This target article presents a critical survey of the scientific literature dealing with the speed/accuracy trade-offs in rapid-aimed movements. It highlights the numerous mathematical and theoretical interpretations that have been proposed in recent decades. Although the variety of points of view reflects the richness of the field and the high degree of interest that such basic phenomena attract in the understanding of human movements, it calls into question the ability of many models to explain the basic observations consistently reported in (...) the field. This target article summarizes the kinematic theory of rapid human movements, proposed recently by R. Plamondon (1993b; 1993c; 1995a; 1995b), and analyzes its predictions in the context of speed/accuracy trade-offs. Data from human movement literature are reanalyzed and reinterpreted in the context of the new theory. It is shown that the various aspects of speed/accuracy trade-offs can be taken into account by considering the asymptotic behavior of a large number of coupled linear systems, from which a delta-lognormal law can be derived to describe the velocity profile of an end-effector driven by a neuromuscular synergy. This law not only describes velocity profiles almost perfectly, it also predicts the kinematic properties of simple rapid movements and provides a consistent framework for the analysis of different types of speed/accuracy trade-offs using a quadratic (or power) law that emerges from the model. (shrink)

Notwithstanding its overwhelming descriptive power for existing data, it is not clear whether the kinematic theory of Plamondon & Alimi could generate new insights into biomechanical constraints and psychological processes underlying the way organisms trade off speed for accuracy. The kinematic model should elaborate on the role of neuromotor noise and on biomechanical strategies for reducing endpoint variability related to such noise.

The idea of a neuromuscular synergy involving independent amplitude commands to the agonist and antagonist musculature is quite an appealing part of Plamondon's theory. One question that might be raised relates to the relative independence of the two commands. Evidence is presented that suggests that the two commands might be related in sequential or simultaneous rapid aiming movements.

Most models of response time (RT) in elementary cognitive tasks implicitly assume that the speed-accuracy trade-off is continuous: When payoffs or instructions gradually increase the level of speed stress, people are assumed to gradually sacrifice response accuracy in exchange for gradual increases in response speed. This trade-off presumably operates over the entire range from accurate but slow responding to fast but chance-level responding (i.e., guessing). In this article, we challenge the assumption of continuity and propose a phase transition model for (...) RTs and accuracy. Analogous to the fast guess model (Ollman, 1966), our model postulates two modes of processing: a guess mode and a stimulus-controlled mode. From catastrophe theory, we derive two important predictions that allow us to test our model against the fast guess model and against the popular class of sequential sampling models. The first prediction—hysteresis in the transitions between guessing and stimulus-controlled behavior—was confirmed in an experiment that gradually changed the reward for speed versus accuracy. The second prediction—bimodal RT distributions—was confirmed in an experiment that required participants to respond in a way that is intermediate between guessing and accurate responding. (shrink)

Fitts' law and the [Delta][Lambda] model are theories of motor control because they are limited to the kinematic aspects of movement and do not capture its essential dynamic nature. The internal source of that determines the speed/accuracy trade-off can be associated with the partial compensation of movement-generated forces.

The speed‐accuracy trade‐off (SAT) effect refers to the behavioral trade‐off between fast yet error‐prone respones and accurate but slow responses. Multiple theories on the cognitive mechanisms behind SAT exist. One theory assumes that SAT is a consequence of strategically adjusting the amount of evidence required for overt behaviors, such as perceptual choices. Another theory hypothesizes that SAT is the consequence of the mixture of multiple categorically different cognitive processes. In this paper, these theories are disambiguated by assessing (...) whether the fixed‐point property of mixture distributions holds, in both simulations and data. I conclude that, at least for perceptual decision making, there is no evidence for a mixture of different cognitive processes to trade off accuracy of responding for speed. (shrink)

