No evidence of attentional bias toward threatening conspecific and allospecific faces in capuchin monkeys (Sapajus [Cebus] apella) using a dot-probe task

The ability to quickly perceive and interpret threatening facial expressions from others is critical for successfully maintaining group cohesion in social nonhuman primate species. Rapid detection of threatening or negative stimuli in the environment compared to neutral stimuli, referred to as an attentional bias toward threat, is adaptive in that faster threat detection can lead to greater survival outcomes. However, the evolutionary roots of attentional bias formation toward social threat are not well understood. The present study investigated attentional biases toward social threat and the factors associated with them, including underlying hormonal mechanisms, in socially housed capuchin monkeys. Attentional biases were assessed using a dot-probe task that measured capuchins' latency to respond to a target using a joystick after viewing threatening or neutral conspecific or allospecific faces or nonface stimuli. In our first study, we examined how age, dominance status, sex, and cortisol level related to attentional biases. In our second study, we examined how manipulated oxytocin (OT) influenced attentional biases. Capuchin monkeys did not show attentional biases toward threatening faces or objects, but they showed attentional avoidance of scrambled familiar conspecific face stimuli. Cortisol and social rank were associated with attentional bias toward threat in the capuchin monkeys that participated in this study, which suggests that stress and dominance relate to attentional bias toward social threat. Manipulated OT increased attentional avoidance of scrambled familiar and unfamiliar face images, but not unscrambled faces or objects. Overall, we did not find compelling evidence of attentional biases toward social threat in capuchin monkeys. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The illusory truth effect: A review of how repetition increases belief in misinformation

Repetition increases belief in information, a phenomenon known as the illusory truth effect. In laboratory experiments, the illusory truth effect has often been examined using general trivia statements as stimuli, but repetition also increases belief in misinformation, such as fake news headlines and conspiracy beliefs. Repetition even increases belief in claims that are implausible or that contradict prior knowledge. Repetition also has broader impacts beyond belief, such as increasing sharing intentions of news headlines and decreasing how unethical an act is perceived to be. Although the illusory truth effect is robust, some interventions reduce its magnitude, including instruction to focus on accuracy and awareness of the illusory truth effect. These strategies may be effective for reducing belief in misinformation.

Age and Gender Differences in the Borrowing of Personal Stories

BACKGROUND

In prior research, about half of undergraduate students claimed to have "borrowed" a story, by telling someone else's autobiographical memory as if it was their own. Given that borrowing stories often involves intentional fabrication, and given that there are age-related declines in lying, we hypothesized that reports of intentionally borrowing stories should decline with age.

METHODS

We recruited participants who ranged in age from 18 to 86 and asked them to complete an online retrospective survey about borrowing stories.

RESULTS

Consistent with our hypothesis, older age was associated with lower reports of borrowing stories. Furthermore, among people who did report borrowing a story, older age was associated with less frequent story borrowing and less recent story borrowing.

CONCLUSION

These findings highlight the importance of using age-diverse samples when examining social memory phenomena. Findings based upon undergraduate students do not always replicate in other age groups.

Association of white matter hyperintensities and clinical vascular burden with depressive symptoms in Black older adults

OBJECTIVES

Black older adults have a higher vascular burden compared to non-Hispanic White (NHW) older adults, which may put them at risk for a form of depression known as vascular depression (VaDep). The literature examining VaDep in Black older adults is sparse. The current study addressed this important gap by examining whether vascular burden was associated with depressive symptoms in Black older adults.

METHODS

Participants included 113 Black older adults from the Healthy Brain Project, a substudy of the Health, Aging, and Body Composition Study. In multiple regression analyses, clinical vascular burden (sum of vascular conditions) and white matter hyperintensity (WMH) volume predicted depressive symptoms as measured by the Center for Epidemiologic Studies Depression Scale, controlling for demographic variables. Follow-up analyses compared the associations in the Black subsample and in 179 NHW older adults.

