Re-examination of the role of the instrumental contingency in the sodium-appetite irrelevant incentive effect

Thirsty rats were trained to perform one action—either lever pressing or chain pulling—for a sodium chloride solution and the other for water on a concurrent random interval schedule. When the experimental groups were tested in extinction under a sodium appetite, the instrumental action trained with the sodium solution was not performed at a significantly higher rate than that reinforced by water relative to control groups tested while thirsty. In a second experiment all animals were tested in extinction under a sodium appetite after training with either a sodium solution and water in the experimental condition or a potassium chloride solution and water in the control condition. The experimental animals chain-pulled more rapidly on test than the control rats, irrespective of whether this action was reinforced with the sodium solution or with water. These results confirm the findings of Dickinson and Nicholas (1983a) that the instrumental contingency plays little role in the irrelevant incentive effect based upon a sodium appetite.     

Fitting the off-diagonal dedicom model in the least-squares sense by a generalization of the harman and jones minres procedure of factor analysis

Harshman's DEDICOM model providesa framework for analyzing square but asymmetric materices of directional relationships amongn objects or persons in terms of a small number of components. One version of DEDICOM ignores the diagonal entries of the matrices. A straight-forward computational solution for this model is offered in the present paper. The solution can be interpreted as a generalized Minres procedure suitable for handing asymmetric matrices.     

Classical Invariantism and the Puzzle of Fallibilism

This paper revisits a puzzle that arises for theories of knowledge according to which one can know on the basis of merely inductive grounds. No matter how strong such theories require inductive grounds to be if a belief based on them is to qualify as knowledge, there are certain beliefs (namely, about the outcome of fair lotteries) that are based on even stronger inductive grounds, while, intuitively, they do not qualify as knowledge. This paper discusses what is often regarded as the most promising classical invariantist solution to the puzzle, namely, that beliefs about the outcomes of fair lotteries do not qualify as knowledge because they are too lucky to do so (or, relatedly, because they do not satisfy a safety condition on knowledge), while other beliefs based on potentially weaker inductive grounds are not too lucky (or, relatedly, because they are safe). A case is presented that shows that this solution to the puzzle is actually not viable. It is argued that there is no obvious alternative solution in sight and that therefore the puzzle still awaits a classical invariantist solution.     

A Solution to the Paradox of Analysis

This essay attempts to solve the so-called paradox of analysis: if one is to have any questions about x , one must know x ; but if one knows x , one has no questions about x . The obvious solution is this: one can inquire into x if one knows some, but not all, of x 's parts. But this solution is erroneous. Let x ' be those parts of x with which one is acquainted, and let S be the percipient in question. As with x , either S knows x ', in which case he has no questions about it; or S does not know x ', in which case he has no questions about it.
My solution is this. Perception and cognition give us, not the thing-in-itself, but a certain analogue of the thing-in-itself. To inquire into x , it is necessary to know not x , but only some analogue of x ; and to learn more about x is to become acquainted with increasingly precise analogues of x .     

A new solution to the problem of luck

The issue of whether and how we have the control necessary for freedom and moral responsibility is central to all control accounts of freedom and moral responsibility. The problem of luck for libertarians aims to show that indeterministic agents are ill-equipped with the control required for freedom and moral responsibility. In view of this, we must either endorse scepticism about the possibility of free and morally responsible agents, or make some form of, possibly revisionary, compatibilism work. In this paper, I shall offer a new solution to the problem of luck for libertarians. After outlining the problem of luck, I shall argue that, given a particular approach to mental causation, indeterminism can be viewed as an essential requirement of free and morally responsible action. After this, I shall distinguish between different types of inability and show how this provides us with a solution to the problem of luck. Finally, I shall consider some advantages and objections to the proposed solution.     

