No link between handedness and spatial navigation: evidence from over 400 000 participants in 41 countries.

There is an active debate concerning the association of handedness and spatial ability. Past studies used small sample sizes. Determining the effect of handedness on spatial ability requires a large, cross-cultural sample of participants and a navigation task with real-world validity. Here, we overcome these challenges via the mobile app Sea Hero Quest. We analysed the navigation performance from 422 772 participants from 41 countries and found no reliable evidence for any difference in spatial ability between left- and right-handers across all countries. A small but growing gap in performance appears for participants over 64 years old, with left-handers outperforming right-handers. Further analysis, however, suggests that this gap is most likely due to selection bias. Overall, our study clarifies the factors associated with spatial ability and shows that left-handedness is not associated with either a benefit or a deficit in spatial ability.

Cultural determinants of the gap between self-estimated navigation ability and wayfinding performance: evidence from 46 countries.

Cognitive abilities can vary widely. Some people excel in certain skills, others struggle. However, not all those who describe themselves as gifted are. One possible influence on self-estimates is the surrounding culture. Some cultures may amplify self-assurance and others cultivate humility. Past research has shown that people in different countries can be grouped into a set of consistent cultural clusters with similar values and tendencies, such as attitudes to masculinity or individualism. Here we explored whether such cultural dimensions might relate to the extent to which populations in 46 countries overestimate or underestimate their cognitive abilities in the domain of spatial navigation. Using the Sea Hero Quest navigation test and a large sample (N = 383,187) we found cultural clusters of countries tend to be similar in how they self-rate ability relative to their actual performance. Across the world population sampled, higher self-ratings were associated with better performance. However, at the national level, higher self-ratings as a nation were not associated with better performance as a nation. Germanic and Near East countries were found to be most overconfident in their abilities and Nordic countries to be most under-confident in their abilities. Gender stereotypes may play a role in mediating this pattern, with larger national positive attitudes to male stereotyped roles (Hofstede's masculinity dimension) associated with a greater overconfidence in performance at the national level. We also replicate, with higher precision than prior studies, evidence that older men tend to overestimate their navigation skill more than other groups. These findings give insight into how culture and demographics may impact self-estimates of our abilities.

Entropy and a sub-group of geometric measures of paths predict the navigability of an environment.

Despite extensive research on navigation, it remains unclear which features of an environment predict how difficult it will be to navigate. We analysed 478,170 trajectories from 10,626 participants who navigated 45 virtual environments in the research app-based game Sea Hero Quest. Virtual environments were designed to vary in a range of properties such as their layout, number of goals, visibility (varying fog) and map condition. We calculated 58 spatial measures grouped into four families: task-specific metrics, space syntax configurational metrics, space syntax geometric metrics, and general geometric metrics. We used Lasso, a variable selection method, to select the most predictive measures of navigation difficulty. Geometric features such as entropy, area of navigable space, number of rings and closeness centrality of path networks were among the most significant factors determining the navigational difficulty. By contrast a range of other measures did not predict difficulty, including measures of intelligibility. Unsurprisingly, other task-specific features (e.g. number of destinations) and fog also predicted navigation difficulty. These findings have implications for the study of spatial behaviour in ecological settings, as well as predicting human movements in different settings, such as complex buildings and transport networks and may aid the design of more navigable environments.

Reported sleep duration reveals segmentation of the adult life-course into three phases.

Classically the human life-course is characterized by youth, middle age and old age. A wide range of biological, health and cognitive functions vary across this life-course. Here, using reported sleep duration from 730,187 participants across 63 countries, we find three distinct phases in the adult human life-course: early adulthood (19-33yrs), mid-adulthood (34-53yrs), and late adulthood (54+yrs). They appear stable across culture, gender, education and other demographics. During the third phase, where self-reported sleep duration increases with age, cognitive performance, as measured by spatial navigation, was found to have an inverted u-shape relationship with reported sleep duration: optimal performance peaks at 7 hours reported sleep. World-wide self-reported sleep duration patterns are geographically clustered, and are associated with economy, culture, and latitude.

