Differences that make a difference: comparisons of metacomponential functioning and knowledge base among groups of high and low IQ learning disabled, mildly mentally retarded, and normally achieving adults.

To determine if cognition among persons with learning disabilities (LD) and mild mental retardation (MMR) is similar, we compared metacomponential functioning and knowledge acquisition across groups of incarcerated adults with LD and high IQ (HIQLD), with LD and low IQ (LIQLD), with normal achievement (NA), and with MMR. The Slosson Intelligence Test Computer Report (Nicholson, 1984) formula established criteria for group inclusion. Metacomponential functioning among 77 males and 26 females was measured by a confidence test (Echternacht, Boldt, & Sellman, 1971) designed for the general knowledge subtest of the SRA Achievement Battery (Naslund, Thorpe, & Lefever, 1982). Knowledge base and group membership were significantly related to metacomponential ability (R2 = .84). Persons with HIQLD and LIQLD performed better than those with MMR on both measures. The HIQLD, however, did not outperform their peers with NA. Results show that (a) knowledge base is the best predictor of metacomponential skill, (b) metacomponential orchestration differentiates persons with HIQLD from those with LIQLD and both groups from persons with MMR, and (c) IQ mediates metacognition, but does not explain it. Education should emphasize knowledge acquisition for people with HIQLD; people with LIQLD and MMR require more attention to metacognition.