Incentive learning and the motivational control of instrumental performance

Hungry rats were trained to press a lever and pull a chain concurrently, with one action being reinforced with a sucrose solution and the other with food pellets. In addition, in the first two experiments all animals experienced non-contingent presentations of the two incentives in the absence of the operant manipulanda while either thirsty or hungry and either before (Experiment 1A) or after (Experiment 1B) the instrumental training. When lever pressing was assessed subsequently in extinction under thirst, the animals pressed at a relatively high rate only if (1) this action had been reinforced with the sucrose solution rather than the food pellets during training and (2) they had received the non-contingent presentations of the sucrose solution and food pellets on days on which they were thirsty rather than hungry. A third experiment demonstrated that non-contingent exposure to the sucrose solution alone, but not to water under thirst was sufficient to bring about this type of motivational control of instrumental performance.     

Have a Cake and Eat it Too: Identifying a Missing Link in the Skeptical Puzzle

The skeptical puzzle consists of three allegedly incompatible claims: S knows that O, S doesn’t know that ~U, and the claim that knowledge is closed under the known entailment. I consider several famous instances of the puzzle and conclude that in all of those cases the presupposition that O entails ~U is false. I also consider two possible ways for trying to make it true and argue that both strategies ultimate fail. I conclude that this result at least completely discredits any solution that denies the principle of epistemic closure. At most, denying that O entails ~U can itself be seen as a novel solution to the puzzle, preferred to any other solution: it accommodates both non-skeptical and skeptical intuitions but does not require us to give up the principle of closure, embrace contextualism or subject-sensitive invariantism, or deny any commonly accepted principle of epistemology or logic.

     

On a medieval solution to the liar paradox

In this paper, I examine a solution to the Liar paradox found in the work of Ockham, Burley, and Pseudo-Sherwood. I reject the accounts of this solution offered by modern commentators. I argue that this medieval line suggests a non-hierarchical solution to the Liar, according to which ‘true’ is analysed as an indexical term, and paradox is avoided by minimal restrictions on tokens of ‘true’. In certain respects, this solution resembles the recent approaches of Charles Parsons and Tyler Burge; in other respects, it is related to a suggestion of Gödel. But, as a whole, it suggests an original solution to the Liar paradox, quite unlike any current proposals.     

Long-delay taste aversion learning in an unpoisoned rat: Exposure to a poisoned rat as the unconditioned stimulus

M. J. Lavin, B. Freise, and S. Coombes (Behavioral and Neural Biology, 1980, 28, 15–33) have shown that if two rats consume a flavored solution and one is poisoned, the unpoisoned partner will also exhibit a flavor aversion during a later preference test. Experiments 1 and 2 showed that a sufficient condition for obtaining this aversion is that the poisoned partner be present with the unpoisoned rat after it has consumed the flavored solution. It is not necessary that the poisoned partner be present when the flavored solution is consumed or indeed have had any exposure to the flavored solution. Experiment 3 showed that the unpoisoned partner can exhibit a flavor aversion when there is a temporal gap of as long as 6 hr between consumption of the flavored solution and exposure to the poisoned rat.     

Engineering and the Problem of Moral Overload

When thinking about ethics, technology is often only mentioned as the source of our problems, not as a potential solution to our moral dilemmas. When thinking about technology, ethics is often only mentioned as a constraint on developments, not as a source and spring of innovation. In this paper, we argue that ethics can be the source of technological development rather than just a constraint and technological progress can create moral progress rather than just moral problems. We show this by an analysis of how technology can contribute to the solution of so-called moral overload or moral dilemmas. Such dilemmas typically create a moral residue that is the basis of a second-order principle that tells us to reshape the world so that we can meet all our moral obligations. We can do so, among other things, through guided technological innovation.     

Solving anagrams: Category priming and the differential availability of category solutions

An experiment was performed to test the hypothesis that the effect of category name priming on anagram solving varies with the strength of the relationship between the solution word and the priming category. Subjects solved anagrams of taxonomic category instances under primed or unprimed conditions. In the primed condition, the name of the taxonomic category from which the solution word was chosen was provided on each trial. Priming was shown to facilitate anagram solution and the extent of this facilitation was directly related to the instance dominance of the solution word in the priming category. The results were discussed in terms of current models of semantic memory.     

