differentiation = (emp, bt) if a reinforcing stimulus is withheld except when a restrictively specified response is given, the frequency of occurrence of the response will increase, and that of alternative responses, even those that differ only slightly, will decrease. This procedure is called response-differentiation, and its outcome a differentiated response. Differentiated responses may become, of course, highly stereotyped and "mechanical." Response differentiation is almost synonymous with approximation conditioning.
discharge = 1. (th, eth) with reference to a drive, the utilization; consumption, annulment, or destruction of a drive (or of an accumulation of action-specific energy or of "impulses") that occurs when its consummatory act is given. The responses that have been activated by the discharged drive will not then recur until the drive is built up in magnitude again by the summated action of internal (e.g., hormonal) changes and environmental stimulation. =2. (emp, eth) with reference to a behavior pattern, emission.
discriminated = (emp, bt) when applied to a response, it refers to one brought under the control of a stimulus by differential reinforcement. When applied to a stimulus, it refers to one differentially responded to by an animal.
discrimination = 1. (emp, bt) differential response to two or more stimuli. When two stimuli are simultaneously or successively presented to an organism, and the quantitative topographic properties of a specified response to the two differ, a discrimination has been demonstrated. By this definition, discrimination is shown in any two S-R correlations. =2. (th, bt) differential response-strength to two or more stimuli. This is the more common, but more specialized, definition. By this usage, one cannot speak of discrimination without being able to relate it to response-strength, so those cases of differential response on the first occasion a second stimulus is introduced cannot be referred to as discrimination. Typically, discriminations are the outcome of discrimination training, although some can be exhibited without such training. Discriminations between similar stimuli are used to explore the sensory and perceptual characteristics of an organism. N.B.: by this definition an animal that jumps 100% to a cross and never to a triangle is discriminating between them. The same animal, presented with the same two stimulus objects, may walk to them equally often and is not discriminating between them. Thus, an animal can discriminate between a pair of stimuli when one response is under investigation and cannot discriminate between the same pair with another response. = 3. (th, eth) a hypothetical sensory or neurophysiological event which makes it possible for an animal to form discriminations as defined above. A capacity. The discriminations of behavior theory arc formed, those of ethology are revealed, by discrimination training.
discrimination training = (emp, bt) the experimental procedure of reinforcing a response in the presence of a discriminative stimulus and not reinforcing the response in the presence of other stimuli. When quantitative measures of the response taken in the presence of the stimulus differ from those in its absence, a discrimination has been formed, and the animal is said to discriminate.
disinhibition = (emp, bt) the term applied to the observation, in the course of extinction of a classical conditioned response, that, when an extraneous stimulus (one not previously present in the situation and which does not evoke the same response) is presented together with the conditioned stimulus, the magnitude of CR may be larger than predicted from its magnitude on previous trials. A like observation can be made, although less predictably, in the extinction of operant CRs.
displacement activity = 1. (emp, bt) a response that has been identified as a member of one instinct (1.) often occurs in others. On these occasions it is termed a displacement activity. A very common and incorrect usage applies the term to any behavior unexpected by the observer. = 2. (th, eth) "A displacement activity is an activity belonging to the executive motor pattern of an instinct other than the instinct(s) activated" (29). It ''…seems to appear when an activated drive is denied discharge through its own consummatory activity" (29). = 3. (emp) a term applied to a response that has been conditioned under one set of deprivations and reinforcement conditions and that then appears under others. Some observations are needed here. See also appetitive behavior. Psychologists are, by and large, not familiar with the empirical content of this term and do not seem to employ an analogous concept. In view of their hours of watching rats, they should be interested to learn that most ethologists would term the face-washings and bar-bitings that appear during extinction, displacement activities. See also redirection activity.
