Conclusive Reasons and Epistemic Luck

What is it to have conclusive reasons to believe a proposition P? According to a view famously defended by Dretske, a reason R is conclusive for P just in case [R would not be the case unless P were the case]. I argue that, while knowing that P is plausibly related to having conclusive reasons to believe that P, having such reasons cannot be understood in terms of the truth of this counterfactual condition. Simple examples show that it is possible to believe P on the basis of reasons that satisfy the counterfactual, and still get things right about P only as a matter of luck. Seeing where this account of conclusive reasons goes wrong points to an important distinction between having conclusive reasons and relying on reasons that are in point of fact conclusive. It also has wider consequences for whether modal principles like sensitivity and safety can rule out the pernicious kind of epistemic luck, or the kind of luck that interferes with knowledge.     

Recognition failure of recallable words: problems of mathematical constraint and dependence

The graph space of P ( RN | RL ) vs. P ( RN ), probabilities of recognition given recall and overall recognition, is the setting for the Tulving-Wiseman (TW) function of recognition failure research. According to Hintzman (1991, 1992), the moderate scatter of data points about the TW curve is an artefactual regularity caused by a mathematical constraint when P ( RN ) < P ( RL ). However, both constrained and unconstrained (when P ( RN ) ≥ P ( RL )) points conform equally well to the TW function, consistent with the unobserved fact that the location of both kinds of points is determined by the same mathematical rule. Hintzman's claim that there is no regularity in the data plot when P ( RN ) < P ( RL ) other than that produced by the constraint is not supported by this study. He based his claim on an incorrect use of the measure of dependence (association) called gamma. The graph space corresponding to gamma is that of P ( RN | RL ) vs. P ( RN | nRL ), as shown by using the Bayes function (Bayes' theorem). The margin-free measure gamma is a function of two thetas, theta being a margin-sensitive measure of dependence that is the parameter of the Bayes function. The variance of gamma reflects the fact that it is compounded of the theta variances, so a margin-free measure is obtained at the expense of greater variability.     

MEMORY FOUNDATIONALISM AND THE PROBLEM OF UNFORGOTTEN CARELESSNESS

Abstract: According to memory foundationalism, seeming to remember that P is prima facie justification for believing that P. There is a common objection to this theory: If I previously believed that P carelessly (i.e. without justification) and later seem to remember that P, then (according to memory foundationalism) I have somehow acquired justification for a previously unjustified belief. In this paper, I explore this objection. I begin by distinguishing between two versions of it: One where I seem to remember that P while also seeming to remember being careless in my original believing that P and the other where I seem to remember that P while not seeming to remember my past carelessness. I argue that the former case is the real challenge for memory foundationalism. After establishing the case of unforgotten carelessness as objection to memory foundationalism, I recast memory foundationalism in way that allows it to escape this objection.     

Properties of behavior under random interval reinforcement schedules

In a temporally defined system of reinforcement schedules, the fixed interval case is defined when reinforcement probability, P, is equal to unity for the first response in any cycle length, T; when P is less than 1.0, random interval schedules emerge wherein T/P specifies the expected interval between reinforcements. Key-pecking rates were found to be: (a) inversely related to T/P; (b) higher at T=1.0 second than at other T parameter values; (c) low and linear at several T and T/P values. The mean post-reinforcement pause, if initially small, increased, and if initially large, decreased, as T/P increased.     

Music training enhances the rapid plasticity of P3a/P3b event-related brain potentials for unattended and attended target sounds

Neurocognitive studies have shown that extensive musical training enhances P3a and P3b event-related potentials for infrequent target sounds, which reflects stronger attention switching and stimulus evaluation in musicians than in nonmusicians. However, it is unknown whether the short-term plasticity of P3a and P3b responses is also enhanced in musicians. We compared the short-term plasticity of P3a and P3b responses to infrequent target sounds in musicians and nonmusicians during auditory perceptual learning tasks. Target sounds, deviating in location, pitch, and duration with three difficulty levels, were interspersed among frequently presented standard sounds in an oddball paradigm. We found that during passive exposure to sounds, musicians had habituation of the P3a, while nonmusicians showed enhancement of the P3a between blocks. Between active tasks, P3b amplitudes for duration deviants were reduced (habituated) in musicians only, and showed a more posterior scalp topography for habituation when compared to P3bs of nonmusicians. In both groups, the P3a and P3b latencies were shortened for deviating sounds. Also, musicians were better than nonmusicians at discriminating target deviants. Regardless of musical training, better discrimination was associated with higher working memory capacity. We concluded that music training enhances short-term P3a/P3b plasticity, indicating training-induced changes in attentional skills.     

