valence–instrumentality–expectancy theory

a theory of work motivation holding that the level of effort exerted by employees will depend on a combination of three variables: (a) the expectancy of employees that effort will lead to success in the job, (b) the belief of employees that success will lead to particular outcomes (see instrumentality theory), and (c) the value of these outcomes (see valence). A numerical value can be obtained for variable (a) using the subjective probability estimates of employees, for variable (b) by measuring the correlation of performance to rewards, and for variable (c) by asking employees to rate the desirability of the rewards. The motivational force, or the amount of effort employees will exert, can then be calculated. See also path–goal theory of leadership; Porter–Lawler model of motivation. [proposed in 1964 by Canadian organizational psychologist Victor H. Vroom (1932– )]

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Psychology term of the day

January 27th 2025

hydrogen-ion concentration

a measure of the acidity or alkalinity of a substance. When acid and alkaline substances dissociate in water, hydrogen ions (H⁺) and hydroxyl ions (OH^–) are released. Acidity and alkalinity are associated with the relative concentrations of H⁺. The hydrogen-ion concentration can be measured using the pH scale, on which values represent the negative logarithm of the H⁺ ion concentration. Thus, the greater the excess of H⁺ ions, the lower the pH value. A pH of 0 represents the greatest possible excess of H⁺ ions, or a “pure” acid. At the other extreme, a pH of 14 represents the maximum degree of alkalinity. A pH of 7 represents a neutral solution. Human body fluids have an average pH of about 7.4, that is, slightly alkaline. If the pH rises above 7.8 or falls below 6.8, enzymes and other biochemical substances in the body malfunction (see acidosis; alkalosis). See also homeostasis.