A comparison of two response time models applied to perceptual matching

Two models, a Poisson race model and a diffusion model, are fit to data from a perceptual matching task. In each model, information about the similarity or the difference between two stimuli accumulates toward thresholds for either response. Stimulus variables are assumed to influence the rate at which information accumulates, and response variables are assumed to influence the level of the response thresholds. Three experiments were conducted to assess the performance of each model. In Experiment 1, observers performed under different response deadlines; in Experiment 2, response bias was manipulated by changing the relative frequency ofsame anddifferent stimuli. In Experiment 3, stimulus pairs were presented at three eccentricities: foveal, parafoveal, and peripheral. We examined whether the race and diffusion models could fit the response time and accuracy data through changes only in response parameters (for Experiments 1 and 2) or stimulus parameters (for Experiment 3). Comparisons between the two models suggest that the race model, which has not been studied extensively, can account for perceptual matching data at least as well as the diffusion model. Furthermore, without the constraints on the parameters provided by the experimental conditions, the diffusion and the race models are indistinguishable. This finding emphasizes the importance of fitting models across several conditions and imposing logical psychological constraints on the parameters of models.     

Dimensionen der Gefühle

Zusammenfassung Es war das Ziel der Untersuchung, ein System der Gefühlsqualitäten zu finden, das im Unterschied zu früheren Klassifikationsversuchen nicht auf der Anwendung formaler Kategorien oder anderer, gewissermaßen von außen an den Gegenstand herangetragener Gesichtspunkte beruhte, sondern aus den Erlebnisinhalten selbst hervorging.Nach verschiedenen Methoden wurden drei Versuche unternommen, in denen die Versuchspersonen auf Grund der Vergegenwärtigung des Erlebnisses Urteile über die Ähnlichkeit und über bestimmte Eigenschaften von Gefühlsqualitäten abzugeben hatten.Aus den Ergebnissen aller drei Versuche konnten Ordnungssysteme der verwendeten Gefühlsqualitäten gebildet werden. Trotz der Verschiedenheit der angewendeten Methoden besteht zwischen den drei Systemen in den vergleichbaren Punkten eine nahezu vollkommene Übereinstimmung.Die Gesamtheit der Gefühlsqualitäten ordnet sich nach dem Resultat dieser Untersuchung in drei Dimensionen an, denen die Bezeichnungen Angenehm—Unangenehm, Unterwerfung—Überhebung und Grad der Motivierung gegeben wurden.Nach einigen Betrachtungen über die der Beurteilung von Gefühlsqualitäten zugrunde liegenden subjektiven Prozesse werden methodische Folgerungen gezogen, die besagen, daß die Voraussetzungen für die Untersuchung der Gefühle weit günstiger sind, als dies nach der vorherrschenden Meinung der Fall ist. Schließlich wird die Anwendungsmöglichkeit der Resultate auf einige Fragestellungen der Gefühlsforschung an Hand von Beispielen erörtert.     

Variability of the MAX and MIN Statistic: A Theory of the Quantile Spread as a Function of Sample Size

The maximum and minimum of a sample from a probability distribution are extremely important random variables in many areas of psychological theory, methodology, and statistics. For instance, the behavior of the mean of the maximum or minimum processing time, as a function of the number of component random processing times (n), has been studied extensively in an effort to identify the underlying processing architecture (e.g., Townsend & Ashby, 1983; Colonius & Vorberg, 1994). Little is known concerning how measures of variability of the maximum or minimum change with n. Here, a new measure of random variability, the quantile spread, is introduced, which possesses sufficient strength to define distributional orderings and derive a number of results concerning variability of the maximum and the minimum statistics. The quantile spread ordering may be useful in many venues. Several interesting open problems are pointed out. This work was supported by an NIH Grant R01 MH57717 to the first author. Some of the collaboration took place during the year 2000 while J.T. Townsend was a Fellow at the Hanse Institute for Advanced Study (HWK), sponsored by H. Colonius at Oldenburg University.     

Towards a bio-psycho-social model of autobiographical memory

Self-awareness and identity are important cornerstones of thinking in social psychology. On the basis of current knowledge and theories from the social, cultural, and biological sciences, this paper attempts to outline an integrative approach to the phenomena of memory and reminiscence. Reference to psychodynamic argumentation is made in addition, where appropriate. The central topic to our argumentation is autobiographical memory, which we analyse according to evolutionary, neuroscientific, and cultural findings. The emotional context and the ontogenetic development of reminiscences (or memories directly relating to one's own self) provide the preliminary framework for an integrated view which includes interactions between the life span, brain development, the social and cultural environment, and genetic predispositions.     

