David DiBattista

Intensity of taste and astringency sensations elicited by red wines is associated with sensitivity to PROP (6-n-propylthiouracil)

Abstract The relationship between sensitivity to 6-n-propylthiouracil (PROP) and taste and astringency perception elicited by red wines was examined. Twenty-five subjects were classified into three PROP sensitivity groups (non-tasters, tasters and super-tasters) based on their bitterness ratings of a 0.32 mM PROP solution as measured on a Labeled Magnitude Scale (LMS). In a completely randomized block design, subjects used the LMS to rate the bitterness, astringency and acidity intensities of three commercial red wines. Contrary to the findings of previous studies with wine, bitterness, astringency and acidity intensities were all correlated with individual PROP taster status. PROP non-tasters gave significantly lower intensity ratings for the bitterness, astringency and acidity of the red wines than did PROP tasters and super-tasters. Individual differences among taster groups may be related to preference and consumption behavior of consumers of wine and other alcoholic beverages.

Acceptance by Undergraduates of the Immediate Feedback Assessment Technique for Multiple-Choice Testing.

Undergraduates completed a questionnaire after using the Immediate Feedback Assessment Technique (IFAT), a commercially available answer form for multiple‐choice (MC) testing that can be used easily and conveniently with large classes. This simple new technique for MC testing provides immediate feedback for each item in an answer‐until‐correct format and permits the earning of partial credit when the students initial response is incorrect. Reaction to the IFAT was extremely positive, with students saying it was easy to use and contributed to their learning, and they indicated a strong desire to use the IFAT for all MC tests. Liking for the IFAT was not related to either personal characteristics or test performance variables, indicating that it has broad appeal to students.

Primary School Teachers' Beliefs and Advice to Parents concerning Sugar Consumption and Activity in Children

The available body of scientific evidence does not support the notion that sugar consumption has significant adverse effects on childrens behaviour; however, responses to a mailed questionnaire indicated that more than 80% of 389 Canadian primary school teachers believed that sugar consumption contributes to increased activity of normal children and to the behavioural problems of hyperactive children. Moreover, in the previous three years, 55% of all respondents had counselled the parents of children whom they believed to be hyperactive to consider reducing their childs sugar consumption to control the childs activity, and parents frequently did so. These results indicate that teachers need to be provided with accurate and up-to-date information about the effects of sugar on childrens behaviour and about effective treatments for hyperactivity. Possible origins of beliefs about the reputed adverse behavioural effects of sugar and about factors that may serve to perpetuate these beliefs are discussed.

Test Anxiety and the Immediate Feedback Assessment Technique

ABSTRACT. The authors examined the relationship between the reactions of undergraduate students to using the Immediate Feedback Assessment Technique (IFAT), an answer form that provides immediate feedback on multiple-choice questions, for the first time on a major examination and their levels of test anxiety and trait anxiety. They also assessed whether students with higher levels of test anxiety and trait anxiety might be disadvantaged relative to other students by use of the IFAT in a testing situation. They found that preference of undergraduates (N = 185) for the IFAT was not related to test anxiety, nor did evidence indicate that the IFAT put students with higher levels of test anxiety at a disadvantage with respect to test performance. Using the IFAT did not generally increase test-related anxiety, and for a majority of students, immediate feedback actually reduced it. Nineteen percent of students felt that immediate feedback interfered with their test performance but would nevertheless still prefer to use the IFAT in future tests. Potential concerns that test-anxious students may either dislike the IFAT or be disadvantaged by its use appear unwarranted and should not deter instructors from adopting the IFAT.

Effects of time-restricted access to protein and to carbohydrate in adult mice and rats

Specific appetites for protein and carbohydrate were investigated by allowing mice and rats time-restricted access to either protein or carbohydrate. Animals were maintained over a period of weeks on a self-selection regimen consisting of three separate macronutrient sources (carbohydrate, fat, and protein). After a baseline phase during which all three diets were freely available, protein-restricted animals were allowed access to the protein diet only during a one-hour period each day, but other diets were always available; access of carbohydrate-restricted animals to the carbohydrate diet was restricted in a similar fashion. Control animals had continuous free access to all three diets throughout the experiment. During the restriction phase, protein-restricted animals showed substantial selective increases in protein intake during the one-hour periods of protein availability, consuming 40-45% of their normal daily protein intake during this phase of the experiment. In contrast, carbohydrate-restricted rats demonstrated no evidence for the development of a carbohydrate appetite, and the carbohydrate appetite of mice was weak and transient. These results are related to current notions concerning specific appetites.

Conditioned taste avoidance induced by lactose ingestion in adult rats.