RESULTS

Higher total WMH volume, but not clinically-defined vascular burden, predicted higher concurrent depressive symptoms and higher average depressive symptoms over 4 years. Similar associations were found between uncinate fasciculus (UF) WMHs and concurrent depressive symptoms and between superior longitudinal fasciculus WMHs and average depressive symptoms. The association between depressive symptoms and UF WMH was stronger in Black compared to NHW individuals.

CONCLUSION

This research is consistent with the VaDep hypothesis and extends it to Black older adults, a group that has historically been underrepresented in the literature. Results highlight WMH in the UF as particularly relevant to depressive symptoms in Black older adults and suggest this group may be particularly vulnerable to the negative effects of WMH.

Younger and older adults' memory of past feelings surrounding an election

People often misremember their past feelings, especially when recalling their prior mood as opposed to their specific emotions in response to events. A previous study also found that the direction of memory errors varies based on feeling type; younger adults overestimated the intensity of prior moods but underestimated the intensity of prior event-specific emotions. This study aimed to replicate these patterns and test whether they vary with age. In doing so, we also tested whether an age-related positivity effect would emerge, such that older adults would be relatively more likely to overestimate past positive feelings and underestimate past negative feelings. Using a sample of American voters, who reported their feelings following the 2020 United States presidential election, we found that both younger and older adults subsequently overestimated the intensity of their past mood in the week following the election but were relatively accurate in recalling the intensity of their prior emotions about the election result. Unexpectedly, among election losers, we also observed an age-related negativity effect in recall for prior mood. When faced with negative real-world events, older adults may not show the same positivity biases that are observed in lab studies.

The illusory truth effect requires semantic coherence across repetitions

Repeated exposure to information increases its' perceived truth, and this illusory truth effect is often explained by two theoretical frameworks: the fluency account and the referential theory of truth. Whereas the fluency account suggests that prior activation of a single referent within a statement should increase its perceived truth, the referential theory makes no such predictions. The referential theory instead proposes that when a statement is processed, it activates the corresponding memory referents within that statement and strengthens the connection between these referents in the semantic memory network. Because repeated statements will have more coherent corresponding referents than new statements, they are perceived as relatively truer. Experiments 1 and 2 focused on testing the fluency account, with participants exposed to one or two of a statement's referents before evaluating that statement's truth. Experiments 3 and 4 focused on the referential theory by exposing participants to non-critical facts that linked together two of a critical statements' referents before evaluating the truth of the critical statements. We consistently observed a standard illusory truth effect, such that facts that repeated verbatim were rated as truer than new facts. However, perceived truth was not affected by prior exposure to the critical statement's topic (Experiment 1) or by prior exposure to non-critical facts related to the same topic(s) as the critical statement (Experiment 2). There was also no boost in perceived truth following prior exposure to non-critical facts that linked together two of the primary referents of the critical statement but did so in a semantically distinct manner from how those same referents were linked in the critical statement itself (Experiments 3 and 4). However, Experiment 4 demonstrated that perceived truth significantly increased if there was prior exposure to non-critical facts that linked two of the critical statement primary referents in a way that was semantically coherent with how those same referents were linked within the critical statement. Together, these results are consistent with the referential theory, and suggest that semantic consistency across repetitions plays a crucial role in leading to repetition-based illusory truth effects.

Impact of cardiovascular risk factors on the relationships of physical activity with mood and cognitive function in a diverse sample

Physical activity has well-known benefits for older adults' mood and cognitive functioning; however, it is not clear whether risk factors for cardiovascular disease (CVD) affect the relationships of physical activity with these health outcomes among diverse older adults. This study investigated the impact of CVD risk burden on the relationships among self-reported physical activity, mood, and cognitive functioning in a diverse sample of 62 adults age 45 and older. We found that higher physical activity was associated with better attention and verbal working memory at lower CVD risk, but with worse attention and verbal working memory at higher CVD risk levels. Thus, higher CVD risk might limit the effectiveness of exercise interventions for mood and cognitive functioning. Future studies are needed to further clarify individual differences that impact the relationships among physical activity, CVD risk, and cognitive outcomes.