The speed-accuracy trade-off effect refers to the behavioral trade-off between fast yet error-prone respones and accurate but slow responses. Multiple theories on the cognitive mechanisms behind SAT exist. One theory assumes that SAT is a consequence of strategically adjusting the amount of evidence required for overt behaviors, such as perceptual choices. Another theory hypothesizes that SAT is the consequence of the mixture of multiple categorically different cognitive processes. In this paper, these theories are disambiguated by assessing whether the fixed-point property (...) of mixture distributions holds, in both simulations and data. I conclude that, at least for perceptual decision making, there is no evidence for a mixture of different cognitive processes to trade off accuracy of responding for speed. (shrink)

We question whether Plamondon & Alimi's model is useful in accounting for the nonsymmetrical and multiple-peaked velocity profiles observed in young and elderly subjects for ballistic aiming tasks. For these subjects, both data and observation suggest that a central representation initiates the movement in an appropriate direction but that multiple adjustments are made, both early and late, to achieve spatial accuracy.

We explore the idea that eye-movement strategies in reading are precisely adapted to the joint constraints of task structure, task payoff, and processing architecture. We present a model of saccadic control that separates a parametric control policy space from a parametric machine architecture, the latter based on a small set of assumptions derived from research on eye movements in reading (Engbert, Nuthmann, Richter, & Kliegl, 2005; Reichle, Warren, & McConnell, 2009). The eye-control model is embedded in a decision architecture (a (...) machine and policy space) that is capable of performing a simple linguistic task integrating information across saccades. Model predictions are derived by jointly optimizing the control of eye movements and task decisions under payoffs that quantitatively express different desired speed-accuracy trade-offs. The model yields distinct eye-movement predictions for the same task under different payoffs, including single-fixation durations, frequency effects, accuracy effects, and list position effects, and their modulation by task payoff. The predictions are compared to—and found to accord with—eye-movement data obtained from human participants performing the same task under the same payoffs, but they are found not to accord as well when the assumptions concerning payoff optimization and processing architecture are varied. These results extend work on rational analysis of oculomotor control and adaptation of reading strategy (Bicknell & Levy, ; McConkie, Rayner, & Wilson, 1973; Norris, 2009; Wotschack, 2009) by providing evidence for adaptation at low levels of saccadic control that is shaped by quantitatively varying task demands and the dynamics of processing architecture. (shrink)

In two studies of a GO–NOGO task assessing sustained attention, we examined the effects of altering speed–accuracy trade-offs through instructions and auditory alerts distributed throughout the task. Instructions emphasizing accuracy reduced errors and changed the distribution of GO trial RTs. Additionally, correlations between errors and increasing RTs produced a U-function; excessively fast and slow RTs accounted for much of the variance of errors. Contrary to previous reports, alerts increased errors and RT variability. The results suggest that standard instructions for sustained (...) attention tasks, emphasizing speed and accuracy equally, produce errors arising from attempts to conform to the misleading requirement for speed, which become conflated with attention-lapse produced errors and auditory alerts have complex, and sometimes deleterious, effects on attention. We argue that instructions emphasizing accuracy provide a more precise assessment of attention lapses in sustained attention tasks. (shrink)

Though capable of reproducing experimentally observed velocity profiles, the model proposed by Plamondon & Alimi (P&A) does not provide a viable theoretical framework for the understanding of trajectory formation and speed/accuracy trade-offs. The issues of variation and stability can be better understood by considering movement as resulting from an underlying dynamic rather than from an impulse-response of the system.

Even if we recognize that the delta-lognormal model provides an excellent fit to a large variety of data, the question remains as to what we actually learn from such a model, which could be seen as merely another multiparameter account? Do we welcome such an encompassing account, or do we expect to learn more from the limitations that become apparent when applying dedicated models addressing specific classes of movements?

Even though Plamondon's kinematic model fits the data well, we do not share the view that it explains movements other than ballistic ones. The model does not account for closed-loop control, which is the more common type of movement in everyday life, nor does it account for recent data indicating interference with ongoing processing.

