The relationship between loneliness and interpersonal trust during middle childhood

The authors administered measures of loneliness, generalized trust beliefs in peers, and trust beliefs in specific familiar peers (i.e., opposite-gender peers, same-gender peers, close same-gender peers) to a sample of 63 children (33 girls, 30 boys) from 4th and 5th grades (M age = 10 years, 6 months). They assessed children's trusting behavior by engaging them in a Prisoner's Dilemma game (reciprocal trusting) and by evaluating teachers' ratings. The authors found that, across gender, loneliness was negatively correlated with each measure of trust beliefs and trusting behavior. As expected, the relationship between children's loneliness and trust, specifically trust beliefs in same-gender peers, was stronger for girls than for boys. In support of an additive risk model, the authors found low trust beliefs in same-gender peers and low reciprocal trusting behavior with peers each statistically contributed to loneliness in girls.     

Temporal and spatial factors reflecting performance improvement during learning three-ball cascade juggling

Beek and van Santvoord [Beek, P. J., & van Santvoord, A. A. M. (1992). Journal of Motor Behavior, 24, 85-94] proposed a three-stage model of learning to juggle based on group analyses of temporal measures. Here, we examined in detail how the temporal and spatial features of juggling evolved in eight individual participants progressing from the second to the third stage of learning. During the second stage, the dwell ratio, defined as the ratio of the time that the juggler holds a ball between catch and toss and the hand cycle time (HCT), was stable when it was about 0.83. The subjects with a dwell ratio near this value and controlled throws exhibited stable juggling, whereas the subjects with a dwell ratio of 0.80 or smaller exhibited unstable juggling. Compared to the former group, the latter group had a longer time from the throw of a ball to the arrival at its zenith (TZ), and a shorter time between the arrival of an airborne ball at its zenith and the subsequent throw (IZR). The latter group also exhibited larger variability in the dwell ratio and IZR. With practice, the subjects appropriated, on average, the duration of TZ and IZR to the dwell ratio and improved the ability to accurately throw balls by changing the motions of the limb segments involved. Although these changes helped to stabilize the performance during the second stage, the variability problem was not sufficiently resolved. Only two out of eight subjects passed on to the third stage by the last (10th) Session. They achieved small variability in IZR, dwell ratio, and flight paths of the ball while juggling with short HCTs and small dwell ratios. These results suggest that the reduction of variability in these variables was essential to pass on to the third stage.     

Neural evidence that vivid imagining can lead to false remembering

The imperfect nature of memory is highlighted by the regularity with which people fail to remember, or worse, remember something that never happened. We investigated the formation of a particular type of erroneous memory by monitoring brain activity using functional magnetic resonance imaging during the presentation of words and photos. Participants generated a visual image of a common object in response to each word. Subsequently, they sometimes claimed to have seen photos of specific objects they had imagined but not actually seen. In precuneus and inferior parietal regions of the cerebral cortex, activations in response to words were greater when participants subsequently claimed to have seen the corresponding object than when a false memory for that object was not subsequently produced. These findings indicate that brain activity reflecting the engagement of visual imagery can lead to falsely remembering something that was only imagined.     

