Blocking in landmark-based search in honeybees

Two experiments tested blocking in landmark-based search in honeybees. Honeybees in the experimental group were trained in Phase 1 with a single landmark in a constant spatial relation to the target (sugar water). In the compound training second phase, the landmark used in Phase 1 (blocking landmark) and a new landmark (blocked landmark) were presented at constant spatial relations to the target. The blocking and blocked landmarks differed from each other in color and position, and the blocking landmark retained the same spatial relationship to the target as in Phase 1. In Experiment 1, the control group experienced only Phase 2 training with two landmarks. In Experiment 2, the control group was trained with a different landmark in a different position in Phase 1. Blocking was found in both cases.     

Learning in honeybees as a function of amount of reward: Rejection of the equal-asymptote assumption

Foraging honeybees were trained individually with successively presented targets differing in odor, one containing 5 µl and the other 20 µl of a 50% sucrose solution, after which preferences were measured in choice tests. In Experiment 1, there were either 8 training trials with each target, 16 trials with each, or 8 trials with the 20-µ1 target and 16 trials with the 5-µl target. In Experiments 2 and 3, the odor-amount relation was reversed after either 24 or 16 trials with each target. In Experiment 4, differential reward was introduced only after two, four, or six feedings-to-repletion on each target. All of the results could be simulated quantitatively and with considerable accuracy on the assumption that the attractiveness of an odor is given by the strength of its association with sucrose; that asymptotic associative strength is an increasing function of amount of reward; and that choice between two odors is determined by their relative associative strength.     

Learning in honeybees as a function of amount of reward: Tests of the equal-asymptote assumption

In Experiments 1 and 2, honeybee foragers visiting the laboratory were fed on targets of two different colors, one containing 5 μl and the other containing 20 μl of 50% sucrose solution. The targets were presented singly in quasi-random sequences on the training visits, after which preference was measured in an unrewarded choice test. In Experiment 1, 16 differentially rewarded training trials with each color were followed by the same number of trials with the color-amount relation reversed; no preference for either color was found in the subsequent choice test. In Experiment 2, 20 differentially rewarded training trials with each color—enough to produce a clear preference for the 20-μl color when given directly after pretraining—were given after 10 feedings to repletion on each color that were calculated to generate near-asymptotic associative strength; no preference for either color was found in the subsequent choice test. In Experiment 3, there were 12 feedings to repletion on one color and, on the other, 12 feedings to repletion followed by 15 trials with a small (5 μl) reward; no preference was found in a subsequent choice test. The results of all three experiments support a nonrepresentational interpretation of the role of amount of reward in the learning of honeybees.     

Sexual approach conditioning: Omission contingency tests

Male Japanese quail learned to approach a light that predicted visual exposure to a female quail. In Experiment 1, duration of visual exposure to the female did not systematically affect the speed or strength of conditioning. Introduction of an omission contingency for approach to the light after acquisition did not suppress conditioned approach relative to the performance of yoked controls. In Experiment 2, males learned to approach a light that predicted visual exposure to a female despite an omission contingency for approach in effect during acquisition. Experimental males were not slower to acquire the approach response under an omission contingency than were yoked controls. The findings indicate strong Pavlovian control of sexual conditioned approach in Japanese quail.     

Blocking of the sexual conditioning of differentially effective conditioned stimulus objects

The blocking phenomenon was investigated in the sexual response system of male Japanese quail. Access to a live female quail served as the unconditioned stimulus (US). The same audiovisual cue served as the pretrained stimulus in all of the experiments. Following asymptotic conditioning of the audiovisual cue, a second conditioned stimulus (CS2) was added. In Experiment 1, CS2 was a rectangular wood block that had little or no resemblance to a female quail and could not support copulatory behavior. In Experiment 2, CS2 was a terrycloth object that had no quail parts but could support copulatory behavior, and, in Experiment 3, CS2 was a terrycloth object that had a taxidermically prepared head of a female quail added. The terrycloth-only object supported more rapid conditioning than did the wood block, but the blocking effect was obtained with both kinds of stimuli. Approach responding to the terrycloth + head object required pairing it with copulatory opportunity, and the terrycloth + head object supported at least as rapid conditioning as did the terrycloth-only object. However, responding to the terrycloth + head object was not blocked by the pretrained audiovisual cue. These results indicate that the blocking effect occurs in sexual conditioning even with stimulus objects that can support copulation. However, the addition of species-typical head cues to an object makes that object such a powerful stimulus that conditioned approach responding to it cannot be blocked by a previously conditioned arbitrary audiovisual cue.     