drive = 1. (th) a hypothetical state of the animal which is identified by: (a) gross changes in the relative frequency of broad classes of behavior that are not attributable to disease, learning, or growth; (b) changes in running-wheel activity; or (c) changes in cage-motility. Drives may be manipulated by: operations of deprivation (as of food and water), alterations of the hormone or other biochemical balance of the blood (e.g., of ACTH, testosterone, sodium chloride), by temperature changes, or intense stimulation. Some can be specified only by stating the time of the year. Particular states so defined sensitize particular S-R correlations: those acquired after the particular drive operations have been performed and those species-specific responses that have been empirically established as covarying. Thus, food elicits eating behavior in hungry animals only, and lordosis can be elicited in the guinea pig only when particular combinations of hormones are present in specific concentrations. = 2. (th, eth) motivation. = 3. (th, eth) a concept equivalent to Hull's 8Er (16). That is to say, a construct expressing the combined action of all causal variables controlling a piece of behavior. Ordinarily, a particular drive is associated with the activation of a corresponding instinct (2.). The third usage is not universal among ethologists but seems embodied in Thorpe's definition (27, 28). It is very difficult to determine just how the word "drive" is being used by ethologists. Sometimes, it seems to be defined as in drive (2.). Sometimes, it seems to refer to a hypothetical construct embodying the combined effect of all the excitational causal variables controlling a response. Sometimes, it seems to include the concept of a hypothetical magnitude of "neural excitation" or "nerve impulses." I hope that someone will straighten out this concept. Nor is this the only definition of which one can complain. The theoretical definition of drive (1.) also leaves something to be demanded. One suspects that the term drive may be a bit too broad and that we should deal rather with specific complexes of operations and behavior, such as those defining "hunger," "maternal behavior" etc., and not try at all to class them together prior to rigorous experimental analysis. = 4. (th, bt) a state of the animal established by deprivation of food or water, or by the presentation of electrical shock, characterized by a change in the relative rates of occurrence of a specified set of operant responses (22). Further operations for producing such states may be experimentally determined =5. (th, bt) Hull's D (16). A construct having the properties of a general state but associated with, or producing, specific stimuli. Its controlling variables are only suggested. =6. (con) one of many hypothesized state variables derived from the effectiveness of particular environmental events as reinforcing stimuli. E.g., the manipulatory drive (9). This is invoked as a consequence of observations that monkeys and apes solve mechanical puzzles without reinforcement administered by the experimenter and that they acquire conditioned responses when the rein-forcing stimulus is the opening of a window through which the animal can look into a space not available to it just before. The absence of any defining operations or manipulations other than the identification of specific events as reinforcers renders this usage unfortunate and misleading. If such behaviors as exploration and manipulation occur in animals whose behavior can also be conditioned with presentations of novel events as reinforcing stimuli, then the term instinct (2.), which lacks any implication with respect to the classes of variables controlling the behavior and which suggests no particular underlying theory, would seem to be the preferable. term to attach to the behavior.
drive-inducing operation = (emp, bt) a generic term for one class of procedures followed before beginning experimental investigations. These procedures are described in sufficient detail in publications of research results so that others can duplicate them. They are the procedures that set up "drives." They include: for hunger and thirst---deprivation according to specified rules of food and water, respectively; for sex-injection of hormones, observation during the reproductive season, manipulation of the light-dark cycle, presentation of an oestrous female rat to a male; for escape or fear-intense electrical stimulation, and so on.
drive/irrelevant = (th, bt) when the inducing operations of two drives (1.) are carried out, and reinforcement of some response is effected by reducing one of them, then the other drive is termed irrelevant. E.g., if an animal is deprived of food and is then shocked electrically until it jumps over a small barrier, shock-avoidance is the drive, and hunger is the irrelevant drive. Syn. alien drive.
drive/primary = (th, bt) any of the drives enumerated under drive (1.). When a drive is termed primary, stress is being laid on the postulate that (a) drive-inducing operations produce states of physiological disequilibrium (needs) and (b) both drive reduction (the opposite operation) and the behavioral changes that occur when a drive is established tend to restore the animal to a state of homeostasis.
drive/secondary (or acquired) = (th, bt) a drive (1.) hypothesized so that the drive variable may be introduced theoretically in order to predict the occurrence of learned behavior in the absence of one or another of the drive manipulations listed under drive (1.). Defining operations of one such drive are given in terms of the establishment of a discriminated avoidance conditioned response. See anxiety.