Predictability and heritability of individual differences in fear learning

Our objective was to characterize individual differences in fear conditioning and extinction in an outbred rat strain, to test behavioral predictors of these individual differences, and to assess their heritability. We fear-conditioned 100 Long-Evans rats, attempted to extinguish fear the next day, and tested extinction recall on the third day. The distribution of freezing scores after fear conditioning was skewed, with most rats showing substantial freezing; after fear extinction, the distribution was bimodal with most rats showing minimal freezing, but a substantial portion showing maximal freezing. Longer rearing episodes measured prior to conditioning predicted less freezing at the beginning of extinction, but differences in extinction learning were not predicted by any baseline exploratory behaviors. We tested the heritability of extinction differences by breeding rats from the top and bottom 20 % of freezing scores during extinction recall. We then ran the offspring through the same conditioning/extinction procedure, with the addition of recording ultrasonic vocalizations throughout training and testing. Only a minority of rats emitted distress vocalizations during fear acquisition, but the incidence was less frequent in the offspring of good extinguishers than in poor extinguishers or randomly bred controls. The occurrence of distress vocalizations during acquisition predicted higher levels of freezing during fear recall regardless of breeding line, but the relationship between vocalization and freezing was no longer evident following extinction training, at which point freezing levels were influenced only by breeding and not by vocalization. The heritability (h ²) of extinction recall was estimated at 0.36, consistent with human estimates.     

The Political Justification of Migrant Workers in Alberta,Canada

Considering a series of oil-driven economic booms, the use of inter-provincial and international migrant labour has become an important part of labour market policy in the Canadian province of Alberta. The increased use of temporary foreign workers is controversial. Narrative analysis of legislators’ statements in the legislature and the press between 2000 and 2011 reveals the government using three narratives to justify policies encouraging greater use of foreign migrant workers: (1) labour shortages require migrant workers, (2) migrants do not threaten Canadian jobs and (3) migrants are not being exploited. Close scrutiny of each narrative demonstrates them to be largely invalid. This suggests a significant disconnect between the real and espoused reasons for the significant changes to labour market policy, changes that advantage employers and disadvantage both Canadian and foreign workers. The findings are relevant to understand the political dynamics of economically related migration.     

An investigation into the psychometric properties of the CORE‐OM in patients with eating disorders

Aim: The current study aimed to explore the psychometric properties of the CORE‐OM (Clinical Outcomes in Routine Evaluation – Outcome Measure) when used in an eating disorder sample. Method: The CORE‐OM was administered at assessment to 360 individuals referred to an eating disorders service. Principal component analysis was conducted to look at the psychometric structure of the CORE‐OM, and psychometric properties were investigated using analyses of reliability and validity. Results: Analyses of the psychometric structure suggested a three‐component solution reflecting negatively worded, positively worded and risk items. The CORE‐OM showed good acceptability, acceptable internal and test‐retest reliabilities, as well as good convergent and known groups validity. Conclusions: The results of the current study support the CORE‐OM as a reliable and valid measure for assessing psychological distress in eating disorders.     

Measuring single-item identification efficiencies for letters and 3-D objects

Identification thresholds and the corresponding efficiencies (ideal/human thresholds) are typically computed by collapsing data across an entire stimulus set within a given task in order to obtain a “multiple-item” summary measure of information use. However, some individual stimuli may be processed more efficiently than others, and such differences are not captured by conventional multiple-item threshold measurements. Here, we develop and present a technique for measuring “single-item” identification efficiencies. The resulting measure describes the ability of the human observer to make use of the information provided by a single stimulus item within the context of the larger set of stimuli. We applied this technique to the identification of 3-D rendered objects (Exp. 1) and Roman alphabet letters (Exp. 2). Our results showed that efficiency can vary markedly across stimuli within a given task, demonstrating that single-item efficiency measures can reveal important information that is lost by conventional multiple-item efficiency measures.     

Elevation and mentoring: An experimental assessment of causal relations

Mentoring is a prosocial behavior in which an experienced person guides someone with less experience. Elevation refers to the responses elicited when a person witnesses others upholding the highest standards of moral virtue. Three experimental studies bring these two domains together. For all three studies, participants were randomly assigned to either read a story of someone exhibiting moral excellence or to a control condition. Participants in the elevation condition reported feeling more elevated, more positive attitudes toward mentoring, less negative attitudes toward mentoring, greater intentions to become a mentor (Study 1); an increased proclivity to gather information about becoming a mentor (Study 2a); and, an increased tendency to engage in mentoring directly via submitting advice to students (Study 2b). In their totality, the current studies link another prosocial outcome with elevation and demonstrate a condition under which individuals are more likely to be motivated to become a mentor.     

