Abstract
Human infants have been shown to implicitly learn rules, such as the repetition of ABB or ABA patterns, regardless of the identity of the participating items, both with sequential information during language development and with simultaneously presented visual patterns. However, in these studies the ABB or ABA patterns were defined by the identity of the items themselves. This leaves open the question of how successful humans are in extracting such rules in more complex situations when the rule is defined by a particular feature dimension of the items rather than by their identity. We examined the performance of adults presented with an implicit rule-learning task where both the color and the size of the items followed some underlying rules. Subjects were first exposed to a series of three different shapes presented simultaneously: five triplet scenes were viewed ten times each in random order during the learning phase. Patterns within each triplet varied in both size and color saturation following two different rules (AAB vs. ABA). The test phase consisted of triplets made of new elements not seen in the learning phase, which varied in size but had identical color saturation. In each trial, subjects saw two triplets, an AAB and an ABA pattern, and judged which triplet seemed more familiar. Surprisingly, adult subjects did not find the pattern of sizes shown during practice more familiar than the alternative, with a size difference of either 100 or 150 percent. These results suggest that successful visual rule-learning requires a much higher saliency of the rule in the given feature dimension than is expected based on the discrimination results.