Evolving Animats

Final behavior (generation 59,904) of one example animat in the Task 4 environment of Albantakis et al. 2014. In Task 4, the animat must catch blocks of size 3 and 6 and avoid blocks of size 4 and 5.

Trial 0


The animat was tested on a total of 128 trials (blocks of 4 different sizes, falling in 2 directions, with 16 different initial animat positions).

  • Trials 1–32: size 3 blocks (catch)
  • Trials 33–64: size 4 blocks (avoid)
  • Trials 65–96: size 6 blocks (catch)
  • Trials 97–128: size 5 blocks (avoid)
  • The animat reached a fitness value of 125/128, meaning it correctly catches or avoids blocks in 125 out of the 128 trials.


    Network structure (connectome) of the animat with two sensors (S1, S2), two motors (M1, M2), and four hidden elements (A–D).

    • Self-loops are indicated by dark circles around the elements.
    • Elements in the “off” state are dimmed, elements in the “on” state are brightly colored.
    • Elements with no connections are grayed-out.


    Albantakis L, Hintze A, Koch C, Adami C, Tononi G. 2014. “Evolution of Integrated Causal Structures in Animats Exposed to Environments of Increasing Complexity.” PLoS computational biology, 10 (12), pp. e1003966.