Age differences in affective forecasting accuracy

Affective forecasts are people's predictions of their future feelings in response to future events. In this study, we examined whether younger and older adults differ in their affective forecasting accuracy. To do so, we recruited younger and older American voters and asked them to predict how they would feel following the 2020 U.S. presidential election. In the general feelings condition, participants predicted how they would feel, in general, following an election victory or loss. In the event-related feelings condition, participants predicted their future feelings specifically about an election victory and about an election loss. Later, these same participants reported their experienced feelings (either in general or about the election outcome). In the general feelings condition, age differences in affective forecasting accuracy varied as a function of whether participants' preferred candidate won or lost the election. Among election victors, there were age-related improvements in affective forecasting accuracy of negative feelings. In contrast, among election losers there were age-related declines in affective forecasting accuracy of both negative and positive feelings. A different pattern emerged for participants in the event-related feelings condition. These participants were highly accurate in their affective forecasts, and there were minimal age differences in forecasting accuracy. Together, these results show that age differences in affective forecasting accuracy depend upon both the type of future event, and the type of future feeling being predicted. When considered together, these results also suggest that the focusing illusion plays a key role in modulating age differences in affective forecasting accuracy. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Rostral anterior cingulate connectivity in older adults with subthreshold depressive symptoms: A preliminary study

Subthreshold depressive symptoms are highly prevalent among older adults and are associated with numerous health risks including cognitive decline and decreased physical health. One brain region central to neuroanatomical models of depressive disorders is the anterior cingulate cortex (ACC). The rostral portion of the ACC-comprised of the pregenual ACC and subgenual ACC-is implicated in emotion control and reward processing. The goal of the current study was to examine how functional connectivity in subregions of the rostral ACC relate to depressive symptoms, measured by the Beck Depression Inventory-Second Edition, in an ethnically diverse sample of 28 community-dwelling older adults. Based on meta-analyses of previous studies in primarily young adults with clinical depression, we hypothesized that greater depressive symptoms would be associated with primarily increased resting-state functional connectivity from both the subgenual ACC and pregenual ACC to default mode network regions and the dorsolateral PFC. We instead found that higher depressive symptoms were associated with lower functional connectivity of the ACC to the dorsolateral PFC and regions within the default mode network, including from the subgenual ACC to the dorsolateral PFC and anterior cingulate and from the pregenual ACC to the middle cingulate gyrus. This preliminary study highlights brain alterations at subthreshold levels of depressive symptoms in older adults, which could serve as targets for interventions.

Preliminary User Evaluation of a Physical Activity Smartphone App for Older Adults

Objectives

Mobile health (mHealth) delivered through smartphone apps is a viable means of improving health behaviors. Technologies can be strengthened and made more age-inclusive by involving older adults as co-designers, resulting in more accessible and effective products. This study's purpose is to describe preliminary acceptability and feasibility of a physical activity (PA) app tailored to underactive older people.

Methods

Moving Up is a multi-feature app designed to increase PA and reduce sedentary behaviors in underactive older adults. The suite houses a core activity tracker and three add-on features that target correlates of inactivity: sedentary behavior, stereotypes about aging, and PA knowledge and routines. Three groups of 4-5 older adult smartphone owners were provided with and oriented to the Moving Up app activity tracker and one add-on feature. Participants beta-tested the app for two weeks, after which each cohort reconvened to discuss experiences, make recommendations for app improvements, and complete a usability questionnaire on their assigned feature.

Results

Thirteen participants (median age, 71 years; iOS users, n=8; females, n=12) completed the beta-testing period and returned for follow-up. Reported usability was moderate across the features. Sentiments about app content and general impressions were mainly positive, although users made several recommendations for app improvements such as more individualized messaging and timely notifications.

