Zone of proximal development (ZPD)

In Vygotsky’s sociohistorical theory of development. the distance between a child’s actual developmental level as she performs a task independently and her potential level of development as she works with an adult or more accomplished peer.  Vygotsky held that because children’s level of functioning is raised to new heights when working with others, their learning …

Zygosity

Types of twins determined by the number of zygotes (fertilised eggs) giving rise to them. Twins are either genetically identical (monozygous (i.e., from just one zygote that later divides into two) or non-identical, sometimes called fraternal (dizygous ( i.e., from two separate zygotes).  See Dizygotic twins, Monozygotic twins

Zero-one time sampling

An historically-important observational data recording strategy for which successive brief intervals (e.g., 10 or 15 seconds) are checked as ‚ayes‚aa (1) or ‚aano‚aa (0) when a particular behavioural code predominates during the interval . See Coding scheme, Interval recording

Working memory

A model of short-term memory  originally proposed by Alan D. Baddeley and Graham J. Hitch in 1974, conceived as a system for temporarily storing and manipulating information in an accessible state,.  It is composed of two temporary storage or buffer systems (the phonological loop and the visuo-spatial scratchpad), responsible for verbal and visual information respectively, and the …

Work

The work (W) done by a force acting on a body is the product of the force and the distance moved by its point of application in the direction of the force. More formally, when a force (f) moves its point of application through a distance (d), then the work done is W=fd cosq, where …

Wisconsin Card Sorting Test (WCST)

A test of abstract thinking and planning, as well as of the ability to change mental set (a temporary readiness to perceive, think or act in a particular way) when circumstances demand it.  It consists of 128 cards that differ in color (red, green, yellow, blue), form (circle, triangle, cross, star), and number (one, two, three, four). …