What are the shapes of response time distributions in visual search?

Many visual search experiments measure response time (RT) as their primary dependent variable. Analyses typically focus on mean (or median) RT. However, given enough data, the RT distribution can be a rich source of information. For this paper, we collected about 500 trials per cell per observer for both target-present and target-absent displays in each of three classic search tasks: feature search, with the target defined by color; conjunction search, with the target defined by both color and orientation; and spatial configuration search for a 2 among distractor 5s. This large data set allows us to characterize the RT distributions in detail. We present the raw RT distributions and fit several psychologically motivated functions (ex-Gaussian, ex-Wald, Gamma, and Weibull) to the data. We analyze and interpret parameter trends from these four functions within the context of theories of visual search.     

Semantic coherence and fallacies in estimating joint probabilities

In three experiments on joint probability estimation, gist representations were manipulated with analogies, and the suboptimal strategy of ignoring relevant denominators was counteracted with training in using 2 × 2 tables to clarify joint probability estimates. The estimated probabilities of two events, as well as their conjunctive and disjunctive probabilities, were assessed against two benchmarks, logical fallacies and semantic coherence—a constellation of estimates consistent with the relationship among sets. Fuzzy‐trace theory (FTT) predicts that analogies will increase semantic coherence, and a table intervention affecting denominator neglect will both increase semantic coherence and reduce fallacies. In all three experiments, analogies increased semantic coherence. In both experiments training participants to use 2 × 2 tables, such tables reduced fallacies and increased semantic coherence. As the relations among sets in the problem materials progressed in cognitive complexity from identical sets, mutually exclusive sets, and subsets to overlapping sets, fallacies generally increased, and semantic coherence generally decreased. These findings indicate that denominator neglect is pervasive, but that it can be remedied with a straightforward intervention that clarifies relations among sets. Further, intuitive gist‐based probability estimation can be improved through the use of simple analogies. Copyright © 2009 John Wiley & Sons, Ltd.     

Human Timeline: A Spatial‐Kinesthetic Exercise in Biblical History

The Human Timeline invites students to physically re‐create biblical history. Each student holds a card that denotes an event randomly selected from the biblical timeline. They then arrange themselves chronologically to learn the correct flow of biblical history. Because of the movement involved and the arbitrary layout of the cards among their classmates, learners engage their spatial‐kinesthetic intelligences through this activity. The exercise proves popular among students who identify themselves as “visual” learners, and ultimately serves the biblical studies classroom by reinforcing biblical history as a necessary framework for understanding the biblical text.     

CHILD MALTREATMENT, BULLYING, GENDER-BASED HARASSMENT, AND ADOLESCENT DATING VIOLENCE: MAKING THE CONNECTIONS

Learning to relate to others begins at birth and carries forward to new relationships, which is why child maltreatment and exposure to intimate partner violence have emerged as powerful risk factors for future coercive and hostile relationship patterns. Although not inevitable, it is more likely that children who are victims of maltreatment will carry forward these behavior patterns into adolescence and adulthood, thus perpetuating bullying and harassment with peers and dating partners. We examine the importance of relationships in understanding how abusive patterns of relating to others are shaped throughout childhood and adolescence and how they can be prevented. While early relationships are very important, they are not deterministic; there are ample opportunities for corrective experiences to offset negative early experiences.     

Even in correctable search, some types of rare targets are frequently missed

Socially important visual search tasks, such as airport baggage screening and tumor detection, place observers in situations where the targets are rare and the consequences of failed detection are substantial. Recent laboratory studies have demonstrated that low target prevalence yields substantially higher miss errors than do high-prevalence conditions, in which the same targets appear frequently (Wolfe, Horowitz, & Kenner, 2005; Wolfe et al., 2007). Under some circumstances, this \ldprevalence effect\rd can be eliminated simply by allowing observers to correct their last response (Fleck & Mitroff, 2007). However, in three experiments involving search of realistic X-ray luggage images, we found that the prevalence effect is eliminated neither by giving observers the choice to correct a previous response nor by requiring observers to confirm their responses. This prevalence effect, obtained when no trial-by-trial feedback was given, was smaller than the effect obtained when observers searched through the same stimuli but were given trial-by-trial feedback about accuracy. We suggest that low prevalence puts pressure on observers in any search task, and that the diverse symptoms of that pressure manifest themselves differently in different situations. In some relatively simple search tasks, misses may result from motor or response errors. In other, more complex tasks, shifts in decision criteria appear to be an important contributor.