Sex differences for selective forms of spatial memory

In the present study, a systematic comparison of sex differences for several tests of spatial memory was conducted. Clear evidence for more accurate male performance was obtained for precise metric positional information in a wayfinding task and in an object location memory task. In contrast, no sex difference characterized topological information processing (object-to-position assignment). Together, these findings provide further insight in the specificity of sex differences in spatial memory and in the functional architecture of spatial memory. Implications for the relevant evolutionary basis are discussed.     

Decision-making impairments in patients with Parkinson's disease

A high percentage of Parkinson's disease (PD) patients show cognitive impairments in addition to the cardinal motor symptoms. These deficits primarily concern executive functions most probably linked to dysfunctions in prefrontal regions due to decreased dopaminergic transmission in fronto-striatal loops. To investigate possible associations between decision-making and executive functions in PD, we examined 20 non-demented PD patients and 20 healthy control subjects with a neuropsychological test battery and the Game of Dice Task. In this computerised decision-making task, the rules for gains and losses and the winning probabilities are obvious and stable. Thus, strategic components besides feedback processing might influence decision-making in this task. We found that PD patients were impaired in the Game of Dice task performance and that the frequency of disadvantageous choices correlated with both executive functions and feedback processing. We suggest that decision-making deficits of PD patients in explicit gambling situations might be associated with dysfunctions in two different fronto-striatal loops: the limbic-orbitofrontal-striatal loop, involved in feedback processing, and the dorsolateral prefrontal-striatal loop, involved in executive functions.     

Countermanding saccades: evidence against independent processing of go and stop signals

In a stop signal paradigm, subjects were instructed to make a saccade to a visual target appearing left or right of the fixation point. In 25% of the trials, an auditory stop signal was presented after a variable delay that required the subject to inhibit the saccade. Observed saccadic response times in stop failure trials were longer than predicted by Logan and Cowan's (1984) race model. Saccadic response time and amplitude decreased with the time between stop signal presentation and saccade execution, suggesting an inhibitory effect between the stop signal and the go signal processes that is not compatible with an independent race assumption. Moreover, countermanding a saccade was more difficult when stop and go signals appeared at the same location.     

Relation of maternal responsiveness during infancy to the development of behavior problems in high-risk youths

Although problematic parenting has been consistently associated with behavior problems in youths, prospective links between early parenting and childhood behavior problems are less well established. This study examined the association of maternal responsiveness (MRes) during infancy and behavior problems in middle childhood (N = 77). MRes was significantly associated with disruptive behavior problems but was unrelated to attention problems. Absence of MRes during infancy increased the risk of disruptive behavior problems in middle childhood, even with concurrent parenting and established risk factors for disruptive behavior controlled. MRes also interacted with concurrent family risk to predict disruptive behavior symptoms. These findings underscore the importance of early parenting for developmental pathways to disruptive behavior disorders in high-risk youths. The identification of a relatively modifiable early risk factor for disruptive behavior problems has important implications for prevention.     

Severe Withdrawal (and Recovery)

The problem of how to remove information from an agent's stock of beliefs is of paramount concern in the belief change literature. An inquiring agent may remove beliefs for a variety of reasons: a belief may be called into doubt or the agent may simply wish to entertain other possibilities. In the prominent AGM framework for belief change, upon which the work here is based, one of the three central operations, contraction, addresses this concern (the other two deal with the incorporation of new information). Makinson has generalised this work by introducing the notion of a withdrawal operation. Underlying the account proffered by AGM is the idea of rational belief change. A belief change operation should be guided by certain principles or integrity constraints in order to characterise change by a rational agent. One of the most noted principles within the context of AGM is the Principle of Informational Economy. However, adoption of this principle in its purest form has been rejected by AGM leading to a more relaxed interpretation. In this paper, we argue that this weakening of the Principle of Informational Economy suggests that it is only one of a number of principles which should be taken into account. Furthermore, this weakening points toward a Principle of Indifference. This motivates the introduction of a belief removal operation that we call severe withdrawal. We provide rationality postulates for severe withdrawal and explore its relationship with AGM contraction. Moreover, we furnish possible worlds and epistemic entrenchment semantics for severe withdrawals.     

Distinguishing Language from Thought: Experimental Evidence That Syntax Is Lexically Rather Than Conceptually Represented

It is generally assumed that syntax is represented linguistically rather than conceptually, consistent with the more general view that language and thought are coded separately. This claim is widely defended on logical grounds, but it has received little experimental support. In the present study, we asked Spanish and English speakers to make semantic and syntactic categorizations for pictures and their corresponding names. Consistent with past results, latencies to semantically categorize pictures and words were similar. The new finding is that participants were faster to make syntactic decisions for words compared with pictures, suggesting that syntactic features such as grammatical gender and the count-mass distinction are more closely linked to lexical than conceptual representations.