Indirect object recognition: evidence for associative processes in recognition memory

Rats' exploration of stimulus P (e.g., a domestic object) is reduced following either its direct exposure or its indirect exposure and is taken to indicate recognition memory. Procedures for demonstrating indirect object recognition involve an initial presentation of object P with stimulus X (and of an object Q with stimulus Y). On test, stimulus X is presented with objects P and Q and rats' exploration of Q exceeds their exploration of P. One interpretation here is that the presentation of stimulus X on test associatively activates the memory of object P, which diminishes exploration of P relative to Q. It is possible, instead, that performance is simply the result of a novel pattern of stimulation generated by the unfamiliar combination of X and Q. The authors modified this procedure to reduce the likelihood of such a process. Their procedure involved first the presentation of PX and QY before the presentation of stimulus X alone. During the test that followed, objects P and Q were presented but stimulus X was removed. The authors found that exploration of Q remained greater than that of P despite these modifications and discuss some theoretical implications of indirect, associative processes in recognition memory.     

Philosophy for Children and the Extrinsic Value of Academic Philosophy

External pressure on Higher Education Institutes in the United Kingdom has brought the question of the extrinsic value of academic philosophy into focus. One line of research into questions about the extrinsic value of philosophy comes from the Philosophy for Children (P4C) movement. There is a large body of literature about the benefits of P4C. This paper argues that the distinctive nature of the P4C pedagogy limits the claims made by the P4C literature about the extrinsic value of philosophy to claims about the value of P4C. While this is not a problem within the P4C literature that recognises these limitations, the paper makes three claims about why it is sometimes inappropriate to extend claims from research into the value of P4C to claims about the value of non-P4C philosophy. It argues that more research is needed to investigate the value of non-P4C philosophy.     

A Game Semantics for System P

In this paper we introduce a game semantics for System P, one of the most studied axiomatic systems for non-monotonic reasoning, conditional logic and belief revision. We prove soundness and completeness of the game semantics with respect to the rules of System P, and show that an inference is valid with respect to the game semantics if and only if it is valid with respect to the standard order semantics of System P. Combining these two results leads to a new completeness proof for System P with respect to its order semantics. Our approach allows us to construct for every inference either a concrete proof of the inference from the rules in System P or a countermodel in the order semantics. Our results rely on the notion of a witnessing set for an inference, whose existence is a concise, necessary and sufficient condition for validity of an inferences in System P. We also introduce an infinitary variant of System P and use the game semantics to show its completeness for the restricted class of well-founded orders.     

Graded changes in evoked response (P300) amplitude as a function of cognitive activity

Using a stepwise discriminant analysis, we demonstrate that the amplitude of P300 is a graded function of the complexity of information processing required of a S following a stimulus. This relationship between cognitive complexity and P300 is apparent only when the S is not pressed to generate fast and accurate discriminant responses to the stimuli. Under a reaction-time regime, a large P300 is elicited independently of stimulus predictability or cognitive complexity. It seems that P300 is a measure of the amount of activity of a general-purpose cortical processor.     

The Composite Nature of Epistemic Justification

According to many, to have epistemic justification to believe P is just for it to be epistemically permissible to believe P. Others think it is for believing P to be epistemically good. Yet others think it has to do with being epistemically blameless in believing P. All such views of justification encounter problems. Here, a new view of justification is proposed according to which justification is a kind of composite normative status. The result is a view of justification that offers hope of solving some longstanding epistemological problems.     

The probability of causal conditionals

Conditionals in natural language are central to reasoning and decision making. A theoretical proposal called the Ramsey test implies the conditional probability hypothesis: that the subjective probability of a natural language conditional, P(if p then q), is the conditional subjective probability, P(q/p). We report three experiments on causal indicative conditionals and related counterfactuals that support this hypothesis. We measured the probabilities people assigned to truth table cases, P(pq), P(p notq), P( notpq) and P( notp notq). From these ratings, we computed three independent predictors, P(p), P(q/p) and P(q/ notp), that we then entered into a regression equation with judged P(if p then q) as the dependent variable. In line with the conditional probability hypothesis, P(q/p) was by far the strongest predictor in our experiments. This result is inconsistent with the claim that causal conditionals are the material conditionals of elementary logic. Instead, it supports the Ramsey test hypothesis, implying that common processes underlie the use of conditionals in reasoning and judgments of conditional probability in decision making.     

