Taste and odor in conditioned flavor preference learning

Almond and peppermint extracts were combined with salt and citric acid as cues in conditioned flavor preference conditioning. In Experiment 1, extracts overshadowed tastes, although tastes and extracts conditioned equally well when presented in isolation. In Experiments 2 and 3, tastes and extracts were conditioned in isolation prior to conditioning of a taste/extract compound. The conditioning history of the tastes and extracts did not affect the overshadowing of taste by extract. The results of Experiment 4 showed that rats could learn to discriminate between a taste and extract presented in isolation vs. the taste/extract compound. Thus, extracts do not interfere with sensing the tastes. We suggest that a taste/extract compound produces a configural stimulus that is more characteristic of the extract than the taste.     

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.     

Conditioning with taste as the CS in conditioned flavor preference learning

There appear to be unconditioned affective reactions to the four basic tastes: liking for sweet and salt and disliking for sour and bitter. We attempted to modify these reactions by pairing the tastes with calories and with sweeter tastes. Differing sucrose concentrations were ineffective in reversing the preference for salt over citric acid or for saccharin over quinine. We could, however, reverse the preference for salt over citric acid, producing an actual preference for sour over salt, by using sucrose and saccharin as the reinforcers. The initial reactions to tastes could also be modified by reducing the initial difference in affect produced by the tastes through mixing both tastes with sucrose.     

Potentiation of taste and extract stimuli in conditioned flavor preference learning

In these experiments, we investigated the nature of potentiation in the conditioned flavor preference paradigm. Almond and banana extracts, which have strong odor components, were combined with salt and saccharin (liked tastes; Experiment 1) or quinine and citric acid (disliked tastes; Experiment 2) in a flavor preference procedure that mixed these solutions with a caloric reinforcer (polycose). The results showed that liked tastes potentiated preference conditioning to extracts (Experiment 1), whereas extracts potentiated preference conditioning to disliked tastes (Experiment 2). In both experiments, the presumably less liked stimulus (i.e., the extract in Experiment 1 and the disliked taste in Experiment 2) was the potentiated cue.     

The effect of learning style on preference for web‐based courses and learning outcomes

As the number of courses offered online increases rapidly, it is important for teachers and institutions to identify specific learner characteristics of successful online students. This paper reports on a study that compared an online group of freshmen computer science majors with an equivalent on‐campus group to find if their individual learning styles play a role in the selection of course delivery mode (online or face to face) and in their academic achievement. No significant statistical differences were detected in learning styles and learning performance between the two groups. Implications for teaching practice and design of learning activities that resulted from this study are discussed.     

年老化对风险选择偏好的影响作用述评

最初,研究者们认为老年人相比青年人在做风险决策时会更加保守。然而,近期的一些研究发现了不一致的结论。本文探索了出现矛盾结论的原因。最后,我们展望了该领域未来需要继续深入进行的研究。     

Generalized conditioned flavor aversions: Effects of toxicosis training with one flavor on the preference for different novel flavors

In two experiments, experimental rats were trained to have strong aversions to one of 10 novel-flavored solutions through contingent lithium injections; control rats were injected with lithium in the absence of prior consumption. Each animal was then tested with each of the 10 solutions, and the preferences of the experimental rats and the control rats were compared. A generalization gradient of the aversion to each conditioned aversive flavor was obtained for each test flavor.     

The effect of learning style on doctoral course completion in a Web-based learning environment

One hundred and fifty-nine doctoral students, majoring in Computing Technology in Education (CTE), were tracked during the coursework phase in a Web-based learning environment. At the beginning of the coursework, each student completed a demographic data form and Kolb's Learning Style Inventory (LSI). Due to the type of program, it was hypothesized that students would primarily fall into Kolb's Converger and Assimilator categories, and learning style would predict completion of the required courses. Results indicated 84.3% (n=134) of all students finished the required coursework. One hundred and twenty-four of the students (78%) fell into the predicted categories and, of these, 87.1% (n=108) finished the coursework. Students not falling into the predicted categories (n=35) had a 74.3% (n=26) completion rate.An examination of the means scores for both groups indicated that students with a preference for Abstract Conceptualization dropped out of the program at significantly lower rates, t(157)=1.667, p=.045(one-tailed), than students with other preferred learning strategies. The implications are clear. First, students, for the most part, are able to adapt their personal learning styles in order to succeed in a Web-based learning environment. Second, students with a preference for systematic planning and an intellectual understanding of a situation are more likely to succeed than students preferring concrete experience and interaction with other students. Institutions offering programs of this type should be prepared to address learning style issues when developing and offering such programs.     

