Founder effect (or principle)

A concept originally proposed by Ernst Mayr (1904-2005) in 1942 in his discontinuous theory of genetic revolution by allopatric speciation to account for rapid biological evolution in a way that the phyletic gradualism of the Modern synthesis could not.  The starting point is that a few individuals within a gene pool (i.e., the founders) become geographically …

Forward genetics

The process of discovering through random mutation, genes that lead to particular phenotypes, with a mutagen being used to accelerate this process.  Once the mutants have been isolated with this screening method, the mutant gene can be identified molecularly and its function discovered.  In contrast to reverse genetics, forward genetics goes from the phenotype to …

Form perception

Sometimes referred to as shape perception, this term is generally applied to the ability to extract form or shape information from a two-dimensional stimulus.  Form perception of two-dimensional information is crucial to the acquisition of reading and writing.    See Gestalt good form, Perception, Shape constancy

Formal operations

The last of Piaget‘s four broad stages of cognitive development.  in formal operations, adolescents become capable of thinking in terms of abstract forms.  Because they involve manipulation of formal rules and abstract expression, algebra and symbolic logic provide examples of formal operational thinking.  See Abstract reasoning, Cognitive development, Piaget’s stage theory, Stage, Stage of cognitive …

Form

An element of language, such as a word or an affix (e.g., case ending, plural marker, past tense marker, prefix such as un- or re-).  The term is also extended to word order patterns (e.g., English subject-verb-object), and to other consistent construction patterns within a language (e.g., the English ditransitive pattern as in “John gave …

Forensic psychologist

A psychologist who works in the field of law and criminal behaviour.  A forensic psychologist must be able to testify in court, thus requiring the ability to formulate psychological findings in appropriate legal language.  Forensic psychologists are employed in a variety of settings, including academia, police, probation and social services.  In the UK, most such …

Form-meaning mapping

Patterns of correspondence between elements of language (forms) and elements of meaning (e.g., agent, patient, number, gender, definiteness, time, location or trajectory).  Such patterns are typically many-to-one or one-to-many: a given form, such as the English ‘my’ can express more than one meaning (here, possession by 1st person, definiteness), and a given meaning, such as number …

Force

An external agent capable of altering the state of rest or motion of a rigid body.  According to Newton’s second law of motion, the force (F) required to produce an acceleration (a) in a mass (m) is given by F=ma.  See Acceleration, Balance scale task, Biomechanics, Center of mass, Centrifugal/centripetal, Dynamics, Isometric contraction, Isotonic contraction, …