The production of complex sequences like music or speech requires the rapid and temporally precise production of events (e.g., notes and chords), often at fast rates. Memory retrieval in these circumstances may rely on the simultaneous activation of both the current event and the surrounding context (Lashley, 1951). We describe an extension to a model of incremental retrieval in sequence production (Palmer & Pfordresher, 2003) that incorporates this logic to predict overall error rates and speed—accuracy trade-offs, as well as types (...) of serial ordering errors. The model—assumes that retrieval of the current event is influenced by activations of surrounding events. Activations of surrounding events increase over time, such that both the accessibility of distant events and overall accuracy increases at slower production rates. The model's predictions were tested in an experiment in which pianists performed unfamiliar music at 8 different tempi. Model fits to speed—accuracy data and to serial ordering errors support model predictions. Parameter fits to individual data further suggest that working memory contributes to the retrieval of serial order and overall accuracy is influenced in addition by motor dexterity and domain-specific skill. (shrink)

The production of complex sequences like music or speech requires the rapid and temporally precise production of events (e.g., notes and chords), often at fast rates. Memory retrieval in these circumstances may rely on the simultaneous activation of both the current event and the surrounding context (Lashley, 1951). We describe an extension to a model of incremental retrieval in sequence production (Palmer & Pfordresher, 2003) that incorporates this logic to predict overall error rates and speed—accuracy trade-offs, as well as types (...) of serial ordering errors. The model—assumes that retrieval of the current event is influenced by activations of surrounding events. Activations of surrounding events increase over time, such that both the accessibility of distant events and overall accuracy increases at slower production rates. The model's predictions were tested in an experiment in which pianists performed unfamiliar music at 8 different tempi. Model fits to speed—accuracy data and to serial ordering errors support model predictions. Parameter fits to individual data further suggest that working memory contributes to the retrieval of serial order and overall accuracy is influenced in addition by motor dexterity and domain-specific skill. (shrink)

A speed-accuracy trade-off (SAT) in behavioural decisions is known to occur in a wide range of vertebrate and invertebrate taxa. Accurate decisions often take longer for a given condition, while fast decisions can be inaccurate in some tasks. Speed-accuracy tactics are known to vary consistently among individuals, and show a degree of flexibility during colour discrimination tasks in bees. Such individual flexibility in speed-accuracy tactics is likely to be advantageous for animals exposed to fluctuating environments, such as changes in predation (...) threat. We therefore test whether individual speed-accuracy tactics are fixed or flexible under different levels of predation threat in a model invertebrate, the bumblebee Bombus terrestris. The flexibility of speed-accuracy tactics in a foraging context was tested in the laboratory using a ‘meadow’ of artificial flowers harbouring ‘robotic’ crab spider predators. We found that while the ranking of bees along the speed and accuracy continuums was consistent across two levels of predation threat, there was some flexibility in the tactics used by individual bees – most bees became less accurate at colour discrimination when exposed to predation threat when flower types were rewarding. The relationship between decision speed and accuracy was influenced by predator detectability and the risk associated with making incorrect choices during the colour discrimination task. Predator crypsis resulted in a breakdown in the relationship between speed and accuracy, especially when making an incorrect floral choice incurred a distasteful quinine punishment. No single speed-accuracy tactic was found to be optimal in terms of foraging efficiency under either predation threat situation. However, bees that made faster decisions achieved higher nectar collection rates in predator free situations, while accurate bees achieved higher foraging rates under predation threat. Our findings show that while individual bees remain relatively consistent in terms of whether they place greater emphasis on speed or accuracy under predation threat, they can respond flexibly to the additional time costs of detecting predators. (shrink)

We review how leaky competing accumulators (LCAs) can be used to model decision making in two‐alternative, forced‐choice tasks, and we show how they reduce to drift diffusion (DD) processes in special cases. As continuum limits of the sequential probability ratio test, DD processes are optimal in producing decisions of specified accuracy in the shortest possible time. Furthermore, the DD model can be used to derive a speed–accuracy trade‐off that optimizes reward rate for a restricted class of two alternative forced‐choice (...) decision tasks. We review findings that compare human performance with this benchmark, and we reveal both approximations to and deviations from optimality. We then discuss three potential sources of deviations from optimality at the psychological level—avoidance of errors, poor time estimation, and minimization of the cost of control—and review recent theoretical and empirical findings that address these possibilities. We also discuss the role of cognitive control in changing environments and in modulating exploitation and exploration. Finally, we consider physiological factors in which nonlinear dynamics may also contribute to deviations from optimality. (shrink)

