Eric W. Holman

Location preference and flavor aversion reinforced by amphetamine in rats

To associate the identical drug state with both a location and a flavor, rats were given intraperitoneal amphetamine injections and then confined for 20 min in one side of a shuttlebox with access to a flavored solution; on control trials without injections, they were confined for 20 min in the opposite side with a different flavor. In the first experiment, the rats were placed in the shuttlebox immediately after injections; in the second experiment, they were placed in the shuttlebox 20 min after injections. Subsequent free-choice tests in both experiments revealed an increased choice of the side of the shuttlebox associated with amphetamine but also an aversion to the flavored solution associated with the drug.

Immediate and delayed reinforcers for flavor preferences in rats

Abstract When rats received, on alternate days, one flavored saccharin solution for 5 min and a differently-flavored saccharin solution for 60 min, they showed no consistent preference between the flavors. On the other hand, when they received one flavor in a concentrated saccharin solution and a different flavor in a dilute one, they preferred the first flavor in tests with saccharin concentration held constant; also, rats learned to prefer a flavor immediately followed by a concentrated saccharin solution to one followed by nothing. They showed no consistent preference, however, between a flavor followed 30 min later by a concentrated saccharin solution and one followed by nothing; but they learned to prefer a flavor followed 30 min later by a dextrose solution to one followed by nothing. In other words, consummatory responding did not reinforce flavor preference, sweet taste did so with immediate but not delayed reinforcement, and nutrition did so even with delayed reinforcement.

Rewarding and aversive effects of morphine: temporal and pharmacological properties.

To assess morphine-induced location preferences and flavor aversions, rats were administered morphine sulfate (10 mg/kg, IP) either immediately before (Experiment 1) or immediately after (Experiment 2) confinement for 20 min in one side of a shuttlebox with access to a flavored solution. On control trails the rats were administered saline and confined for 20 min on the opposite side with a differently flavored solution. In subsequent choice tests, it was found that morphine injections before confinement produced a preference for the side associated with morphine and indifference to the flavors, whereas morphine injections after confinement produced an aversion to the flavor paired with morphine and indifference to the sides. Experiments 3 and 4, using a procedure similar to that of Experiment 1, showed that naloxone (1 mg/kg, IP) blocked the morphine-induced side preference, although given alone it was without effect in this test.

Temporal properties of the rewarding and aversive effects of amphetamine in rats

To associate amphetamine with a location and a flavor, rats were given amphetamine injections and then confined for 20 min in one side of a shuttlebox with access to a flavored solution; on control trials with saline injections, they were confined for 20 min on the opposite side with a different flavor. Three groups of rats were placed in the shuttlebox either 5 min, 120 min, or 240 min after the injections. In subsequent choice tests, the 5 min and 120 min groups preferred the side and avoided the flavor associated with amphetamine; the 240 min group was indifferent between the sides and the flavors.

Explorations in automated language classification

An earlier paper, to which some authors of the present paper have contributed (Brown et al. 2008), describes a method for automating language classification based on the 100-item referent list of Swadesh (1955). Here we discuss a refinement of the method, involving calculation of relative stabilities of list items and reduction of the list to a shorter one by eliminating least stable items. The result is a 40-item referent list. The method for determining stabilities is explained, as well as a method for comparing the classificatory performance of different-sized reduced lists with that of the full 100-item list. A statistical investigation of the relationship of lexical similarity of languages to their geographical proximity is presented. Finally, we test the possibility that information involving typological features of languages can be combined with lexical data to enhance classificatory accuracy.

Automated dating of the world’s language families based on lexical similarity

This paper describes a computerized alternative to glottochronology for estimating elapsed time since parent languages diverged into daughter languages. The method, developed by the Automated Similarity Judgment Program (ASJP) consortium, is different from glottochronology in four major respects: (1) it is automated and thus is more objective, (2) it applies a uniform analytical approach to a single database of worldwide languages, (3) it is based on lexical similarity as determined from Levenshtein (edit) distances rather than on cognate percentages, and (4) it provides a formula for date calculation that mathematically recognizes the lexical heterogeneity of individual languages, including parent languages just before their breakup into daughter languages. Automated judgments of lexical similarity for groups of related languages are calibrated with historical, epigraphic, and archaeological divergence dates for 52 language groups. The discrepancies between estimated and calibration dates are found to be on average 29% as large as the estimated dates themselves, a figure that does not differ significantly among language families. As a resource for further research that may require dates of known level of accuracy, we offer a list of ASJP time depths for nearly all the world’s recognized language families and for many subfamilies.

Adding typology to lexicostatistics: a combined approach to language classification

Abstract The ASJP project aims at establishing relationships between languages on the basis of the Swadesh word list. For this purpose, lists have been collected and phonologically transcribed for almost 3,500 languages. Using a method based on the algorithm proposed by Levenshtein (Cybernetics and Control Theory 10: 707–710, 1966), a custom-made computer program calculates the distances between all pairs of languages in the database. Standard software is used to express the relationships between languages graphically. The current article compares the results of our lexicon-based approach with the results of a similar exercise that takes the typological variables contained in the WALS database as a point of departure. We establish that the latter approach leads to even better results than the lexicon-based one. The best result in terms of correspondence with some well-established genetic and areal classifications, however, is attained when the lexical and typological methods are combined, especially if we select both the most stable Swadesh items and the most stable WALS variables.

THE RELATION BETWEEN HIERARCHICAL AND EUCLIDEAN MODELS FOR PSYCHOLOGICAL DISTANCES

In one well-known model for psychological distances, objects such as stimuli are placed in a hierarchy of clusters like a phylogenetic tree; in another common model, objects are represented as points in a multidimensional Euclidean space. These models are shown theoretically to be mutually exclusive and exhaustive in the following sense. The distances among a set ofn objects will be strictly monotonically related either to the distances in a hierarchical clustering system, or else to the distances in a Euclidean space of less thann — 1 dimensions, but not to both. Consequently, a lower bound on the number of Euclidean dimensions necessary to represent a set of objects is one less than the size of the largest subset of objects whose distances satisfy the ultrametric inequality, which characterizes the hierarchical model.

Some conditions for the dissociation of consummatory and instrumental behavior in rats

Abstract To investigate whether consummatory and instrumental behavior depend upon different motivational factors, rats were trained to press a bar for saccharin solution, then given various treatments designed to reduce the palatability of saccharin, and finally tested for bar-pressing in extinction and for free intake of saccharin. Prefeeding with dextrose, prefeeding with saccharin, and association of saccharin with injections of lithium chloride all reduced intake of saccharin compared to control treatments, but only prefeeding with dextrose also reduced barpressing in extinction. Thus, performance of an instrumental response may depend upon need for food rather than appetite for it.

Monotonic models for asymmetric proximities

Abstract A series of models is proposed that each represent an asymmetric square data matrix as a monotonic combination of a symmetric function and a bias function. These models generalize several previous models for proximity and dominance data. A computer program is described that estimates from data the ordinal functions in the models. Previously published data on journal citations and acoustic confusions fit the strongest models in the series as well as the weaker ones.