Does the Flynn Effect Differ by IQ Level in Samples of Students Classified as Learning Disabled?

Abstract

This research examined scores from two learning-disabled (LD) samples for evidence of the Flynn Effect (FE; Flynn, 1999) to determine (a) whether the FE was evident, and (b) if the magnitude of the FE differed on IQ scores at varying levels of intelligence. Sample 1 consisted of 40 children who were administered the Woodcock-Johnson Tests of Cognitive Ability-Revised (WJ-R Cog) and the Woodcock-Johnson Tests of Cognitive Ability-Ill (WJ-III Cog) approximately 8 weeks apart. Sample 2 consisted of triennial test data for 169 students who were tested once with the Wechsler Intelligence Scale for Children-Revised (WISC-R) and 3 years later with the Wechsler Intelligence Scale for Children-Third Edition (WISC-III). After an initial analysis for the overall FE, Samples 1 and 2 were each divided into IQ level groups (e.g., 91-105) and analyzed accordingly. Results for Sample 1 (W-J) indicated that the 2+ point observed IQ change was not significant for this relatively small sample, although it appeared to be consistent with the direction and degree predicted by the FE (Flynn, 1984). Results for Sample 2 (WISC) indicated a significant IQ change consistent with the FE. Neither sample exhibited statistically significant differences for FE by IQ level. However, consistent with previous research, observed differences increased from lower to higher IQ levels. Consequently, this research cannot rule out the possibility that a child's IQ level influences the degree to which the FE is apparent.