Lane et al. propose an integrative model for the reconsolidation of traces in their timely and impressive article. This commentary draws attention to tradeoffs between accuracy and self-narrative integrity in the model. The tradeoffs concern the sense of agency in memory and its role in both implicit and explicit memory reconsolidation, rather than balances concerning degrees of emotional arousal.

The hypothesis that there has been selection pressure for mechanisms which enable us to perceive the present tends to be conflated with the hypothesis that there has been selection pressure for mechanisms that compensate for inevitable neural delay. The relationship between the two is more subtle, because increases in neural delay can be advantageous for building more useful perceptions.

In alphabetic writing systems (such as English), the spaces between words mark the word boundaries, and the basic unit of reading is distinguished during visual-level processing. The visual-level information of word boundaries facilitates reading. Chinese is an ideographic language whose text contains no intrinsic inter-word spaces as the marker of word boundaries. Previous studies have shown that the basic processing unit of Chinese reading is also a word. However, findings remain inconsistent regarding whether inserting spaces between words in Chinese text (...) promotes reading performance. Researchers have proposed that there may be a trade-off between format familiarity and the facilitation effect of inter-word spaces. In order to verify this, this study manipulated the format familiarity via reversing the Chinese reading direction from right to left to investigate this issue in Experiment 1 and Experiment 2. The purpose of Experiment 1 was to examine whether inter-word spaces facilitated Chinese reading in an unfamiliar format. Experiment 1 was conducted that 40 native Chinese undergraduates read Chinese sentences from right to left on four format conditions. The results showed faster reading speed and shorter total reading time for the inter-word spaced format. Based on this finding, Experiment 2 examined whether the facilitation effect of inter-word spaces would reduce or disappear after improving the format familiarity; this experiment was conducted that 40 native Chinese undergraduates who did not participate in Experiment 1 read Chinese sentences from right to left on four format conditions after ten-day reading training. There was no significant difference between the total reading time and reading speed in the inter-word spaced format and unspaced format, which suggests that the facilitation effect of inter-word spaces in Chinese reading changed smaller. The combined results of the two experiments suggest that there is indeed a trade-off between format familiarity and the facilitation of word segmentation, which supports the assumption of previous studies. (shrink)

Teleological accounts of sensory normativity treat normal functioning for a species as a standard: sensory error involves departure from normal functioning for the species, i.e. sensory malfunction. Straightforward reflection on sensory trade-offs reveals that normal functioning for a species can exhibit failures of accuracy. Acknowledging these failures of accuracy is central to understanding the adaptations of a species. To make room for these errors we have to go beyond the teleological framework and invoke the notion of an ideal observer from (...) vision science. The notion of an ideal observer also sheds light on the important distinction between sensory malfunction and sensory limitation. (shrink)

The paper deals with the introduction of nanotechnology in biochips. Based on interviews and theoretical reflections, it explores blind spots left by technology assessment and ethical investigations. These have focused on possible consequences of increased diffusability of a diagnostic device, neglecting both the context of research as well as increased accuracy, despite it being a more essential feature of nanobiochip projects. Also, rather than one of many parallel aspects in innovation processes, ethics is considered here as a ubiquitous system of (...) choices between sometimes antagonistic values. Thus, the paper investigates what is at stake when accuracy is balanced with other practical values in different contexts. Dramatic nanotechnological increase of accuracy in biochips can raise ethical issues, since it is at odds with other values such as diffusability and reliability. But those issues will not be as revolutionary as is often claimed: neither in diagnostics, because accuracy of measurements is not accuracy of diagnostics; nor in research, because a boost in measurement accuracy is not sufficient to overcome significance-chasing malpractices. The conclusion extends to methodological recommendations. (shrink)