Exploring the effect of learning styles on learning achievement in a u-Museum

In recent years, mobile technology has been developing rapidly and has been widely used. There are many successful cases of mobile technology applied greatly in today’s teaching and even combined with sensing devices to overcome the limitations of traditional learning environment. In order to make teaching more diversified, teachers currently treat field trips as one of the major ways to aid traditional classroom teaching. Based on Keller’s ARCS motivation model, this study used the natural disaster section in the sixth graders’ Natural Science-Taiwan subject as an example and application of radio frequency identification (RFID) technology in mobile devices to develop a context-aware ubiquitous learning system to be applied in the 921 Earthquake Museum of Taiwan. With the guide of the system, learners can use mobile carriers to receive content information displayed in the Museum for learning. This study conducted experiment in the 921 Earthquake Museum of Taiwan to explore whether using the system for learning significantly improves learning outcomes and motivation in comparison to traditional navigation learning. Felder & Silverman’s theory of learning style was incorporated to explore whether there exists differences in learning performance and outcome among learners with different learning styles so design and strategies for future teaching system can be improved.     

Feature-negative effect in rats’ discrimination learning in the runway

In two experiments, rats were trained on a successive go/no-go discrimination problem in the runway in which the positive (S+) and negative (S?) discriminanda were differentiated by the presence or absence of a distinctive feature. The feature in Experiment 1 was a series of flashing lights over the runway. In Experiment 2, the feature was a pretrial reinforcement (Phase 1), or pretrial reinforcement versus pretrial nonreinforcement (Phase 2). The feature signaled S+ trials in feature-positive (FP) groups and S? trials in feature-negative (FN) groups. The original discrimination was reversed in Phase 2 of both experiments. With the exception of the pretrial nonreinforcement groups in Experiment 2, there was an asymmetry in discrimination learning in both phases of both experiments favoring superior discrimination learning by FN subjects over FP subjects, a feature-negative effect. Implications of the results for an information processing account of asymmetries in learning feature discriminations are discussed.     

The effect of effort grading on learning

In the fall of 2004, Benedict College – a Historically Black College in Columbia, SC – began enforcing a new grading policy called Success Equals Effort (SE²). Under this policy, students taking freshman and sophomore level courses were assigned grades that explicitly rewarded not only content learning (“knowledge” grade) but also measures of effort (“effort” grade). This paper examines the effects of effort grading using two stage least squares and fixed effect estimates. I find evidence of a strong positive correlation between “effort” grades and “knowledge” grades. Under some restrictions this relationship can be interpreted as “effort” producing “knowledge”.     

The effect of sensory modalities on learning

As the importance of modalities to learning becomes increasingly apparent, the dearth of modality tests and assessment techniques becomes a critical problem. A classroom model for assessing modality strengths is suggested in which students learn to spell nonsense words via six different modalities: visual, auditory, audiovisual, vocal, motor, and tactile. The technique was used and proven effective in a study involving 396 eighth-grade students. Results of the study indicated that the presentation modality did significantly affect the amount of information learned (F = 12.36, p < .01), and that the auditory and visual modalities were most effective for this particular learning task. It is felt that this assessment technique can facilitate application of modality theory in classroom teaching.     

Effects of food deprivation on learning and expression of flavor preferences conditioned by saccharin or sucrose

In four experiments, food deprivation was varied during conditioning and testing of conditioning of flavor preferences by sweeteners. Conditioned preferences for a flavor associated with a more concentrated solution were enhanced by increased deprivation in training whether sucrose or saccharin was used when rats consumed solutions freely during training. When consumption of solutions was controlled and higher deprivation levels were used, preference for the higher concentration of sucrose was still enhanced by increased deprivation in training, but this did not occur with saccharin. We suggest that deprivation may enhance the reinforcing value of sweetness only when calories increase along with sweetness. We also suggest that deprivation can enhance flavor preference learning by increasing consumption and thereby increasing exposure to the flavored solutions.     

