Semantic diversity: A measure of semantic ambiguity based on variability in the contextual usage of words

Semantic ambiguity is typically measured by summing the number of senses or dictionary definitions that a word has. Such measures are somewhat subjective and may not adequately capture the full extent of variation in word meaning, particularly for polysemous words that can be used in many different ways, with subtle shifts in meaning. Here, we describe an alternative, computationally derived measure of ambiguity based on the proposal that the meanings of words vary continuously as a function of their contexts. On this view, words that appear in a wide range of contexts on diverse topics are more variable in meaning than those that appear in a restricted set of similar contexts. To quantify this variation, we performed latent semantic analysis on a large text corpus to estimate the semantic similarities of different linguistic contexts. From these estimates, we calculated the degree to which the different contexts associated with a given word vary in their meanings. We term this quantity a word’s semantic diversity (SemD). We suggest that this approach provides an objective way of quantifying the subtle, context-dependent variations in word meaning that are often present in language. We demonstrate that SemD is correlated with other measures of ambiguity and contextual variability, as well as with frequency and imageability. We also show that SemD is a strong predictor of performance in semantic judgments in healthy individuals and in patients with semantic deficits, accounting for unique variance beyond that of other predictors. SemD values for over 30,000 English words are provided as supplementary materials.     

ROCs in Eyewitness Identification: Instructions versus Confidence Ratings

From the perspective of signal detection theory, different lineup instructions may induce different levels of response bias. If so, then collecting correct and false identification rates across different instructional conditions will trace out the receiver operating characteristic (ROC)—the same ROC that, theoretically, could also be traced out from a single instruction condition in which each eyewitness decision is accompanied by a confidence rating. We tested whether the two approaches do in fact yield the same ROC. Participants were assigned to a confidence rating condition or to an instructional biasing condition (liberal, neutral, unbiased, or conservative). After watching a video of a mock crime, participants were presented with instructions followed by a six‐person simultaneous photo lineup. The ROCs from both methods were similar, but they were not exactly the same. These findings have potentially important policy implications for how the legal system should go about controlling eyewitness response bias.Copyright © 2017 John Wiley & Sons, Ltd.     

Development of a Behavioral Activation–Based Intervention for Cigarette-Smoking Young Adults

Quitting smoking during young adulthood can substantially reduce tobacco-related morbidity and mortality later in life. Depressive symptomatology is prevalent among smokers and increases risk for poor smoking cessation outcomes. However, few integrated behavioral interventions simultaneously target smoking and depressive symptoms and rarely have young smokers been included in the development of these interventions. In this paper we describe an 8-session behavioral activation–based treatment for smoking (BATS; MacPherson et al., 2010) adapted for youth. We conducted a series of focus groups with young adult smokers with depressive symptoms in order to modify treatment manuals to be developmentally appropriate. Subsequently, we completed a small pilot group (n = 5) of the intervention to provide preliminary data on feasibility, acceptability, and outcomes. We provide a case series of the participants in order to provide clinical illustrations of how the modified BATS treatment was implemented among young adults. Most pilot study participants exhibited smoking abstinence and smoking reductions at the end of treatment, as well as improvement in depressive symptoms and maintenance of levels of activation and environmental reward. Participants provided positive qualitative constructive feedback regarding the intervention.     

Secondary migration and relocation among African refugee families in the United States

The purpose of this study was to understand the secondary migration and relocation of African refugees resettled in the United States. Secondary migration refers to moves out of state, while relocation refers to moves within state. Of 73 recently resettled refugee families from Burundi and Liberia followed for 1 year through ethnographic interviews and observations, 13 instances of secondary migration and 9 instances of relocation were identified. A family ecodevelopmental framework was applied to address: Who moved again, why, and with what consequences? How did moving again impact family risk and protective factors? How might policies, researchers, and practitioners better manage refugees moving again? Findings indicated that families undertook secondary migration principally for employment, affordable housing, family reunification, and to feel more at home. Families relocated primarily for affordable housing. Parents reported that secondary migration and relocation enhanced family stability. Youth reported disruption to both schooling and attachments with peers and community. In conclusion, secondary migration and relocation were family efforts to enhance family and community protective resources and to mitigate shortcomings in resettlement conditions. Policymakers could provide newly resettled refugees jobs, better housing and family reunification. Practitioners could devise ways to better engage and support those families who consider moving.     

