The structure of pigeon multiple-class same-different learning

Three experiments examined the structure of the decision framework used by pigeons in learning a multiple-class same-different task. Using a same-different choice task requiring the discrimination of odd-item different displays (one or more of the display's component elements differed) from same displays (all display components identical), pigeons were concurrently trained with sets of four discriminable display types. In each experiment, the consistent group was tested such that the same and different displays of four display types were consistently mapped onto their choice alternatives. The inconsistent group received a conflicting mapping of the same and different displays and the choice alternatives that differed across the four display types but were consistent within a display type. Experiment 1 tested experienced pigeons, and Experiment 2 tested naive pigeons. In both experiments, the consistent group learned their discrimination faster and to a higher level of choice accuracy than did the inconsistent group, which performed poorly in general. Only in the consistent group was the discrimination transferred to novel stimuli, indicative of concept formation in that group. A third experiment documented that the different display classes were discriminable from one another. These results suggest that pigeons attempt to generate a single discriminative rule when learning this type of task, and that this general rule can cover a large variety of stimulus elements and organizations, consistent with previous evidence suggesting that pigeons may be capable of learning relatively unbounded relational same-different concepts.     

Navigation in the Morris swim task as a baseline for drug discrimination: a demonstration with morphine

A morphine versus saline discrimination was demonstrated using the Morris swim task as the behavioral baseline. The apparatus was a large circular pool filled with water made opaque by floating polypropylene pellets. Rats were placed in the tank in randomly selected locations (12 trials per session) and could escape by swimming to a platform submerged 2 cm below the surface. Morphine (5.6 mg/kg) or saline was injected prior to training sessions. The position of the platform in a given session depended on the drug condition, thus forming the basis for discriminative responding. Three of the 4 rats acquired the discrimination, as evidenced by direct swims to the condition-appropriate platform. Generalization probe sessions were conducted following acquisition. Probe sessions were preceded by injections of morphine (0, 1.0, 3.0, 5.6, or 10.0 mg/kg) and involved placing the rat in the pool for 1 min without a platform. Swim patterns revealed a gradient, with probe swimming more concentrated in the area of the morphine platform position after higher morphine doses. In addition, dose-dependent increases in the likelihood of swimming first to the morphine-associated platform location were obtained. These results illustrate the generality of drug discrimination across different behavioral procedures, and of particular interest with respect to spatial learning, demonstrate interoceptive stimulus control of navigation.     

Conflicts of interest in science and medicine: the physician's perspective

The various statements and declarations of the World Medical Association that address conflicts of interest on the part of physicians as (1) researchers, and (2) practitioners, are examined, with particular reference to the October 2000 revision of the Declaration of Helsinki. Recent contributions to the literature, notably on conflicts of interest in medical research, are noted. Finally, key provisions of the American Medical Association’s Code of Medical Ethics (2000–2001 Edition) that address the various forms of conflict of interest that can arise in the practice of medicine are outlined. An earlier version of this paper was presented at an International Conference on “Conflict of Interest and its Significance in Science and Medicine” held in Warsaw, Poland on 5–6 April, 2002. The World Medical Association (WMA) is a global federation of National Medical Associations representing the millions of physicians worldwide. Acting on behalf of patients and physicians, the WMA endeavours to achieve the highest possible standards of medical care, ethics, education and health-related human rights for all people.     

Learning phonotactic constraints from brief auditory experience

Three experiments asked whether phonotactic regularities not present in English could be acquired by adult English speakers from brief listening experience. Subjects listened to consonant-vowel-consonant (CVC) syllables displaying restrictions on consonant position. Responses in a later speeded repetition task revealed rapid learning of (a) first-order regularities in which consonants were restricted to particular positions (e.g. [baep] not *[paeb]), and (b) second-order regularities in which consonant position depended on the adjacent vowel (e.g. [baep] or [pIb], not *[paeb] or *[bIp]). No evidence of learning was found for second-order regularities in which consonant position depended on speaker's voice. These results demonstrated that phonotactic constraints are rapidly learned from listening experience and that some types of contingencies (consonant-vowel) are more easily learned than others (consonant-voice).     

