A Web-Based Archive of Norms,Stimuli, and Data

A new public archive of norms, stimuli, data, and source code,www.psychonomic.org/archive, is at the service of researchers and students in experimental psychology. The archive has received contributions from more than 60 researchers. The August and November 2004 issues ofBehavior Research Methods, Instruments, & Computers comprise articles related to the inaugural contents of the archive, which will henceforth accept contributions related to articles published in all Psychonomic Society journals.     

Letter string processing and visual short-term memory

The present study investigated whether expertise with letter string processing influences visual short-term memory capacity. Specifically, we examined whether performance in a change-detection task would vary as a function of stimulus type (letters vs. symbols) and type of display (horizontal, vertical, and circular). Participants were asked to detect a one-character change in a briefly presented character array following a delay of 900?ms. Concurrent articulation was used to limit effects of rehearsal. Type of display significantly affected performance with letters, but not with symbols, with a selective increase in change-detection accuracy for horizontally presented letter arrays compared with vertical and circular arrays. These findings confirm the standard limits of storage in visual short-term memory, but critically reveal a selective advantage for letter arrays over symbol arrays when presented horizontally. Such an advantage is probably due to the utilization of a specialized encoding mechanism built up over years of reading experience.     

Bridging the gap on Facebook: assessing intergroup contact and its effects for intergroup relations

In line with Allport's contact hypothesis, previous research showed that direct intergroup contact can reduce prejudices. However, establishing face-to-face contact is not always feasible. We postulate that Facebook-groups are a setting where direct and observed intergroup contact can develop, reducing prejudices and increasing mutual acceptance. Analyzing the comments of nine Facebook-groups with the destructive and constructive conflict scale, our results indicated that the expression of prejudices decreased and that of mutual acceptance increased over time, both for in- and outgroup members of the Facebook-groups. Only the expression of less prejudices, but not that of more mutual acceptance was predicted by intergroup contact. The influence of group-based motivations on the engagement in intergroup contact is discussed, and the overall findings are integrated in Steele and Brown's process model of media practices.     

Close encounters of the distracting kind: Identifying the cause of visual tracking errors

Why can we track only so many objects? We addressed this question by asking when and how tracking errors emerge. To test the hypothesis that many tracking errors are target/nontarget confusions emerging from close encounters, we compared standard multiple-object tracking trials with trials on which a nontarget turned a random color whenever it approached within 4° of a target. This manipulation significantly improved performance by alleviating the correspondence challenge of a close encounter. Two control experiments showed that color change benefits were not merely due to target recovery. Follow-up experiments demonstrated that color change benefits did not accrue monotonically with distance but, instead, seemed to obey a step function; and an additional experiment demonstrated that, without color changes, the frequency of close encounters predicts tracking performance. Taken together, these experiments suggest that uncertainty about target location imposes the primary constraint on tracking, at times causing errors by leading to confusions between targets and nontargets.     

Severity of childhood attention-deficit hyperactivity disorder--a risk factor for personality disorders in adult life?

Some evidence points to an increased rate of cluster B and C personality disorders (PDs) in adult ADHD patients. In order to assess axis II disorders comprehensively we used the diagnostic instrument of the WHO. In sixty adult out-patients with ADHD according to DSM-IV criteria PDs were assessed with the International PD Examination (IPDE) and severity of childhood ADHD with the Wender-Utah-Rating Scale (WURS). We found at least one PD in 25% of cases. Cluster C PDs were most common (36.6%) followed by Cluster B (23.3%) and A (8.3%). Avoidant (21.7%) and borderline (18.3%) were the most frequent single PD entities. ADHD patients with PD suffered from significantly more severe childhood ADHD compared to those without co-occurring PD. Applying the IPDE we confirmed a high number of PDs among adult ADHD patients. Our findings point to a higher vulnerability for the development of PDs in patients with severe childhood ADHD.     

Stop and start control: A distinction within self‐control

A theoretical distinction within self‐control, between stop control and start control, was investigated in two studies. Study 1 consisted of a pilot study in which expert ratings of existing self‐control items were used to distinguish between stop and start control items and a confirmatory factor analyses of these items using a student sample (N = 474). Also, stop and start control were related to overall affect and behavioural outcomes. Stop control was negatively related to negative affect, whereas start control was positively related to positive affect. Study 2 (N = 226) replicated some of these findings; stop control was the best predictor (?) of smoking and alcohol consumption whereas start control was the best predictor (+) of exercising and studying. Copyright © 2010 John Wiley & Sons, Ltd.     

The Ways of Criticism

This paper attempts to systematically characterize critical reactions in argumentative discourse, such as objections, critical questions, rebuttals, refutations, counterarguments, and fallacy charges, in order to contribute to the dialogical approach to argumentation. We shall make use of four parameters to characterize distinct types of critical reaction. First, a critical reaction has a focus, for example on the standpoint, or on another part of an argument. Second, critical reactions appeal to some kind of norm, argumentative or other. Third, they each have a particular illocutionary force, which may include that of giving strategic advice to the other. Fourth, a critical reaction occurs at a particular level of dialogue (the ground level or some meta-level). The concepts here developed shall be applied to discussions of critical reactions by Aristotle and by some contemporary authors.     

The Unchangeable Judicial Formats

An analysis of a broad sample of Dutch judicial and semi-judicial decisions shows similar structures as the ones Bhatia and Mazzi found before. The question is posed what explains this seemingly unchangeable judicial format. From a perspective of argumentative and communicative efficacy and comprehensibility, the format is certainly not the optimal choice. The explanation is that the format is a sign of an ideology. The format suggests an objectivity of the decision taken. This is actually a myth. This makes a decision to change the format an ideological one.     

A phase transition model for the speed-accuracy trade-off in response time experiments

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.