A joint treatment of varimax rotation and the problem of diagonalizing symmetric matrices simultaneously in the least-squares sense

The present paper contains a lemma which implies that varimax rotation can be interpreted as a special case of diagonalizing symmetric matrices as discussed in multidimensional scaling. It is shown that the solution by De Leeuw and Pruzansky is essentially equivalent to the solution by Kaiser. Necessary and sufficient conditions for maxima and minima are derived from first and second order partial derivatives. A counter-example by Gebhardt is reformulated and examined in terms of these conditions. It is concluded that Kaiser's method or, equivalently, the method by De Leeuw and Pruzansky is the most attractive method currently available for the problem at hand.The author is obliged to Dirk Knol for computational assistance and to Dirk Knol, Klaas Nevels and Frits Zegers for critically reviewing an earlier draft of this paper.     

The role of the instrumental contingency in the motivational control of performance

In four experiments we investigated an irrelevant incentive effect based upon a transition from hunger to thirst. Hungry rats were trained to lever press either for sucrose solution or for food pellets before performance was tested in extinction while they were thirsty. Reinforcer-specific motivational control was found in the first experiment in that the animals pressed the lever more on tests following training with the sucrose solution rather than with food pellets. Moreover, this effect was seen only when testing was conducted following water, but not following food deprivation. The outcome of the remaining experiments suggests that this motivational control is not mediated by the instrumental contingency between lever pressing and the sucrose reinforcer during training. In these studies lever pressing and chain pulling were reinforced concurrently, one with sucrose and the other with food pellets, in order to equate the noninstrumental functions of the incentives. Following this training, lever pressing in extinction under thirst was unaffected by the type of incentive used as its reinforcer during training.     

Computational aspects of the greatest lower bound to the reliability and constrained minimum trace factor analysis

In the last decade several algorithms for computing the greatest lower bound to reliability or the constrained minimum-trace communality solution in factor analysis have been developed. In this paper convergence properties of these methods are examined. Instead of using Lagrange multipliers a new theorem is applied that gives a sufficient condition for a symmetric matrix to be Gramian. Whereas computational pitfalls for two methods suggested by Woodhouse and Jackson can be constructed it is shown that a slightly modified version of one method suggested by Bentler and Woodward can safely be applied to any set of data. A uniqueness proof for the solution desired is offered.The authors are obliged to Charles Lewis and Dirk Knol for helpful comments, and to Frank Brokken and Henk Camstra for developing computer programs.     

Disjunctivism and the Epistemological Holy Grail

The grounding or motivating intuitions behind internalism and externalism seem to be fundamentally at odds. If there is ever to be a viable or satisfying solution to the problem, it must satisfy the grounding intuitions behind both sides of the debate. Duncan Pritchard claims his theory of epistemological disjunctivism (ED) does just this, arguing that it could be the holy grail we have all been waiting for. However, I believe the holy grail is already out there in the form of the theory that knowledge is a mental state (KMS). In this article, I defend the idea the KMS is far better able to satisfy the internalist and externalist intuitions than ED.     

Dealing with Poor Performance: Supervisor Attributions and the Cost of Responding1

The Green and Mitchell (1979) model of the process by which supervisors diagnose and deal with the causes of subordinates' poor performance is based upon attribution theory. The notion is that the supervisor makes an attribution about the cause of the poor performance and then selects an appropriate response or solution to deal with the problem. Two ways in which this can lead to an inapprorpriate solution are, first, a bias toward making internal attributions and, second, an aversion to using costly, even though appropriate, solutions. This study demonstrates that it is possible to prompt participants to make more external attribution about poor performance. It also demonstrates that whichever attributions they make (either internal or external), the solutions they select to deal with the poor performance are congruent with their attributions provided that the solutions do not have explicit implementation costs associated with them. However, when implementation costs are made explicit, costs influence solution selection and reduce the congruence between the attributions and the selected solutions. The possible implications of this finding for success in dealing with poor performance are discussed.     

