The stability of cognitive abilities: A meta-analytic review of longitudinal studies

Abstract

Cognitive abilities, including general intelligence and domain-specific abilities such as fluid reasoning, comprehension knowledge, working memory capacity, and processing speed, are regarded as some of the most stable psychological traits, yet there exist no large-scale systematic efforts to document the specific patterns by which their rank-order stability changes over age and time interval, or how their stability differs across abilities, tests, and populations. Determining the conditions under which cognitive abilities exhibit high or low degrees of stability is critical not just to theory development but to applied contexts in which cognitive assessments guide decisions regarding treatment and intervention decisions with lasting consequences for individuals. In order to supplement this important area of research, we present a meta-analysis of longitudinal studies investigating the stability of cognitive abilities. The meta-analysis relied on data from 205 longitudinal studies that involved a total of 87,408 participants, resulting in 1,288 test-retest correlation coefficients among manifest variables. For an age of 20 years and a test-retest interval of 5 years, we found a mean rank-order stability of ρ = .76. The effect of mean sample age on stability was best described by a negative exponential function, with low stability in preschool children, rapid increases in stability in childhood, and consistently high stability from late adolescence to late adulthood. This same functional form continued to best describe age trends in stability after adjusting for test reliability. Stability declined with increasing test-retest interval. This decrease flattened out from an interval of approximately 5 years onward. According to the age and interval moderation models, minimum stability sufficient for individual-level diagnostic decisions (r_tt = .80) can only be expected over the age of 7 and for short time intervals in children. In adults, stability levels meeting this criterion are obtained for over 5 years. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Figure 1. The Top Two Levels of the CHC-Model

Notes. The acronyms are defined in Table 1.

Figure 2.. Some Possible Age Moderation Trends.

Notes. Age Moderation of Rank-Order Stability of Cognitive Abilities in Schuerger and Witt (1989), Tucker-Drob and Briley (2014), and an Example of an Alternative Inverse U Shaped Moderation Trend Expected Based on A Model in Which Stability is Inversely Related to the Absolute Magnitude of Mean Change.

Figure 3. Study Identification and Screening Process as a PRISMA Chart

Notes. This figure presents the literature search and gives information on the number of coded studies and effect sizes. k = number of records, h = number of included samples, e = number of effect sizes. *One additional record (one subsample, six effect sizes) was added after suggestion by a reviewer.

Figure 4. Rank-Order Stability as an Exponential Function of Test-Retest Interval Based on the Complete Dataset

Notes. Larger points represent larger weight of the effect sizes.

Figure 5. Rank-Order Stability as Exponential (black) and Connected Linear Spline (blue) Functions of Age Based on the Complete Dataset

Notes. Larger points represent larger weight of the effect sizes. As reported in Table S2, the mean test-retest interval was 6.52 years.

Figure 6

Temporal Decay of Stability of Cognitive Abilities in Childhood and Adolescence Based on the Exponential Age and Interval Moderator Functions, where Each Plotted Line Represents a Different Baseline Age Followed With Increasing Time Lags

Figure 7. Rank-Order Stability as an Exponential Function of Test-Retest Interval Based on Effect Sizes for Which Reliability Information was Available

Notes. Larger points represent larger weight of the effect sizes. Depicted points represent unadjusted effect sizes.

Figure 8

Maximum Intervals (in Years) for Which a Stability of .70 and .80 is Obtained for Measures of General Intelligence, as Implied by the Age and Interval Duration Moderator Analyses of General Cognitive Ability (Exponential Models)