Developmental profiles for multiple object tracking and spatial memory: typically developing preschoolers and people with Williams syndrome

The ability to track moving objects, a crucial skill for mature performance on everyday spatial tasks, has been hypothesized to require a specialized mechanism that may be available in infancy (i.e. indexes). Consistent with the idea of specialization, our previous work showed that object tracking was more impaired than a matched spatial memory task in individuals with Williams syndrome (WS), a genetic disorder characterized by severe visuo‐spatial impairment. We now ask whether this unusual pattern of performance is a reflection of general immaturity or of true abnormality, possibly reflecting the atypical brain development in WS. To examine these two possibilities, we tested typically developing 3‐ and 4‐year‐olds and people with WS on multiple object tracking (MOT) and memory for static spatial location. The maximum number of objects that could be correctly tracked or remembered (estimated from the k‐statistic) showed similar developmental profiles in typically developing 3‐ and 4‐year‐old children, but the WS profile differed from either age group. People with WS could track more objects than 3‐year‐olds, and the same number as 4‐year‐olds, but they could remember the locations of more static objects than both 3‐ and 4‐year‐olds. Combining these data with those from our previous studies, we found that typically developing children show increases in the number of objects they can track or remember between the ages of 3 and 6, and these increases grow in parallel across the two tasks. In contrast, object tracking in older children and adults with WS remains at the level of 4‐year‐olds, whereas the ability to remember multiple locations of static objects develops further. As a whole, the evidence suggests that MOT and memory for static location develop in tandem typically, but not in WS. Atypical development of the parietal lobe in people with WS could play a causal role in the abnormal, uneven pattern of performance in WS. This interpretation is consistent with the idea that multiple object tracking engages different mechanisms from those involved in memory for static object location, and that the former can be particularly disrupted by atypical development.     

Neural markers of subordinate‐level categorization in 6‐ to 7‐month‐old infants

Subordinate‐level category‐learning processes in infants were investigated with ERP and looking‐time measures. ERPs were recorded while 6‐ to 7‐month‐olds were presented with Saint Bernard images during familiarization, followed by novel Saint Bernards interspersed with Beagles during test. In addition, infant looking times were measured during a paired‐preference test (novel Saint Bernard vs. novel Beagle) conducted at the conclusion of ERP recording. Slow wave activity corresponded with learning a familiarized category at the subordinate and basic levels, whereas Negative central (Nc) and P400 components were linked with novel category preference. The results provide the first evidence identifying the neural markers of subordinate‐level categorization observed in looking‐time tasks conducted with infants. Moreover, when considered in conjunction with prior research investigating the neural markers of basic‐level categorization in infants, the findings indicate that (1) slow wave and Nc components of infant ERP waveforms are general markers for processes of category learning on the one hand and novel category preference on the other, (2) novel category preference for a contrast category at the basic and subordinate levels have the Nc component in common, but novel category preference at the subordinate level is accompanied by an additional P400 component, a finding in keeping with the notion that subordinate‐level categorization is governed by mechanisms supplementary to those underlying basic‐level categorization, and (3) slow wave activity associated with subordinate‐level learning followed that associated with basic‐level learning by approximately 200 ms, a result in accord with a coarse‐to‐fine scheme for the emergence of category partitioning.     

The role of visual attention in multiple object tracking: Evidence from ERPs

We examined the role of visual attention in the multiple object tracking (MOT) task by measuring the amplitude of the N1 component of the event-related potential to probe flashes presented on targets, distractors, or empty background areas. We found evidence that visual attention enhances targets and suppresses distractors (Experiments 1 and 3). However, we also found that when tracking load was light (two targets and two distractors), accurate tracking could be carried out without any apparent contribution from the visual attention system (Experiment 2). Our results suggest that attentional selection during MOT is flexibly determined by task demands, as well as tracking load, and that visual attention may not always be necessary for accurate tracking.