This article describes a left-corner parser implemented within a cognitively and neurologically motivated distributed model of memory. This parser's approach to syntactic ambiguity points toward a tidy account both of surprisal effects and of locality effects, such as the parsing breakdowns caused by center embedding. The model provides an algorithmic-level account of these breakdowns: The structure of the parser's memory and the nature of incremental parsing produce a smooth degradation of processing accuracy for longer center embeddings, and a steeper degradation (...) when they are nested, in line with recall observations by Miller and Isard and speed-accuracy trade-off observations by McElree et al.. Modeling results show that this effect is distinct from the effects of ambiguity and exceeds the effect of mere sentence length. (shrink)

The umbrella-term ‘executive functions’ includes various domain-general, goal-directed cognitive abilities responsible for behavioral self-regulation. The influential unity and diversity model of EF posits the existence of three correlated yet separable executive domains: inhibition, shifting and updating. These domains may be influenced by factors such as socioeconomic status and culture, possibly due to the way EF tasks are devised and to biased choice of stimuli, focusing on first-world testees. Here, we propose a FREE test battery that includes two open-access tasks for (...) each of the three abovementioned executive domains to allow latent variables to be obtained. The tasks were selected from those that have been shown to be representative of each domain, that are not copyrighted and do not require special hardware/software to be administered. These tasks were adapted for use in populations with varying SES/schooling levels by simplifying tasks/instructions and using easily recognized stimuli such as pictures. Items are answered verbally and tasks are self-paced to minimize interference from individual differences in psychomotor and perceptual speed, to better isolate executive from other cognitive abilities. We tested these tasks on 146 early adolescents of both sexes and varying SES, because this is the age group in which the executive domains of interest become distinguishable and in order to confirm that SES effects were minimized. Performance was determined by Rate Correct Scores, which consider speed-accuracy trade-offs. Scores were sensitive to the expected improvement in performance with age and rarely/inconsistently affected by sex and SES, as expected, with no floor or ceiling effects, or skewed distribution, thus suggesting their adequacy for diverse populations in these respects. Using structural equation modeling, evidence based on internal structure was obtained by replicating the three correlated-factor solution proposed by the authors of the model. We conclude that the FREE test battery, which is open access and described in detail, holds promise as a tool for research that can be adapted for a wide range of populations, as well as altered and/or complemented in coming studies. (shrink)

The development of action representation during adolescence was investigated using a visually guided pointing motor task to test motor imagery. Forty adolescents and 33 adults were instructed to both execute and imagine hand movements from a starting point to a target of varying size. Reaction time was measured for both Execution and Imagery conditions. There is typically a close association between time taken to execute and image actions in adults because action execution and action simulation rely on overlapping neural circuitry. (...) Further, representations of actions are governed by the same speed-accuracy trade-off as real actions, as expressed by Fitts’ Law. In the current study, performance on the VGPT in both adolescents and adults conformed to Fitts’ Law in E and I conditions. However, the strength of association between E and I significantly increased with age, reflecting a refinement in action representation between adolescence and adulthood. (shrink)

Plamondon & Alimi (P&A) have unified much data on speed/accuracy trade-offs during reaching movements using a delta-lognormal form factor that describes notably neuromuscular systems. Their approach raises questions about whether a large number of systems is needed, whether they are linear, and whether the results disclose the neural design principles that control reaching behaviors. The authors admit that (sect. 6, para. 4).

Several issues are raised concerning the notion that a single strategy explains Fitts' law and the linear speed/accuracy trade-off. Two additional concerns are discussed: (1) distance is programmed, (2) the fact that movements produced without the aid of vision obey Fitts' law does not mean that sighted movements must be explained without regard to vision.

