An encompassing framework for Paraconsistent Logic Programs

We propose a framework which extends Antitonic Logic Programs [Damásio and Pereira, in: Proc. 6th Int. Conf. on Logic Programming and Nonmonotonic Reasoning, Springer, 2001, p. 748] to an arbitrary complete bilattice of truth-values, where belief and doubt are explicitly represented. Inspired by Ginsberg and Fitting's bilattice approaches, this framework allows a precise definition of important operators found in logic programming, such as explicit and default negation. In particular, it leads to a natural semantical integration of explicit and default negation through the Coherence Principle [Pereira and Alferes, in: European Conference on Artificial Intelligence, 1992, p. 102], according to which explicit negation entails default negation. We then define Coherent Answer Sets, and the Paraconsistent Well-founded Model semantics, generalizing many paraconsistent semantics for logic programs. In particular, Paraconsistent Well-Founded Semantics with eXplicit negation (WFSX_p) [Alferes et al., J. Automated Reas. 14 (1) (1995) 93–147; Damásio, PhD thesis, 1996]. The framework is an extension of Antitonic Logic Programs for most cases, and is general enough to capture Probabilistic Deductive Databases, Possibilistic Logic Programming, Hybrid Probabilistic Logic Programs, and Fuzzy Logic Programming. Thus, we have a powerful mathematical formalism for dealing simultaneously with default, paraconsistency, and uncertainty reasoning. Results are provided about how our semantical framework deals with inconsistent information and with its propagation by the rules of the program.     

Reasoning and concurrent timing: a study of the mechanisms underlying the effect of emotion on reasoning

Negative emotions typically have an adverse effect on reasoning, especially analytic or logical reasoning. This effect can be explained using an attentional framework in which emotion detracts limited-capacity cognitive resources which are required for reasoning. Another possibility is that the effect of emotion on reasoning is mediated by arousal, as previous research has shown that physiological arousal can be associated with decreased reasoning performance. In this research, we used a dual-task paradigm combining a syllogistic reasoning task and a time production task. Prospective timing allows to disentangle the effects of attention and arousal: time productions should lengthen if emotion takes up cognitive resources that are therefore not available for timing, whereas time productions should shorten if emotional reasoning results from increased arousal. Results from two experiments confirm the adverse impact of emotion on logical reasoning performance. Reasoning about emotional contents led to lengthened time productions, which suggests that the capture of limited cognitive resources is the main factor accounting for the adverse effect of emotion on reasoning and not arousal.     

The Role of Concurrent Feedback in Learning to Walk Through Sliding Doors

Concurrent feedback is defined as information about performance given to participants during the execution of an action. This article investigates whether concurrent feedback is beneficial or detrimental to the learning of an ecologically relevant task. Eighteen participants were asked to walk through a virtual corridor and they practiced over 1110 trials to adjust their walking speed so as to pass through sliding doors that opened and closed at a frequency of 1 Hz. Concurrent feedback informed them about the possible need to accelerate or decelerate. Performance of participants who received concurrent feedback on 66% of the practice trials (on average) did not differ significantly from performance of participants who did not receive concurrent feedback. Furthermore, participants of both of these groups significantly outperformed participants who received concurrent feedback on all practice trials. These results are discussed in relation to the perceptual-motor mechanisms that underlie the control of the action. Also discussed are implications for future research, including the use of self-controlled feedback and the use of multisensory training programs.     

Interference between storage and processing in working memory: Feature overwriting,not similarity-based competition

Eight experiments with the complex span paradigm are presented to investigate why concurrent processing disrupts short-term retention. Increasing the pace of the processing task led to worse recall, supporting the hypothesis that the processing task distracts attention from maintenance operations. Neither phonological nor semantic similarity between memory items and processing-task material impaired memory. In contrast, the degree of phonological overlap between memory items and processing-task material affected recall negatively, supporting feature overwriting as one source of interference in the complex span paradigm. When compared directly, phonological overlap impaired memory, but similarity had a beneficial effect. These findings rule out response competition or confusion as a mechanism of interference between storage and processing.     

Resource Bounded Belief Revision

The AGM paradigm for belief revision provides a very elegant and powerful framework for reasoning about idealized agents. The paradigm assumes that the modeled agent is a perfect reasoner with infinite memory. In this paper we propose a framework to reason about non-ideal agents that generalizes the AGM paradigm. We first introduce a structure to represent an agent's belief states that distinguishes different status of beliefs according to whether or not they are explicitly represented, whether they are currently active and whether they are fully accepted or provisional. Then we define a set of basic operations that change the status of beliefs and show how these operations can be used to model agents with different capacities. We also show how different operations of belief change described in the literature can be seen as special cases of our theory.     

