An individually-administered test of intelligence originally designed for deaf children and adolescents (or those with speech impairments) that does not require verbal communication or instructions, and with norms ranging from 2 to 21 years. Originally devised by Russell G. Leiter in 1929 at the University of Hawaii, it has undergone a number of revisions, and is …
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Learning
A concept with a long history and many shades of meaning. Commonly, learning is understood to be a slow change of behavior induced by experience. Habituation, conditioning, stimulus-response association, and adaptation are all forms of learning. More generally, it is a change in capacity or disposition to behave resulting from experience, and that leads to a …
Laws of nature
Generalizations that attempt to describe and explain recurring facts or events in nature by means of scientific laws. Attempts to achieve to this include, for example, Boyle’s law, Hooke’s law, Kepler’s law of planetary motion, Newton’s laws of motion, the Weber-Fechner law, and the law of effect. Most of these laws submit to two general …
Learned helplessness
A learned attitude of passivity in face of a problem situation and awaiting help indiscriminately from someone or somewhere. The theoretical foundations of learned helplessness began with a serendipitous finding reported by Martin Seligman and associates in 1967 that emerged from an experiment endeavoring to subject dogs to classical conditioning that was completely at odds …
Law
In contrast to theories that are intended to explain phenomena, laws serve to describe them. Scientific laws describe observed universal regularities in nature, For example, the laws of thermodynamics describe what happens when heat is transformed in mechanical energy, while theories of thermodynamics explain this event. The elevation of a principle to law in a …
Law-like statement
Sometimes a statement resembling a law that is not accepted and perhaps rejected, and sometimes not general enough to be a law because it refers to single objects [e.g., Johannes Kepler (1571-1630) and his laws of planetary motion around the sun, which do not mention suns and planets in general]. Statements made about the nature …
Lateral sound
A class of speech sounds produced with a midline obstruction by raising the tip of the tongue against the roof of the mouth that causes sound to be emitted laterally as in the case of the first sound in the word ‘law’. The l sounds of English and Welsh are laterals. However, in Welsh (and Polish) …
Laterality
A structural (i.e., neural) asymmetry or a functional one expressed in behavior. In the latter case, it is performed in a consistent, but not inflexible, manner. The ongoing question is how structural asymmetries relate to functional asymmetries. See Ambidexterity, Apraxia, Bimanual task, Hand preference, Handedness (bimanual vs unimanual), Lateral bias, Peg-moving task
Lateral bias
A generic term referring to any kind of bias favouring one side of the body over the other. It includes biases in head-turning and hand and arm use as well as biases of the feet, legs, eyes, ears, and even side-of-mouth for chewing. While lateral biases characterize much of human behavior, if too inflexible they can …
Lateral geniculate nucleus (or body)
The size of a peanut, situated either side of the rear end of the thalamus, it receives most of its input from the contralateral half of the visual field of the retina via the optic nerve that crosses at the optic chasm, and relays it to primary visual cortex from which it also receives inputs …