For a given sample on whom past data are available, data at a later (or present) time (or age) are obtained from archival material such as medical or criminal justice records. In this way, a longitudinal dimension is given to the study. Also known as retrospective design, but a follow-back study differs in that …
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Folk wisdom
Common sense knowledge held by members of a society or culture, and incorporated, for example, into proverbs. A part of folk wisdom is folk psychology: the method used by non-professionals for explaining, predicting and manipulating other people’s behavior by the use of propositional attitudes (e.g., belief, desire, fear). A number of philosophers and cognitive scientists claim …
Focus groups
Organized discussions, held where researchers are seekingviews on specific issues. The groups consider topics introduced by theresearcher and offer their opinions and experiences. A key aspect of suchgroups are the additional insights into the subjects discussed, generated bythe interaction between group members. See Delphi method, Qualitative research
Focused attention
A state in which attention is directed to one target, ignoring potential distractors. It is usually contrasted with divided attention. The inability to sustain focused attention is a defining characteristic of some children with ADHD. See Attention, Attention deficit hyperactivity disorder (ADHD), Controlled attention, Selective attention
Flynn effect
The continued year-on-year rise of IQ test scores world wide, but with varying rates across countries. From 1952 to 1982, IQ rose on average by 20 points, giving a mean rate of increase of about 3 points per decade. The highest gains were for so-called culturally-reduced tests measuring fluid intelligence (e.g., Raven’s Progressive Matrices), and …
FM system
A wireless system in the classroom or other area with teacher and student supplied with microphone and receiver, respectively, so that the deaf person can hear the teacher’s voice better than with a hearing aid alone. See Cochlear implant, Frequency
Fluorescent in situ hybridization (FISH)
A laboratory technique that helps diagnose Williams syndrome among other disorders (and also various forms of mosaicism). A DNA probe for the elastin gene is made with a fluorescent label, and mixed with a sample of the patient’s DNA. If the elastin DNA is present, the probe will be attached (hybridise). This allows a determination …
Fluid intelligence
The ability to develop techniques for solving problems that are new and unusual. As such, it corresponds approximately to non-verbal reasoning as measured, for example, by Raven’s Progressive Matrices. The claim has been made that fluid intelligence declines with the ageing process while crystallised intelligence (e.g., vocabulary knowledge) increases into adulthood and beyond (as long …
Fluid mechanics
the study of the mechanics of fluids consisting of two branches. Hydrostatics studies the mechanical properties of fluids that are not in motion, while hydrodynamics (or hydrokinetics) is concerned with fluids in motion. See Hydraulics
Flagella
Long hair-like protoplasmic structures or extensions (actually organelles or rather microtubules)) composed of helically-coiled protein units that form the basal body of the cytoplasm of cells, and which enable cell locomotion (e.g., of spermatozoa) through a liquid medium by means of having a whip-like motility driven by the protein dyne in. They have the same …