Complexity in the righting behavior of the starfish Asterina pectinifera

Righting behavior of the starfish Asterina pectinifera was investigated to determine whether the starfish can learn to complete the action in a shorter amount of time or to use specific arms as leaders. In this study, A. pectinifera individuals were placed on the bottom of an aquarium on the aboral surface, and the righting time and leading arms were recorded. Preliminary results suggested that neither variable showed an apparent adaptive change. Subsequently, a computer model of the righting behavior was constructed from the observations on A. pectinifera that described righting in terms of changes in arm states determined in relation to the states of all other arms. Results of the computer simulations suggest that the intrinsic complexity of the process of righting is such that A. pectinifera can neither learn to right itself in less time nor use specific arms to do so.