Fig. 1.

The left panels (Expt 3) provide an illustration of the trained and emergent relations in Urcuioli (2008, Experiment 3). The uppercase letters stand for characteristics of the training stimuli (R = red; G = green; T = triangle; H = horizontal line) and the lowercase letters “s” and “c” refer to the sample and comparison positions respectively. Trained relations and the two-member classes they form are depicted at the top (A). In the panels below (B), the common stimuli that result in class merger are circled, and the four-member classes that result are depicted. The dotted arrow shows that emergent symmetry is predicted. The right panels (Expt 4) provide a comparable illustration for Urcuioli (2008, Experiment 4) with trained relations at the top (C), and class merger and four-member classes below (D). The dotted line shows that anti-symmetry, not symmetry, is predicted