Testing the channel-based model of duration perception

The channel-based model of duration perception postulates the existence of neural mechanisms that respond selectively to a narrow range of stimulus durations centred on their preferred duration (Heron et al Proceedings of the Royal Society B 279 690–698). In principle the channel-based model could
explain recent reports of adaptation-induced, visual duration compression effects (Johnston et al Current Biology 16 472–479; Curran and Benton Cognition 122 252–257); from this perspective duration compression is a consequence of the adapting stimuli being presented for a longer duration than the test stimuli. In the current experiment observers adapted to a sequence of moving random dot patterns at the same retinal position, each 340ms in duration and separated by a variable (500–1000ms) interval. Following adaptation observers judged the duration of a 600ms test stimulus at the same location. The test stimulus moved in the same, or opposite, direction as the adaptor. Contrary to the channel-based
model’s prediction, test stimulus duration appeared compressed, rather than expanded, when it moved in the same direction as the adaptor. That test stimulus duration was not distorted when moving in the opposite direction further suggests that visual timing mechanisms are influenced by additional neural processing associated with the stimulus being timed.

Quantifying consumer portion control practices. A cross-sectional study

The use of portion control practices has rarely been quantified. The present study aimed to: (1) explore which portion control practices are actually used by the general population and their association with cognitive restraint, demographic background and general health interest (GHI), and (2) examine how the usage of portion control practices predicts the estimated consumption of an energy dense food (i.e. pizza). Twenty-two portion control practices were rated in terms of their frequency of use from 'never' to 'very often' by a representative sample of 1012 consumers from the island of Ireland. Three factors were extracted and named: measurement-strategy scale, eating-strategy scale, and purchasing-strategy scale. The eating-strategy scale score was the highest, while the measurement-strategy scale carried the lowest frequency score. For each strategy scale score, the strongest predictor was GHI, followed by gender. Having higher GHI and being female were independently associated with more frequent portion control. Both the eating-strategy scale score and the purchasing-strategy scale score were negatively associated with pizza portion size consumption estimates. In conclusion, while this study demonstrates that the reported use of portion control practices is low, the findings provide preliminary evidence for their validity. Further studies are needed to explore how portion control practices are used in different kinds of portion size decisions and what their contribution is to the intake of food over an extended period of time.

Change in psychological distress in longer-term oesophageal cancer carers: are clusters of illness perception change a useful determinant?

Objective: This study provides a longitudinal assessment of distress in longer-term oesophageal cancer carers, while examining illness perception schema as a possible determinant of change in distress over time.
Methods: Oesophageal cancer carers (n=171), 48-months post-diagnosis, were assessed at baseline and 12-months later with the Illness Perception Questionnaire-Revised, Cancer Coping Questionnaire, Hospital Anxiety and Depression Scale and Concerns About Recurrence Scale.
Results: Findings report deterioration from normal to probable anxiety in 35.7% of carers and probable depression in 28.7% carers over time. Fear of recurrence remained stable. Changes in control, consequence and cause beliefs were identified as key determinants of a change in psychological morbidity.
Conclusions: Illness beliefs appear to be valuable targets for psychological intervention to improve wellbeing among carers of people with oesophageal cancer.

Health care professionals’ experience, understanding and perception of need of advanced cancer patients with cachexia and their families: The benefits of a dedicated clinic.

Background: Cachexia has been defined as an on-going loss of skeletal muscle mass that cannot be fully reversed by conventional nutritional support. It can be found in up to 80% of patients with advanced cancer and has profound psycho-social consequences for patients and their families. There is a paucity of studies examining the role and experience of healthcare professionals in relation to cachexia and existing studies suggest that professional staff have limited understanding and do not intervene effectively.
Aim: To identify barriers and facilitators to good practice in cachexia care in order to inform future developments in service provision.
Design: An exploratory qualitative study was conducted employing semi-structured interviews with a range of healthcare professionals recruited purposefully from an Australian hospital. Interviews were conducted in private rooms within the hospital.
Setting/participants: A range of healthcare professionals responsible for cancer care were recruited from a large Australian teaching hospital.
Results: Interviews were conducted with 8 healthcare professionals responsible for delivering cancer care. Four themes were identified: formal and informal education, knowledge and understanding, truth telling in cachexia and palliative care, and, a multi-disciplinary approach. Findings show how improved knowledge and understanding across a staff body can lead to improved staff confidence and a willingness to address cancer cachexia and its consequences with patients and their families.
Conclusion: Comparison with previous studies illustrates the importance of improving knowledge and understanding about cachexia and how this can contribute to staff having the skills and experience necessary to address cachexia and provide an improved care experience for patients and carers.

Adapting to time: duration channels do not mediate human time perception

Accurately encoding the duration and temporal order of events is essential for survival and important to everyday activities, from holding conversations to driving in fast flowing traffic. Although there is a growing body of evidence that the timing of brief events (< 1s) is encoded by modality-specific mechanisms, it is not clear how such mechanisms register event duration. One approach gaining traction is a channel-based model; this envisages narrowly-tuned, overlapping timing mechanisms that respond preferentially to different durations. The channel-based model predicts that adapting to a given event duration will result in overestimating and underestimating the duration of longer and shorter events, respectively. We tested the model by having observers judge the duration of a brief (600ms) visual test stimulus following adaptation to longer (860ms) and shorter (340ms) stimulus durations. The channel-based model predicts perceived duration compression of the test stimulus in the former condition and perceived duration expansion in the latter condition. Duration compression occurred in both conditions, suggesting that the channel-based model does not adequately account for perceived duration of visual events.

