Tackling obesity in aged-care homes: the effects of environmental cues

BACKGROUND/OBJECTIVESFood consumption directly affects human health. Nevertheless, the mechanisms underlying the food portion-size effect related to the visual cues significantly affecting food intake are unclear. This study examined the effects of visual cues on food consumption and satiety.SUBJECTS/METHODSThe subjects (16 females and 14 males) were exposed to one of the following 4 experimental conditions for 4 weeks: blindfolded large unit, blindfolded small unit, visible large unit, and visible small unit. The subjects were served 600 mL of a multigrain shake (a single 600 mL cup as a large unit or six 100 mL cups as a small unit).RESULTSThe subjects’ food intake was similar under the blindfolded and visible conditions, regardless of the unit size. Under the blindfolded condition, the subjects significantly overestimated their intake when served small units compared to large units (63.50 mL vs. 110.01 mL, P < 0.05). Under the visible condition, however, the actual and estimated consumption volumes were similar. In addition, although the participants consumed larger portions when served large units, there was no significant difference in subjective fullness between the 2 portion size conditions. The thirst levels did not vary significantly according to the portion sizes or visibility conditions.CONCLUSIONSmall food units facilitate more effective consumption monitoring through visual cues, which might contribute to reduced food intake. Previous studies on solid foods have revealed significant effects of portion size and visual cues on satiety. Nevertheless, this study, which focused on liquid food, showed no significant differences in satiety despite the variations in perceived fullness across conditions. This suggests that the effect of portion size on satiety may differ according to solid and liquid foods. Considering these findings, future research should examine the mechanisms underlying the portion-size effects in liquid foods with more refined methodologies.

Effectiveness of food-related cues and portion size effect

Increases in portion size lead to increases in energy intake, yet the mechanisms behind this "portion size effect" are unclear. This study tested possible mechanisms of the portion size effect, i.e., bite size and visual cues. A 2 × 2 repeated measures, within-subject design was used to test the effects of portion size (410 g vs. 820 g of a pasta dish) and visual cues (blindfolded vs. visible) on energy intake in 30 individuals (15 men, 15 women). At each meal participants were exposed to one of four experimental conditions (small portion/visible; small portion/blindfold; large portion/visible; large portion/blindfold). Participant characteristics, food intake, number of bites, meal duration, palatability measures and hunger and fullness were assessed. In response to a doubling of the portion presented, entrée energy intake increased 26% (220 kcal; P < 0.001) and mean bite size increased 2.4 g/bite (P < 0.05). Overweight (OW) individuals consumed 40% (334 kcal) more of the entrée in response to the large portion condition (P < 0.05), while lean individuals' intakes did not differ (P < 0.56). A 12% (122 kcal) decrease in entrée intake was observed in the blindfolded condition (P < 0.01), but no portion by visual cue interaction was found; indicating that blindfolding did not significantly attenuate the portion size effect. These data suggest that the portion size effect is not impacted by removing the visual cue of food and that this effect occurs via changes in bite size in adults.

The aims of this study was to investigate the effects of visual and auditory cues on the freezing of gait in Parkinson disease patients (PDF) compared with Parkinson disease patients without freezing of gait (PDNF). Fifteen PDF, 10 PDNF, and 10 age-matched healthy volunteers were recruited. Subjects walked back and forth on a 7-m walkway under three different conditions: baseline condition without cues, with visual cues, and with auditory cues. Visual cues consisted of white stripes located along the walkway. For auditory cues, a metronome was used. Gait was analyzed using three-dimensional computerized analysis. In the PDF group, both visual and auditory cues significantly affected visuospatial and kinematic gait parameters. PDF group benefited more from visual cues than auditory cues. In the PDNF and healthy volunteer groups, visual cues significantly decreased patient velocity. Auditory cues affected some kinematic parameters on PDNF group. Compared among three groups, visual cues more positively affected the PDF group, and auditory cues more positively affected kinematic parameters in the PDNF group. This study suggests that gait training using visual and auditory cues can improve PDF patient gait and that auditory cues enhance gait in PDNF patients with hypokinetic gait patterns.

