A term defined by the English psychiatrist John Bowlby to describe the critical period of around 6 months to 3 years during which the child needs continuous love and care from one person, the mother or a permanent mother-substitute.

The stage in human development when the adult is seen as having achieved certain socially-acceptable levels of sexual, intellectual and emotional fullness. As defined by Erik Erikson, the adult at this stage develops the need to concern him/herself with the development of the next generation, either through parenthood or through the passing on of skills and knowledge to others.

An explanation for the effects of content in the selection task, which suggests that familiar concrete content can remind a person of a similar problem that they have encountered in the past.

The onset of menstruation in adolescent girls.

In intelligence testing, the mental level at which a person has arrived compared with their actual, chronological age.

A framework for presenting research in thinking and reasoning based on manipulation of the models of parts of the world that people have in their minds.

The three layers of connective tissue that cover the brain and spinal cord.

In the study of evolution, the expenditure of metabolic energy by brain tissue in order to support intelligence.

In psychological analysis, a quick overall summary of individuality prepared in a test format, enabling comparisons to be drawn across a whole sample.

In the study of evolution, the mechanism of variation which occurs when the genetic code along the DNA molecule in a chromosome is replicated inaccurately, a process which is not always destructive.