Because adult rats have very low levels of the intestinal enzyme lactase, the ingestion of appreciable quantities of the disaccharide lactose may cause gastrointestinal distress. The present experiment was designed to demonstrate that adult rats will learn to avoid previously neutral stimuli which have been paired with lactose ingestion. Adult rats ingested both a novel solution [either tap water (WA) or 0.1% saccharin (SA)] and a novel food substance (49% powdered lab chow + 50% added disaccharide + 1% saccharin) during a single conditioning session. The added disaccharide was either sucrose (group SU-SA), lactose (groups HL-SA and HL-WA), or equal amounts of these two disaccharides (group LL-SA); a fifth group (LC-SA) consumed a sucrose-containing diet to which lithium chloride was added (5 mg per 1 g of diet). Separate feeding tests and drinking tests, carried out over several weeks, were used to assess the extent of conditioned taste avoidance. In the four feeding tests, rats were allowed to ingest powdered lab chow with added saccharin (but without added disaccharide), while in the four drinking tests, rats chose between tap water and a 0.1% saccharin solution. Group HL-SA demonstrated a substantial conditioned avoidance in both feeding and drinking tests, but group HL-WA showed avoidance only in feeding tests. Conditioned avoidance was weak in group LL-SA; the strongest avoidance was observed in lithium chloride-treated rats (group LC-SA). Results are related to previous research and to the hypothesis that a learned avoidance of milk may facilitate the weaning process in mammals.

Role of learning in the selection of dietary protein in the golden hamster (Mesocricetus auratus).

Hamsters (Mesocricetus auratus) were kept for several weeks on maintenance diets (MDs) that were either nutritionally complete or protein deficient, and had periodic access to protein-free and high-protein conditioning diets (CDs) with marker flavors (anise and clove). In Experiment 1, protein-restricted hamsters came to prefer the flavor of high-protein CDs but did not prefer unflavored high-protein CD. Thus, hamsters learned to select dietary protein by attending to the flavor of the CD. In Experiment 2, a within-subjects design was used, and MDs also had marker flavors (garlic and sage). Hamsters came to prefer the flavor of high-protein CD when protein restricted, and they showed this preference even in the absence of protein restriction if reexposed for only 90 min to merely the flavor of a protein-deficient MD. Thus, learned associations between the flavor and the usual postingestional consequences of a recently ingested MD can affect short-term dietary protein selection.

Dietary variety enhances meal size in golden hamsters

The effect of dietary variety on meal size was investigated in golden hamsters. Hamsters ate meals (four courses x 12 min/course) in which either the same food was offered in all four courses (one of powdered Purina chow, shortcake cookie, process cheddar cheese, or milk chocolate) or four different foods were offered in successive courses. Total energy intake was significantly greater in the variety condition than in any of the single-food conditions. Thus, although previous research indicates that the meal size of hamsters is relatively resistant to change, hamsters do increase meal size in response to dietary variety. This finding indicates that the satiety mechanisms of golden hamsters share at least some important features with those of other species.

Cholecystokinin reduces ethanol consumption in golden hamsters

In experimental conditions, golden hamsters (Mesocricetus auratus) avidly consume ethanol solutions. However, they are relatively resistant to the deleterious effects of ethanol even after months of continuous consumption, apparently because they metabolize ethanol rapidly and efficiently. Male hamsters with ad libitum access to food and water were presented with isocaloric solutions [weight/weight (wt./wt.)] of 10% ethanol and 17.75% glucose for 40-min periods on alternate days. When hamsters were injected with 0.9% saline before solution presentation the mean intake of ethanol solution (0.55 g) was about half that of glucose solution (1.08 g). Hamsters derived a mean of 0.36 g/kg/40 min of absolute ethanol from the ethanol solution, an amount that does not seem to exceed their metabolic capacity for ethanol. An intraperitoneal injection of a 2.0-microg/kg dose of the C-terminal octapeptide of cholecystokinin (CCK-8) reduced intakes of both solutions by >50% if administered 5 min before solution presentation, but it was ineffectual if administered 45 min before presentation. When citric acid (2.5 g/l) was added to the glucose solution the baseline intakes of the two solutions were virtually equivalent, and when CCK-8 was administered over a range of doses (0.5-2.0 microg/kg) the intakes of the solutions did not differ significantly at any dose, supporting the suggestion that the pharmacological properties of ethanol play little or no role in mediating the consumption-inhibiting effect of exogenously administered cholecystokinin (CCK). Prior administration of lorglumide, a selective CCK type A receptor antagonist, completely attenuated the inhibitory effect of CCK-8. Findings are consistent with the notion that endogenous CCK plays a key role in the short-term control of ethanol intake in hamsters.

Voluntary lactose ingestion in gerbils, rats, mice, and golden hamsters

Over a period of 20 days, adult male gerbils, rats, mice, and hamsters were allowed to choose between tap water and a sugar solution (either sucrose, glucose, or lactose) presented in increasing concentrations (maximum concentration = 24% weight/volume). Rats, mice, and hamsters preferred both glucose and sucrose solutions to water across a wide range of concentrations; gerbils preferred sucrose solutions at concentrations of 8% and above, but preferences for glucose solutions were not significant. Gerbils, mice, and rats did not prefer lactose solutions to water at any concentration, and actually preferred water at higher lactose concentrations; in contrast, hamsters preferred lactose solutions to water at concentrations of 4% and above, and never preferred water to lactose solutions. As solution concentrations increased, all species consumed increasing amounts of glucose and sucrose (i.e., solute). The lactose intake of gerbils, rats, and mice tended to remain quite low even as solution concentration increased; in contrast, the lactose intake of hamsters was substantially greater than that of other species and increased to a maximum of 1.95 g/100 g body weight/day at the 24% concentration. These results indicate that gerbils and mice, like rats, have a low preference for lactose and consume very little of this disaccharide, and confirm that golden hamsters are exceptional in demonstrating both a preference for lactose solutions and an apparent tolerance to the effects of ingestion of substantial amounts of lactose.