Hemifield asymmetry in the potency of exogenous auditory and visual cues

This study was conducted to investigate the relative dominance of visual, auditory and olfactory cues in lambs' distinction of their own mother from alien ewes. Subjects were eight Suffolk lambs and were given a series of 20 choice trials between their own and alien mothers in a Y-maze. In the choice trials, four kinds of sensory cues (compound and one of visual, auditory and olfactory cues) were provided for lambs. As results of χ2-test, only five subjects exposed to the compound cues could significantly choose their own mother. The Wilcoxon rank-sum test showed that lambs exposed to the compound (P < 0.05) and the visual cues (P < 0.10) tended to choose their own mothers than alien ewes. The analysis of the first ten and the later ten trials indicated significant choices of their own mothers (χ2-test, P < 0.05) by three, one, one and one lambs exposed to the compound, visual, auditory and olfactory cues, respectively. In addition, two lambs tended to choose their own mothers when exposed to the compound, visual and auditory cues (P < 0.1). It is concluded that lambs usually distinguish their own mothers by means of the compound cue, but they can distinguish their own mother in case that only one kind of sensory cue is available. The relative dominance in the sensory modalities involved in lambs' distinction of their own mothers could be visual > auditory ≥ olfactory cues in order.

Effects of visual and auditory cues on gait in individuals with Parkinson's disease

Food quality is an important consideration in the foraging strategy of all animals, including herbivores. Those that can detect and assess the nutritional value of plants from afar, using senses such as smell and sight, can forage more efficiently than those that must assess food quality by taste alone. Selective foraging not only affects herbivore fitness but can influence the structure and composition of plant communities, yet little is known about how olfactory and visual cues help herbivores to find preferred plants. We tested the ability of a free‐ranging, generalist mammalian browser, the swamp wallaby Wallabia bicolor , to use olfactory and visual plant cues to find and/or browse differentially on Eucalyptus pilularis seedlings grown under different nutrient conditions. Low‐nutrient seedlings differed from high‐nutrient seedlings, having lighter coloured leaves, red stems and lower biomass and nitrogen content. In the absence of visual cues, wallabies used odour to differentiate vials containing cut seedlings. They visited and investigated patches with high‐nutrient seedling odour most, followed by patches with low‐nutrient seedling odour, and patches with no added odour least. However, when visual and olfactory cues of seedlings were present, wallabies reversed their foraging response and were more likely to browse low‐ than high‐nutrient seedlings. This browsing difference, in turn, disappeared when long‐range visual cues were reduced by pinning seedlings horizontal to the ground. We suggest that visual cues overrode the effects of olfactory cues on browsing patterns of intact seedlings. Our study shows that herbivores can respond to odours of higher nutrient plants but in ecologically realistic scenarios they use a variety of visual and olfactory cues, with a context‐dependent outcome that is not always selection of high nutrient food. Our results demonstrate the importance of testing the sensory abilities of herbivores in realistic multi‐sensory settings to understand their function in selective foraging.

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is a highly invasive pest, infesting many species of plants worldwide, but few studies have investigated the visual and olfactory cues associated with their foraging behaviors. In this study, the distance traveled by WFT to locate yellow cards using only visual cues and visual cues plus olfactory cues was studied first. Subsequently, preferences for colors (white, red, green, purple, yellow and blue) and patterns (triangle, rectangle, circle and flower-shape) over short distances were assessed with free-choice tests. Finally, as yellow was the most efficient color to catch WFT under laboratory conditions, the yellow flower-shape was used as the visual cue, and preferences between visual and olfactory cues were evaluated with dual choice tests. The results showed that the capture rate of WFT by visual cues decreased as selection distance increased, however capture rate remained higher with the addition of olfactory cues. The flower shape attracted the greatest number of WFT among all shapes tested. The combination of visual cues and extracted volatiles from flowering Medicago sativa L. attracted higher numbers of WFT than to the olfactory cues alone, however these were similar to visual cues alone. The presence of olfactory cues resulted in higher residence times by WFT than did the absence of olfactory cues. These results show the relative effects of visual and olfactory cues on the orientation of WFT to hosts and highlight that visual cues dominate selection behavior at short distances. These findings can be used in the development of efficient trapping products and management strategies for thrips.

Responses of Domestic Horses and Ponies to Single, Combined and Conflicting Visual and Auditory Cues

