Publications by authors named "Luckman A"

Violations of transitive preference can be accounted for by both the noncompensatory lexicographic semiorder heuristic and the compensatory additive difference model. However, the two have not been directly compared. Here, we fully develop a simplified additive difference (SAD) model, which includes a graphical analysis of precisely which parameter values are consistent with adherence to, or violation of, transitive preference, as specified by weak stochastic transitivity (WST) and triangle inequalities (TI).

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Article Synopsis
  • Real-world decisions in fields like finance, environment, and health are significantly shaped by individual experiences, prompting renewed interest in the study of Decision-making under Experience (DfE) over the past two decades.
  • *To improve the standard experimental design in DfE research, it's suggested to incorporate more complex choice scenarios, delayed feedback, and social interactions, reflecting the intricacies of real-life environments.
  • *Integrating cognitive processes, such as how we perceive experiences and utilize memory, can enhance our understanding and prediction of DfE, potentially improving methodologies for better decision-making and policy formulation.*
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We provide novel support for Query Theory, a reason-based decision framework, extending it to multialternative choices and applying it to the classic phenomenon known as the attraction effect. In Experiment 1 (N = 261), we generalised the two key metrics used in Query Theory from binary to multialternative choices and found that reasons supporting the target option were generated earlier and in greater quantity than those supporting the competitor, as predicted by the theory. In Experiment 2 (N = 703), we investigated the causal relationships between reasoning and choices by exogenously manipulating the order in which participants generated their reasons.

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Decades of work have been dedicated to developing and testing models that characterize how people make inter-temporal choices. Although parameter estimates from these models are often interpreted as indices of latent components of the choice process, little work has been done to examine their reliability. This is problematic because estimation error can bias conclusions that are drawn from these parameter estimates.

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Understanding and responding to the voice of people receiving mental health and addiction services is imperative. The policy environment in Aotearoa New Zealand is shifting to place greater value on gathering input and feedback from people accessing health services. This viewpoint article looks at the use of patient reported experience measures (PREMs), with a particular focus on mental health and addiction services and the development of Mārama Real-Time Feedback (Mārama).

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To reduce the spread of COVID-19, governments around the world have recommended or required minimum physical distancing between individuals, as well as either mandating or recommending the use of face coverings (masks) in certain circumstances. When multiple risk reduction activities can be adopted, people may engage in risk compensation by responding to a reduced (perceived) risk exposure due to one activity by increasing risk exposure due to another. We tested for risk compensation in two online experiments that investigated whether either wearing a mask or seeing others wearing masks reduced physical distancing.

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Risky intertemporal choices involve choosing between options that can differ in outcomes, their probability of receipt, and the delay until receipt. To date, there has been no attempt to systematically test, compare, and evaluate theoretical models of such choices. We contribute to theory development by generating predictions from 7 models for 3 common manipulations-magnitude, certainty, and immediacy-across 6 different types of risky intertemporal choices.

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Suture zones are abundant on Antarctic ice shelves and widely observed to impede fracture propagation, greatly enhancing ice-shelf stability. Using seismic and radar observations on the Larsen C Ice Shelf of the Antarctic Peninsula, we confirm that such zones are highly heterogeneous, consisting of multiple meteoric and marine ice bodies of diverse provenance fused together. Here we demonstrate that fracture detainment is predominantly controlled by enhanced seawater content in suture zones, rather than by enhanced temperature as previously thought.

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Temporal variations in ice sheet flow directly impact the internal structure within ice sheets through englacial deformation. Large-scale changes in the vertical stratigraphy within ice sheets have been previously conducted on centennial to millennial timescales; however, intra-annual changes in the morphology of internal layers have yet to be explored. Over a period of 2 years, we use autonomous phase-sensitive radio-echo sounding to track the daily displacement of internal layers on Store Glacier, West Greenland, to millimeter accuracy.

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Glacier flow instabilities can rapidly increase sea level through enhanced ice discharge. Surge-type glacier accelerations often occur with a decadal to centennial cyclicity suggesting internal mechanisms responsible. Recently, many surging tidewater glaciers around the Arctic Barents Sea region question whether external forces such as climate can trigger dynamic instabilities.

