Drivers of food choice among women living in informal settlements in Nairobi, Kenya.

Suboptimal diets drive the multiple burdens of malnutrition among women living in informal settlements. Women's food choices have important implications for their health, as well as that of their families. The purpose of this study was to examine how food choice decisions might differ across different age groups of women living in informal settlements in Nairobi, Kenya. Using in-depth interviews which incorporated a free-listing task, we determined the factors influencing food choice decisions in women in two informal settlements, Kibera and Mukuru. Among women in all age groups, we found income and food price to be the most salient factors influencing food choice decisions. Differences across age groups regarding food choice considerations included individual preference and quality being more salient factors amongst younger women while household preferences were more salient among older women. Women also reported making trade-offs between food affordability and other factors including time and nutrition, which led to sub-optimal diets. Our findings suggest that interventions in these settings may need to be tailored to specific age groups. Additionally, interventions may need to target both individual factors and the external food environment to help women overcome the trade-offs they often find themselves making in food choice decisions.

A focused ethnographic study on the role of health and sustainability in food choice decisions.

In the United States, typical dietary patterns are not necessarily healthy and sustainable. In order to shift diets, we need to provide support to individuals in a way that reflects what matters most to them. In this study, we aimed to identify the considerations that are most important to individuals regarding food-related decisions, and to determine how those considerations relate to specific foods, with a focus on health and environmental sustainability. In a sequential mixed-methods design, we first conducted 27 semi-structured interviews with participants in California and Nebraska. These interviews included a free-listing activity, where we used a technical construct of salience, Smith's S Index, to identify the considerations that were most important to our participants. We followed up with 20 of those participants to complete a pile-sorting survey, where participants sorted and rated 42 food items for price, taste, health, convenience, familiarity, and environmental impact. Our findings showed that the most salient considerations cited by our participants were price, health, taste, and time. There was consensus for how participants rated the foods for price, taste, convenience, and familiarity. However, there was only weak consensus for how participants rated the foods for health impact, and no consensus for how participants rated the foods for environmental impact. There was also disagreement on how to sort new plant-based products intended to replace or substitute meat and other animal-based foods. These findings have implications for how to communicate about healthy and sustainable diets. They highlight conflicting considerations, disagreement in classification of new products, and limited consensus for perceived health and environmental impact of foods, which present challenges to the achievement of diets that are healthy and environmentally sustainable in the United States.

Derivation and Demonstration of a New Metric for Multitasking Performance.

OBJECTIVE: We proposed and demonstrate a theory-driven, quantitative, individual-level estimate of the degree to which cognitive processes are degraded or enhanced when multiple tasks are simultaneously completed. BACKGROUND: To evaluate multitasking, we used a performance-based cognitive model to predict efficient performance. The model controls for single-task performance at the individual level and does not depend on parametric assumptions, such as normality, which do not apply to many performance evaluations. METHODS: Twenty participants attempted to maintain their isolated task performance in combination for three dual-task and one triple-task scenarios. We utilized a computational model of multiple resource theory to form hypotheses for how performance in each environment would compare, relative to the other multitask contexts. We assessed if and to what extent multitask performance diverged from the model of efficient multitasking in each combination of tasks across multiple sessions. RESULTS: Across the two sessions, we found variable individual task performances but consistent patterns of multitask efficiency such that deficits were evident in all task combinations. All participants exhibited decrements in performing the triple-task condition. CONCLUSIONS: We demonstrate a modeling framework that characterizes multitasking efficiency with a single score. Because it controls for single-task differences and makes no parametric assumptions, the measure enables researchers and system designers to directly compare efficiency across various individuals and complex situations. APPLICATION: Multitask efficiency scores offer practical implications for the design of adaptive automation and training regimes. Furthermore, a system may be tailored for individuals or suggest task combinations that support productivity and minimize performance costs.

Who knows what: An exploration of the infant feeding message environment and intracultural differences in Port-au-Prince, Haiti.

Worldwide, mothers with young children receive many messages about infant feeding. Some messages are generated by health providers and others by the households, communities, and social contexts in which women live. We aimed to determine the scope of infant feeding messages in urban Haiti and to examine intracultural differences in salience of these messages and their alignment with international guidelines. We applied the method of free listing with 13 health workers and 15 human immunodeficiency virus (HIV)-infected and 15 HIV-uninfected mothers with infants 0-6 months old at Groupe Haïtien d'Etude du Sarcome de Kaposi et des Infections Opportunistes in Port-au-Prince, Haiti. Participants listed all messages women receive about infant feeding and specifically about HIV and infant feeding. Message salience was determined by frequency of mention and recall order; messages were coded for key themes. For all groups, the World Health Organization infant feeding recommendations were salient, especially those related to exclusive breastfeeding. Messages across all groups focused on infant health outcomes, with less emphasis on maternal outcomes. Cultural beliefs were also elicited and showed higher salience for mothers than health workers, particularly for consequences of poor maternal nutrition. Health workers' free lists were poorly correlated to those of mothers, whereas those of mothers were highly correlated, regardless of HIV status. Inasmuch as many salient messages were culturally generated, and differences existed between mothers and health workers, we conclude that it is important for health workers to acknowledge the broader infant feeding message environment, and discrepancies within that environment, to address successes and failures in the messages reaching mothers, given potential consequences for mothers' breastfeeding behaviours.

