The levels of soluble urokinase plasminogen activator receptor (suPAR) in saliva are influenced by acute stress.

Although elevations in systemic suPAR levels have been associated with inflammatory conditions and with exposure to life stress and adversity, it is not yet clear whether acute psychological stress influences suPAR levels, either systemically and/or in saliva. The aim of this study was to investigate whether salivary suPAR levels are increased following exposure to acute psychological stress. Healthy subjects, aged 18-40 years, completed a laboratory psychological stressor and provided saliva samples before and after the stress test (60 min apart). Levels of suPAR as well as those of cytokines increased in the post-stress samples (all ps < .001). Baseline and post-stress IL-1ß and TNF-α as well as post-stress IL-6 correlated significantly with suPAR (all ps < .01), but IL-10 and baseline IL-6 did not. These results show that suPAR levels in saliva are stress-reactive and suggest a potential application as stress biomarkers in saliva, particularly given the advantage of easily detectable concentrations.

Effects of active engagement and spaced retrieval practice on knowledge and application of a self-assessment rubric.

PURPOSE/OBJECTIVES: This study examined effects of active engagement (ENG) and spaced retrieval practice (SRP) on D1 dental students' self-assessment knowledge acquisition. METHODS: D1 dental students (N = 120) were randomly assigned to one of four conditions in a 2 (ENG or no ENG) X 2 (SRP or no SRP) design. Students were tested on their knowledge of a self-assessment grading rubric (on a 30-item multiple-choice exam) and their ability to apply the rubric (on a simulated dentoform assessment). RESULTS: There were significant main effects of both ENG and SRP on both outcome measures. Both ENG and SRP increased students' knowledge of, and ability to apply, the self-assessment rubric. Effects of ENG were larger than those of SRP. There was also a significant ENG X SRP interaction on the knowledge measure. The effect of SRP was larger in the no-ENG conditions than the ENG conditions, which may reflect a ceiling effect in the ENG conditions. CONCLUSIONS: ENG and SRP have the potential to substantially enhance D1 dental students' learning outcomes. These results should motivate dental educators to reject outdated instructional techniques and thereby unleash students' full learning potential. Additional research is needed with a wider range of dental students and learner topics.

Why are consistently-handed individuals more authoritarian? The role of need for cognitive closure.

Recent studies indicate that individuals with consistent hand preference are more authoritarian than individuals whose preference is relatively inconsistent. We explored the role of epistemic needs in the handedness-authoritarianism relationship. Based on findings that consistent individuals are less cognitively flexible than inconsistent individuals, we hypothesized that consistent-handers would report greater need for definite knowledge. To measure this, we administered the revised Need for Cognitive Closure scale to a sample of undergraduates (N = 235), along with measures of handedness consistency and authoritarian submission. Consistent individuals scored significantly higher on authoritarian submission and need for closure. Need for closure fully mediated the relationship between consistency and submission. Consistent individuals also expressed greater prejudice against authoritarian out-groups such as immigrants and liberals. This effect was partially mediated by authoritarian submission. We theorize that consistent-handers' cognitive inflexibility leads them to covet definite knowledge. These individuals turn to authoritarianism because it promises to stifle dissent and protect existing (conventional) knowledge.

Is self-report a valid measure of unimanual object-based task performance?

Hand preference is commonly measured via self-report using instruments known as handedness inventories. These instruments query which hand subjects use to perform unimanual object-based tasks and also the consistency of usage. Scores reveal which hand people report using most (i.e., which hand is preferred). Some people report highly consistent usage of their preferred hand while others report relatively inconsistent usage. These reports are often assumed to be accurate descriptions of people's actual behavior, but empirical evidence concerning their validity is surprisingly scant. In the present research, subjects completed a handedness inventory on which higher scores indicated more consistent usage of the preferred hand. After a brief filled interval, subjects performed tasks listed on the inventory, spontaneously choosing which hand to use for each task. Subjects who scored higher on the inventory used the preferred hand more often. Subjects were then timed while performing the tasks as fast as they could with each hand. Subjects were faster when using their preferred hand and the magnitude of the preferred hand advantage was positively correlated with self-reported consistency. These results support the validity of inventory scores by showing that they are related to spontaneous hand choice and manual fluency when performing inventory tasks.

Handedness and the neurocognitive foundations of public attitudes about international laws and norms.

