1 What is Abstraction? How is it Used? Why is it Important?.- 1.1 Introduction.- 1.2 Definitions, Distinctions, and Contrasts.- 1.3 Psychological Perspectives on Abstraction.- 1.4 Some Concrete Abstractions.- 1.5 Abstraction in Education.- 1.6 Refining the Definition of Abstraction.- 1.7 Chapter Summary.- 2 Abstraction Over the Life Course: Developmental and Methodological Concerns.- 2.1 Introduction.- 2.2 Abstraction and Cognitive Growth in Childhood.- 2.3 Intellectual Decline in Adulthood?.- 2.4 Mistaking Cohort Differences for Age Effects in Cross-Sectional Data.- 2.5 The Longitudinal Study of Adult Intellectual Development.- 2.6 Shortcomings of Longitudinal Designs and Studies.- 2.7 Differential Patterns of Development.- 2.8 Chapter Summary and Directions for Empirical Research.- 3 The Social Bases of Intellectual Functioning.- 3.1 Introduction.- 3.2 Ethnocentrism, Prejudice, and Abstraction.- 3.3 Constrained Belief Systems, Abstract Communication Styles, and Elaborated Speech Codes.- 3.4 Work and Personality.- 3.5 The Theory of Psychological Effects of Complex Environments.- 3.6 Societal Development and Individual Modernity.- 3.7 The Sociology of Knowledge.- 3.8 The Structural Overlap Hypothesis.- 3.9 A Note on the Link Between Complex Environments and Intellectual Functioning.- 3.10 Chapter Summary.- 4 Empirical Findings.- 4.1 Introduction.- 4.2 Measuring Abstraction.- 4.3 Coding Similarities Items.- 4.4 The Sample.- 4.5 Environmental Complexity from Status-Related Sources.- 4.6 Environmental Complexity of Elders: Retirement and Social Isolation.- 4.7 Environmental Complexity from Structural Overlap.- 4.8 Chapter Summary.- 5 The Study of the Social Bases of Intellectual Functioning Across the Life Course: Issues, Findings, Directions for Further Research on Abstraction.- 5.1 Introduction.- 5.2 The Three Challenges.- 5.3 Conclusions From the Social Psychological Study of Abstraction and Age.- 5.4 Abstraction, Human Development, and the Concept of Differentiation: New Directions in Theory.- Author Index.