Effects of testing on learning of functions

Is learning of a complex functional relationship enhanced by trying to predict what output will go with a given input, as compared to studying an input–output pair? We examined learning of a bilinear function and transfer to new items outside the trained range. Subjects either saw the input–output pairs (study-only condition) or attempted to guess the output and then saw the pair (test/study condition). The total study times were equated, and motivation was enhanced with a monetary bonus. Performance was markedly better for the test/study condition, both within the trained range and in the transfer test. This benefit of testing during training was observed on a criterial test administered shortly after training. Testing has long been shown to enhance the explicit learning and retention of verbal material; our present findings reveal a novel domain for which testing can also be advantageous—that is, function learning.     

Correlating the internal length in strain gradient plasticity theory with the microstructure of material

The internal length is the governing parameter in strain gradient theories which among other things have been used successfully to interpret size effects at the microscale. Physically, the internal length is supposed to be related with the microstructure of the material and evolves during the deformation. Based on Taylor hardening law, we propose a power-law relationship to describe the evolution of the variable internal length with strain. Then, the classical Fleck–Hutchinson strain gradient theory is extended with a strain-dependent internal length, and the generalized Fleck–Hutchinson theory is confirmed here, by comparing our model predictions to recent experimental data on tension and torsion of thin wires with varying diameter and grain size. Our work suggests that the internal length is a configuration-dependent parameter, closely related to dislocation characteristics and grain size, as well as sample geometry when this affects either the underlying microstructure or the ductility of the material.     

Sex differences in adolescent ethanol drinking to behavioral intoxication

Rodent models have been especially useful for investigating adolescent ethanol exposure. However, there is a paucity of studies examining sex differences in behavioral intoxication from adolescent ethanol drinking. Here, we used an ethanol drinking model to investigate if adolescent rats of both sexes readily drink ethanol to measurable behavioral intoxication, indicated by increased impulsive action and motor incoordination. Beginning on postnatal day (P) 28, male and female Long‐Evans rats were given 30‐min access to a solution of sucrose (20%) or sweetened ethanol (20% sucrose +15% ethanol) every other day until P60 and once after 2 weeks of forced abstinence (on P75). On alternate (nondrinking) days, rats were reinforced with a food pellet for making a cued nosepoke response. Beginning on P56, rats were tested in this task after drinking sessions to assess ethanol‐induced changes in impulsive action, defined as premature responding prior to cue presentation. Motor coordination was assessed before and after drinking sessions using an incline plane test. Adolescent male and female rats readily consumed ethanol to behavioral intoxication, measured as reduced motor coordination. Following forced abstinence, females displayed greater ethanol‐induced impulsive action. These studies provide evidence for sex differences in behavioral intoxication following adolescent ethanol drinking.     

Bayesian Diagnostics of Hidden Markov Structural Equation Models with Missing Data

Cocaine is a type of drug that functions to increase the availability of the neurotransmitter dopamine in the brain. However, cocaine dependence or abuse is highly related to an increased risk of psychiatric disorders and deficits in cognitive performance, attention, and decision-making abilities. Given the chronic and persistent features of drug addiction, the progression of abstaining from cocaine often evolves across several states, such as addiction to, moderate dependence on, and swearing off cocaine. Hidden Markov models (HMMs) are well suited to the characterization of longitudinal data in terms of a set of unobservable states, and have increasingly been used to uncover the dynamic heterogeneity in progressive diseases or activities. However, the existence of outliers or influential points may misidentify the hidden states and distort the associated inference. In this study, we develop a Bayesian local influence procedure for HMMs with latent variables in the presence of missing data. The proposed model enables us to investigate the dynamic heterogeneity of multivariate longitudinal data, reveal how the interrelationships among latent variables change from one state to another, and simultaneously conduct statistical diagnosis for the given data, model assumptions, and prior inputs. We apply the proposed procedure to analyze a dataset collected by the UCLA center for advancing longitudinal drug abuse research. Several outliers or influential points that seriously influence estimation results are identified and removed. The proposed procedure also discovers the effects of treatment and individuals’ psychological problems on cocaine use behavior and delineates their dynamic changes across the cocaine-addiction states.     