An extension of the shifted Wald model of human response times: Capturing the time dynamic properties of human cognition : Trial-varying Wald model.

Despite the ubiquitous nature of evidence accumulation models in cognitive and experimental psychology, there has been a comparatively limited uptake of such techniques in the applied literature. While quantifying latent cognitive processing properties has significant potential for applied domains such as adaptive work systems, accumulator models often fall short in practical applications. Two primary reasons for these shortcomings are the complexities and time needed for the application of cognitive models, and the failure of current models to capture systematic trial-to-trial variability in parameters. In this manuscript, we develop a novel, trial-varying extension of the shifted Wald model to address these concerns. By leveraging conjugate properties of the Wald distribution, we derive computationally efficient solutions for threshold and drift parameters which can be updated instantaneously with new data. The resulting model allows the quantification of systematic variation in latent cognitive parameters across trials and we demonstrate the utility of such analyses through simulations and an exemplar application to an existing data set. The analytic nature of our solutions opens the door for real-world applications, significantly extending the reach of computational models of behavioral responses.

Predictions of task using neural modeling.

Introduction: A well-designed brain-computer interface (BCI) can make accurate and reliable predictions of a user's state through the passive assessment of their brain activity; in turn, BCI can inform an adaptive system (such as artificial intelligence, or AI) to intelligently and optimally aid the user to maximize the human-machine team (HMT) performance. Various groupings of spectro-temporal neural features have shown to predict the same underlying cognitive state (e.g., workload) but vary in their accuracy to generalize across contexts, experimental manipulations, and beyond a single session. In our work we address an outstanding challenge in neuroergonomic research: we quantify if (how) identified neural features and a chosen modeling approach will generalize to various manipulations defined by the same underlying psychological construct, (multi)task cognitive workload. Methods: To do this, we train and test 20 different support vector machine (SVM) models, each given a subset of neural features as recommended from previous research or matching the capabilities of commercial devices. We compute each model's accuracy to predict which (monitoring, communications, tracking) and how many (one, two, or three) task(s) were completed simultaneously. Additionally, we investigate machine learning model accuracy to predict task(s) within- vs. between-sessions, all at the individual-level. Results: Our results indicate gamma activity across all recording locations consistently outperformed all other subsets from the full model. Our work demonstrates that modelers must consider multiple types of manipulations which may each influence a common underlying psychological construct. Discussion: We offer a novel and practical modeling solution for system designers to predict task through brain activity and suggest next steps in expanding our framework to further contribute to research and development in the neuroergonomics community. Further, we quantified the cost in model accuracy should one choose to deploy our BCI approach using a mobile EEG-systems with fewer electrodes-a practical recommendation from our work.

Food Environments and Their Influence on Food Choices: A Case Study in Informal Settlements in Nairobi, Kenya.

The food environments that people have access to shape their food choices. The purpose of this study was to use mixed methods to characterize the external food environment in informal settlements in Nairobi, Kenya and to examine the individual factors that influence the way in which women interact with those environments to make food choices. We used a combination of food environment assessments (vendor mapping, collection of food prices, food quality assessments) and five focus group discussions with women (n = 26) in four villages within two informal settlements in Nairobi (Mukuru and Kibera) to better understand the drivers of food choice. We found a large number (n = 1163) of vendors selling a variety of food within the settlements. The highest number of vendors were selling fruits and/or vegetables; however, there was limited diversity of fruits available. Animal-source foods were considered relatively expensive as compared to plant-based foods, including prepared fried snacks. We found that the way women interacted with their food environments was influenced by individual factors such as income, time, convenience, and preferences. Our findings suggest that interventions targeting both the external food environment as well as individual factors such as income will be necessary to support healthy diets among low-income populations living in informal settlements in Kenya.

Dietary Risk Factors for Cardiovascular Disease among Low-Income Haitian Adults: Findings from a Population-Based Cohort.