Asymmetrical access to color and location in visual working memory

Models of visual working memory (VWM) have benefitted greatly from the use of the delayed-matching paradigm. However, in this task, the ability to recall a probed feature is confounded with the ability to maintain the proper binding between the feature that is to be reported and the feature (typically location) that is used to cue a particular item for report. Given that location is typically used as a cue-feature, we used the delayed-estimation paradigm to compare memory for location to memory for color, rotating which feature was used as a cue and which was reported. Our results revealed several novel findings: 1) the likelihood of reporting a probed object’s feature was superior when reporting location with a color cue than when reporting color with a location cue; 2) location report errors were composed entirely of swap errors, with little to no random location reports; and 3) both colour and location reports greatly benefitted from the presence of nonprobed items at test. This last finding suggests that it is uncertainty over the bindings between locations and colors at memory retrieval that drive swap errors, not at encoding. We interpret our findings as consistent with a representational architecture that nests remembered object features within remembered locations.     

USING CALIBRATION AND INTEROBSERVER AGREEMENT ALGORITHMS TO ASSESS THE ACCURACY AND PRECISION OF DATA FROM ELECTRONIC AND PEN‐AND‐PAPER CONTINUOUS RECORDING METHODS

Often it is assumed that electronic recording by observers necessarily provides better quality data than pen‐and‐paper methods. Fifteen novice observers recorded rates of responding from 10 role‐played video samples using one of three continuous recording input formats: keyboard (laptop), touchscreen (personal digital assistants), or pen‐and‐paper. We evaluated the quality of the observers' data compared with criterion records using calibration and interobserver agreement algorithms. Results of the calibration analysis revealed that observers in the touchscreen group produced the most consistently accurate and precise data, the keyboard group observers showed wide variation in precision and accuracy, and the pen‐and‐paper group observers were significantly less precise than the touchscreen group. We conclude that although electronic recording has the potential to be as accurate as, and more precise than, pen‐and‐paper methods, this is far from guaranteed. Analyses of observers' errors advise recommendations for improving data accuracy and precision when using each method. Copyright © 2014 John Wiley & Sons, Ltd.     

A generalized,likelihood-free method for posterior estimation

Recent advancements in Bayesian modeling have allowed for likelihood-free posterior estimation. Such estimation techniques are crucial to the understanding of simulation-based models, whose likelihood functions may be difficult or even impossible to derive. However, current approaches are limited by their dependence on sufficient statistics and/or tolerance thresholds. In this article, we provide a new approach that requires no summary statistics, error terms, or thresholds and is generalizable to all models in psychology that can be simulated. We use our algorithm to fit a variety of cognitive models with known likelihood functions to ensure the accuracy of our approach. We then apply our method to two real-world examples to illustrate the types of complex problems our method solves. In the first example, we fit an error-correcting criterion model of signal detection, whose criterion dynamically adjusts after every trial. We then fit two models of choice response time to experimental data: the linear ballistic accumulator model, which has a known likelihood, and the leaky competing accumulator model, whose likelihood is intractable. The estimated posterior distributions of the two models allow for direct parameter interpretation and model comparison by means of conventional Bayesian statistics—a feat that was not previously possible.     

The perception of a familiar face is no more than the sum of its parts

Why do faces become easier to recognize with repeated exposure? Previous research has suggested that familiarity may induce a qualitative shift in visual processing from an independent analysis of individual facial features to analysis that includes information about the relationships among features (Farah, Wilson, Drain, & Tanaka Psychological Review, 105, 482–498, 1998; Maurer, Grand, & Mondloch Trends in Cognitive Science, 6, 255–260, 2002). We tested this idea by using a “summation-at-threshold” technique (Gold, Mundy, & Tjan Psychological Science, 23, 427–434, 2012; Nandy & Tjan Journal of Vision, 8, 3.1–20, 2008), in which an observer’s ability to recognize each individual facial feature shown independently is used to predict their ability to recognize all of the features shown in combination. We find that, although people are better overall at recognizing familiar as opposed to unfamiliar faces, their ability to integrate information across features is similar for unfamiliar and highly familiar faces and is well predicted by their ability to recognize each of the facial features shown in isolation. These results are consistent with the idea that familiarity has a quantitative effect on the efficiency with which information is extracted from individual features, rather than a qualitative effect on the process by which features are combined.