Whether Geneva Conventions (GC) rights should apply to terrorists is a contentious question that has received little attention in public opinion research. Both personality and contextual factors may be important. We queried participants' support for applying the GC to alleged terrorists, but first we measured participants' authoritarianism and presented them with a scenario concerning an alleged terrorist. We manipulated whether (1) the scenario contained examples of GC rights and (2) the alleged terrorist's religious affiliation was Muslim or non-Muslim. Support for applying the GC to alleged terrorists was high and unaffected by providing examples of GC provisions, but it was negatively related to authoritarianism. Support was reduced by priming with a Muslim terrorist, but only among participants exhibiting a behavioral marker for limited interhemispheric interaction - consistent-handedness. Consistent-handers in our sample expressed greater authoritarianism, suggesting that limited interhemispheric interaction promotes greater authoritarianism, which decreases support for applying the GC to alleged terrorists.

Making remembering more memorable.

Memory retrieval is a cognitive operation that itself can be remembered or forgotten, with potentially important consequences. To study memory for prior remembering, we had participants first study target words (e.g., bark) alongside semantically related cue words (e.g., dog). Then, on Test 1, participants retrieved targets in response to either the study cue or a changed cue that was semantically related to a homograph of the target (e.g., birch). Finally, on Test 2, participants retrieved all targets in response to the original study cues, and participants judged whether targets were previously retrieved on Test 1. As in previous research, cue change on Test 1 rendered target retrievals less memorable, suggesting context changes harm memory for prior remembering. We hypothesised that the negative effect of context change could be ameliorated by reminding participants of the original study cues during Test 1. We had participants either retrieve (Experiments 1 and 3, Ns = 46 and 62) or view (Experiment 2, N = 118) the study cue following each target retrieval. Reminding significantly reduced the negative effect of cue change, with self-generation being especially potent. This indicates that reminding can make remembering more memorable in the face of context change.

Effects of handedness consistency and saccade execution on eyewitness memory in cued- and free-recall procedures.

Identifying characteristics that distinguish between people with relatively good versus poor episodic memory is an important goal of eyewitness-memory research, as is identifying activities that can improve people's ability to retrieve episodic memories. Consistency of hand preference is a trait associated with the quality of people's episodic memory and repetitive saccade execution is an activity known to improve people's ability to retrieve episodic memories. These factors were examined in relation to cued and free recall of a staged criminal event. Individuals with inconsistent hand preference (versus consistent) remembered more on a cued-recall test and also freely recalled a larger amount of victim information. Repetitive saccade execution did not increase cued recall but did increase free recall of victim information. Theoretical implications are discussed, as is potential practical significance, with an emphasis on the size of the observed effects.

Bimanual coordination positively predicts episodic memory: A combined behavioral and MRI investigation.

Some people remember events more completely and accurately than other people, but the origins of individual differences in episodic memory are poorly understood. One way to advance understanding is by identifying characteristics of individuals that reliably covary with memory performance. Recent research suggests motor behavior is related to memory performance, with individuals who consistently use a single preferred hand for unimanual actions performing worse than individuals who make greater use of both hands. This research has relied on self-reports of behavior. It is unknown whether objective measures of motor behavior also predict memory performance. Here, we tested the predictive power of bimanual coordination, an important form of manual dexterity. Bimanual coordination, as measured objectively on the Purdue Pegboard Test, was positively related to correct recall on the California Verbal Learning Test-II and negatively related to false recall. Furthermore, MRI data revealed that cortical surface area in right lateral prefrontal regions was positively related to correct recall. In one of these regions, cortical thickness was negatively related to bimanual coordination. These results suggest that individual differences in episodic memory may partially reflect morphological variation in right lateral prefrontal cortex and suggest a relationship between neural correlates of episodic memory and motor behavior.

Salivary cytokine response in the aftermath of stress: An emotion regulation perspective.