Poor diets are responsible for a large burden of noncommunicable disease (NCD). The prevalence of modifiable dietary risk factors is rising in lower-income countries such as Haiti, along with increasing urbanization and shifts to diets high in sugar, salt, and fat. We describe self-reported dietary patterns (intake of fruits, vegetables, fried food, sugar-sweetened beverages, and added salt and oil) among a population-based cohort of low-income adults in Port-au-Prince and assess for associated sociodemographic factors (age, sex, income, education, body mass index). Among 2989 participants, the median age was 40 years, and 58.0% were women. Less than 1% met the World Health Organization recommendation of at least five servings/day of fruits and vegetables. Participants consumed fried food on average 1.6 days/week and sugar-sweetened beverages on average 4.7 days/week; young males of low socioeconomic status were the most likely to consume these dietary risk factors. The vast majority of participants reported usually or often consuming salt (87.1%) and oil (86.5%) added to their meals eaten at home. Our findings underscore the need for public health campaigns, particularly those targeting young males and household cooks preparing family meals at home, to improve dietary patterns in Haiti in order to address the growing NCD burden.

Why Marginalization, Not Vulnerability, Can Best Identify People in Need of Special Medical and Nutrition Care.

In a 2015 paper published in the Journal of Bioethical Inquiry, bioethicist Henk ten Have identifies vulnerability as a "controversial topic in bioethics" and argues that bioethical attention to vulnerability comes at the expense of sufficient attention to the social structures that shape human life. In this paper, we situate ten Have's argument within the broader bioethical literature, emphasizing how critiques of vulnerability can enrich approaches in clinical settings, including in nutrition, where the concept of vulnerability is not foreign (eg, children are often labeled members of a vulnerable group). We use an example of food (in)security to show how reframing vulnerability to capture "layers of marginalization" can help clinicians and organizations more clearly identify who is most in need, develop solutions for what should be done, and determine how and by whom those solutions should be implemented.

Capturing Changes in HIV-Infected Breastfeeding Mothers' Cognitive Processes from Before Delivery to 5 Months Postpartum: An Application of the Pile-Sorting Technique in Haiti.

BACKGROUND: The cognitive processes involved in individuals' perceptions and prioritization of information, and how these change with experience or exposure to interventions, are rarely examined in the evaluation of nutrition interventions. Exclusive breastfeeding counseling is a common infant and young-child feeding intervention and is used to promote HIV-free survival in the prevention of mother-to-child transmission programs. However, it is often designed without adequate attention to the changes in mothers' perceptions over the course of their early breastfeeding experiences. OBJECTIVE: The aim of this study was to identify HIV-infected breastfeeding mothers' cognitive structure (their organization of messages and ideas) of infant feeding messages and to characterize whether their cognitive organization of infant feeding messages changed from pregnancy through the first 5 mo postpartum. METHODS: With the use of semistructured interviews and the cognitive mapping technique of pile sorting, we interviewed 30 HIV-infected breastfeeding mothers in Port-au-Prince, Haiti. We asked them to sort and rate 18 infant feeding messages 3 times (during pregnancy, 0- to 1-mo postpartum, and 3- to 5-mo postpartum). We analyzed their responses by using multidimensional scaling, property fitting, and partition analyses. RESULTS: At all 3 visits, we found consistency in women's cognitive mapping of messages. For example, mothers consistently differentiated messages pertinent for exclusive breastfeeding compared with those that pertained to other practices. However, subtle variations in mothers' cognition over time were also evident, particularly at 0- to 1-mo postpartum, when message proximity was tightly clustered compared with the earlier and later periods. CONCLUSIONS: We conclude that mothers share a common cognitive organization of infant feeding messages and that this organization changes over time. Attention to variations in cognition can support context-sensitive, patient-centered counseling by practitioners and improve the effectiveness of nutrition interventions. Pile sorting is an efficient, systematic technique to examine cognitive processes related to health and nutrition.

The perceptual processing of fused multi-spectral imagery.

Multi-spectral imagery can enhance decision-making by supplying multiple complementary sources of information. However, overloading an observer with information can deter decision-making. Hence, it is critical to assess multi-spectral image displays using human performance. Accuracy and response times (RTs) are fundamental for assessment, although without sophisticated empirical designs, they offer little information about why performance is better or worse. Systems factorial technology (SFT) is a framework for study design and analysis that examines observers' processing mechanisms, not just overall performance. In the current work, we use SFT to compare a display with two sensor images alongside each another with a display in which there is a single composite image. In our first experiment, the SFT results indicated that both display approaches suffered from limited workload capacity and more so for the composite imagery. In the second experiment, we examined the change in observer performance over the course of multiple days of practice. Participants' accuracy and RTs improved with training, but their capacity limitations were unaffected. Using SFT, we found that the capacity limitation was not due to an inefficient serial examination of the imagery by the participants. There are two clear implications of these results: Observers are less efficient with multi-spectral images than single images and the side-by-side display of source images is a viable alternative to composite imagery. SFT was necessary for these conclusions because it provided an appropriate mechanism for comparing single-source images to multi-spectral images and because it ruled out serial processing as the source of the capacity limitation.