体育专业大学生网络心理特点研究

目的:探讨体育专业大学生网络心理的特点。方法:采用自编大学生网络心理问卷,对某省236名体育专业大学生和331名非体育专业大学生的网络心理进行调查和比较。结果:(1)体育专业大学生网络喜好程度显著低于非体育专业大学生。(2)体育专业大学生对网络依恋程度低于非体育专业大学生。(3)体育专业大学生对网络人际交往依赖程度低于非体育专业大学生。(4)体育专业大学生在上网目的性上表现为"学习需要"等,非体育专业大学生上网是为了"寻求自信"等。     

The Medieval Octagon of Opposition for Sentences with Quantified Predicates

The traditional Square of Opposition consists of four sentence types. Two are universal and two particular; two are affirmative and two negative. Examples, where ‘S’ and ‘P’ designate the subject and the predicate, are: ‘every S is P’, ‘no S is P’, ‘some S is P’ and ‘some S is not P’. Taking the usual sentences of the square of opposition, quantifying over their predicates exhibits non-standard sentence forms. These sentences may be combined into non-standard Squares of Opposition (an Octagon in this case), and they reveal a new relationship not found in the usual Square. Medieval logicians termed ‘disparatae’ pairs of sentences like ‘every S is some P’ and ‘some S is every P’, which are neither subaltern nor contrary, neither contradictory nor subcontrary. Walter Redmond has designed a special language L to express the logical form of these sentences in a precise way. I will use this language to show how Squares of Opposition, standard and non-standard, form a complex network of relations which bring to light the subtleties contained in this traditional doctrine.     

句子加工中的语义P600效应

句子加工领域的研究中,一般认为,N400效应与语义加工有关,句法违反通常引发P600效应。然而近年来一些研究发现,句子语义违反时也引发了P600效应,即语义P600效应。对语义P600效应的诱发原因及其功能意义,目前有三种代表性的解释:监控说认为,P600效应是由语言理解过程中的认知冲突引发的,反映了认知监控系统对可能出现的加工错误的检测与解决;而非句法中心动态模型认为语义P600效应反映的是句子理解过程中两条通路之间出现冲突时的持续分析;扩展的论元依赖模型则用新的句子加工模型来解释语义P600效应,认为语义P600效应与句法违反引发的P600效应产生于句子加工的不同过程。     

Phosphorylation of mitogen-activated protein kinase in the medial prefrontal cortex and the amygdala following memory retrieval or forgetting in developing rats

We examined neuronal correlates of forgetting in rats by detection of phosphorylated mitogen-activated protein kinase (pMAPK) in the medial prefrontal cortex (mPFC) and amygdala. In Experiment 1, postnatal day (P)23 and P16 rats received paired noise CS-shock US presentations. When tested immediately after conditioning, P23 and P16 rats exhibited similar levels of conditioned fear; when tested after 2 days, however, P16 rats showed poor CS-elicited freezing relative to P23 rats. In Experiment 2, P16 and P23 rats received either paired or unpaired CS-US presentations, and then were tested 48 h later. Consistent with Experiment 1, P16 rats showed forgetting whereas P23 rats exhibited good retention at test. Additionally, unpaired groups showed poor CS-elicited freezing at test. Immunohistochemistry showed that P23 and P16 rats given paired presentations exhibited significant elevation of pMAPK-immunoreactive (ir) neurons in the amygdala compared to rats given unpaired presentations. That is, MAPK phosphorylation in the amygdala tracked learning history rather than behavioral performance at test. In contrast, only the P23-paired group showed an elevated number of pMAPK-ir neurons in mPFC, indicating that MAPK phosphorylation in the mPFC tracks memory expression. Different test-perfusion intervals were employed in Experiment 3, which showed that the developmental dissociation in the pMAPK-ir neurons observed in the mPFC in Experiment 2 was not due to age differences in the rate of phosphorylation of MAPK. These findings provide initial evidence suggesting that while the mPFC is involved in memory retrieval, MAPK phosphorylation in the amygdala may be a persisting neural signature of fear memory.     