Medicine and pharmacy — facts and myths about the development of an innovative pharmaceutical industry in Poland

Innovation is fundamental to the pharmaceutical industry and a key to improvements in healthcare. Its effectiveness depends on huge, constant investments in research. This innovative industry directly affects the course of studies in healthcare and medicine. Its efforts translate directly into the length and quality of our lives. For several years now, the progress underway in pharmaceutical industry has produced measurable benefits. Doctors have new pharmaceuticals at their disposal, including many types of antibiotics and anti-viral drugs, vaccines and a wide range of drugs which save lives or make them more comfortable. In the near future, ever more efficient cures for neoplastic, rheumatic, neurological, psychic, metabolic, circulatory or respiratory diseases can be expected. Innovation is necessary. The human population is ageing, and the task of an innovative pharmaceutical industry is to keep it in a good condition. The use of innovative drugs can translate directly into lowering the costs of illness. A continuous reduction in spending on healthcare has been observed. The costs of inventing an innovative drug are enormous though (US$ 800 million), and studies on a new drug last between 10 and 13 years. An essential element in recovering the incurred costs and ensuring funds needed for new research is protection by patent. Innovative pharmaceutical companies in Poland are committed to increasing the competitiveness and sustaining the development of not only the market, but also the entire pharmaceutical sector. It is a group of companies of crucial importance to the Polish healthcare system, as it influences improvement in the quality of medical services. Through their investments and spending on research and development, innovative companies accelerate economic growth. In Poland, the innovative pharmaceutical industry is represented by the Association of Pharmaceutical Companies Representatives in Poland (SPFFwP). An earlier version of this paper was presented at an international conference, “The Ethics of Intellectual Property Rights and Patents,” held in Warsaw, Poland on 23–24 April, 2004.     

What's different in second-language processing? Evidence from event-related brain potentials

German sentences which were either correct, contained a selectional restriction violation, or a word category violation were presented auditorily to 16 native speakers of German (L1 group) and to 16 native speakers of Russian, who had learned German after the age of 10 (L2 group). Semantic violations elicited an N400 effect for both groups, but with a reduced amplitude and a longer peak latency in the L2 group. Compared to correct sentences, sentences with a phrase structure violation elicited an early anterior negativity followed by a broad centro-parietal positivity in native speakers. By contrast, there was no differential modulation of the early anterior negativity in the L2 group. A late positivity was also elicited in the second language learners, but it was slightly delayed compared to that shown by native speakers. This pattern is discussed in terms of different degrees of automaticity with respect to the subprocesses involved in sentence comprehension.     

Acquisition of navigation by chimpanzees (Pan troglodytes) in an automated fingermaze task

These experiments investigated how chimpanzees learn to navigate visual fingermazes presented on a touch monitor. The aim was to determine whether training the subjects to solve several different mazes would establish a generalized map-reading skill such that they would solve new mazes correctly on the first presentation. In experiment 1, two captive adult female chimpanzees were trained to move a visual object (a ball) with a finger over the monitor surface toward a target through a grid of obstacles that formed a maze. The task was fully automated with storage of movement paths on individual trials. Training progressed from very simple mazes with one obstacle to complex mazes with several obstacles. The subjects learned to move the ball to the target in a curved path so as to avoid obstacles and blind alleys. After training on several mazes, both subjects developed a high level of efficiency in moving the ball to the target in a path that closely approached the ideal shortest path. New mazes were then presented to determine whether the subjects had acquired a more generalized maze-solving performance. The subjects solved 65–100% of the new mazes the first time they were presented by moving the ball around obstacles to the target without making detours into blind alleys. In experiment 2, one of the chimpanzees was trained using mazes with two routes to the target. One of the routes was blocked at one of many possible locations. After training to avoid the blind alley in different mazes, new mazes were presented that also had one route blocked. The subject correctly solved 90.7% of the novel mazes. When the mazes had one short and one long open route to the target the subject preferred the shorter route. When the short route was blocked, the subject solved only 53.3% of the mazes because of the preference for the shorter route even when blocked. The overall results suggest that with the training methods used the subjects learned to solve specific mazes with a trial-and-error method. Although both subjects were able to solve many of the novel mazes they did not fully develop a more general "map-reading" skill. Accepted after revision: 30 July 2001 Electronic Publication     

Test of a potential link between analytic and nonanalytic category learning and automatic, effortful processing

The link between automatic and effortful processing and nonanalytic and analytic category learning was evaluated in a sample of 29 college undergraduates using declarative memory, semantic category search, and pseudoword categorization tasks. Automatic and effortful processing measures were hypothesized to be associated with nonanalytic and analytic categorization, respectively. Results suggested that contrary to prediction strong criterion-attribute (analytic) responding on the pseudoword categorization task was associated with strong automatic, implicit memory encoding of frequency-of-occurrence information. Data are discussed in terms of the possibility that criterion-attribute category knowledge, once established, may be expressed with few attentional resources. The data indicate that attention resource requirements, even for the same stimuli and task, vary depending on the category rule system utilized. Also, the automaticity emerging from familiarity with analytic category exemplars is very different from the automaticity arising from extensive practice on a semantic category search task. The data do not support any simple mapping of analytic and nonanalytic forms of category learning onto the automatic and effortful processing dichotomy and challenge simple models of brain asymmetries for such procedures.