RESUMO
In order to uncover processes in the acquisition of spatial representation, we tested voles, jirds, and mice in a dark grid maze-a relatively homogenous environment comprising 16 identical equispaced crossroads and similar choice of paths at each crossroad. The three species initially displayed a tendency to retrace sections of their recently traversed path, perhaps indicating exploration and learning of an unfamiliar environment by virtue of repetition. All three species displayed the same decision making at crossroads. They had an equal tendency to progress forward, turn sideways, or turn back to retrace their path upon the first arrival at each crossroad. Over repeated visits to the same crossroad, however, progressing forward increased along with a decrease in turning back, but there was no change in the incidence of turning sideways. It is suggested that progressing forward is easier than making turns, since the latter oblige the navigator to remember the location of turning in order to retrace or integrate the path and remain oriented. The incidence of turning sideways, in being more difficult than forward progression and retracing, yet necessary in a restricted maze space, did not change over repeated visits to crossroads. Altogether, decision making at a crossroad may be described as going straight ahead for simplicity, retracing a path to memorize it, or turning sideways at a constant rate. The present tests in the grid maze illustrate how tangible entities (crossroads, paths) are integrated during the early phase of acquiring an abstract representation (map) of the maze.