Memory reactivation and consolidation during sleep

Do our memories remain static during sleep, or do they change? We argue here that memory change is not only a natural result of sleep cognition, but further, that such change constitutes a fundamental characteristic of declarative memories. In general, declarative memories change due to retrieval events at various times after initial learning and due to the formation and elaboration of associations with other memories, including memories formed after the initial learning episode. We propose that declarative memories change both during waking and during sleep, and that such change contributes to enhancing binding of the distinct representational components of some memories, and thus to a gradual process of cross-cortical consolidation. As a result of this special form of consolidation, declarative memories can become more cohesive and also more thoroughly integrated with other stored information. Further benefits of this memory reprocessing can include developing complex networks of interrelated memories, aligning memories with long-term strategies and goals, and generating insights based on novel combinations of memory fragments. A variety of research findings are consistent with the hypothesis that cross-cortical consolidation can progress during sleep, although further support is needed, and we suggest some potentially fruitful research directions. Determining how processing during sleep can facilitate memory storage will be an exciting focus of research in the coming years.The idea that memory storage is supported by events that take place in the brain while a person is sleeping is an idea that is only rarely acknowledged in the neuroscience community. At present, most memory research proceeds with no mention of any influence of sleep on memory. Nonetheless, this hypothesis is gaining empirical support. Research into connections between memory and sleep represents a burgeoning enterprise at the crossroads of traditional memory research and sleep research, an enterprise poised to provide novel insights into the human experience.This article presents some speculations about connections between memory and sleep. We entertain the notion that declarative memories are subject to modification during sleep, and that enduring storage of such memories is systematically influenced by neural events taking place during sleep. Although other types of memory may also be subject to change during sleep (see Maquet et al. 2003), we emphasize declarative memory here.This article also functions as an introduction to the set of papers selected for this special issue of Learning & Memory. These papers together outline portions of the current empirical basis for memory-sleep connections, including research in humans and in nonhuman animals. The findings are tantalizing, and yet there are undoubtedly major gaps in our knowledge about the functions of sleep and about how sleep may be related to memory storage. Future research on this topic is bound to grow in exciting and unpredictable ways. Here, we explore questions about declarative memory and sleep that may serve as a useful guide for such research.     

Children's use of gaze and limb movement cues to infer deception

A sample of 96 children from kindergarten, 2nd, 4th, and 6th grades judged the truthfulness of peers who varied in gaze and limb movement while providing verbal communications. Results indicated that children attributed greater lying to the peers who displayed indirect rather than direct gaze and active rather than nonactive limb movement. The use of these cues was more evident in 4th- and 6th-grade children than it was in kindergarten and 2nd-grade children. Pilot studies indicated that adults and children as young as 5-6 years of age associated indirect gaze and active limb movement with anxiety. The findings are discussed with respect to children's theory of mind, concepts of lying, understanding of display rules, and learning of physiological cues associated with deception.     

Change in perceptual form attenuates the use of the fluency heuristic in recognition

Four experiments (total N=295) were conducted to determine whether within-modality changes in perceptual form between the study and the test phases of an experiment would moderate the role of the fluency heuristic in recognition memory. Experiment 1 showed that a change from pictures to words reduced the role of fluency in recognition memory. In Experiment 2, the same result was found using counterfeit study lists that supposedly consisted of pictures or words. Experiments 3 and 4 showed that changes in the font used to present the study and test words also attenuated the contribution of fluency to the recognition decision when font change was manipulated between subjects, but not within subjects. Results suggest that the fluency heuristic is subject to metacognitive control, since participants' attributions of perceptual fluency depend on the perceived usefulness of fluency as a cue to recognition.     

Sensitivity and specificity of MMPI-2 neurologic correction factors: receiver operating characteristic analysis

A number of Minnesota Multiphasic Personality Inventory-2 (MMPI-2) items have been hypothesized to reflect neurologic symptomatology, rather than psychopathology, among closed-head-injury (CHI) patients. Some investigators have proposed a correction factor interpretive approach, which involves the deletion of such items from the MMPI-2 profile, as a method of reducing the probability of artificial clinical scale elevations due to the symptoms of CHI. The present study employed receiver operating characteristic (ROC) analysis to evaluate the sensitivity and specificity of three correction factors. All three factors demonstrated strong sensitivity when discriminating CHI patients from normal individuals but demonstrated poor specificity when discriminating CHI patients from psychiatric patients. These findings suggest that caution should be applied in using MMPI-2 neurologic correction factors, particularly with patients who might have comorbid psychiatric conditions.     

Cooling blocks ITM and LTM formation and preserves memory

In Lymnaea aerial respiratory behaviour can be operantly conditioned; snails learn not to perform this behaviour. Depending on the training procedure used, snails are competent to form either intermediate-term (ITM; lasting 1-3 h) or long-term (LTM; >4 h) memory. We found that cooling the snails for 1 h immediately after training was sufficient to block either ITM or LTM. Cooling snails for a similar period 10 or 15 min after cessation of training, failed to block ITM and LTM formation, respectively. Finally, we employed the cooling technique to extend both ITM and LTM. That is, cooling could prevent forgetting. Cooling extended LTM that normally persisted for 2 days to at least 8 days. These data are consistent with the hypothesis that forgetting is due to the learning and remembering of interfering events, and thus is an active process.