In response to several requests from commentators, an unambiguous definition of time-varying joint stiffness is provided. However, since a variety of different operations can be used to measure stiffness, a problem for quantification admittedly still exists. Several commentaries pointed out the advantage of controlling joint stiffness in optimizing the speed-accuracy trade-off known as Fittss law. The deficit in rapid reciprocal movements and the impact on joint stiffness inhibition caused by cerebellar lesions is clarified here, as the target article was apparently (...) misinterpreted by some readers. In response to the challenge that there is little consensus among cerebellar physiologists, several areas of tacit agreement with other theories of cerebellar function are enumerated. An alternative interpretation of studies showing a transient activation of the cerebellum in motor learning is suggested. Finally, the relationship between the command signals generated by supraspinal centers such as the cerebellum and spinal interneuron networks controlling muscle synergies is discussed. (shrink)

Plamondon & Alimi propose a universal account of trajectory formation and speed/accuracy trade-off in rapid movements but fail, because: (1) the kinematic model ignores the more fundamental dynamics of movement generation, and (2) it does not capture the essential space-time constraints of movement accuracy. Hence, the modeling lacks a biologically and behaviorally principled foundation and is driven by pragmatic function fitting.

This commentary cites several findings of neuromuscular research that are consistent with aspects of Plamondon's kinematic theory. In addition, we point out certain biomechanical properties of the limb that influence the requirements for the production of accurate movement, and might thus compromise the global applicability of any law governing speed/accuracy trade-offs.

Here, we provide an ethical analysis of discrimination in private insurance to guide the application of non-discriminatory algorithms for risk prediction in the insurance context. This addresses the need for ethical guidance of data-science experts, business managers, and regulators, proposing a framework of moral reasoning behind the choice of fairness goals for prediction-based decisions in the insurance domain. The reference to private insurance as a business practice is essential in our approach, because the consequences of discrimination and predictive inaccuracy in (...) underwriting are different from those of using predictive algorithms in other sectors. Here we focus on the trade-off in the extent to which one can pursue indirect non-discrimination versus predictive accuracy. The moral assessment of this trade-off is related to the context of application—to the consequences of inaccurate risk predictions in the insurance domain. (shrink)

Should the Western democracies, contrary to their prevailing self-image as "planned" and "managed," be seen as highly disorganized systems of social power and political authority? If so, what are the symptoms, consequences of, and possible remedies for these disorganizing tendencies?In these ten essays, Claus Offe seeks to answer such questions. Moving beyond the boundaries of both Marxism and established forms of political sociology, he focuses on the growth of serious divisions within the work force, the importance of the "informal" sector, (...) the severe difficulties faced by trade unions in coping with the present economic crisis, the vulnerability of neocorporatist mechanisms, and the failures of state policymaking based on either majority rule or bureaucratic administration.In examining these and other fundamental problems of advanced capitalist democracies, Offe also contests some widely held assumptions of contemporary social science. He calls into question the neutrality of liberal democratic mechanisms of participation and representation, the centrality of the category of work and the division between labor and capital, and the feasibility and desirability of full employment.Claus Offe is the author of numerous books and essays, including Contradictions of the Welfare State. He is currently Professor of Political Science and Sociology in the Faculty of Sociology, University of Bielefeld, West Germany. John Keane is Senior Lecturer in Political Theory and Sociology at the Polytechnic of Central London. Disorganized Capitalism is included in the series, Studies in Contemporary German Social Thought, edited by Thomas McCarthy. (shrink)

Odor and color are strongly associated. Numerous studies demonstrate consistent odor‐color associations, as well as effects of color on odor perception and language. Yet, we know little about how these associations arise. Here, we test whether language is a possible mediator of odor‐color associations, specifically whether odor‐color associations are mediated by implicit odor naming. In two experiments, we used an interference paradigm to prevent the verbalization of odors during an odor‐color matching task. If participants generate color associations subsequent to labeling (...) an odor, interfering with verbalization during the task should affect the ability to make color associations. In Experiment 1, contrary to our hypothesis, verbal interference did not affect odor‐color matches. However, since performance accuracy on the verbal interference task was high, it is possible our task did not sufficiently disrupt verbal processing. In Experiment 2, we, therefore, used an active verbal interference task, and still found no difference across interference conditions. Odor naming accuracy, odor familiarity, and odor pleasantness, however, did predict odor‐color matches. This suggests that although color associations are related to semantic factors, they are not generated by recruiting odor labels in the moment. Overall, our results do not provide evidence that language plays an online role in odor‐color associations, instead, they are consistent with the claim that language may have shaped associations during development. (shrink)