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Recent work has highlighted that 'energy landscapes' should affect animal movement trajectories although expected patterns are rarely quantified. We developed a model, incorporating speed, substrate, superstrate and terrain slope, to determine minimized movement costs for an energetically well-understood model animal, Homo sapiens, negotiating an urban environment, to highlight features that promote increased tortuosity and affect area use. The model showed that high differential travel power costs between adjacent areas, stemming from substantial environmental heterogeneity in the energy landscape, produced the most tortuous least-cost paths across scales.

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A range of species exploit anthropogenic food resources in behaviour known as 'raiding'. Such behavioural flexibility is considered a central component of a species' ability to cope with human-induced environmental changes. Here, we study the behavioural processes by which raiding male chacma baboons (Papio ursinus) exploit the opportunities and mitigate the risks presented by raiding in the suburbs of Cape Town, South Africa.

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There is growing interest in modelling how people make choices that involve both risks and delays, i.e., risky inter-temporal choices.

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In combination, the breakaway of icebergs (calving) and submarine melting at marine-terminating glaciers account for between one third and one half of the mass annually discharged from the Greenland Ice Sheet into the ocean. These ice losses are increasing due to glacier acceleration and retreat, largely in response to increased heat flux from the oceans. Behaviour of Greenland's marine-terminating ('tidewater') glaciers is strongly influenced by fjord bathymetry, particularly the presence of 'pinning points' (narrow or shallow parts of fjords that encourage stability) and over-deepened basins (that encourage rapid retreat).

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In recent decades, hundreds of glaciers draining the Antarctic Peninsula (63° to 70°S) have undergone systematic and progressive change. These changes are widely attributed to rapid increases in regional surface air temperature, but it is now clear that this cannot be the sole driver. Here, we identify a strong correspondence between mid-depth ocean temperatures and glacier-front changes along the ~1000-kilometer western coastline.

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Surface melt ponds form intermittently on several Antarctic ice shelves. Although implicated in ice-shelf break up, the consequences of such ponding for ice formation and ice-shelf structure have not been evaluated. Here we report the discovery of a massive subsurface ice layer, at least 16 km across, several kilometres long and tens of metres deep, located in an area of intense melting and intermittent ponding on Larsen C Ice Shelf, Antarctica.

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Rates of ice mass loss at the calving margins of tidewater glaciers (frontal ablation rates) are a key uncertainty in sea level rise projections. Measurements are difficult because mass lost is replaced by ice flow at variable rates, and frontal ablation incorporates sub-aerial calving, and submarine melt and calving. Here we derive frontal ablation rates for three dynamically contrasting glaciers in Svalbard from an unusually dense series of satellite images.

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Understanding the way humans inform themselves about their environment is pivotal in helping explain our susceptibility to stimuli and how this modulates behaviour and movement patterns. We present a new device, the Human Interfaced Personal Observation Platform (HIPOP), which is a head-mounted (typically on a hat) unit that logs magnetometry and accelerometry data at high rates and, following appropriate calibration, can be used to determine the heading and pitch of the wearer's head. We used this device on participants visiting a botanical garden and noted that although head pitch ranged between -80° and 60°, 25% confidence limits were restricted to an arc of about 25° with a tendency for the head to be pitched down (mean head pitch ranged between -43° and 0°).

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The collapses of the Larsen A and B ice shelves on the Antarctic Peninsula in 1995 and 2002 confirm the impact of southward-propagating climate warming in this region. Recent mass and dynamic changes of Larsen B's southern neighbour Larsen C, the fourth largest ice shelf in Antarctica, may herald a similar instability. Here, using a validated ice-shelf model run in diagnostic mode, constrained by satellite and in situ geophysical data, we identify the nature of this potential instability.

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We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth's polar ice sheets. We find that there is good agreement between different satellite methods--especially in Greenland and West Antarctica--and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by -142 ± 49, +14 ± 43, -65 ± 26, and -20 ± 14 gigatonnes year(-1), respectively.

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