Ankle Intrinsic Stiffness in Subcortical Poststroke Subjects

The authors' purpose was to evaluate bilateral ankle intrinsic stiffness in subcortical poststroke subjects. Ten subcortical poststroke subjects and 10 healthy controls participated in this study. The ankle passive stiffness at 3 different speeds and the electromyographic activity of the soleus, the gastrocnemius, and the tibialis anterior muscles of poststroke contralesional (CONTRA) and ipsilesional (IPSI) limbs and of one limb of healthy subjects were assessed. Ankle electromyographic activity was collected to ensure that reflexive or voluntary muscle activity was not being elicited during the passive movements. A significant interaction was observed between the effects of the limb (IPSI vs. CONTRA vs. control) and ankle position, F(4, 28) = 3.285, p = .025, and between the effects of the limb and the velocity of stretch, F(2, 14) = 4.209, p = .037. While increased intrinsic stiffness was observed in the CONTRA limb of poststroke subjects at ankle neutral position when the passive stretch was applied with a velocity of 1°/s (p = .021), the IPSI limb of poststroke subjects presented increased stiffness at 20º of plantar flexion when the stretch was applied with a velocity of 5°/s (p = .009) when compared to healthy group. Subcortical poststroke subjects present increased intrinsic stiffness in both the CONTRA and IPSI limbs in specific ankle amplitudes.     

Reinforcement value and fixed‐interval performance

The concept of reinforcement value summarizes the effect of different variables, such as reinforcement delay, reinforcement magnitude, and deprivation level, on behavior. In the present set of experiments, we evaluated the effect of reinforcement devaluation on performance under FI schedules. The literature on timing and reinforcement value suggests that devaluation generates longer expected times to reinforcement than the same intervals trained under control conditions. We devalued reinforcement with delay in Experiments 1A, 1B, and 2, and diminished deprivation in Experiments 3A and 3B. Devaluation reduced response rates, increased the number of one‐response intervals, and lengthened postreinforcement pauses, but had inconsistent effects on other timing measures such as quarter life and breakpoint. The results of delayed reinforcement and diminished deprivation manipulations are well summarized as reinforcement devaluation effects. These results suggest that devaluation may reduce stimulus control. In addition, we argue that the process by which delayed reinforcement affects behavior might also explain some effects observed in other devaluation procedures through the concept of reinforcement value.     

“To‐be‐forgotten” statements become less true: Memory processes involved in selection and forgetting lead to truthfulness changes of ambiguous sentences

What happens when people try to forget something? What are the consequences of instructing people to intentionally forget a sentence? Recent studies employing the item‐method directed forgetting paradigm have shown that to‐be‐forgotten (TBF) items are, in a subsequent task, emotionally devaluated relative to to‐be‐remembered (TBR) items, an aftereffect of memory selection (Vivas, Marful, Panagiotidou & Bajo, 2016). As such, distractor devaluation by attentional selection generalizes to memory selection. In this study, we use the item‐method directed forgetting paradigm to test the effects of memory selection and inhibition on truth judgments of ambiguous sentences. We expected the relative standing of an item in the task (i.e., whether it was instructed to be remembered or forgotten) to affect the truthfulness value of that item, making TBF items less valid/truthful than TBR items. As predicted, ambiguous sentences associated with a “Forget” cue were subsequently judged as less true than sentences associated with a “Remember” cue, suggesting that instructions to intentionally forget a statement can produce changes in the validity/truthfulness of that statement. To our knowledge, this is the first study to show an influence of memory processes involved in selection and forgetting on the perceived truthfulness of sentences.     

Psychopathology and behavior problems in children and adolescents with Williams syndrome: Distinctive relationships with cognition

Several studies have documented the high prevalence of psychopathology and behavior problems in Williams syndrome (WS). However, the links between cognitive development and such symptoms need further clarification. Our study aims to expand current knowledge on levels of behavior problems and its links to cognition in a sample of Brazilian individuals with WS. A total of 25 children and adolescents with WS and their parents participated in this study. The participants’ IQs were assessed with the Wechsler Scales of Intelligence (for children or adults) and parental reports of psychopathology/behavior problems were collected using the Child Behavior Checklist (CBCL). The presence of clinically significant attention problems was a main feature in our sample of children and adolescents with WS. In the children, higher IQ scores were found to be significantly associated with less externalizing problems, while in the adolescents cognitive abilities were found to be associated with less internalizing symptoms. These results provide further insight into the links between psychopathology and behavior problems and cognitive abilities in WS, and suggest the need to take age into consideration when analyzing such relationships.     