Conscious Parenting: A Qualitative Study on Swedish Parents’ Motives to Participate in a Parenting Program

Triple P is a parenting program that aims to prevent behavioral, emotional, and developmental problems in children. Because Triple P is a new parenting program in Sweden, it is important to see how parents felt about the intervention. The aim of this study was to find out why parents of preschool children chose to participate in Triple P in Sweden, what they thought of the Triple P curriculum, and how the program related to their parenting philosophy in general. This is a qualitative study using semi-structured interviews with seven mothers and three fathers who participated in Triple P. The interviews were transcribed verbatim and were analysed using Malterud’s method of Systematic Text Condensation. Parents chose to participate in Triple P for several reasons: they wanted to learn more about the intervention; they had specific problems that they sought help for; or they felt encouraged to participate due to advertisements and recommendations from friends. Of the Triple P curriculum, the participants especially enjoyed the “directed discussion” technique, the positive reinforcement sections, and the instructions on how to communicate effectively with their child by staying calm, close, and maintaining eye contact. It was important for many of the parents to feel validated and respected, and they liked having discussions with the preschool teacher rather than being told what to do. Parents in this Swedish sample generally liked and selectively used the strategies they learned from participating in Triple P, depending on how well these fit with their own parenting experiences and philosophy.     

Slippery Slopes and Collapsing Taboos

A slippery slope argument is an argument to this twofold effect. First, that if a policy or practice P is permitted, then we lack the dialectical resources to demonstrate that a similar policy or practice P* is not permissible. Since P* is indeed not permissible, we should not endorse policy or practice P. At the heart of such arguments is the idea of dialectical impotence, the inability to stop the acceptance of apparently small deviations from a heretofore secure policy or practice from leading to apparently large and unacceptable deviations. Using examples of analogical arguments and sorites arguments I examine this phenomenon in the context of collapsing taboos.     

Task complexity and habituation effects on frontal P300 topography

The P3(00) event-related potential (ERP) component is usually reported as having a centroparietal maximum. However, the P3 topography is more frontal in early-session trials which may be masked by averaging over the entire session and is evident longer into the test session among elderly subjects. This hyperfrontality is interpreted as a sign of poor prefrontal adaptive functioning. In the present study, P3 amplitude was examined in university students to determine how early a change in amplitude would be evident and the effect of task complexity on the amplitude across electrode sites. ERPs were elicited using a working-memory n-back task where participants pressed a key to target letter presentations in three conditions of increasing complexity. Single-trial ERP waveforms were then averaged in successive sequences of five trials. Results revealed a greater decrease in frontal P3 amplitude compared to the central and parietal P3 after the first block of five target trials until the third block. The results are interpreted as indicating rapid decrease in hyperfrontality with habituation to an easy task. Increases in task complexity (the 2-back paradigm), however, reduced this frontal P3 attenuation. Results support a P3 ERP model of hyperfrontality reflecting short-term adaptive function by the prefrontal cortex.     

Reading “glasses” will prime “vision,” but reading a pair of “glasses” will not

In a lexical decision task with two primes and a target, the target was preceded 300 msec by the second prime (P2) which in turn was preceded by a brief forward and backward masked first prime (P1). When P1 and P2 were unrelated, reaction times were faster when the target was related to P2 (e.g.,wave SALT ... pepper) than when the target was unrelated to P2 (and P1—e.g.,wave LOAN ... pepper). However, this semantic priming effect was reduced to statistically nonsignificant levels when P1 and P2 were repetitions of the same word. That is, priming did not occur forsalt SALT ... pepper relative toloan LOAN ... pepper. This reduction in priming was observed whether P2 and the target were strongly or weakly related. These findings raise problems for current accounts of semantic priming.     

Event-related potentials in a two-interval forced-choice detection task

In an attempt to elucidate the nature of the subject’s strategy in a two-interval forcedchoice auditory detection task, event-related potentials were studied at two intensities which yielded mean accuracies of 82% and 98%. Subjects reported the observation interval in which they judged the signal to be present and the confidence of the judgment. Principal components varimax analyses yielded four components: a CZ maximal P300, a Slow Wave, a slow negative shift, and a late negative component. The P300 amplitude findings suggest that different strategies are utilized for high-confidence and low-confidence detections. At high confidence, P300 amplitude is large for the observation interval in which the signal is presented, indicating a strategy involving serial independent detection. However, the P300 latency findings at high confidence suggest that absence of the signal in the first observation interval is nonetheless noted: P300 latency in response to signal presence is shorter for the second observation interval than for the first observation interval. At low confidence, P300 is small or absent for both observation intervals, indicating a deferred decision, presumably arrived at through comparison of the two percepts.