Observer agreement for event sequences: Methods and software for sequence alignment and reliability estimates

When sequences of discrete events, or other units, are independently coded by two coders using a set of mutually exclusive and exhaustive codes, but the onset times for the codes are not preserved, it is often unclear how pairs of protocols should be aligned. Yet such alignment is required before Cohen’s kappa, a common agreement statistic, can be computed. Here we describe a method—based on the Needleman and Wunsch (1970) algorithm originally devised for aligning nucleotide sequences—for optimally aligning such sequences; we also offer the results of a simulation study of the behavior of alignment kappa with a number of variables, including number of codes, varying degrees of observer accuracy, sequence length, code variability, and parameters governing the alignment algorithm. We conclude that (1) under most reasonable circumstances, observer accuracies of 90% or better result in alignment kappas of .60 or better; (2) generally, alignment kappas are not strongly affected by sequence length, the number of codes, or the variability in the codes’ probability; (3) alignment kappas are adversely affected when missed events and false alarms are possible; and (4) cost matrices and priority orders used in the algorithm should favor substitutions (i.e., disagreements) over insertions and deletions (i.e., missed events and false alarms). Two computer programs were developed: Global Sequence Alignment, or GSA, for carrying out the simulation study, and Event Alignment, or ELign, a user-oriented program that computes alignment kappa and provides the optimal alignment given a pair of event sequences.     

Sleep,sex, and the Web: Surveying the difficult-to-reach clinical population suffering from sexsomnia

One major advantage of Web-based research lies in its ability to reach and study people who have rare conditions of interest. Another advantage is that, due to the anonymity of the survey situation, the Internet is particularly suited for surveys on sensitive topics. Sexsomnia is a newly identified medical condition whose sufferers engage in sexual behavior during their sleep. Problematic cases are highly distressing and have forensic implications. The consensus among opinion leaders in sleep medicine is that sexsomnia may be quite common but that it often goes unreported because of shame and embarrassment. Thus, little is known about this condition’s demographics and clinical features. This article reports findings from a sample analysis of 20 years of research on sexsomnia and discusses the results, strengths, and weaknesses of a recent Web-based survey conducted on the difficult-to-reach clinical population that suffers from sexsomnia.     

Synchrony effects in automatic and controlled retrieval

Using a speeded retrieval procedure, we investigated time-of-day effects in automatic and controlled retrieval. Morning-type adults were tested at either peak (early morning) or off-peak (late afternoon) times on a speeded implicit (Experiment 1) or explicit (Experiment 2) stem completion task. In Experiment 1, retrieval strategies were identified by changes in response speed between a practice phase with rapid retrieval and an implicit memory test phase. Performance based on controlled retrieval (shown by slowdown participants) showed more priming at peak than at off-peak times of day, a finding confirmed in Experiment 2, in which the participants were given intentional retrieval instructions when the materials switched. In contrast, performance based on automatic retrieval (shown by nonslowdown participants) did not differ across peak and off-peak times. The finding suggests a robust synchrony effect in controlled retrieval, but not in automatic retrieval, which does not appear to vary across the day.     

Collaboration during visual search

Two experiments examine how collaboration influences visual search performance. Working with a partner or on their own, participants reported whether a target was present or absent in briefly presented search displays. We compared the search performance of individuals working together (collaborative pairs) with the pooled responses of the individuals working alone (nominal pairs). Collaborative pairs were less likely than nominal pairs to correctly detect a target and they were less likely to make false alarms. Signal detection analyses revealed that collaborative pairs were more sensitive to the presence of the target and had a more conservative response bias than the nominal pairs. This pattern was observed even when the presence of another individual was matched across pairs. The results are discussed in the context of task-sharing, social loafing and current theories of visual search.     

Moving eyes and moving thought: On the spatial compatibility between eye movements and cognition

Grant and Spivey (2003) proposed that eye movement trajectories can influence spatial reasoning by way of an implicit eye-movement-to-cognition link. We tested this proposal and investigated the nature of this link by continuously monitoring eye movements and asking participants to perform a problem-solving task under free-viewing conditions while occasionally guiding their eye movements (via an unrelated tracking task), either in a pattern related to the problem’s solution or in unrelated patterns. Although participants reported that they were not aware of any relationship between the tracking task and the problem, those who moved their eyes in a pattern related to the problem’s solution were the most successful problem solvers. Our results support the existence of an implicit compatibility between spatial cognition and the eye movement patterns that people use to examine a scene.     

Why do children perseverate when they seem to know better: Graded working memory,or directed inhibition?

Children sometimes have trouble switching from one task to another, despite demonstrating an awareness of current task demands. This behavior could reflect problems either directly inhibiting previously relevant information or sufficiently activating graded working memory representations for the current task. We tested competing predictions from each account, using a computerized card-sorting task in which we assessed children’s task switching abilities and their response speed to simple questions about current task demands. All children answered these questions correctly, but children who successfully switched tasks responded more quickly to questions than did children who perseverated on previous tasks, even after factoring out processing speed and age. This reaction time difference supports graded working memory accounts, with stronger representations of current task demands aiding both task-switching and responses to questions. This result poses a challenge for directed inhibition accounts, because nothing needs to be inhibited to answer simple questions that lack conflicting information.     

Accomplishing Meaning in a Stratified World: An Existential-Phenomenological Reading of Max Weber’s ‘Class,Status, Party’

This is an existential-phenomenological reading of Max Weber’s “Class, Status, Party” that seeks a fuller understanding of meaning accomplishment in a stratified World. I appropriate stratification as a single meaning structure ontically defined by domination, intersubjectivity, and life-chances and ontologically determined by the power-to-be (Seinkönnen), There-being-with-others (Mitdasein), and potentiality (Möglichkeit). I then discuss the significance of these structures in finite transcendence (There-being, Dasein) and describe ways they factually unfold in World achievement. I conclude with logotherapeutic reflections concerning meaning accomplishment in a stratified World and a summary of key questions facing existential-phenomenology in light of the likelihood that There-being must embrace, indeed, live, the inherent equality of Being (Gleichheit des Seins) among Daseins to accomplish its authenticity.     

Models of covariation-based causal judgment: A review and synthesis

Causal judgment is assumed to play a central role in prediction, control, and explanation. Here, we consider the function or functions that map contingency information concerning the relationship between a single cue and a single outcome onto causal judgments. We evaluate normative accounts of causal induction and report the findings of an extensive meta-analysis in which we used a cross-validation model-fitting method and carried out a qualitative analysis of experimental trends in order to compare a number of alternative models. The best model to emerge from this competition is one in which judgments are based on the difference between the amount of confirming and disconfirming evidence. A rational justification for the use of this model is proposed.     

Modeling the word recognition data of Vitevitch and Luce (1998): Is it ARTful?

Vitevitch and Luce (1998) showed that the probability with which phonemes co-occur in the language (phonotactic probability) affects the speed with which words and nonwords are named. Words with high phonotactic probabilities between phonemes were named more slowly than words with low probabilities, whereas with nonwords, just the opposite was found. To reproduce this reversal in performance, a model would seem to require not merely sublexical representations, but sublexical representations that are relatively independent of lexical representations. ARTphone (Grossberg, Boardman, & Cohen, 1997) is designed to meet these requirements. In this study, we used a technique called parameter space partitioning to analyze ARTphone’s behavior and to learn if it can mimic human behavior and, if so, to understand how. To perform best, differences in sublexical node probabilities must be amplified relative to lexical node probabilities to offset the additional source of inhibition (from top-down masking) that is found at the sublexical level.