Developmental psychology

The study of change and continuity in behaviour and mental processes across development. Age differences alone do not identify their causes: task demands, experience, selection and retention intervals can change along with age.

A framework concerning enduring caregiver relationships and their contribution to security and development. Attachment-related predictions require measures of relationship organization and subsequent functioning, not simply a count of separations.

Organization of a caregiver relationship supporting exploration and access to comfort under psychological stress. It concerns a relationship rather than a context-free ranking of a child's strength; experimentally changing a care package does not independently randomize attachment security.

The study of how adaptive and maladaptive functioning emerges and changes over development. Similar early risks can lead to different outcomes, and similar outcomes can arise through different pathways. Explanations therefore examine timing, transactions and context rather than treating a diagnosis as a single fixed developmental destination.

Experiences or conditions threatening relevant development, safety or functioning. Adversity exposure should be characterized by nature, severity, duration, timing and context rather than assumed identical across people with the same event count. Objective circumstances and their subjective appraisal provide different information.

Adversity exposure is a person's history of experiences or conditions classified as adversity under a stated research definition. Event type, severity, duration, developmental timing and available support can all distinguish histories that receive the same simple event count. An exposure measure and the person's response to it are different variables.

A longitudinal design can measure early adversity exposure, later psychological stress and subsequent symptoms separately. This allows a stress sensitization hypothesis to predict a different relation between later stressors and symptoms according to earlier history. Constance Hammen and collaborators tested that possibility in a prospective study of young women.^[ref]

An observed association does not uniquely identify a biological mechanism or make exposure randomly assigned. Measurement differences, earlier symptoms and confounding remain relevant. Nor does evidence of varied responses justify treating additional adversity as a beneficial intervention.

Childhood adversity refers to adverse exposures or conditions during development, with definitions varying across studies. A useful measurement specifies the exposure, timing, duration and severity rather than treating every difficulty as one identical cause. Research on stress sensitization asks whether earlier adversity changes the relation between later stressors and outcomes such as depression. Observed associations can reflect several pathways, including continuing exposure and differences in available support. ^[ref]

A research collaboration conducting coordinated developmental experiments across laboratories, including a preregistered study of infant-directed speech preference.^[ref]

Changes in cognitive capacities, representations and their deployment with experience and maturation. A change in test performance may reflect a change in understanding, a change in access or response demands, or both.

Explaining something in terms of a purpose or what it is for. Appropriate functional questions about an artifact or decision must be distinguished from claims about the physical causes of a natural event.

Everyday expectations and explanations concerning living things and biological events. Intuitive biology can contain structured insights alongside incomplete or mistaken mechanisms; factual vocabulary does not alone establish an integrated theory.

Reasoning about whether and why illness can pass between individuals. A response based on a symptom label differs from an explanation that tracks the relevant cause; such judgments also depend on the child's interpretation of the task.