Elevated inflammation in the context of stress has been implicated in mental and physical health. Approaching this from an emotion regulation perspective, we tested whether the salivary cytokine response to stress is dampened by using distraction to minimize opportunity for poststressor rumination. Healthy young adults were randomized to an acute stressor: modified Trier Social Stress Test (TSST, Study 1) or angry memory retrieval (Study 2). Within each study, participants were randomized to poststressor condition-rest or distraction-at a 3:1 ratio. Saliva, collected before and 40 min after the end of each stressor, was assayed for proinflammatory cytokines (PICs): interleukin-1ß (IL-1ß), TNF-α, and IL-6. Both stressors increased all PICs, and both provoked negative emotion. At 40 min post-TSST, salivary PIC increases did not differ between distraction and rest, but correlated positively with emotional reactivity to stress. At 40 min after memory retrieval, IL-1ß increases and intrusive rumination were lower during distraction than rest, but did not correlate with emotional reactivity. Trait rumination and interference control mechanisms, also measured, played little role in PIC increases. Overall, after some stressors, some salivary cytokine responses are lower during distraction than rest. The roles of specific emotions, emotional intensity, and poststressor timing of saliva collection in this finding require clarification. Furthermore, the possibility of two affective paths to inflammation in the context of stress-one sensitive to opportunities for early occurring emotion regulation (as reflected in emotional reactivity), and one sensitive to late-occurring emotion regulation (as reflected in distraction after stress)-deserves attention. (PsycINFO Database Record

Acute stress induces increases in salivary IL-10 levels.

The purpose of this study was to investigate the stress-reactivity of the anti-inflammatory cytokine, IL-10, in saliva and to determine how salivary IL-10 levels change in relation to those of IL-1ß, a pro-inflammatory cytokine, following stress. Healthy young adults were randomly assigned to retrieve a negative emotional memory (n = 46) or complete a modified version of the Trier Social Stress Test (n = 45). Saliva samples were taken 10 min before (baseline) and 50 min after (post-stressor) onset of a 10-min stressor, and were assayed using a high sensitivity multiplex assay for cytokines. Measurable IL-10 levels (above the minimum detectable concentration) were found in 96% of the baseline samples, and 98% of the post-stressor samples. Flow rate-adjusted salivary IL-10 levels as well as IL-1ß/IL-10 ratios showed moderate but statistically significant increases in response to stress. Measurement of salivary IL-10 and pro-/anti-inflammatory cytokine ratios may be useful, noninvasive tools, in stress research.

A ten-year follow-up of a study of memory for the attack of September 11, 2001: Flashbulb memories and memories for flashbulb events.

Within a week of the attack of September 11, 2001, a consortium of researchers from across the United States distributed a survey asking about the circumstances in which respondents learned of the attack (their flashbulb memories) and the facts about the attack itself (their event memories). Follow-up surveys were distributed 11, 25, and 119 months after the attack. The study, therefore, examines retention of flashbulb memories and event memories at a substantially longer retention interval than any previous study using a test-retest methodology, allowing for the study of such memories over the long term. There was rapid forgetting of both flashbulb and event memories within the first year, but the forgetting curves leveled off after that, not significantly changing even after a 10-year delay. Despite the initial rapid forgetting, confidence remained high throughout the 10-year period. Five putative factors affecting flashbulb memory consistency and event memory accuracy were examined: (a) attention to media, (b) the amount of discussion, (c) residency, (d) personal loss and/or inconvenience, and (e) emotional intensity. After 10 years, none of these factors predicted flashbulb memory consistency; media attention and ensuing conversation predicted event memory accuracy. Inconsistent flashbulb memories were more likely to be repeated rather than corrected over the 10-year period; inaccurate event memories, however, were more likely to be corrected. The findings suggest that even traumatic memories and those implicated in a community's collective identity may be inconsistent over time and these inconsistencies can persist without the corrective force of external influences.

On the use (and misuse?) of the Edinburgh Handedness Inventory.

Researchers who study human cognition and behavior, especially from a neuroscience perspective, often measure subjects' handedness. The most common measure of handedness is the Edinburgh Handedness Inventory (EHI; Oldfield, 1971). Several potential problems with the EHI have been identified during its long history. We informally observed that individual researchers have adopted a variety of modified versions of the EHI, each addressing perceived shortcomings in its own way. To confirm this, we reviewed 899 articles reporting usage of the EHI from 1998 to 2012. For those articles reporting details of the instrument used, we coded information about test items, response format, and scheme for classifying individuals as right-handed. We found tremendous diversity in all three components of the inventory, confirming that many variants of the EHI are used in contemporary research. We furthermore report evidence that researchers who use variants may be unaware that they are not using the original instrument. Variant usage appears to be largely ad hoc and lacking any semblance of uniformity within the scientific community. We discuss how highly variable usage of the EHI may imperil efforts to produce replicable and convergent research findings, and we offer recommendations for future action.

Why does saccade execution increase episodic memory retrieval? A test of the top-down attentional control hypothesis.