This article suggests an enhancement of the Masek circle model approach usually used to find a trade-off between modeling complexity, algorithm accuracy, and computational time, mainly for embedded systems where the real-time aspect is a high challenge. Moreover, most commercialized systems today frame iris regions by circles. This work led to several novelties: first, in the segmentation process, the corneal reflection removal method based on morphological reconstruction and pixel connectivity was implemented. Second, the picture size reduction was applied according to (...) nearest-neighbor interpolation. Third, the image gradient of the convolved-reduced picture was then generated using four proposed matrices. Fourth, and to reduce the complexity of the traditional method for the detection of the top and lower eyelids, a new method based on the Radon transform and the least squares fitting method was applied. Fifth, eyelashes were detected via the diagonal gradient and thresholding method. Monogenic signal was used in the feature extraction process. Finally, two distance measures were selected as a metric for recognition. Our experimental results using CASIA iris database V3.0 reveal that the proposed method provides a high performance in terms of speed and accuracy. Using dissimilarity modified Hamming distance, the accuracy of iris recognition was improved, with a false acceptance rate equal to 3% and a speed at least eight times as compared with the state of the art. (shrink)

Three issues related to Feldman and Levin's treatment of biological variability are discussed. We question the usefulness of the indirect component of δλ. We suggest that trade-offs between speed and accuracy in aimed movements support identification of δλ, rather than λ, as a control variable. We take issue with the authors' proposal for resolving redundancy in multi-joint movements, given recent data.

The increasing application of artificial intelligence (AI) to healthcare raises both hope and ethical concerns. Some advanced machine learning methods provide accurate clinical predictions at the expense of a significant lack of explainability. Alex John London has defended that accuracy is a more important value than explainability in AI medicine. In this article, we locate the trade-off between accurate performance and explainable algorithms in the context of distributive justice. We acknowledge that accuracy is cardinal from outcome-oriented justice because it helps (...) to maximize patients’ benefits and optimizes limited resources. However, we claim that the opaqueness of the algorithmic black box and its absence of explainability threatens core commitments of procedural fairness such as accountability, avoidance of bias, and transparency. To illustrate this, we discuss liver transplantation as a case of critical medical resources in which the lack of explainability in AI-based allocation algorithms is procedurally unfair. Finally, we provide a number of ethical recommendations for when considering the use of unexplainable algorithms in the distribution of health-related resources. (shrink)

Recently, unrestrained consequentialism has been defended against the charge that it leads to unacceptable trade-offs by showing a tradeoff accepted by many of us is not justified by any of the usual nonconsequenlist arguments. The particular trade-off involves raising the speed limit on the Interstate Highway System. As a society, we seemingly accept a trade-off of lives for convenience. This defense of consequentialism may be a tu quoque, but it does challenge nonconsequentialists to adequately justify a multitude of social decisions. (...) Work by the deontologist Frances Kamm, conjoined with a perspective deployed by several economists on the relation between social costs and lives lost, is relevant. It provides a starting point by justifying decisions which involve trading lives only for other lives. But the perspective also recognizes that using resources in excess of some figure to save a life causes us to forego other live-saving activities, thus causing a net loss of life. Setting a speed limit as low as 35 miles per hour might indeed save some lives, but the loss of productivity due to the increased time spent in travel would cost an even greater number of lives. Therefore, many trade-offs do not simply involve trading lives for some lesser value, but are justified as allowing some to die in order to save a greater number. (shrink)