Nocturnal mammals have unique sensory adaptations to facilitate foraging at night. Owl monkeys (Aotus spp.) are pair-living nocturnal platyrrhines adept at capturing insect prey under low-light conditions. Owl monkeys use acoustic and chemical cues in intraspecific communication and use olfaction to detect fruit as they forage. We conducted an experiment to determine which cues (auditory, olfactory, and visual) Aotus nancymaae rely upon when foraging for insects. We scored the behavior of 23 captive owl monkeys during a series of trials in which monkeys were provided sensory boxes with insect cues either present (experimental box) or absent (control box). Each cue was tested alone and in combination with all other cues (multimodal cues). We used generalized linear mixed models to determine which cues elicited the greatest behavioral response. Owl monkeys approached and spent more time near experimental boxes than control boxes. Male owl monkeys were quicker than their female partners to approach the sensory boxes, suggesting that males may be less neophobic than females. The owl monkeys exhibited behaviors associated with olfaction and foraging (e.g., sneezing, trilling) during trials with multimodal cues and when only olfactory cues were present. When only visual or auditory cues were present, owl monkeys exhibited fewer foraging-related behaviors. After approaching a sensory box, however, they often touched boxes containing visual cues. A. nancymaae may rely on olfactory cues at night to detect a food source from several meters away and then rely more on visual cues once they are closer to the food source. Their use of sensory cues during insect foraging differs from nocturnal strepsirrhines, possibly reflecting physiological constraints associated with phylogeny, given that owl monkeys evolved nocturnality secondarily from a more recent diurnal ancestor.

Oligolectic bees collect pollen from only a few related plant taxa, and our understanding of both the bees' innate and learned behavior in host-plant recognition is incomplete. For the oligolectic bee Chelostoma rapunculi, whose host plants are within Cam- panula, we conducted choice tests on foraging-naive individuals to investigate the bee's innate preference for visual and olfactory floral cues of its host plants over those of nonhost plants. In addition, we tested both foraging-naive and foraging-experienced individuals to determine the relative importance of these 2 sensory modalities in the bee's innate and learned host-flower location. Visual and olfactory cues of Campanula trachelium flowers, both separately and combined, attracted significantly more foraging-naive bees than equivalent cues of nonhost plants. Furthermore, for both foraging-naive and -experienced bees, the visual cues of host plants were more attractive than the olfactory ones, and the 2 cues combined attracted more bees than either alone. In foraging- naive bees, visual and olfactory cues alone elicited almost exclusively approaches, whereas after the bees gained foraging experi- ence, landings became more frequent in response to visual cues but not to olfactory cues; in both bee groups, the combination of visual and olfactory cues was most effective in promoting landings. We conclude that Ch. rapunculi has an innate preference for the floral cues of its host plants over those of nonhost species and that both foraging-naive and foraging-experienced bees integrate visual and olfactory cues to find their host flowers, with a slightly greater reliance on visual cues in bees with foraging experience.

The effects of visual, auditory, and mixed cues on choice reaction in Parkinson's disease

Objective: To evaluate the effects of auditory and visual cues on gait initiation in people with Parkinson's disease. Subjects: Fourteen subjects with Parkinson's disease were recruited from community support groups, seven of whom reported having experienced freezing when walking. Design and setting: This study was a repeated measures analysis of gait initiation performance during a single visit to a university-based motion laboratory. Following baseline trials, auditory and visual cue conditions were presented in random order. The auditory cues were rhythmic sounds with an interval matching the subject's average step time. The visual cues were high-contrast transverse lines on the floor adjusted for the subject's first step length and overall height. Main measures: Kinematic recordings enabled calculation of the timing and length of steps as well as overall velocity. The timing and magnitude of weight shift and push-off force were obtained from a force platform. Results: The magnitudes of first and second step lengths, of push-off force and of overall gait velocity were significantly greater in the visual cue condition than in the baseline condition, whereas there was no significant effect of auditory cue on these measures. Neither cue had any significant effect on the timing of key events in gait initiation. Conclusions: Transverse line visual cues enable people with Parkinson's disease to begin walking with longer steps, greater push-off force and higher velocity. Auditory cues that others have shown to improve aspects of gait in people with Parkinson's disease do not appear to have any systematic effect on the first two steps of gait initiation.

Many studies have looked at how dogs respond to human communicative information. Here, we examined which human communicative factors were important in influencing dogs’ responses. Eleven healthy pet dogs with no apparent aggressive behaviour toward people were recruited. Five sensory conditions (all cues presented; either a visual, an auditory, or an olfactory cue presented; no cues presented) were provided three times randomly to each dog during the tests. All tests were video recorded, and both the dogs’ behaviour and time taken to reach the person when she presented each of the sensory cue conditions were observed. Total rates of reaching the person were as follows: 97.0% (all cues), 87.9% (auditory cues), 84.4% (visual cues), 84.4% (olfactory cues), and 69.7% (no cues). The time taken for the dog to notice the person in the box and then obtain a reward from her differed among the five conditions: all cues (6.00 ± 0.32 s) and visual cues (6.02 ± 0.91 s) were significantly faster than auditory cues (18.56 ± 9.57 s) and no cues (26.55 ± 11.72 s). Thus the type of information input was important in recognition of the person by the dogs and influenced the dogs’ response times; visual cues appeared advantageous in confirming the person’s presence.