thematic apperception test: see psychological tests.

test-tube baby: see in vitro fertilization.

test-ban treaty, nuclear: see disarmament, nuclear.

stress test or exercise electrocardiography, in medicine, a test that evaluates the performance of the heart by subjecting it to controlled amounts of physical stress. Such tests, which include walking on a treadmill, measure the heart's reaction to an increased demand for oxygen. The test ends when the patient reaches a predetermined heart rate or experiences chest pain or fatigue. See electrocardiography.

psychological test, any of a variety of testing procedures for measuring psychological traits and behavior, or for studying some specialized aspect of ability. Several forms of testing have arisen from the need to understand personality and its relationship to psychological disorders.

Projective tests attempt to measure personality based on the theory that individuals tend to project their own unconscious attitudes into ambiguous situations. Best known of the projective tests is that of the Swiss psychiatrist Hermann Rorschach (1884-1922), who used a group of standardized inkblots and asked the client to relate what the pictures brought to mind. The thematic apperception test (TAT), developed by the American psychologist Henry A. Murray, uses a standard series of provocative yet ambiguous pictures about which the client must tell a story. Each story is carefully analyzed to uncover underlying needs, attitudes, and patterns of reaction.

Other personality tests use questionaires that limit the test-taker's responses to "true," "false," or "cannot say." These tests have a much higher level of standardization than projective tests, and hence are often called objective tests. One of the most widely used objective tests is the Minnesota Multiphasic Personality Inventory (MMPI), created in 1942 (and updated in the early 1990s) with the goal of defining a "normal" personality and detecting specific deviances. The test produces profiles that can predict class inclusion for such psychological disorders as schizophrenia, sociopathy, depression, and hysteria. The MMPI has been useful in distinguishing individuals with mental illness from the normal population, but has been less helpful in diagnosing specific disorders.

Behavioral assessments are also used by many psychologists, in which the psychologist observes the individual's actions, usually in a natural setting. Behavior is coded quantitatively—for example, the observer may record the number of times the individual initiates social interactions with others. Such behavior checklists can be used by parents and teachers in evaluating children.

Several diagnostic techonologies are used today to measure brain activity. The electroencephalogram (EEG) records the brain's electrical activity, and its responses to stimuli, through placement of electrodes on the skull. Other brain exams, including the computerized axial tomography (CAT) scan, the positron emission tomography (PET) scan, and the magnetic resonance image (MRI), have shown increasing accuracy in providing detailed pictures of the brain. Such advances may prove indispensable in the understanding of the neurological roots of psychological disorders.

Tests specifically designed to measure abilities include achievement and intelligence tests. Achievement tests measure attainments in a variety of fields, e.g., academic subjects, aptitude for civil service positions. Tests of abilities include intelligence quotient (IQ) tests (see intelligence), spatial-perceptual tests, and motor skills tests. Schools use educational aptitude and achievement tests to compare ability with actual accomplishment, while employers use tests to learn the potential special talents, vocational interests, motor skills, and other such capacities of a prospective employee. Sensory functions, such as visual acuity and hearing, are also measured, and tests have also been devised for special aptitudes, such as memory and creativity.

nuclear test-ban treaty: see disarmament, nuclear.

flame test, test used in the identification of certain metals. It is based on the observation that light emitted by any element gives a unique spectrum when passed through a spectroscope. When a salt of the metal is introduced into a Bunsen burner flame, the metallic ion produces characteristic color in the flame. Some metals and the colors they produce are: barium, yellow-green; calcium, red-orange; copper salts (except halides), emerald green; copper halides or other copper salts moistened with hydrochloric acid, blue-green; lithium, crimson; potassium, violet; sodium, yellow; and strontium, scarlet. The value of this simple flame test is limited by interferences (e.g., the barium flame masks calcium, lithium, or strontium) and by ambiguities (e.g., rubidium and cesium produce the same color as potassium). A colored glass is sometimes used to filter out light from one metal; for instance, blue cobalt glass filters out the yellow of sodium.

chi-square test: see statistics.

borax bead test: see bead test.

blood test, examination of blood routinely or as an aid in diagnosing a suspected disease. Tests may be performed on whole blood or on the plasma portion only. Blood typing identifies the proteins at specific sites on red blood cells, a necessity in determining compatibility for blood transfusion. Human Lymphocyte Antigens (HLA) is a form of white blood cell typing prerequisite for organ and bone marrow transplants. The Coulter Cell Counter is widely used in electronic counts of red blood cells for the diagnosis of anemia and polycythemia. White cell counts are vital in detecting infections or in confirming leukemia. Serum or plasma may be collected, cultured, and inoculated with bacteria or other substances for the purpose of detecting the body's reaction to infections, cancer, or HIV, the virus that causes AIDS. Plasma may also be examined for evidence of functional disorders, e.g., for blood sugar in testing for diabetes mellitus. Blood tests for tumor markers, such as prostate-specific antigen, are effective in detecting cancer in high risk groups. Almost all blood tests are now performed by electronic equipment, and results are evaluated and printed out by computer.

