  “Bystander” fish were then forced to make a decision about which fish they would share tank space with.  Despite the fact that two fish to choose from may have never directly fought (example Fish A and Fish E) the bystander fish typically chose the weaker fish (D or E) as companions.  It is thought that these experiments demonstrate the cichlids’ ability to use transitive inference (TI) to determine that a D or E fish is a more suitable companion than an A or B. TI  reasoning is commonly used as a developmental benchmark in 4- and 5-year old children and has also been demonstrated in monkeys, rats and birds. 

Written by Al Ulrich

Based on an article by 

Lloyd, Robin.  “Fish capable of human-like logic: Freshwater cichlids have reasoning capacity of 4- or 5-year old child”. 

http://www.msnbc.msn.com/id/16796139/

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