Making repetitive saccadic eye movements has been found to increase subsequent episodic memory retrieval and also to increase subsequent top-down attentional control. We theorise that these effects are related such that saccade-induced changes in attentional processing facilitate memory retrieval. We tested this idea by examining the effect of saccade execution on retrieval conditions that differed in relative ease of consciously accessing episodic memories. Based on recent theories of episodic retrieval, we reasoned that there is a larger role for top-down attention when memories are more difficult to access. Consequently, we expected saccade execution to have a greater facilitative effect on retrieval when memories were more difficult to access. We obtained the expected result in a recall procedure in Experiment 1 and in a recognition procedure in Experiment 2. We also examined an individual difference factor--consistency of handedness--as a possible moderator of saccade execution effects on retrieval. We discuss how our top-down attentional control hypothesis can be extended to explain beneficial effects of saccade execution on other types of cognition, as well as negative effects on retrieval in some cases.

Consistent-handed individuals are more authoritarian.

Individuals differ in the consistency with which they use one hand over the other to perform everyday activities. Some individuals are very consistent, habitually using a single hand to perform most tasks. Others are relatively inconsistent, and hence make greater use of both hands. More- versus less-consistent individuals have been shown to differ in numerous aspects of personality and cognition. In several respects consistent-handed individuals resemble authoritarian individuals. For example, both consistent-handedness and authoritarianism have been linked to cognitive inflexibility. Therefore we hypothesised that consistent-handedness is an external marker for authoritarianism. Confirming our hypothesis, we found that consistent-handers scored higher than inconsistent-handers on a measure of submission to authority, were more likely to identify with a conservative political party (Republican), and expressed less-positive attitudes towards out-groups. We propose that authoritarianism may be influenced by the degree of interaction between the left and right brain hemispheres, which has been found to differ between consistent- and inconsistent-handed individuals.

Memory for hand-use depends on consistency of handedness.

Individuals who do not consistently use the same hand to perform unimanual tasks (inconsistent-handed) outperform consistent right- and left-handed individuals on tests of episodic memory. We explored whether the inconsistent-hander (ICH) memory advantage extends to memory for unimanual hand use itself. Are ICHs better able to remember which hand they used to perform actions? Opposing predictions are possible, stemming from the finding that some regions of the corpus callosum are larger in ICHs, especially those that connect motor areas. One hypothesis is that greater callosally mediated interhemispheric interaction produces ICHs' superior retrieval of episodic memories, and this may extend to episodic memories for hand use. Alternatively, we also hypothesized that greater interhemispheric interaction could produce more bilateral activation in motor areas during the performance and retrieval of unimanual actions. This could interfere with ICHs' ability to remember which hand they used. To test these competing predictions in the current study, consistent- and inconsistent-handers performed unimanual actions, half of which required manipulating objects and half of which did not. Each action was performed four times in one of five conditions that differed in the ratio of left to right hand use: always left (4:0), usually left (3:1), equal (2:2), usually right (1:3), or always right (0:4). We compared consistent- and inconsistent-handers on recall of the left:right ratio for each action. ICHs remembered how they performed actions better than consistent-handers, regardless of ratio. These findings provide another example of superior episodic retrieval in ICHs. We discuss how greater interaction might benefit memory for hand use.

The effect of repetitive saccade execution on the attention network test: enhancing executive function with a flick of the eyes.

The simple act of repeatedly looking left and right can enhance subsequent cognition, including divergent thinking, detection of matching letters from visual arrays, and memory retrieval. One hypothesis is that saccade execution enhances subsequent cognition by altering attentional control. To test this hypothesis, we compared performance following repetitive bilateral saccades or central fixation on the revised attention network test, which measures the operation of three distinct attentional networks: alerting, orienting, and executive function. The primary finding was that saccade execution increased the subsequent operation of the executive function network, which encompasses attentional control. Specifically, saccade execution decreased response time to target stimuli in the presence of response-incongruent flankers. A secondary finding was that saccade execution decreased response time to targets when an invalid location was cued prior to target onset. These findings suggest that saccades are an effective means of improving attentional control. Of greater theoretical importance, the study establishes attentional enhancement as a potential mechanism by which saccades enhance other aspects of cognition. Although some saccade execution effects have been found to depend on consistency of handedness (i.e., the consistency with which an individual uses one hand over the other), saccade-induced enhancement of attentional control occurred independently of handedness consistency.

Is handedness related to anxiety? New answers to an old question.