bead test, test used in the identification of certain metals. Some metallic ions that cannot be identified by a flame test are identified by a bead test. The test can also be used to confirm the results of a flame test. The borax bead test is the most common. A small loop is formed at the end of a platinum wire. The loop is cleaned with concentrated hydrochloric acid and dipped in powdered borax, then heated in the flame of a Bunsen burner until the borax melts, forming a bead. The bead is dipped into a tiny amount of the compound to be tested and is reheated in the flame. The metal borate that is formed colors the bead. Some metals and the colors they produce in an oxidizing flame are: chromium, green; cobalt, blue; copper, blue-green; iron, yellow to brown; manganese, violet; nickel, reddish-brown. If too much of the unknown compound is used, the bead may be opaque and the color difficult to determine. A different color is often obtained in a reducing flame. Several metals may give the same color. Some metals give only colorless or gray beads. A test similar to the borax bead test is often made using microcosmic salt. Results of the bead test may be confirmed by other methods of chemical analysis.

Turing test, a procedure to test whether a computer is capable of humanlike thought. As proposed (1950) by the British mathematician Alan Turing, a person (the interrogator) sits with a teletype machine isolated from two correspondents—one is another person, one is a computer. By asking questions through the teletype and studying the responses, the interrogator tries to determine which correspondent is human and which is the computer. The computer is programmed to give deceptive answers, e.g., when asked to add two numbers together, the computer pauses slightly before giving the incorrect sum—to imitate what a human might do, the computer gives an incorrect answer slowly since the interrogator would expect the machine to give the correct answer quickly. If it proves impossible for the interrogator to discriminate between the human and the computer, the computer is credited with having passed the test.

Test Act, 1673, English statute that excluded from public office (both military and civil) all those who refused to take the oaths of allegiance and supremacy, who refused to receive the communion according to the rites of the Church of England, or who refused to renounce belief in the Roman Catholic doctrine of transubstantiation. Although directed primarily against Roman Catholics, it also excluded Protestant nonconformists. In 1678 it was extended to members of Parliament. The law was modified by the Act of Toleration of 1689, which enabled most non-Catholics to qualify. However, some Protestants did not conform and were disqualified from office until the repeal of the act at the time of Catholic Emancipation. See Penal Laws.

Szondi test: see psychological tests.

Schick test, diagnostic test designed to evaluate susceptibility to diphtheria. A small amount of diphtheria toxin is injected into the skin; the injection will produce an area of redness and swelling in individuals with low levels of antibody (i.e., little immunity) against the toxin. If the individual is immune to diphtheria, the antibody in the system will neutralize the toxin and no skin reaction will occur.

Rorschach test: see personality; psychological tests.

Pap test, Pap smear, or Papanicolaou test, medical procedure used to detect cancer of the uterine cervix. A scraping, brushing, or smear, is taken from the surface of the vagina or cervix and is prepared on a slide and stained for microscopic examination and cytological analysis. The appearance of the cells determines whether they are normal, suspicious, or cancerous. Although the test is 80% to 95% reliable, results termed suspicious may indicate infection or some abnormal condition other than cancer. The smear technique is also used to detect cancer of other tissues, e.g., in the bladder. The Pap test was developed by G. N. Papanicolaou and H. F. Traut in 1943.

Marsh test, method for the detection of arsenic, so sensitive that it can be used to detect minute amounts of arsenic in foods (the residue of fruit spray) or in stomach contents. The sample is placed in a flask with arsenic-free zinc and sulfuric acid. Arsine gas (also hydrogen) forms and is led through a drying tube to a hard glass tube in which it is heated. The arsenic is deposited as a "mirror" just beyond the heated area and on any cold surface held in the burning gas emanating from the jet. Antimony gives a similar test, but the deposit is insoluble in sodium hypochlorite, whereas arsenic will dissolve. The test was named for its inventor, the English chemist James Marsh.

(1673) Act passed by the British Parliament that required holders of civil and military offices to profess the established religion and to receive Holy Communion according to the rites of the Church of England. Though directed primarily against Roman Catholics, it extended in principle to all non-Anglicans; it was modified in 1689 to enable most non-Catholics to qualify. An act adopted in 1828 removed the test. In the U.S. Constitution, Article VI prescribes that “no religious test” shall be required for any officeholder. Seealso Catholic Emancipation.

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Controlled application of biological or chemical substances to the skin to test for allergy. Small amounts of diluted test substances applied under a patch of cloth or soft paper and an impermeable membrane are left in place for 48 hours, and the skin reaction is then examined and scored from 0 (none) to 4+ (severe blistering and redness).

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Laboratory examination of the physical and chemical properties and components of a sample of blood. Analysis includes number of red and white blood cells (erythrocytes and leukocytes); red cell volume, sedimentation (settling) rate, and hemoglobin concentration; blood typing; cell shape and structure; hemoglobin and other protein structure; enzyme activity; and chemistry. Special tests detect substances characteristic of specific infections.

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Test proposed by Alan M. Turing to determine whether a computer can be said to “think.” Turing suggested the “imitation game,” wherein a remote human interrogator, within a fixed time frame, must distinguish between a computer and a human subject based on their replies to questions posed by the interrogator. A series of such tests would measure the computer's success at “thinking” by the probability of its being misidentified as the human subject. The test is performed today in competitions that test the success of artificial intelligence.

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