Integrated versus segregated accounting and the magnitude effect in temporal discounting

Temporal discounting rates in humans generally decrease as the amount of reward increases, a phenomenon known as themagnitude effect. In the present study, we examined whether temporal discounting and the magnitude effect are related to segregation of choices in terms of gains or losses for waiting for or expediting receipt of a reward. Subjects (N = 24) responded to a series of hypothetical choices about amounts of money available either immediately or after a delay. The immediate and delayed amounts either were presented as integrated amounts in the baseline condition or were segregated as differential gains or losses for choosing delayed or expedited consumption (delay and speedup conditions, respectively). Temporal discounting rates decreased in the segregated conditions, in accord with the standard discounted utility model but contrary to the hypothesis that the subjects were choosing on the basis of reward differentials in the baseline condition. The size of the magnitude effect was comparable in the baseline and the delay conditions but decreased in the speed-up condition. These results challenge explanations of the magnitude effect in terms of an increasing proportional sensitivity property of the utility function (Loewenstein & Prelec, 1992) and the hypothesis that subjects choose on the basis of differentials even when the rewards are presented as integrated amounts.     

WebDiP: A tool for information search experiments on the World-Wide Web

We describe WebDiP (Web Decision Processes)—an open-source, online tool—which enables a researcher to track participants while they search for information in a database, available through the Internet. After various instructions on setup and configuration are given, a detailed view of WebDiP explains the system’s technical features. Furthermore, other open-source tools are mentioned that helped in programming WebDiP, running it, or analyzing data gathered with it. We present new approaches of how open-source thinking can be incorporated into a research process and discuss future perspectives of WebDiP.     

Sequential task predictability in task switching

Many studies of task switching have found that a prolonged preparation time reduces switch costs. An alternative manipulation of task preparation is based on sequential task predictability, rather than preparation time. In Experiments 1 and 2 of the present study, participants performed explicitly instructed task sequences (i.e., AABB) and were then transferred to a random sequence. The observed benefit of predictability-based task preparation was not switch specific. In Experiment 3, the participants changed from random to predictable tasks. The observed predictability benefit again was not switch specific. The data thus suggest that task switching does not necessarily require a switch-specific reconfiguration process. Rather, task-specific control processes may be needed in both task switches and repetitions.     

Cross-cultural similarities and differences in North Americans’ geographic location judgments

We examined some potential causes of bias in geographic location estimates by comparing location estimates of North American cities made by Canadian, U.S., and Mexican university students. All three groups placed most Mexican cities near the equator, which implies that all e influenced by shared beliefs about the locationthree groups wers of geographical regions relative to global reference points. However, the groups divided North America into different regions and differed in the relative accuracy of the estimates within them, which implies that there was an influence of culture-specific knowledge. The data support a category-based system of plausible reasoning, in which biases in judgments are multiply determined, and underscore the utility of the estimation paradigm as a tool in cross-cultural cognitive research.     

Using the score method to construct asymmetric confidence intervals: An SAS program for content validation in scale development

Expert review sessions are often conducted to determine the content validity of scale items. The accurate quantification of content validity is usually limited by a relatively small number of experts as well as by a small number of rating categories. These factors, combined with the bounded and discrete nature of rating scale categories, hinder use of traditional methods for computing standard errors and confidence intervals. Using an application of the score method, researchers can construct an asymmetric interval that is better suited for these situations. SAS code is provided to automate the computations, and a discussion of two methods for using the obtained results for content validation decisionmaking follows.     

The role of working memory in attentional capture

Much previous research has demonstrated that visual search is typically disrupted by the presence of a unique “singleton” distractor in the search display. Here we show that attentional capture by an irrelevant color singleton during shape search critically depends on availability of working memory to the search task: When working memory is loaded in a concurrent yet unrelated verbal short-term memory task, capture increases. These findings converge with previous demonstrations that increasing working memory load results in greater distractor interference in Stroop-like tasks (de Fockert, Rees, Frith, & Lavie, 2001; Lavie, Hirst, de Fockert, & Viding, 2004), which support the hypothesis that working memory provides goal-directed control of visual selective attention allowing to minimize interference by goal-irrelevant distractors.     

Speeded retrieval abolishes the false-memory suppression effect: Evidence for the distinctiveness heuristic

We examined two different accounts of why studying distinctive information reduces false memories within the DRM paradigm. The impoverished relational encoding account predicts that less memorial information, such as overall familiarity, is elicited by the critical lure after distinctive encoding than after nondistinctive encoding. By contrast, the distinctiveness heuristic predicts that participants use a deliberate retrieval strategy to withhold responding to the critical lures. This retrieval strategy refers to a decision rule whereby the absence of memory for expected distinctive information is taken as evidence for an event’s nonoccurrence. We show that the typical false-recognition suppression effect only occurs when the recognition test is self paced. This suppression effect is abolished when participants make recognition decisions under time pressure, such as within 1 second of seeing the test item. These results are consistent with the distinctiveness heuristic that a time-consuming retrieval strategy is used to reduce false-recognition responses.     

An introduction to Bayesian hierarchical models with an application in the theory of signal detection

Although many nonlinear models of cognition have been proposed in the past 50 years, there has been little consideration of corresponding statistical techniques for their analysis. In analyses with nonlinear models, unmodeled variability from the selection of items or participants may lead to asymptotically biased estimation. This asymptotic bias, in turn, renders inference problematic. We show, for example, that a signal detection analysis of recognition memory data leads to asymptotic underestimation of sensitivity. To eliminate asymptotic bias, we advocate hierarchical models in which participant variability, item variability, and measurement error are modeled simultaneously. By accounting for multiple sources of variability, hierarchical models yield consistent and accurate estimates of participant and item effects in recognition memory. This article is written in tutorial format; we provide an introduction to Bayesian statistics, hierarchical modeling, and Markov chain Monte Carlo computational techniques.     

An on-line task for contrasting auditory processing in the verbal and nonverbal domains and norms for younger and older adults

Contrasting linguistic and nonlinguistic processing has been of interest to many researchers with different scientific, theoretical, or clinical questions. However, previous work on this type of comparative analysis and experimentation has been limited. In particular, little is known about the differences and similarities between the perceptual, cognitive, and neural processing of nonverbal environmental sounds and that of speech sounds. With the aim of contrasting verbal and nonverbal processing in the auditory modality, we developed a new on-line measure that can be administered to subjects from different clinical, neurological, or sociocultural groups. This is an on-line task of sound to picture matching, in which the sounds are either environmental sounds or their linguistic equivalents and which is controlled for potential task and item confounds across the two sound types. Here, we describe the design and development of our measure and report norming data for healthy subjects from two different adult age groups: younger adults (18–24 years of age) and older adults (54–78 years of age). We also outline other populations to which the test has been or is being administered. In addition to the results reported here, the test can be useful to other researchers who are interested in systematically contrasting verbal and nonverbal auditory processing in other populations.