The effect of drug habituation before and after taste aversion learning in rats

In Experiment I, rats received eight habituation injections of either lithium chloride (LiCl) or sodium chloride (NaCl), then two aversion training trials in which access to saccharin solution was followed by LiCl injections, and finally eight extinction trials with saccharin but no injections. The rats habituated to LiCl showed less aversion to saccharin during training and extinction. In Experiment II, rats received two aversion training trials, then eight habituation trials to either LiCl or NaCl, then eight extinction trials, four more aversion training trials, and eight more extinction trials. The rats habituated to LiCl did not differ during the first extinction period from those habituated to NaCl, but showed less aversion to saccharin during the second training and extinction periods. Consequently, habituation to LiCl reduces the learning of an aversion to saccharin but does not reduce the performance of a previously learned aversion.     

The preference of rats for free or response-produced food

Three experiments were performed to investigate the preference of rats for either free or response-produced food. Rats were trained to free feed in an operant chamber and then to leverpress for food. Subsequently, they were given a choice between continuing to leverpress for food on CRF, FR 2, and FR 10 schedules or free feeding. In three experiments the independent variable was the method of free-food presentation: A fixed free-food dish was used in the first experiment, a movable dish in the second, and a large flat dish in the third experiment. The results of the three experiments were very similar, with most of the rats showing a preference for the free food. This preference increased further when more than one response was required to produce a food pellet. These results contradict any conclusion that rats have a generalized tendency to prefer response-produced to free food but provide no answer to the question of why rats do on occasion respond for food in the presence of free food.     

The moderating effect of instructional conceptions on the effect of powerful learning environments

This study aimed at experimentally investigating the moderating role of instructional conceptions on the effectiveness of powerful learning environments (PLE) designed in line with the four-component instructional design model (4C/ID-model). The study also investigated the influence of learning in a 4C/ID PLE on students’ instructional conceptions. To achieve its goal, a study with a one by one by two pre-test post-test quasi-experimental design was done. Three functionally equivalent classes of students from three similar (secondary technical) schools were randomly exposed to three different treatments. The participants consisted of 129 (47, 41, 41) students. The treatments were one control group with a regular method of teaching, and two experimental groups: a 4C/ID PLE with ICT, and a 4C/ID PLE without ICT. The instructional conceptions questionnaire was administered both in the pre-and the post-test to assess students’ instructional conceptions. Pre- and post-tests contain retention and transfer items. Technical teachers were trained to implement the interventions. In contrast to expectation, findings show no moderating effects of students’ instructional conceptions on the learning environments. Finally, the results indicate that students’ instructional conceptions positively change after implementation of the three interventions. The theoretical, research, and practical implications of the results for the instructional design and technology community as well as educational practice are discussed.     

A history of morphine-induced taste aversion learning fails to affect morphine-induced place preference conditioning in rats

Drugs of abuse have both rewarding and aversive effects, as indexed by the fact that they support place preferences and taste aversions, respectively. In the present study, we explored whether having a history with the aversive effects of morphine (via taste aversion conditioning) impacted the subsequent rewarding effects of morphine, as measured in the place preference design. In Experiment 1, rats were exposed to a taste aversion procedure in which saccharin was followed by morphine. Place preference conditioning was then initiated in which animals were injected with morphine and placed on one side of a two-chambered apparatus. Animals with a taste aversion history acquired place preferences to the same degree as controls without such a history, suggesting that morphine’s affective properties condition multiple effects, dependent on the specific stimuli present during conditioning. To determine whether these results were a reflection of processes operating in traditional associative conditioning, in a modified blocking procedure, place preference conditioning was attempted in the presence of a taste previously associated with morphine (Exp. 2). Under these conditions, animals still acquired morphine-induced place preferences comparable to those of animals without a morphine or conditioning history. These results are consistent with the position that drugs of abuse have multiple stimulus effects (positive and negative) that are differentially associated with specific stimuli (environmental and taste) that drive different behavioral responses (approach and avoidance).