Branding strategies for high technology products: The effects of consumer and product innovativeness

Choice of an appropriate branding strategy is a critical determinant of new product success. Prior work on fast-moving-consumer-goods (FMCG) prescribes that new products carry new (vs. existing) brand names to appeal to earlier adopters - a critical target for new products. However, such a prescription may not be prudent for high-technology (HT) products, as they often involve considerably more consumer perceived risk than FMCG. By drawing on Dowling and Staelin's (1994) framework of perceived-risk handling, we propose that both earlier and later adopters will favor existing brands to cope with the elevated risk associated with an innovative HT product. Two studies - one conducted in an experimental setting and the other in a field setting - support the proposition that both earlier and later adopters respond more favorably to existing (vs. new) brands on innovative HT products.

Psychological determinants of consumer acceptance of personalised nutrition in 9 European countries

OBJECTIVE: To develop a model of the psychological factors which predict people's intention to adopt personalised nutrition. Potential determinants of adoption included perceived risk and benefit, perceived self-efficacy, internal locus of control and health commitment.

METHODS: A questionnaire, developed from exploratory study data and the existing theoretical literature, and including validated psychological scales was administered to N=9381 participants from 9 European countries (Germany, Greece, Ireland, Poland, Portugal, Spain, the Netherlands, the UK, and Norway).

RESULTS: Structural equation modelling indicated that the greater participants' perceived benefits to be associated with personalised nutrition, the more positive their attitudes were towards personalised nutrition, and the greater their intention to adopt it. Higher levels of nutrition self-efficacy were related to more positive attitudes towards, and a greater expressed intention to adopt, personalised nutrition. Other constructs positively impacting attitudes towards personalised nutrition included more positive perceptions of the efficacy of regulatory control to protect consumers (e.g. in relation to personal data protection), higher self-reported internal health locus of control, and health commitment. Although higher perceived risk had a negative relationship with attitude and an inverse relationship with perceived benefit, its effects on attitude and intention to adopt personalised nutrition was less influential than perceived benefit. The model was stable across the different European countries, suggesting that psychological factors determining adoption of personalised nutrition have generic applicability across different European countries.

CONCLUSION: The results suggest that transparent provision of information about potential benefits, and protection of consumers' personal data is important for adoption, delivery of public health benefits, and commercialisation of personalised nutrition.

Living to the range limit: consumer isotopic variation increases with environmental stress

Background: Theoretically, each species’ ecological niche is phylogenetically-determined and expressed spatially as the species’ range. However, environmental stress gradients may directly or indirectly decrease individual performance, such that the precise process delimiting a species range may not be revealed simply by studying abundance patterns. In the intertidal habitat the vertical ranges of marine species may be constrained by their abilities to tolerate thermal and desiccation stress, which may act directly or indirectly, the latter by limiting the availability of preferred trophic resources. Therefore, we expected individuals at greater shore heights to show greater variation in diet alongside lower indices of physiological condition.

Methods: We sampled the grazing gastropod Echinolittorina peruviana from the desert coastline of northern Chile at three shore heights, across eighteen regionally-representative shores. Stable isotope values (δ13C and δ15N) were extracted from E. peruviana and its putative food resources to estimate Bayesian ellipse area, carbon and nitrogen ranges and diet. Individual physiological condition was tracked by muscle % C and % N.

Results: There was an increase in isotopic variation at high shore levels, where E. peruviana’s preferred resource, tide-deposited particulate organic matter (POM), appeared to decrease in dietary contribution, and was expected to be less abundant. Both muscle % C and % N of individuals decreased with height on the shore.

Discussion: Individuals at higher stress levels appear to be less discriminating in diet, likely because of abiotic forcing, which decreases both consumer mobility and the availability of a preferred resource. Abiotic stress might be expected to increase trophic variation in other selective dietary generalist species. Where this coincides with a lower physiological condition, this may be a direct factor in setting their range limit.

Development of the Consumer Refrigerator Safety Questionnaire (CRSQ): A Measure of Consumer Perceptions and Practices

Food preparation and storage behaviors in the home deviating from the ‘best practice’ food safety recommendations may result in food borne illnesses. Currently, there are limited tools available to fully evaluate the consumer knowledge, perceptions and behavior in the area of refrigerator safety. The current study aimed to develop a valid and reliable tool in the form of a questionnaire (CFSQCRSQ) for assessing systematically all these aspects. Items relating to refrigerator safety knowledge (n=17), perceptions (n=46), reported behavior (n=30) were developed and pilot tested by an expert reference group and various consumer groups to assess face and content validity (n=20), item difficulty and item consistency (n=55) and construct validity (n=23). The findings showed that the CFSQCRSQ has acceptable face and content validity with acceptable levels of item difficulty. Item consistency was observed for 12 out of 15 refrigerator safety knowledge. Further, all five of the subscales of consumer perceptions of refrigerator safety practices relating to risk of developing foodborne disease food poisoning showed acceptable internal consistency (Cronbach’s α value > 0.8). Construct validity of the CFSQCRSQ was shown to be very good (p=0.022). The CFSQCRSQ exhibited acceptable test-retest reliability at 14 days with majority of knowledge items (93.3%) and reported behavior items (96.4%) having correlation coefficients of greater than 0.70. Overall, the CFSQCRSQ was deemed valid and reliable in assessing refrigerator safety knowledge and behavior and therefore has the potential for future use in identifying groups of individuals at increased risk of deviating from recommended refrigerator safety practices as well as the assessment of refrigerator safety knowledge, behavior for use before and after an intervention.