Re-evaluating how sweet-liking and PROP-tasting are related.

Past research has identified distinct phenotypic differences in responses to sweet taste, although the origins of these differences remain unclear. One possibility is that these individual differences in sweet-liking are a manifestation of the more widely known differences in sensitivity to the bitter tastant 6-n-propylthiouracil (PROP), which has been related to wider differences in food liking and preference. However, previous studies exploring the relationship between sweet-liking and PROP-tasting have had mixed outcomes. This is possibly due to older studies using a more simplistic dichotic characterisation of sweet likers, whereas recent research suggests three sweet-liking phenotypes (extreme sweet likers, ESL; moderate sweet likers, MSL; and sweet dislikers, SD). To re-assess how sweet-liking and PROP tasting are inter-related, 236 volunteers evaluated their liking for 1.0 M sucrose and the intensity of three concentrations of each NaCl and PROP. Using three different methods for classifying PROP taster status, our analysis confirmed that all three sweet-liking phenotypes were represented in all three PROP taster groups (super-tasters, ST; medium tasters, MT; and non-tasters, NT), but relatively few ESL were classified as ST, or SD as NT. Overall, these data suggest that while PROP tasting and sweet-liking are not causally related, the SD phenotype may partly be explained by a broader tendency for anhedonia.

Visual cues associated with sweet taste increase short-term eating and grab attention in healthy volunteers.

Most studies that examine responses to food cues use images of actual foods as stimuli. Since foods are rewarding in multiple ways, it then becomes difficult to try and partial out the role of the importance of different aspects of food reward. Here we aimed to evaluate the impact of novel visual cues specifically associated with the immediate sensory reward from a liked sweet taste. In the training phase, one visual cue (CSsweet) was associated with the experience of sweet taste (10%sucrose) and a second, control cue (CSneutral) with a neutral taste (artificial saliva) using a disguised training procedure. In Experiment 1, participants (n = 45) were given an ad libitum snack intake test 30 min post-training, either labelled with CSsweet or CSneutral. Total caloric consumption was significantly higher in the CSsweet (650 ± 47 kcal) than CSneutral (477 ± 45 kcal) condition, but ratings of liking for the snacks did not differ significantly between conditions. In Experiment 2, participants (n = 80) exhibited an overall attentional bias (22.1 ± 9.9 ms) for the CSsweet relative to CSneutral cue (assessed using a dot-probe task), however rated liking for the CSsweet did not change significantly after cue-sweet training. Likewise, measures of expected satiety for drinks labelled with CSsweet did not differ significantly from CSneutral. Overall these two experiments provide evidence that associations between neutral visual cues and the experience of a liked sweet taste leads to cue-potentiated eating in the presence of the CSsweet cue. With no evidence that cue-sweet training altered rated liking for the visual cues, and in keeping with extant literature on the dissociation of hedonic and rewarding properties of food rewards, we propose this potentiation effect to reflect increased incentive salience.

Tattoo visualization using cross-polarized lighting and infrared photography.

Identification of the deceased is a critical responsibility of the death investigation system. If visual identification is inconclusive, tattoos can provide secondary identification but may be difficult to visualize at various stages of decomposition. We describe the case of a 35-year-old male found submerged underwater by police after swimming at a pier. The decedent was last seen earlier that day. Signs of immersion including sodden hands, feet, and clothing, wet sand on the torso and legs, and heavy edematous legs were observed. The post-mortem blood alcohol concentration was 427 mg/100 mL; signs of recent traumatic injury were not present. The immediate cause of death was drowning as a consequence of ethanol intoxication. When pulled from the water, the decedent's shoulder tattoo was not visible. Cross-polarized lighting and infrared photography visualized the tattoo to help confirm identity. These photographic methods were compared to hydrogen peroxide and optical coherence tomography techniques and described in detail to assist with future cases.

Ingested but not perceived: Response to satiety cues disrupted by perceptual load.

Selective attention research has shown that when perceptual demand is high, unattended sensory information is filtered out at early stages of processing. We investigated for the first time whether the sensory and nutrient cues associated with becoming full (satiety) would be filtered out in a similar manner. One-hundred and twenty participants consumed either a low-satiety (75 kcal) or high-satiety (272 kcal plus thicker texture) beverage, delivered via an intra-oral infusion device while participants simultaneously completed a task which was either low or high in perceptual demand. Among participants who performed the low perceptual load task, ingestion of the high-satiety beverage increased rated satiety and reduced consumption at a subsequent snack test. However, both effects were eliminated by the high perceptual load task. Therefore, the processing of satiety cues was dependent on the availability of attention, identifying a novel perceptual load mechanism of inattentive eating and supporting more recent cognitive models of appetite control.

Sour Promotes Risk-Taking: An Investigation into the Effect of Taste on Risk-Taking Behaviour in Humans.

Taking risks is part of everyday life. Some people actively pursue risky activities (e.g., jumping out of a plane), while others avoid any risk (e.g., people with anxiety disorders). Paradoxically, risk-taking is a primitive behaviour that may lead to a happier life by offering a sense of excitement through self-actualization. Here, we demonstrate for the first time that sour - amongst the five basic tastes (sweet, bitter, sour, salty, and umami) - promotes risk-taking. Based on a series of three experiments, we show that sour has the potential to modulate risk-taking behaviour across two countries (UK and Vietnam), across individual differences in risk-taking personality and styles of thinking (analytic versus intuitive). Modulating risk-taking can improve everyday life for a wide range of people.