The role of cognitive flexibility and vocabulary abilities of younger and older users in searching for information on the web

The present study investigated the role of cognitive flexibility and vocabulary abilities in explaining age‐related differences in information searching with a search engine. Nineteen older and 20 younger participants had to carry out nine searches and to complete a battery of cognitive tests. Older participants obtained poorer search performance with fewer correct answers, and lower task completion speed. They interacted little with the system, and showed specific difficulties in getting out of impasses and reformulating unfruitful requests. Regression analyses suggested that age differences in the number of requests were moderated by differences in cognitive flexibility and that the older participants did not leverage their increased vocabulary in producing new keywords. The findings suggest that the age‐related decline in cognitive flexibility plays a role in the age‐related differences observed in searching for information, especially in the way users get out of impasses. The results have implications for designing search engine tools. Copyright © 2010 John Wiley & Sons, Ltd.     

Congruence of the Marital Relationship During Transition to Parenthood: A Study with Couples Who Conceived Spontaneously or Through Assisted Reproductive Technologies

In this study we examined the congruence between partners’ perceptions of their marital relationship during the transition to parenthood and the effect of depression during pregnancy on couples’ congruence during the early postpartum period. Thirty-one couples who conceived spontaneously, along with thirty-five who conceived through assisted reproductive technologies (ART), provided data on their marital relationship and depression at their 24th pregnancy week and four months after the partum. All couples reported a decrease in marital congruence. Couples who conceived through ART reported lower marital congruence. For these subjects, women’s depression was associated with lower congruence. Interventions that focus on strengthening the marital relationship across the transition to parenthood should assess and promote couples’ congruence.     

Monkeys represent others' knowledge but not their beliefs

The capacity to reason about the false beliefs of others is classically considered the benchmark for a fully fledged understanding of the mental lives of others. Although much is known about the developmental origins of our understanding of others' beliefs, we still know much less about the evolutionary origins of this capacity. Here, we examine whether non-human primates - specifically, rhesus macaques (Macaca mulatta) - share this developmental achievement. We presented macaques with a looking-time measure of false belief understanding, one that had recently been developed for use with 15-month-old human infants. Like human infants, monkeys look longer when a human experimenter fails to search in the correct location when she has accurate knowledge. In contrast to infants, however, monkeys appear to make no prediction about how a human experimenter will act when she has a false belief. Across three studies, macaques' pattern of results is consistent with the view that monkeys can represent the knowledge and ignorance of others, but not their beliefs. The capacity to represent beliefs may therefore be a unique hallmark of human cognition.     

Inferring social attributes from different face regions: evidence for holistic processing

Two experiments investigated the role that different face regions play in a variety of social judgements that are commonly made from facial appearance (sex, age, distinctiveness, attractiveness, approachability, trustworthiness, and intelligence). These judgements lie along a continuum from those with a clear physical basis and high consequent accuracy (sex, age) to judgements that can achieve a degree of consensus between observers despite having little known validity (intelligence, trustworthiness). Results from Experiment 1 indicated that the face's internal features (eyes, nose, and mouth) provide information that is more useful for social inferences than the external features (hair, face shape, ears, and chin), especially when judging traits such as approachability and trustworthiness. Experiment 2 investigated how judgement agreement was affected when the upper head, eye, nose, or mouth regions were presented in isolation or when these regions were obscured. A different pattern of results emerged for different characteristics, indicating that different types of facial information are used in the various judgements. Moreover, the informativeness of a particular region/feature depends on whether it is presented alone or in the context of the whole face. These findings provide evidence for the importance of holistic processing in making social attributions from facial appearance.     

Object based implicit contextual learning: a study of eye movements

Implicit contextual cueing refers to a top-down mechanism in which visual search is facilitated by learned contextual features. In the current study we aimed to investigate the mechanism underlying implicit contextual learning using object information as a contextual cue. Therefore, we measured eye movements during an object-based contextual cueing task. We demonstrated that visual search is facilitated by repeated object information and that this reduction in response times is associated with shorter fixation durations. This indicates that by memorizing associations between objects in our environment we can recognize objects faster, thereby facilitating visual search.