Emergence of Memory-like Behavior in Reactive Agents Using External Markers

Early primitive animals with simple feed-forward neuronal circuits were limited to reactive behavior. Through evolution, they were gradually equipped with memory and became able to utilize information from the past. Such memory is usually implemented with recurrent connections and certain behavioral changes are thought to precede the reconstitution of the neuronal circuit's topology. If so, what could have been the behavior to drive such a rewiring? Our hypothesis is that the secretion and detection of chemical markers in the environment could be a precursor of internal memory. We will show how memory-like behavior can be expressed in memoryless reactive agents by taking advantage of the external chemical markers. Our results show that given chemical marker use, reactive agents are able to develop intelligent strategies in solving a biologically plausible food foraging task requiring spatial memory. We also found interesting analogy between the evaporation of the chemical markers and the recency effect in memory and how it affects the foraging strategy. These results are expected to help us better understand the possible evolutionary route from reactive to cognitive agents.