Blocking and enhancement of fear conditioning by appetitive CSs

Prior research on Pavlovian-to-instrumental transfer has shown that when a CS previously associated with shock (AvCS+) is presented contingent upon a choice response to a discriminative stimulus for food reinforcement, it facilitates discrimination learning. Conversely, a response-contingent CS previously associated with the absence of shock (AvCS?) retards discrimination learning. To evaluate whether these findings reflect across-reinforcement blocking and enhancement effects, two experiments investigated the effects of appetitively conditioned stimuli on fear conditioning to a novel stimulus that was serially compounded with the appetitive CS during conditioned-emotional-response (CER) training. Although there were no differential effects of the appetitive CSs in CER acquisition, Experiment 1, using a relatively weak shock US, showed that a CS previously associated with food (ApCS+) retarded CER extinction to the novel stimulus, in evidence of enhanced fear conditioning to that stimulus. In addition, Experiment 2, using a stronger shock US, showed that a CS previously associated with the absence of food (ApCS?) facilitated CER extinction to the novel stimulus, in evidence of weaker fear conditioning to that stimulus. These results parallel traditional blocking effects and indicate not only that an ApCS+ and an ApCS? are functionally similar to AvCSs of opposite sign, but that their functional similarity is mediated by common central emotional states.     

Blocking in eyelid conditioning: Effect of changing the CS-US interval and introducing an intertriai stimulus

Kamin’s three-stage blocking paradigm was investigated in rabbit eyelid conditioning, Two manipulations were examined. A change in the CS-US interval from Stage 1 to Stage 2 did not attenuate blocking. The introduction of a salient stimulus during the intertriai interval in Stage 2 also failed to attenuate blocking. The first result is not consistent with Kamin’s interpretation of the blocking effect in terms of US surprisingness. The second resuit is inconsistent with a prediction based on the Rescorla-Wagner model.     

Reciprocal overshadowing in the discrimination of color-odor compounds by honeybees: Further tests of a continuity model

Honeybees were trained to discriminate between simultaneously presented color-odor compounds, one group with color and odor confounded and a control group with color relevant and odor irrelevant; in subsequent differentially reinforced training with the colors in the absence of the odors, the performance of the two groups was the same (Experiment 1). When, however, response to the colors was measured in a 10-min extinction test, discrimination was found to be poorer after confounded training (Experiment 2), and like results were obtained in an extinction test with the odors after control animals had been trained with odor relevant and color irrelevant, the confounded animals showing poorer discrimination of the odors than the controls (Experiment 3). The results of the first two experiments, in which overshadowing of color by odor was found only with an extinction test, require us to take seriously the possibility that our previous modeling experiments (with probability of correct choice in differentially reinforced training as the measure of performance) may have been insufficiently sensitive to noncontinuity effects. Our first efforts to model extinction suggest, however, that all the results of the present experiments can be understood without sacrifice of the parsimonious independence principle.     

Blocking with serial and simultaneous compounds in a trace conditioning procedure

Blocking of conditioned suppression in rats was studied in three experiments using serial and simultaneous compounds in Pavlovian trace conditioning procedures. Experimental groups were first given trace conditioning trials with a 2-sec stimulus (A) presented at least 60 sec before an electric grid shock US. Next, both experimental and control groups received reinforced trials with a compound stimulus (AB). Both A and B were 2 sec in duration and were presented at least 60 sec before the US. For some groups during AB training, the A stimulus preceded the B stimulus; for others, B preceded A; for still others, A and B occurred simultaneously. Conditioning was subsequently assessed separately to both A and B. The results were as follows: First, varying the interval between the onset of A and the US during A training appeared to produce significantly different levels of conditioning to A but did not detectably affect A’s ability to block conditioning to B. Second, blocking was observed in both simultaneous and serial procedures. Third, in the serial procedure, A blocked conditioning to B whether it preceded B or followed B in the AB compound. Fourth, in tests given after AB conditioning, the experimental and control groups suppressed similarly to A. The relevance of these results to the conditioning model of Rescorla and Wagner (1972) and to Mackintosh’s (1975b) theory of attention are discussed.     

Context specificity of conditioning in flavor-aversion learning: Extinction and blocking tests

In three experiments using rats as subjects, we investigated the degree to which a conditioned flavor aversion transfers from one context to another. Experiment 1, using a one-trial conditioning procedure, found no effect of a change of context on a conditioned aversion. Experiment 2 employed a multitrial procedure and demonstrated that a conditioned aversion was extinguished more rapidly after a change of context. Experiment 3 showed that context change decreased the effectiveness with which a conditioned flavor could block acquisition of an aversion by a second flavor. It is argued that these data cannot be explained in associative terms, and that they constitute evidence of conditionality in a simple aversive conditioning procedure.     

Compound-component and conditional discrimination of colors and odors by honeybees: Further tests of a continuity model

In experiments previously reported, individual honeybees were trained in a variety of problems to discriminate color-odor compounds. The results could be modeled accurately on the assumption that the associative strength of each component of a compound stimulus changes independently with reinforcement or nonreinforcement of the compound (independence rule) and that the associative strength of a compound is equal to the sum of the strengths of its components (summation rule). In the present experiments, which were designed to challenge the model, honeybees were trained in compound-component problems (choosing between compounds and their separate components) and in conditional problems (choosing between colors on the basis of a common odor or between odors on the basis of a common color). The new data, together with all of the previous data, could be modeled accurately on the further assumption that interaction among the components of a compound generates a new, compound-unique component that gains and loses associative strength in the same way as other components and contributes in the same way to the strength of the compound; the independence and summation rules continue to apply.     