Conclusions

A PA app for older adults demonstrated generally good usability and acceptability. Integrating the impressions and recommendations from older adults into the design of mHealth tools will enhance overall usability and likelihood to positively influence PA behaviors long-term.

Age-differences in interpreting the valence of ambiguous facial expressions: evidence for multiple contributing processes

Surprised facial expressions, which are ambiguous in valence, are interpreted more positively by older adults than by younger adults. To evaluate the processes contributing to this age difference, we varied the spatial frequency of the surprised-face stimuli. When faces were presented in a low-spatial-frequency band, it biased participants to rate them negatively. Although this occurred for both younger and older adults, the older adults' ratings of the low-spatial-frequency faces were more positive than that of the younger adults. This suggests that there is an age-related reduction in the default negativity of interpretations. We also found that older adults, as a whole, rated the high-spatial-frequency faces more positively than did younger adults. However, this effect was eliminated for the subset of older adults with poor high-spatial-frequency perception abilities for whom these faces were difficult to perceive. Thus, older adults' more positive interpretations of surprised faces may also reflect cognitively-effortful regulatory processes.

Thinking about the past, present, and future: Time perspective and self-esteem in adolescents, young adults, middle-aged adults, and older adults

We examined time perspective and self-esteem in adolescents, young adults, middle-aged adults, and older adults. Time perspective was measured with scales that assess relative orientations and relationships among the past, present, and future. Age effects were examined with standard analytic strategies to determine categorical differences between age groups and with new statistical techniques designed to show continuous age patterns. Findings indicated that (1) thinking about the future was greatest for adolescents and young adults and lowest for middle-aged and older adults, and thinking about the present increased across ages; (2) fewer adolescents and middle-aged participants perceived that the time periods were interrelated compared to younger and older adults; and (3) across ages, a greater emphasis towards the past compared to other time periods was associated with lower self-esteem, whereas emphasizing the present and the future jointly was associated with higher self-esteem.

The effects of repetition frequency on the illusory truth effect

Repeated information is often perceived as more truthful than new information. This finding is known as the illusory truth effect, and it is typically thought to occur because repetition increases processing fluency. Because fluency and truth are frequently correlated in the real world, people learn to use processing fluency as a marker for truthfulness. Although the illusory truth effect is a robust phenomenon, almost all studies examining it have used three or fewer repetitions. To address this limitation, we conducted two experiments using a larger number of repetitions. In Experiment 1, we showed participants trivia statements up to 9 times and in Experiment 2 statements were shown up to 27 times. Later, participants rated the truthfulness of the previously seen statements and of new statements. In both experiments, we found that perceived truthfulness increased as the number of repetitions increased. However, these truth rating increases were logarithmic in shape. The largest increase in perceived truth came from encountering a statement for the second time, and beyond this were incrementally smaller increases in perceived truth for each additional repetition. These findings add to our theoretical understanding of the illusory truth effect and have applications for advertising, politics, and the propagation of "fake news."

COVID-19 Worries and Behavior Changes in Older and Younger Men and Women

OBJECTIVES

The case fatality rate of coronavirus disease 2019 (COVID-19) is higher among older adults than younger adults and is also higher among men than women. However, worry, which is a key motivator of behavioral health changes, occurs less frequently for older than younger adults, and less frequently for men than women. Building on this, we tested whether older adults-and particularly older men-would report the least amount of COVID-19 worry and also fewer COVID-19 behavior changes.

METHOD

From March 23-31, 2020, we administered an online questionnaire assessing COVID-19 perceptions, worries, and behavior changes. Participants were a convenience sample of U.S. residents, who were community-dwelling younger adults (18-35) or older adults (65-81). Analyses included 146 younger adults (68 men, 78 women) and 156 older adults (82 men, 74 women). Participants were predominately white, living in suburban/urban areas, and had completed some college.