Exploring the effects of ownership and choice on self-memory biases

Objects encoded in the context of temporary ownership by self enjoy a memorial advantage over objects owned by other people. This memory effect has been linked to self-referential encoding processes. The current inquiry explored the extent to which the effects of ownership are influenced by the degree of personal choice involved in assigning ownership. In three experiments pairs of participants chose objects to keep for ownership by self, and rejected objects that were given to the other participant to own. Recognition memory for the objects was then assessed. Experiment 1 showed that participants recognised more items encoded as "self-owned" than "other-owned", but only when they had been chosen by self. Experiment 2 replicated this pattern when participants' sense of choice was illusory. A source memory test in Experiment 3 showed that self-chosen items were most likely to be correctly attributed to ownership by self. These findings are discussed with reference to the link between owned objects and the self, and the routes through which self-referential operations can impact on cognition.     

Exploring early self‐referential memory effects through ownership

The self‐reference effect (SRE) is the reliable memory advantage for information encoded about self over material encoded about other people. The developmental pathway of the SRE has proved difficult to chart, because the standard SRE task is unsuitable for young children. The current inquiry was designed to address this issue using an ownership paradigm, as encoding objects in the context of self‐ownership have been shown to elicit self‐referential memory advantages in adults. Pairs of 4‐ to 6‐year‐old children (n = 64) sorted toy pictures into self‐ and other‐owned sets. A surprise recognition memory test revealed a significant advantage for toys owned by self, which decreased with age. Neither verbal ability nor theory of mind attainment predicted the size of the memory advantage for self‐owned items. This finding suggests that contrary to some previous reports, memory in early childhood can be shaped by the same self‐referential biases that pervade adult cognition.     

Modeling the conscious correlates of recognition memory: Reflections on the remember-know paradigm

Understanding how memory processes contribute to the conscious experience of memory is central to contemporary cognitive psychology. Recently, many investigators (e.g., Gardiner, 1988) have examined theremember-know paradigm to understand the conscious correlates of recognition memory. A variety of studies have demonstrated that variables have different effects on remember and know responses, and these findings have been interpreted in the context of dual-process models of recognition memory. This paper presents a single-process model of the remember-know paradigm, emphasizing the dependence of remember and know judgments on a set of common underlying processes (e.g., criterion setting). We use this model to demonstrate how a single-process model can give rise to the functional dissociations presented in the remember-know literature. We close by detailing procedures for testing our model and describing how those tests may facilitate the development of dual-process models.     

Memory Functioning Questionnaire: concurrent validity with memory performance and self-reported memory failures

Concurrent validity of factor scores from the Memory Functioning Questionnaire (MFQ; Gilewski, Zelinski, & Schaie, in press) with memory performance was investigated in 2 studies. Study 1 involved 198 adults aged 55-85; Study 2, 89 adults aged 50-87. After effects of depression, education, and health were partialed out, MFQ scores predicted performance on laboratory memory tests in Study 1 and performance on clinical memory tests and diaries of memory failures over 2 weeks in Study 2. Additional variance in predicting performance and failures recorded in diaries is accounted for by MFQ scores after partialing out subjects' responses to a yes-no question about whether they have memory problems. Results suggest that the MFQ has moderate concurrent validity with memory measures and is preferable to responses to a single question about memory self-perception in assessing memory complaints in normal adults.     

Visual context does not promote concurrent sequence learning

Concurrent sequence learning (CSL) of two or more sequences refers to the concurrent maintenance, in memory, of the two or more sequence representations. Research using the serial reaction time task has established that CSL is possible when the different sequences involve different dimensions (e.g., visuospatial locations versus manual keypresses). Recently some studies have suggested that visual context can promote CSL if the different sequences are embedded in different visual contexts. The results of these studies have been difficult to interpret because of various limitations. Addressing the limitations, the current study suggests that visual context does not promote CSL and that CSL may not be possible when the different sequences involve the same elements (i.e., the same target locations, response keys and effectors).     