Is handedness related to anxiety? Two separable dimensions of handedness have been considered in previous studies: Direction of the preferred hand (left or right) and the consistency with which the preferred hand is used over the nonpreferred hand (consistent or inconsistent). Findings have included (1) left-handedness being associated with greater anxiety than right-handedness, (2) consistent-handedness being associated with greater anxiety than inconsistent-handedness and (3) neither dimension being associated with anxiety. Here, we administered measures of trait anxiety, state anxiety and worry to individuals classified as consistent-left, inconsistent-left, inconsistent-right or consistent-right. Neither direction nor consistency had a main effect on any measure. However, there was a direction by consistency interaction in trait and state anxiety measured on the State/Trait Anxiety Inventory. Among right-handers, inconsistent individuals reported less anxiety than consistent individuals. Among left-handers, consistency was unrelated to anxiety. In consequence of this pattern, inconsistent right-handers were less anxious than inconsistent left-handers. Hence, supporting prior studies, left-handedness was associated with greater anxiety than right-handedness (but only among inconsistent individuals) and consistency was associated with greater anxiety than inconsistency (but only among right-handers). These findings advance our understanding of handedness consistency as an important individual difference factor in personality and cognition.

Consistency of handedness, regardless of direction, predicts baseline memory accuracy and potential for memory enhancement.

Research has shown that consistently right-handed individuals have poorer memory than do inconsistently right- or left-handed individuals under baseline conditions but more reliably exhibit enhanced memory retrieval after making a series of saccadic eye movements. From this it could be that consistent versus inconsistent handedness, regardless of left/right direction, is an important individual difference factor in memory. Or, more specifically, it could be the presence or absence of consistent right-handedness that matters for memory. To resolve this ambiguity, we compared consistent and inconsistent left- and right-handers on associative recognition tests taken after saccades or a no-saccades control activity. Consistent-handers exhibited poorer memory than did inconsistent-handers following the control activity, and saccades enhanced retrieval for consistent-handers only. Saccades impaired retrieval for inconsistent-handers. None of these effects depended on left/right direction. Hence, this study establishes handedness consistency, regardless of direction, as an important individual difference factor in memory.

Inconsistent handedness and saccade execution benefit face memory without affecting interhemispheric interaction.

Individuals who consistently use their dominant hand for most tasks exhibit poorer memory than individuals whose handedness is relatively inconsistent, but consistent-handers' memory can be enhanced by making repetitive saccadic eye movements before attempting retrieval. One account of these effects is that inconsistent handedness and saccade execution are associated with increased interhemispheric interaction, which putatively facilitates retrieval. We tested this account by having participants classify faces as famous or novel. Faces were presented in the left and right visual fields simultaneously (bilaterally) or in one field only (unilaterally). As in prior studies, famous faces were classified more quickly and more accurately given bilateral presentation, but novel faces were not. These bilateral gain effects indicate that interhemispheric interaction specifically facilitates famous-face recognition, and therefore larger gains may reflect greater interhemispheric interaction. However, neither inconsistent handedness nor saccade execution increased the size of bilateral gain. Inconsistent handedness and saccade execution (the latter for consistent-handers only) did increase face-classification accuracy, but the increases were not specific to famous-face recognition, and, in fact, were somewhat stronger for novel-face identification. These results extend the beneficial mnemonic effects of inconsistent handedness and saccade execution to faces, but indicate that these benefits are not caused by increased interhemispheric interaction.

Is saccade-induced retrieval enhancement a potential means of improving eyewitness evidence?

Saccade-induced retrieval enhancement (SIRE) is the effect whereby making bilateral saccades enhances the subsequent retrieval of memories. Two experiments explored SIRE's potential to improve eyewitness evidence. Participants viewed slideshows depicting crimes, and received contradictory and additive misinformation about event details either once (Experiment 1) or three times (Experiment 2). Participants then performed saccades or a fixation control task before being tested on their memory for the slideshows and making confidence judgements. Saccades increased discrimination between seen and unseen event details regardless of whether or what type of misinformation was presented. Because prior studies indicated that SIRE might be more robust for individuals who are strongly right-handed versus not, we examined SIRE as a function of handedness and found that saccades improved memory for event details regardless of participants' handedness. However, participants who were not strongly right-handed had fewer false memories than participants who were strongly right-handed, extending previous findings of superior memory among individuals who are not strongly right-handed. Saccades also increased confidence in true memories (Experiment 1) and decreased confidence in false memories (Experiment 2). The results support SIRE's potential to improve eyewitness evidence.