Acquiring complex partial orderings in comparison with acquiring similar-sized linear orderings

The acquisition of a 14-term partial ordering was compared with the acquisition of a 14-term linear ordering. Learning the partial ordering was found to be more difficult because of two factors: (1) Subjects do not appear to have in their knowledge systems a prototype or rule for representing a long list of comparative relations as a partial ordering structure, and (2) the partial ordering must be presented so that some of the adjacently presented premises do not contain a common element. When these two factors were controlled, the partial ordering was as easy to learn as the linear ordering. It was also found that subjects learning the partial ordering showed no evidence of a serial position learning curve, whereas subjects learning the linear ordering showed some tendency to produce a serial position learning curve.