The Prospective and Retrospective Memory Questionnaire (PRMQ): factorial structure, relations to global subjective memory ratings, and Swedish norms

The factorial structure of the Prospective and Retrospective Memory Questionnaire (PRMQ; Smith et al., 2000) was examined in a Swedish population based sample (N= 540, age range; 35-90 years). Concurrent validity was assessed by relating PRMQ to global ratings of memory. Confirmatory factor analyses of the PRMQ items indicated a superior fit of a three-factor model, with prospective and retrospective memory as orthogonal factors and episodic memory as a common factor. Furthermore, the PRMQ scales correlated with the global ratings of memory, suggesting that each rating contributed with unique variance in predicting PRMQ scores. Given differences in levels of complaints as compared with prior research (Crawford et al., 2003) norms for the Swedish version are provided. In conclusion, the present findings extend earlier work by providing additional support for the construct and concurrent validity of the PRMQ scales.     

Working memory and behavioral inhibition in children with attention-deficit/hyperactivity disorder (ADHD): an examination of varied central executive demands,construct overlap,and task impurity

The stop-signal paradigm is the premier metric of behavioral inhibition in contemporary attention-deficit/hyperactivity disorder (ADHD) research. The stop-signal paradigm’s choice-reaction time component, however, arguably places greater demands on working memory processes (e.g., controlled-focused attention) relative to alternative inhibition metrics (i.e., go/no-go (GNG) tasks), and consequently obscures conclusions about inhibition and working memory deficits in affected children. The current study, therefore, aimed to determine whether shared variance between stop-signal behavioral inhibition and working memory performance in children with ADHD reflects overlap between the working memory and inhibition constructs or insufficient specificity of the stop-signal paradigm. Fifty-five children (8–12 years) with and without ADHD were administered established phonological (PH) and visuospatial (VS) working memory measures, as well as stop-signal and GNG tasks that vary with respect to demands on controlled-focused attention. Although working memory and GNG performance each uniquely predicted children’s inattention, stop-signal task performance was not a significant predictor of unique variance in inattention, above and beyond variance associated with working memory. Collectively, these findings suggest that performance on the stop-signal task, compared to the GNG task, is confounded by greater demands associated with working memory and consequently reflects an impure estimate of the inhibition construct.     

Some effort for some: further evidence that scalar implicatures are effortful

Under the assumption of the principle of cooperation (Grice, 1989), a statement such as "some eels are fish" is thought to be false since it contains less information than is considered sufficient. However, the statement is logically sound since the meaning of "some" is compatible with "all". Currently, the primary interpretation of such underinformative statements remains subject to debate. According to Levinson (2000), the pragmatic "some but not all" interpretation is the default interpretation, while others (e.g., Sperber & Wilson, 1995) argue that this pragmatic interpretation only comes to the fore when relevant within the context and is thus considered secondary to the logical "some and perhaps all" interpretation. In this study, three factors that may influence the answer pattern are studied: task load, working memory capacity, and repetition of the statements. In Experiment 1, we used a secondary task paradigm to manipulate the cognitive load under which a number of underinformative statements had to be judged. We observed that for participants with a rather limited working memory span it is harder to reach a pragmatic interpretation under cognitive load. In Experiment 2, we manipulated the repetition of the statements. We observed that with a higher number of filler statements, participants produced fewer consistent answer patterns. This study provides further evidence against the automaticity of the pragmatic interpretation: It shows that the pragmatic interpretation requires more cognitive effort than the logical interpretation and that increasing the number of filler statements inhibits the development of a response strategy.     

A logic for diffusion in social networks

This paper introduces a general logical framework for reasoning about diffusion processes within social networks. The new “Logic for Diffusion in Social Networks” is a dynamic extension of standard hybrid logic, allowing to model complex phenomena involving several properties of agents. We provide a complete axiomatization and a terminating and complete tableau system for this logic and show how to apply the framework to diffusion phenomena documented in social networks analysis.     

Time-related processes in time-based prospective memory and in time-interval production

Time-based prospective memory tasks require the retrieval of previously formed plans (e.g., call me on my mobile phone) either at a specified time (e.g., at 3 p.m.) or after a specified period of time has elapsed (e.g., in 3 min). In the present study, we investigated whether the same time-related processes are recruited for a short-duration time-based prospective memory task and for a time-interval production task. In a dual-task paradigm, we required young adult participants to make category-membership decisions, while they were simultaneously engaged either in a time-based prospective memory tasks or in a time-interval production task. Under one set of conditions, participants were instructed to allocate attention equally to the two tasks, whereas in another set of conditions, they allocated attention primarily to the time-relevant task. The findings revealed that time estimates were not affected by the attention allocation manipulation, although it influenced performance on the concurrent category membership decision making task, and as expected time estimates were more accurate on the prospective memory task than on the time-production task. Based on the preponderance of the findings, we suggest that timing is managed by different mechanisms and/or strategies on time-interval production tasks and on short-duration time-based prospective memory tasks.     