RESULTS

During the early phase of the outbreak in the United States, older adults perceived the risks of COVID-19 to be higher than did younger adults. Despite this, older men were comparatively less worried about COVID-19 than their younger counterparts. Compared with the other participants, older men had also implemented the fewest behavior changes.

DISCUSSION

Interventions are needed to increase COVID-19 behavior changes in older men. These results also highlight the importance of understanding emotional responses to COVID-19, as these are predictive of their behavioral responses.

Confucian Values as a Buffer Against Age-Based Stereotype Threat for Chinese Older Adults

OBJECTIVES

Research has shown that stereotype threat can impair older adults' memory in Western cultures. We tested whether this also occurs for older adults from the East Asian Chinese culture. We also tested whether an intervention that highlighted Confucian principles would protect Chinese older adults from stereotype threat's detrimental effects.

METHOD

Culturally-Chinese older adults residing in the United States completed a memory test either under age-based stereotype threat about cognitive decline or not. Prior to this, some participants were also reminded of Confucian traditions of filial piety and were assured these values had been transmitted to the younger generation.

RESULTS

Stereotype threat impaired Chinese older adults' memory performance. However, our intervention was effective in eliminating this deficit. When the Chinese participants were reminded of the Confucian principle of filial piety they did not exhibit stereotype threat effects.

DISCUSSION

Confirming that younger adults have an obligation to respect their elders can eliminate the social-evaluative pressure of stereotype threat for Chinese older adults. These findings are noteworthy since population aging is happening at an unprecedented pace in East Asia. Although our results suggest that stereotype threat can adversely affect older adults' cognitive performance in these societies, we also identify a culturally-based intervention to alleviate this impairment.

Wisdom Once Gained Is Not Easily Lost: Implicit Theories About Wisdom and Age-Related Cognitive Declines

Background and Objectives

Most people agree that cognitive capabilities are an integral component of wisdom and its development. However, a question that has received less attention is whether people view maintaining cognitive capabilities as a necessary prerequisite for maintaining wisdom.

Research Design and Methods

This study used a mixed-methods approach to evaluate people's views about the relationship between age-related cognitive declines, Alzheimer's disease (AD), and wisdom. Our final sample of 1,519 adults ranged in age from 18 to 86.

Results

The majority of participants stated that wisdom could be present even in people with significant age-related cognitive declines or with AD. In the qualitative responses, common justifications for this were (a) that even people with severe AD can still exhibit wise behaviors during lucid moments, (b) that wisdom is an immutable characteristic that is impossible to lose, and (c) that wisdom maintenance and cognitive capability maintenance are separate constructs.

Discussion and Implications

Although prior research has examined implicit theories about the role of cognition in the development of wisdom, this is the first study to examine implicit theories about whether cognitive declines lead to wisdom declines. The results suggest that most people hold essentialist beliefs about wisdom, viewing it as a fixed and unchangeable trait rather than as a malleable skill.

The limited roles of cognitive capabilities and future time perspective in contributing to positivity effects

When compared to younger adults, older adults tend to favor positive over negative information in attention and memory. This is known as the positivity effect. Although this is a robust phenomenon, there is still debate about how it relates to individual differences in cognitive capabilities and future time perspective (FTP). To address this, we investigated how measures of fluid cognitive capabilities and FTP related to positivity effects within the domains of episodic memory, visual attention, and autobiographical memory. Cognitive capabilities were assessed using the National Institute of Health Toolbox Cognition battery, and included assessments of executive function, working memory, episodic memory, and processing speed. FTP was assessed via the Carstensen and Lang (1996) scale. Within our final sample (N = 196), we replicated positivity effects in all three task domains, which were all driven by age differences in how people responded to negative (but not positive) information. However, there was limited evidence that the magnitude of these age-related reductions in negativity varied as a function of individual differences in older adults' cognitive capabilities or FTP. Furthermore, when FTP did emerge as a predictor, the pattern was not in line with expectations based upon socioemotional selectivity theory. Thus, the positivity effect may be less reliant on cognitive capabilities and self-reported FTP than is often assumed. Given that there was also very little consistency in the extent to which participants displayed positivity effects across the task domains, these results also raise the possibility that there may be multiple mechanisms underlying positivity effects.

