Two tests of instance-based and abstract rule-based accounts of invariant learning.

Two manipulations are argued to distinguish between instance-based and abstract rule-based accounts of invariant learning. Three experiments examined the effects of manipulating the type of invariant feature in the learning set, and the type of training schedules prior to test. In line with traditional research, selection bias at test was present when the invariant was the consistent inclusion of a stimulus item in the learning set. However, the degree of bias was identical when the invariant was the consistent exclusion of the stimulus item. In addition, negative transfer of training was observed when subjects were trained on one learning set and then shifted training to the opposite learning set, but no positive transfer of training was observed when subjects were trained on one learning set and then continued training using the same learning set. These results are argued to be evidence for instance-based accounts of invariant learning.

An investigation of cued recall of multiattribute stimuli.

Memory performance for sequences of letters positioned in particular spatial locations in a 3 x 3 grid was examined by requiring participants to recall attributes of the target stimuli given 1 or 2 features of the stimuli as cues. Cuing asymmetry was observed between the serial-position curves of object and sequential-order information, and location and sequential-order information, when the stimuli were presented in both the same and different locations. After correcting for response bias, this asymmetry was attenuated for the stimuli presented in different locations and was eliminated for the stimuli presented in the same location. Contrary to the predictions of the fragmentation hypothesis (G. V. Jones, 1976), asymmetry was also observed between object and location information. The roles of spatial location and response bias are offered as explanations for previous contradictory claims for cuing symmetry between item and order information.