刍创新教学方法的多种形式

创新，是教学改革的热点，也是教育发展的目标。本文探讨了语文教学中教学方法的创新和学生自主学习中的创新。     

Analysis of the overlearning-extinction effect in honeybees

In previous experiments with individual honeybees that visited the laboratory regularly to take sucrose solution from a target set on the shelf of an open window, the overlearning-extinction effect was found for high concentrations of sucrose but not for low. The purpose of the present experiment was to examine the possibility that declining resistance to extinction in the course of prolonged training with a high concentration of sucrose could be explained in terms of increasing nutritive level. Three groups of animals were extinguished on a distinctive target, one group after 6 visits to the target, a second after 18 visits to the target, and a third after 6 visits to the target that were interspersed among 12 visits to a different target. More rapid extinction in the second group than in the third, which had fewer training visits to the extinction target than the second but the same total number of training visits, rules out an explanation in terms of nutritive level and points instead to a frustration-like process evidenced also in earlier work on incentive contrast.     

Analysis of choice in honeybees

Free-flying honeybees were trained in a set of four problems to choose between two differently scented targets, one or the other of which contained sucrose solution. The training was simulated quantitatively, always with the same simple linear equations for computing changes produced by reinforcement and nonreinforcement in the strength of association between each target and the sucrose, but with a diverse array of functions for predicting choice on the basis of relative strength. Accuracy of prediction was indexed by the root-mean-square (RMS) deviation of simulated data from real data. The results provide some good approximations of what is tentatively assumed to be the true choice function, setting the stage for further development of the associative features of the model to encompass more complex phenomena of honeybee learning in choice situations.     

Relation of field independence and test-item format to student performance on written piagetian tests

In this study we have investigated the relationship between the field-dependence-independence (FDI) dimension as measured by the Group Embedded Figures Test (GEFT) and subject performance on the Longeot test, a pencil-and-paper Piagetian test, through the open or closed format of its items. The sample consisted of 141 high school students. Correlation and variance analysis show that the FDI dimension and GEFT correlate significantly on only those items on the Longeot test that require formal reasoning. The effect of open- or closed-item format is found exclusively for formal items; only the open format discriminates significantly (at the 0.01 level) between the field-dependent and -independent subjects performing on this type of item. Some implications of these results for science education are discussed.     

Comparative analysis of learning in honeybees

The performance of free-flying and harnessed honeybees has been studied in a variety of experiments patterned after those in which learning in vertebrates has been studied—among them experiments on amount, quality, and probability of reward; on compound conditioning and discrimination; and on spatial learning and memory. Despite the remoteness of the evolutionary relationship and the vast differences in brain size and structure, the results for honeybees are strikingly similar to those for vertebrates in many respects and different in only a few. The extent to which phenomena of learning common to honeybees and vertebrates can be understood in terms of common functional principles and mechanisms remains to be determined. None of the differences in the results for honeybees and vertebrates points unmistakably to a difference in their learning.     

谈假设法在物理解题中的应用

提出了在物理教学中应用特殊值假设、穷举假设、条件假设、过程假设、结果假设等假设方法求解物理习题的几个方面，在培养学生科学的方法论方面的重要性。     

Second-order conditioning: Different outcomes in fear and eyelid conditioning

Second-order conditioning has been frequently observed with the fear response but not with the eyelid response. The present experiments manipulated the temporal relationship between the second-order and first-order stimulus on second-order conditioning trials. Our results indicated that a trace second-order procedure is not effective with either response system. Second-order fear conditioning was most prominent when the second-order CS terminated at the onset of the first-order CS. This arrangement, however, did not produce second-order eyelid CRs. In eyelid conditioning, the second-order CS appears to inhibit responding to the first-order CS which immediately follows it.     

Reward and learning in honeybees: analysis of an overshadowing effect

Previous experiments have shown that honeybees trained with colored targets baited with 5- versus 20-µl drops of sucrose solution fail to develop a preference for the 20-µl color when the location of the drop on each target is marked by a white dot (dot-color overshadowing) but that discrimination is not impaired by dots when the targets differ in odor rather than in color. In Experiments 1–3, dot-color overshadowing failed to appear with differences in concentration rather than amount of sucrose (50% vs. 20% or 0%), but it did appear in Experiments 4 and 5 with a difference in probability of reward (consistent vs. partial). Experiment 6 showed no dot-odor overshadowing with a difference in probability of reward. The results are not generally predictable from the Rescorla-Wagner principle of shared associative strength, but point instead (in conjunction with those of earlier experiments) to competition for visual attention.     

Performance of honeybees in analogues of the rodent radial maze

The performance of individual honeybees pretrained to forage at a laboratory window was studied in three rudimentary analogues of the radial maze designed for the study of short-term spatial memory in rats. A linear arrangement of three targets was used in Experiment 1, a triangular arrangement of three targets in Experiment 2, and a rectangular arrangement of four targets in Experiment 3, with reward only for the first response to each of the targets presented on any given trial. Several systematic patterns of responding were observed, with no indication that the choices made by the animals were influenced by memory of targets recently visited.