Entropy of city street networks linked to future spatial navigation ability.

The cultural and geographical properties of the environment have been shown to deeply influence cognition and mental health1-6. Living near green spaces has been found to be strongly beneficial7-11, and urban residence has been associated with a higher risk of some psychiatric disorders12-14-although some studies suggest that dense socioeconomic networks found in larger cities provide a buffer against depression15. However, how the environment in which one grew up affects later cognitive abilities remains poorly understood. Here we used a cognitive task embedded in a video game16 to measure non-verbal spatial navigation ability in 397,162 people from 38 countries across the world. Overall, we found that people who grew up outside cities were better at navigation. More specifically, people were better at navigating in environments that were topologically similar to where they grew up. Growing up in cities with a low street network entropy (for example, Chicago) led to better results at video game levels with a regular layout, whereas growing up outside cities or in cities with a higher street network entropy (for example, Prague) led to better results at more entropic video game levels. This provides evidence of the effect of the environment on human cognition on a global scale, and highlights the importance of urban design in human cognition and brain function.

Planning paths to multiple targets: memory involvement and planning heuristics in spatial problem solving.

For large numbers of targets, path planning is a complex and computationally expensive task. Humans, however, usually solve such tasks quickly and efficiently. We present experiments studying human path planning performance and the cognitive processes and heuristics involved. Twenty-five places were arranged on a regular grid in a large room. Participants were repeatedly asked to solve traveling salesman problems (TSP), i.e., to find the shortest closed loop connecting a start location with multiple target locations. In Experiment 1, we tested whether humans employed the nearest neighbor (NN) strategy when solving the TSP. Results showed that subjects outperform the NN-strategy, suggesting that it is not sufficient to explain human route planning behavior. As a second possible strategy we tested a hierarchical planning heuristic in Experiment 2, demonstrating that participants first plan a coarse route on the region level that is refined during navigation. To test for the relevance of spatial working memory (SWM) and spatial long-term memory (LTM) for planning performance and the planning heuristics applied, we varied the memory demands between conditions in Experiment 2. In one condition the target locations were directly marked, such that no memory was required; a second condition required participants to memorize the target locations during path planning (SWM); in a third condition, additionally, the locations of targets had to retrieved from LTM (SWM and LTM). Results showed that navigation performance decreased with increasing memory demands while the dependence on the hierarchical planning heuristic increased.

What happened to long-term care in the health reform debate of 1993-1994? Lessons for the future.

During 1993 and 1994, the United States debated but did not enact major health care reform. Although the reform efforts focused on providing health coverage for the uninsured and controlling acute care costs, many proposals included substantial long-term care initiatives. President Clinton proposed creating a large home-care program for severely disabled people of all ages and all income groups, among several other initiatives. By stressing non-means-tested public programs, the president's plan was a major departure from the Medicaid-dominated financing system for long-term care. In designing the long-term care component, the Clinton administration addressed many of the basic policy choices that must be decided in all reform efforts, including whether initiatives should be limited to older people or cover people of any age, how to balance institutional and noninstitutional care, whether to rely on government programs or on the private sector, and how to control costs. Analyzing the political and intellectual history of long-term care during the health reform debate provides lessons for future reform.

Consumer-directed home and community services programs in eight states: policy issues for older people and government.

This study assesses consumer-directed home and community services for older persons by examining public programs that serve this population in eight states. These programs give beneficiaries, rather than agencies, the power to hire, train, supervise, and fire workers. Most stakeholders interviewed, in addition to the quantitative research, indicate that many older beneficiaries want to and can manage their services, although significant issues arise for persons with cognitive impairments. Research results suggest better, or, at least, no worse, quality of life for beneficiaries when they direct their services, although quality of services remains a contentious issue. For workers, consumer-directed care has some disadvantages, including fewer fringe benefits. With exceptions, state agencies have not provided extensive consumer or worker support or aggressively regulated quality of care.