Young children discover how to deceive in 10 days: a microgenetic study

We investigated how the ability to deceive emerges in early childhood among a sample of young preschoolers (Mean age = 34.7 months). We did this via a 10‐session microgenetic method that took place over a 10‐day period. In each session, children played a zero‐sum game against an adult to win treats. In the game, children hid the treats and had opportunities (10 trials) to win them by providing deceptive information about their whereabouts to the adult. Although children initially showed little or no ability to deceive, most spontaneously discovered deception and systematically used it to win the game by the tenth day. Both theory of mind and executive function skills were predictive of relatively faster patterns of discovery. These results are the first to provide evidence for the importance of cognitive skills and social experience in the discovery of deception over time in early childhood.     

The Effect of Ad Skepticism and Celebrity Preference on Brand Attitude Change in Celebrity-Endorsed Advertising

The use of a celebrity endorser who is well recognized and favorably evaluated by the target viewers is a common strategy used by advertisers to increase the persuasiveness of an advertisement. Yet, at the same time, being skeptical of the claim being made by the celebrity endorser is the typical response of the viewers to such persuasion attempts. The present research examines how these effects potentially counterbalance each other as viewers evaluate the advertised brand in a low-involvement setting. The results show that the degree of ad skepticism and the relative allocation of attentional resources to celebrity and brand elements in advertisements determine how preference for a celebrity endorser is transferred to the advertised brand. The findings provide a more complete understanding of the psychological mechanisms by which celebrity preference influences brand attitude change than has previously been available. They indicate that ad skepticism may be the missing link in understanding the effectiveness of celebrity-endorsed advertising.     

阅读训练对儿童早期字词意识发展的作用

该研究探讨了幼儿园中、大班及小学一、二年级儿童在完成字／词意识任务上的年龄差异以及阅读训练对字／词意识发展的影响。实验结果表明：（1）5岁儿童的字词意识尚处于不断的发展之中。6岁及7岁儿童的字意识发展已经达到了成熟水平,但他们的词意识正处于不断的发展之中。（2）初级的阅读训练促进了5岁儿童字意识的发展,但对词意识的发展没有影响。（3）小学语文教学对6岁儿童的口头任务没有影响,但显著地促进了圈词任务成绩的提高。     

Lying in the elementary school years: verbal deception and its relation to second-order belief understanding

The development of lying to conceal one's own transgression was examined in school-age children. Children (N=172) between 6 and 11 years of age were asked not to peek at the answer to a trivia question while left alone in a room. Half of the children could not resist temptation and peeked at the answer. When the experimenter asked them whether they had peeked, the majority of children lied. However, children's subsequent verbal statements, made in response to follow-up questioning, were not always consistent with their initial denial and, hence, leaked critical information to reveal their deceit. Children's ability to maintain consistency between their initial lie and subsequent verbal statements increased with age. This ability is also positively correlated with children's 2nd-order belief scores, suggesting that theory of mind understanding plays an important role in children's ability to lie consistently.     

What are you looking at? Acuity for triadic eye gaze

The authors measured observers' ability to determine direction of gaze toward an object in space. In Experiment 1, they determined the difference threshold for determining whether a live "looker" was looking to the left or right of a target point. Acuity for eye direction was quite high (approximately 30 s arc). Viewing the movement of the looker's eyes did not improve acuity. When one of the looker's eyes was occluded, the observers' acuity was disrupted and their point of subjective equality was shifted away from the exposed eye. Experiment 2 was a replication of Experiment 1, but digitized gaze displays were used. The results of Experiment 3 showed that the acuity for direction of gaze depended on the position of the looker's target. Overall, the results indicated that humans are highly sensitive to gaze direction and that information from both eyes is used to determine direction of regard.