A reading sub-skill involving the ability to translate letters into sounds to derive the pronunciation of a printed word. Together with vocabulary level and spelling, decoding ability has a high correlation with reading comprehension. Research in the US has shown that first-grade decoding ability predicts 80 to 90 percent of reading comprehension in 2nd and …
Author Archives: Brian Hopkins
Debriefing
A procedure implemented after research participation has ended, and designed to explain to participants the nature and purpose of the research in detail (including any deception), and to check on their well-being, offer reassurance and answer their queries etc. While national psychological associations and societies, as well as other professional bodies, strongly recommend debriefing in …
Declarative (or explicit) and procedural memory
Both are classes of long-term memory. Declarative memory is the portion of long-term memory where information about facts and specific events is stored, involves structures in the temporal lobe (especially the hippocampus), and which is distinguished in terms of episodic and semantic memory. Procedural memory, which is governed by different brain systems, is a storage …
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De Morsier-Kallmann syndrome
A spectrum of rare (1 in 10.000, male/femaleratio 5/1) congenital disorders caused by failure of the hypothalamus to release the gonadotropin hormone (GnRH) during embryonic brain differentiation. Afflicted patients evinceabsent or incomplete puberty, and somatic and reproductive problems associatedwith hypogonadism. In addition to hypogonadism, there may be a loss or reduced sense of smell (hence …
Darwinism
Darwin’s theory of natural selection of small, inherited variations that increase an individual’s ability to compete for resources, survive and reproduce. The problems for Darwin were how such genetic variations arose and how they were transmitted from one generation to the next. The answer to the first problem was random mutation, with chromosomal rearrangement and …
Data-driven processes
Those processes that operate in response to information coming into the system. A young child might try to keep her balance on a roundabout by feeling her way to where it seems safest; an older child might have reasoned out that the rim of the roundabout is the most challenging. Where the younger child’s decision …
Dandy Walker malformation
A structuraldevelopmental abnormality occurring during embryonic development in which the cerebellar vermis has not developedappropriately (partially or completely absent) and there is dilatation of the fourth ventricle. As with Chiari II malformation, it is frequently associated with agenesis of the corpus callosum, and also hydrocephalus (20-80% of cases). Infants with the malformation can manifest delayed …
Cytoskeleton
The internal framework (or ‘scaffolding’) of a cell within the cytoplasm, composed largely of actin filaments and microtubules (see figure below). In eukaryotic cells, actin filaments (or microfilaments) are active in muscle contraction, intermediate filaments hold microfilaments and microtubules in place, and microtubules serve as routes for organelles to move along. In general, the cytoskeleton …
Décalage
From the French for ‘time lag’, the Piagetian idea that cognitive abilities develop at different rates in the same individual. For example, children solve conservation of number tasks before they solve conservation of mass tasks and the latter before they can conserve weight, a phenomenon termed horizontal décalage (i.e., the inability of a child to …
Cytosine
A pyrimidine base found in DNA and RNA, as well as nucleotides and their derivatives. It always bonds with the purine guanine. See DNA (deoxyribonucleic acid), Guanine, Methylation, Nucleotide, Purines, Pyrimidines, RNA (ribonucleic acid)