Can social insurance for long-term care work? The experience of Germany.

In 1994 Germany enacted a universal-coverage social insurance program for long-term care to largely replace its means-tested system. The program has achieved many of its stated policy goals: shifting the financial burden of long-term care off the states and municipalities; expanding home and community-based services; lessening dependence on means-tested welfare; and increasing support of informal caregivers. Many of these goals were reached without exploding caseloads or uncontrolled expenditures. We examine the German long-term insurance program, focusing on issues of financing, eligibility and assessment, benefits, availability of services, and quality assurance.

Public and private responsibilities: home- and community-based services in the United Kingdom and Germany.

In the late 1980s, the United States, the United Kingdom, and Germany had roughly the same system of financing and delivering long-term care. In contrast to the United States, the United Kingdom and Germany enacted radical reform. The United Kingdom converted an open-ended, means-tested national entitlement for institutional care to a block grant to local governments, whereas Germany enacted a nationally uniform, non-means-tested social insurance program. This article analyzes the postreform experience of the United Kingdom and Germany with respect to issues of financing, assessment and case management, and the availability of home- and community-based services. Policy implications for the United States are developed.

Controlling the supply of long-term care providers in thirteen states.

Many states have responded to growing Medicaid long-term care expenditures by limiting the number of long-term care providers through certificate-of-need (CON) programs and moratoriums on new construction or certification for participation in the Medicaid program. This article focuses on the use of these policies in 13 states. Most of the 13 states control the supply of nursing home beds and hospital conversions with CONs or moratoriums, but they are struggling to adapt the role of supply policy to the growth of home health and residential care. As an increasing proportion of Medicaid long-term care spending goes to these nursing home alternatives, supply policy needs to keep pace with the changing provider market and the changing demographics of the consumer market if it hopes to ensure access to long-term care and control Medicaid expenditures.

State policy on long-term care for the elderly.

In the thirteen Assessing the New Federalism states, strategies to control the rate of increase in long-term care spending are extremely varied, especially in comparison with acute care's single-minded focus on managed care. States use three broad strategies: offsetting state spending with increased private and federal contributions, making the delivery system more efficient, and using traditional cost-control mechanisms, including controlling the nursing home bed supply and cutting Medicaid reimbursement rates.

Can Medicaid long-term care expenditures for the elderly be reduced?

During 1995 and 1996 Congress debated numerous proposals that would dramatically reduce the rate of growth in Medicaid spending, initiatives that inevitably would affect long-term care for the elderly. There are three broad strategies that states might use to control long-term care spending-bring more private resources into the long-term care system to offset Medicaid's expenditures, reform the delivery system so that care can be provided more cheaply, and reduce Medicaid eligibility, reimbursement, and service coverage. Based on the available research evidence, there is little evidence to suggest that large savings are possible without adversely affecting beneficiaries' eligibility, access to services, and quality of care received.

Financing reform for long-term care: strategies for public and private long-term care insurance.

The way the nation provides for the financing and delivery of long-term care is badly in need of reform. The principal options for change are private insurance, altering Medicaid, and public long-term care insurance. This article uses the Brookings-ICF Long-Term Care Financing Model to evaluate each of these options in terms of affordability, distribution of benefits, and ability to reduce catastrophic out-of-pocket costs. So long as private insurance is aimed at the elderly, its market penetration and ability to finance long-term care will remain severely limited. Affordability is a major problem. Selling to younger persons could solve the affordability problem, but marketing is extremely difficult. Liberalizing Medicaid could help solve the problems of long-term care, but there is little public support for means-tested programs. Finally, universalistic public insurance programs do well in meeting the goals of long-term care reform, but all social insurance programs are expensive and seem politically infeasible in the current political environment.