Constrained Candecomp/Parafac via the Lasso

The Candecomp/Parafac (CP) model is a well-known tool for summarizing a three-way array by extracting a limited number of components. Unfortunately, in some cases, the model suffers from the so-called degeneracy, that is a solution with diverging and uninterpretable components. To avoid degeneracy, orthogonality constraints are usually applied to one of the component matrices. This solves the problem only from a technical point of view because the existence of orthogonal components underlying the data is not guaranteed. For this purpose, we consider some variants of the CP model where the orthogonality constraints are relaxed either by constraining only a pair, or a subset, of components or by stimulating the CP solution to be possibly orthogonal. We theoretically clarify that only the latter approach, based on the least absolute shrinkage and selection operator and named the CP-Lasso, is helpful in solving the degeneracy problem. The results of the application of CP-Lasso on simulated and real life data show its effectiveness.     

Perceived optimality of competing solutions to the Euclidean travelling salesperson problem

The Travelling Salesperson Problem (TSP) is a nondeterministic-polynomial hard (NP-hard) combinatorial problem that occurs in a wide range of industrial domains, including logistics, route finding, and computer wiring. Interestingly, despite the problem’s inherent computational difficulty, when presented in Euclidean space (ETSP), human participants can produce close-to-optimal solutions in near-linear time. However, when asked to compare and select the most optimum solution from a set of pre-defined competing solution options, participants can struggle. In this study we investigate this paradox by asking participants to compare four closed-loop Euclidean TSP solutions, in order to determine which solution they perceived to have the most optimal tour cost. We hypothesise that the extracted geometric properties have an effect on stimulus selection in a discrimination task (selection or no selection). Accordingly, we extracted four geometric properties from competing stimuli in order to create a perceptual activation function. Predictive analytics demonstrated that a classification model could identify the most optimal solution 97% of the time using the perceptual activation scores alone, yet human participants only correctly determined the most optimal solution 47% of the time. Mixed-effects models suggest that ‘likelihood of stimulus selection’ can be modelled as a function of the weighted coefficients of competing perceptual activation scores within each trial; however only a small amount of the variance is explained by these perceptual activation scores. Finally, a drift–diffusion model was used to create a theoretical framework of how likelihood of stimulus selection is influenced by competing perceptual activators. Our study highlights a novel way of extracting and analysing the importance of geometric properties that influence ETSP discrimination tasks, and links this analysis to human behaviour when discriminating between competing ETSP solutions.     

The aesthetic appeal of minimal structures: judging the attractiveness of solutions to traveling salesperson problems

Ormerod and Chronicle (1999) reported that optimal solutions to traveling salesperson problems were judged to be aesthetically more pleasing than poorer solutions and that solutions with more convex hull nodes were rated as better figures. To test these conclusions, solution regularity and the number of potential intersections were held constant, whereas solution optimality, the number of internal nodes, and the number of nearest neighbors in each solution were varied factorially. The results did not support the view that the convex hull is an important determinant of figural attractiveness. Also, in contrast to the findings of Ormerod and Chronicle, there were consistent individual differences. Participants appeared to be divided as to whether the most attractive figure enclosed a given area within a perimeter of minimum or maximum length. It is concluded that future research in this area cannot afford to focus exclusively on group performance measures.     

Moral responsibility and the continuation problem

Typical incompatibilists about moral responsibility and determinism contend that being basically morally responsible for a decision one makes requires that, if that decision has proximal causes, it is not deterministically caused by them. This article develops a problem for this contention that resembles what is sometimes called the problem of present (or cross-world) luck. However, the problem makes no reference to luck nor to contrastive explanation. This article also develops a solution.