The effects of stereotype threat on older adults' walking performance as a function of task difficulty and resource evaluations

Stereotype threat occurs when people are concerned about confirming a negative stereotype about their social group, and this often leads people to underperform within the threatened domain. Although this is well-documented, the majority of prior studies examining stereotype threat in older adults have focused on cognitive outcomes and comparatively less research has focused on how stereotype threat affects physical outcomes. In this study, we examined whether negative age-based evaluations invoke stereotype threat and adversely affect older adults' gait, and whether this depends upon the difficulty of the gait task and upon participants' evaluations of their own resources to cope with the demands of the gait task. To test this, we recruited 163 healthy, community-dwelling older adults and asked them to complete either an "easy" gait task (i.e., walking at their own comfortable pace) or a "difficult" gait task (i.e., walking within a 15 cm narrow base of support) along a 24' temporospatial-measuring walkway. This was done in either the presence or absence of a negative age-based evaluation. Results showed that the adverse effects of stereotype threat (i.e., walking slower, with relatively more variability in speed, and with more step errors) were generally limited to participants completing the difficult gait task who were not confident that they had sufficient resources to cope with the demands of the task. Thus, stereotype threat can impair older adults' physical performance, but the magnitude of this effect depends upon the task's objective difficulty and on participants' subjective evaluations of their own resources. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Emotional expressions affect perceptions of younger and older adults' everyday competence

Facial expressions of emotion allow us to predict other people's intentions and behaviors. However, we often overextend these predictions to also make inferences about other people's underlying tendencies and dispositions. People with happy expressions are perceived to have stable positive traits whereas people with sad expressions are perceived to have stable negative traits. In these studies, we tested whether this extends to inferences about younger and older adults' abilities to complete fundamental activities of independent living, such as independently getting dressed, preparing food, and remembering directions. Our results showed that both younger and older adult targets were perceived to have greater everyday competence in completing activities of daily living (ADLs), instrumental activities of daily living (IADLs), and memory tasks when they displayed happy or neutral expressions rather than sad expressions. This pattern did not vary based upon either the target's gender or the participant's age. However, for the ADL and IADL ratings, the overgeneralization of emotions to ratings of everyday competence was greater for the older adult targets than for the younger adult targets. Drawing from the ecological approach to social perception, these results suggests that spontaneous trait inferences are most likely to occur when the age-trait association is strong. Given that perceptions of competence are also associated with behavioral ramifications, such as being subjected to patronizing behavior, having lower employment opportunities, and being seen as low in social status, our results also suggest that older adults whose facial expressions appear sad may be especially prone to these adverse outcomes. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Stereotype Threat Reduces the Positivity of Older Adults' Recall

OBJECTIVES

As people get older, they show a relative preference to remember positive information over negative information. In two experiments, we tested whether the positivity of older adults' memory is affected by stereotype threat about age-related cognitive declines. We also tested whether highlighting a positive aging stereotype (older adults are wise) would inoculate older adults from stereotype threat's adverse effects.

METHOD

In Experiments 1 and 2, we manipulated whether stereotypes about age-related cognitive decline were highlighted (stereotype threat) or mitigated (stereotype alleviation). In Experiment 2, we included a third condition (intervention + stereotype threat), which highlighted positive and negative aging stereotypes. Participants then saw emotionally evocative pictures and completed a memory test.

