Relationship between food preferences and PROP taster status of college students.

How food tastes plays a key role in our food choices and eating behavior, with important implications for health and nutrition. The negative relationship of genetically predisposed sensitivity to 6-n-propylthiouracil (PROP) and food preferences for bitter, creamy, and spicy foods, and alcohol is often reported in both scholarly and popular literature. Our review of research indicates the empirical results are far from conclusive. We conducted a questionnaire-based study to examine enjoyment ratings for 12 foods and beverages often reported to be disliked by PROP supertasters. We measured PROP ratings on the modified gLMS scale and administered a questionnaire to assess food preferences of a sample of 139 college undergraduates. Analysis of variance showed no significant group differences between supertasters, medium tasters, and nontasters in ratings of how much they liked brussels sprouts, raw broccoli, cabbage, spinach, black coffee, dark chocolate, crushed red pepper, jalapenos, chili peppers, red wine, beer, creamy salad dressing, or mayonnaise. Preferences for only two foods out of twelve, dark chocolate and chili peppers, had a significant correlation with PROP sensitivity in the predicted negative direction. While statistically significant, these correlations were low and of little practical significance. The role of culture in shaping attitudes toward food is proposed as a more powerful influence than the genetic factors that relate to PROP sensitivity.

Female zebrafish (Danio rerio) demonstrate stronger preference for established shoals over newly-formed shoals in the three-tank open-swim preference test.

Zebrafish (Danio rerio) share a considerable amount of biological similarity with mammals, including identical or homologous gene expression pathways, neurotransmitters, hormones, and cellular receptors. Zebrafish also display complex social behaviors like shoaling and schooling, making them an attractive model for investigating normal social behavior as well as exploring impaired social function conditions such as autism spectrum disorders. Newly-formed and established shoals exhibit distinct behavior patterns and inter-member interactions that can convey the group's social stability. We used a three-chamber open-swim preference test to determine whether individual zebrafish show a preference for an established shoal over a newly-formed shoal. Results indicated that both sexes maintained greater proximity to arena zones nearest to the established shoal stimulus. In addition, we report the novel application of Shannon entropy to discover sex differences in systematicity of responses not revealed by unit-based measurements; male subjects spent more time investigating between the two shoals than female subjects. This novel technique using established versus newly-formed shoals can be used in future studies testing transgenics and pharmacological treatments that mimic autism spectrum disorder and other disorders that affect social interaction.

High fidelity: Assessing zebrafish (Danio rerio) responses to social stimuli across several levels of realism.

Behavioral assays of zebrafish shoaling have recently been employed to investigate social behavior in zebrafish models of psychiatric disease. Many studies have developed simulated models of conspecifics to serve as alternatives to live shoals in order to examine specific cues that contribute to shoaling behavior. However, no studies have investigated the extent to which zebrafish prefer one stimulus over another when given the choice between two conspecific alternatives (live or simulated). In the present study, we employed a new, four-quadrant choice preference task that allowed zebrafish to swim freely between a live shoal and a motorized mobile shoal, a live shoal and playback of a video-recorded shoal, or a motorized mobile shoal and playback of a video-recorded shoal. Behavior tracking software was used to track subjects' movements in upper and lower quadrants on either side of the test arena. Subjects spent more time near the live shoal, especially in the lower quadrant, and exhibited different swim patterns in response to each simulated conspecific alternative, suggesting that zebrafish prefer a live shoal over models of lower fidelity.

Enumeration produces poor primacy for tactile presentation relative to visual and auditory presentation as the only modality effect.

Methodological biases may help explain the modality effect, which is superior recall of auditory recency (end of list) items relative to visual recency items. In 1985 Nairne and McNabb used a counting procedure to reduce methodological biases, and they produced modality-like effects, such that recall of tactile recency items was superior to recall of visual recency items. The present study extended Nairne and McNabb's counting procedure and controlled several variables which may have enhanced recall of tactile end items or disrupted recall of visual end items in their study. Although the results of the present study indicated general serial position effects across tactile, visual, and auditory presentation modalities, the tactile condition showed lower recall for the initial items in the presentation list than the other two conditions. Moreover, recall of the final list item did not differ across the three presentation modalities; modality effects were not found. These results did not replicate the findings of Nairne and McNabb, or much of the past research showing superior recall of auditory recency items. Implications of these findings are discussed.

The generalized matching law as a predictor of choice between cocaine and food in rhesus monkeys.

RATIONALE: The generalized matching law predicts that the relative rate of behavior maintained by different reinforcers will match the relative rate of reinforcement. It has previously been shown that responding maintained by either food deliveries or cocaine injections under concurrent variable-interval (conc VI) schedules is well described by the generalized matching law. However, the generality of this conclusion to the choice between a drug and a non-drug reinforcer has not been well established. OBJECTIVE: The objective of the present study was to determine the extent to which the generalized matching law could account for choice between cocaine and food. METHODS: Four male rhesus monkeys (Macaca mulatta) lever pressed under various pairs of conc VI schedules with food and/or cocaine injection as the maintaining events. Two doses of cocaine (0.025 and 0.05 mg/kg per injection) were selected to provide information about reinforcer magnitude. RESULTS: As has been found in a context of choice between identical reinforcers, the generalized matching law accounted for most behavior. As in earlier studies with identical reinforcers, there was less responding apportioned to the alternative with the greater reinforcement frequency than predicted by the generalized matching law, i.e., undermatching was observed frequently. There was a tendency for more responding to be emitted toward the food alternative when the lower dose of cocaine was available and toward the drug alternative when the higher dose of cocaine was available. CONCLUSION: These results suggest that, as proposed by the generalized matching law, relative reinforcement rate is an important determinant of choice between a drug and a non-drug reinforcer.

Instrumental conditioning of choice behavior in male Siamese fighting fish (Betta splendens).

Despite the differences in the response of male Betta splendens toward various stimuli, no research has attempted to determine the preference for a live conspecific versus a mirror presentation. A submerged T-maze was used to present both stimuli to healthy male B. splendens (N=16). The results indicated that subjects' start box and swimway latencies decreased significantly over the 30 trials. Moreover, the analysis of choices demonstrated a modest, but statistically significant, preference for the live conspecific over the mirror presentation. The results are discussed in terms of the stimuli qualities that elicit an aggressive response in B. splendens and the implications for common experimental procedures.