The ability to perceive a unitary object despite the fact that parts of it are out of sight or partly occluded. In infancy, common motion of parts leading to constant deletion and accretion of background, and Gestalt good form, contribute to perception of object unity. When they do not share a common translation, then the …
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Object reversal test
An experimental paradigm that involves reversal of a previously learnt association. In a typical example, subjects are repeatedly presented with a pair of objects, one of which is associated with a reward (the sample) and one of which is not (the foil). After learning the association between the sample and reward, the association is unexpectedly …
Object identity
The ability to perceive an object as the same object despite a gap in perceiving it, such as being able to identify an object as the same entity although it passes behind a screen on part of its trajectory. Movement on a constant trajectory is one cue that may be used to infer identity. Identity …
Object permanence
The knowledge or awareness that objects continue to exist when they are out of sight, either through being in view but out of the visual field, or through being hidden by another object. According to Jean Piaget, infants develop the beginnings of object permanence at 9 months, with further progress taking place up to 24 …
Object-directed behaviors
Behaviors directed toward visible or occluded objects, such as reaching, grasping, and looking. See Action, Movement, Prehension
Nursery school
A school specifically for children younger than the normal age for starting school, and may be part-time or full-time. It will have educational input in a curriculum adjusted to the needs of the young children (typically 3-5 year-olds in the UK at present). There have tended to be a high percentage of trained teachers and …
Nystagmus
Small, involuntary jerky movements of tremors of the eyes. Everyone shows such movements to some extent, but it is usually considered to be abnormal when it occurs spontaneously. Vertical nystagmus, which occurs much less frequently than horizontal nystagmus, can be a sign of serious brain damage. Railway or optokinetic nystagmus occurs when a person is on …
Numerical identity
This term is often used to describe the ability to identify the number of objects involved in an event on the basis of the structure of the event. For instance, a discontinuity in a moving object event, or moving object events, both sides of an impenetrable barrier, signals that more than one object is involved. …
Numbers
Numbers are used to classify, count and in the service of measurement. The most familiar are natural numbers: those that enable counting (cardinal numbers) and ordering (ordinal numbers). Examples of other types of numbers are the following: * Complex numbers: in algebra, solutions to equations that cannot be resolved by real numbers * Dimensionless numbers: …
Number mathematics
The domain of knowledge founded on an ordered set of words that label successive increases in the numerosity of sets of things. The child has to acquire the crucial concept of a cardinal number, that there is one number-word that represents a numerosity total. Problems with number mathematics or the learning of math skills are …