RESULTS

In both experiments, stereotype threat selectively reduced older adults' memory for positive pictures but did not affect their memory for negative pictures. This eliminated the positivity effect (i.e., the Age × Valence interaction; Experiment 1). Our positive stereotype intervention did not reduce stereotype threat's adverse effect (Experiment 2).

DISCUSSION

Our findings show that the positivity effect is more robust when testing situations minimize stereotype threat. They also suggest that health interventions designed to capitalize on the positivity effect should ensure that ageist stereotypes are mitigated in the environment.

Optimism for the Future in Younger and Older Adults

OBJECTIVES

Research has suggested that older adults are less optimistic about their future than younger adults; however, a limitation of prior studies is that younger and older adults were forecasting to different ages and stages of life. To address this, we investigated whether there are age differences in future optimism when people project to the exact same age. We also tested whether optimism differs when projecting one's own future versus another person's future.

METHOD

Participants were 285 younger and 292 older adults recruited from Amazon Mechanical Turk. Participants completed writing and word-rating tasks in which they imagined their own future in 15 years, their own future at age 85, or the average person's future at age 85.

RESULTS

Younger adults were more optimistic than older adults about their own future in 15 years. In contrast, both age groups were similarly optimistic about their future at age 85 and expected it to be more positive than others' future at age 85.

DISCUSSION

Contrary to previous research, younger and older adults had comparable future forecasts when projecting to the exact same age. These findings emphasize the need to consider age and stage of life when examining age differences in future optimism.

Negative Aging Stereotypes Impair Performance on Brief Cognitive Tests Used to Screen for Predementia

Objectives

There is today ample evidence that negative aging stereotypes impair healthy older adults' performance on cognitive tasks. Here, we tested whether these stereotypes also decrease performance during the screening for predementia on short cognitive tests widely used in primary care.

Method

An experiment was conducted on 80 healthy older adults taking the Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) under Threat or Reduced-threat condition.

Results

Stereotype threat significantly impaired older adults' performance on both tests, resulting in 40% of older adults meeting the screening criteria for predementia, compared with 10% in Reduced-threat condition (MMSE and MoCA averaged).

Discussion

Our research highlights the influence of aging stereotypes on short cognitive tests used to screen for predementia. It is of critical importance that physicians provide a threat-free testing environment. Further research should clarify whether this socially induced bias may also operate in secondary care by generating false positives.

An Examination of Age-Based Stereotype Threat About Cognitive Decline

"Stereotype threat" is often thought of as a singular construct, with moderators and mechanisms that are stable across groups and domains. However, this is not always true. To illustrate this, the current review focuses on the stereotype threat that older adults face about their cognitive abilities. Drawing upon the multithreat framework, I first provide evidence that this is a self-concept threat and not a group-reputation threat. Because this differs from the forms of stereotype threat experienced by other groups (e.g., the threat that minority students face about their intellectual abilities), the moderators of stereotype threat observed in other groups (i.e., group identification) do not always generalize to age-based stereotype threat about cognitive decline. Looking beyond the forms of stereotype threat elicited, this review also provides evidence that the mechanisms underlying stereotype-threat effects may vary across the adult life span. Because of age-related improvements in emotion-regulation abilities, stereotype threat does not seem to reduce older adults' executive-control resources. Overall, this review highlights the need to approach the concept of stereotype threat with more granularity, allowing researchers to design more effective stereotype-threat interventions. It will also shed light on why certain stereotype threat effects "fail to replicate" across domains or groups.

Stereotypes, Warnings, and Identity-Related Variables Influence Older Adults' Susceptibility to Associative False Memory Errors

Background and Objectives

Activating ageist stereotypes can impair older adults' ability to remember information. This effect has been shown to be strongest for older adults who possess certain characteristics (e.g., young-old, highly educated). The present study extended this line of research to investigate the relationship between stereotyping and false memory susceptibility in older adults.

