Two different environments or regimes of selection. An r-selection regime consists of environments with abundant resources, but which are short-lived and unstable, and therefore liable to produce high random rates of mortality. Consequently, the optimal parenting strategy is the production of numerous offspring and a low degree of investment in their nurture and protection. With …
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Quantum mechanics
In physics, the theory that energy does not have a continuous range of values. It is instead absorbed or radiated discontinuously in multiples of discrete and indivisible units or packages called quanta. Previous theories had shown how light, depicted as a wave motion, could also be regarded as composed of discrete particles. Quantum mechanics, for …
Quantitative research
Research in which the measurement/assessment (in terms of numeric data such as quantity, amount or frequency) of the phenomena that are being examined is emphasised. A major aim of such research is to obtain findings that are generalizable (i.e., they have external validity). See External validity, Generalization, Qualitative research
Quantitative and qualitative regressions
During development, reductions in the numbers of axons, cells, neurons, and synapses (quantitative regression), and the loss of structures and their replacement by new ones, with possibly new functions (qualitative regression). Behavioral examples of both are less clear-cut and in particular with regard to human development. A major problem, especially for the different forms of …
Quantitative genetic theory
A mathematical theory that aims to predict the responses to natural selection, given data on phenotypes and relationships among individuals. In recent times, the theory has been extended to include the analysis of quantitative trait loci. Quantitative traits are those that are under the influence of a number of genes, and their mapping onto a …
Quantitative and qualitative change
Change that is continuous, and which follows certain trends over time (e.g., asymptotic, exponential, logistic, monotonic) is considered to be quantitative. Appositional growth is a good example of this type of change. Allometric growth is an example of qualitative change, with metamorphosis being its most extreme expression. It not only signifies changes in form and …
Quality of daycare
Refers to characteristics that differentiate better from worse daycare settings. The criteria for better or worse will depend upon the perspective taken and hence there are areas of debate about how to measure quality. The approach taken in most child development research is to regard quality as reflecting characteristics associated with beneficial effects upon development. …
Quantifier
A predicate, or adjective, that expresses the amount of its argument, as in ‘five dollars’ where ‘five’ describes the quantity of dollars. It does not have to be numerical in nature, but can refer to approximate answers to questions such as “How much?” as, as for example, in “A lot of …”. Developmentally, the problem is …
Qualitative research
Research with an emphasis on the understanding of processes and meanings using textual rather than quantitative data; often these are considered not to be open to experimental and/or psychometric examination, and not to be measurable in terms of quantity, amount, etc. Examples of qualitative research are case studies and ethnography. The findings from such research …
Purkinje cells
Large efferent neurons in the middle layer of the cerebellar cortex, packed together in the Purkinje cell layer directly under the molecular layer, that process the input from parallel and climbing fibers. Their inhibitory GABA axons, projecting to the deep cerebellar nuclei, provide the sole output from the cerebellum. This output has a relatively high …