How human performance is helped or hindered by the design of tools that help us accomplish everyday tasks.
Industrial/Organizational Psychology: Work and family issues, human error, individual differences.
Applied Developmental Psychology: Social and emotional development of children
Human Factors/Applied Cognition: Genetic modulation of cognitive and brain aging, interventions for cognitive aging (behavioral and non-invasive brain stimulation).
Clinical Psychology: Maddux's major scholarly interest is the interface of social, clinical, and health psychology, which is concerned with the ways that theory and research from social psychology can help us understand psychological adjustment, psychological disorders, and health-related behavior.
Cognitive-behavioral research, treatment, and theory of anxiety, mood, and related disorders.
Applied Developmental Psychology: Intellectual and developmental disabilities, especially  challenging behaviors and other forms of psychopathology (assessment, applied behavior analysis, epidemiology) and  socio-emotional development and social adaptation. For free access to the Behavior Problems Inventory (BPI-01 and BPI-S) see below.
Human Factors/Applied Cognition
Cognitive and Behavioral Neuroscience: The effects of adolescent drug consumption, especially nicotine.
Industrial/Organizational Psychology: Occupational health psychology including stress, work-family, and safety; the employee-organization relationship including psychological contracts, social exchange theory, and the norm of reciprocity; organizational climate and culture; innovation and creativity; positive aging and retirement transitions; cross-cultural aspects of industrial organizational psychology.