Working memory demands modulate cognitive control in the Stroop paradigm

One important task of cognitive control is to regulate behavior by resolving information processing conflicts. In the Stroop task, e.g., incongruent trials lead to conflict-related enhancements of cognitive control and to improved behavioral performance in subsequent trials. Several studies suggested that these cognitive control processes are functionally and anatomically related to working memory (WM) functions. The present study investigated this suggestion and tested whether these control processes are modulated by concurrent WM demands. For this purpose, we performed three experiments in which we combined different WM tasks with the Stroop paradigm and measured their effects on cognitive control. We found that high WM demands led to a suppression of conflict-triggered cognitive control, whereas our findings suggest that this suppression effect is rather due to WM updating than to maintenance demands. We explain our findings by assuming that WM processes interfere with conflict-triggered cognitive control, harming the efficiency of these control processes.     

Is Default Logic a Reinvention of Inductive-Statistical Reasoning?

Currently there is hardly any connection between philosophy of science and Artificial Intelligence research. We argue that both fields can benefit from each other. As an example of this mutual benefit we discuss the relation between Inductive-Statistical Reasoning and Default Logic. One of the main topics in AI research is the study of common-sense reasoning with incomplete information. Default logic is especially developed to formalise this type of reasoning. We show that there is a striking resemblance between inductive-statistical reasoning and default logic. A central theme in the logical positivist study of inductive-statistical reasoning such as Hempels Criterion of Maximal Specificity turns out to be equally important in default logic. We also discuss to what extent the relevance of the results of Logical Positivism to AI research could contribute to a reevaluation of Logical Positivism in general.     

工作记忆影响时距加工的初步研究

工作记忆会影响时距加工吗？这是一个值得关注的问题。为此,该研究采用双任务范式,选择1～6秒为考察对象,操纵时距编码阶段的工作记忆负荷,以平均复制时距、比率分数及差异系数为因变量指标,旨在探讨不同工作记忆负荷对时距加工的影响。结果发现,1秒、2秒、3秒平均复制长度、复制准确性及变异性不随记忆负荷的大小而变化,4秒、5秒及6秒的平均复制长度随着记忆负荷变大而缩短、复制准确性随着记忆负荷变大而降低、复制变异性随着记忆负荷变大而增大。这意味着工作记忆对时距加工影响具有选择性,可以由时距加工分层机制假说得以解释。     

Laboratory behavioral measures of impulsivity

Previous research and theory have conceptualized impulsivity as a multifaceted construct that requires multiple modes of measurement for accurate assessment. This article describes a software package that includes four paradigms for measuring multiple and unique aspects of impulsivity. Specifically, four tasks are described: (1) the two choice impulsivity paradigm, (2) the single key impulsivity paradigm, (3) the GoStop impulsivity paradigm, and (4) the time paradigm. These tasks measure processes related to the capacity to tolerate delay for reward, to inhibit an already initiated response, and to estimate the passage of time. These processes have been found to be important to the understanding of impulsive behaviors. The programs are flexible and allow the experimenter to manipulate a number of parameters related to delay-reward contingencies, timing, performance feedback/payment, and data output variables. Manipulation of these parameters makes the paradigms scalable to a wide range of ability levels and appropriate for samples ranging from children to adults. The four paradigms in this software package are available at no cost and can be obtained by contacting the corresponding author.     

Inducing and modulating intrusive emotional memories: a review of the trauma film paradigm

Highly affect-laden memory intrusions are a feature of several psychological disorders with intrusive images of trauma especially associated with post-traumatic stress disorder (PTSD). The trauma film paradigm provides a prospective experimental tool for investigating analogue peri-traumatic cognitive mechanisms underlying intrusion development. We review several historical papers and some more recent key studies that have used the trauma film paradigm. A heuristic diagram is presented, designed to simplify predictions about analogue peri-traumatic processing and intrusion development, which can also be related to the processing elements of recent cognitive models of PTSD. Results show intrusions can be induced in the laboratory and their frequency amplified/attenuated in line with predictions. Successful manipulations include competing task type (visuospatial vs. verbal) and use of a cognitive coping strategy. Studies show that spontaneous peri-traumatic dissociation also affects intrusion frequency although attempts to manipulate dissociation have failed. It is hoped that further use of this paradigm may lead to prophylactic training for at risk groups and an improved understanding of intrusions across psychopathologies.