Research Design and Methods

We first presented older adults with lists of associated words in an incidental learning paradigm. Afterward, we manipulated whether participants were presented with stereotypes about aging and whether they were given warnings about the associative nature of the lists. Participants then completed a yes/no recognition test and answered demographic questions.

Results

Older adults in the stereotyped group were more likely to falsely recognize non-presented theme words than older adults in the control group. Further, those who were highly educated and/or retired were most likely to experience this false memory susceptibility.

Discussion and Implications

Similar to the research on veridical memory, these findings suggest that the effects of ageist stereotyping on older adults' false memory susceptibility may be best understood in terms of the individual differences that older adults possess. Identifying the types of people who are at risk of experiencing stereotype threat is an important step toward helping older adults avoid memory impairment in the presence of common stereotypes.

On the attempts to measure water (and other volatiles) directly at the surface of a comet

The Ptolemy instrument on the Philae lander (of the Rosetta space mission) was able to make measurements of the major volatiles, water, carbon monoxide and carbon dioxide, directly at the surface of comet 67P/Churyumov-Gerasimenko. We give some background to the mission and highlight those instruments that have already given insights into the notion of water in comets, and which will continue to do so as more results are either acquired or more fully interpreted. On the basis of our results, we show how comets may in fact be heterogeneous over their surface, and how surface measurements can be used in a quest to comprehend the daily cycles of processes that affect the evolution of comets.This article is part of the themed issue 'The origin, history and role of water in the evolution of the inner Solar System'.

Thinking about a limited future enhances the positivity of younger and older adults' recall: Support for socioemotional selectivity theory

Compared with younger adults, older adults have a relative preference to attend to and remember positive over negative information. This is known as the "positivity effect," and researchers have typically evoked socioemotional selectivity theory to explain it. According to socioemotional selectivity theory, as people get older they begin to perceive their time left in life as more limited. These reduced time horizons prompt older adults to prioritize achieving emotional gratification and thus exhibit increased positivity in attention and recall. Although this is the most commonly cited explanation of the positivity effect, there is currently a lack of clear experimental evidence demonstrating a link between time horizons and positivity. The goal of the current research was to address this issue. In two separate experiments, we asked participants to complete a writing activity, which directed them to think of time as being either limited or expansive (Experiments 1 and 2) or did not orient them to think about time in a particular manner (Experiment 2). Participants were then shown a series of emotional pictures, which they subsequently tried to recall. Results from both studies showed that regardless of chronological age, thinking about a limited future enhanced the relative positivity of participants' recall. Furthermore, the results of Experiment 2 showed that this effect was not driven by changes in mood. Thus, the fact that older adults' recall is typically more positive than younger adults' recall may index naturally shifting time horizons and goals with age.

Sympathetic arousal increases a negative memory bias in young women with low sex hormone levels

Emotionally arousing events are typically better attended to and remembered than neutral ones. Current theories propose that arousal-induced increases in norepinephrine during encoding bias attention and memory in favor of affectively salient stimuli. Here, we tested this hypothesis by manipulating levels of physiological arousal prior to encoding and examining how it influenced memory for emotionally salient images, particularly those that are negative rather than positive in valence. We also tested whether sex steroid hormones interact with noradrenergic activity to influence these emotional memory biases in women. Healthy naturally cycling women and women on hormonal contraception completed one of the following physiological arousal manipulations prior to viewing a series of negative, positive and neutral images: (1) immediate handgrip arousal-isometric handgrip immediately prior to encoding, (2) residual handgrip arousal-isometric handgrip 15min prior to encoding, or (3) no handgrip. Sympathetic arousal was measured throughout the session via pupil diameter changes. Levels of 17β-estradiol and progesterone were measured via salivary samples. Memory performance was assessed approximately 10min after encoding using a surprise free recall test. The results indicated that handgrip successfully increased sympathetic arousal compared to the control task. Under immediate handgrip arousal, women showed enhanced memory for negative images over positive images; this pattern was not observed in women assigned to the residual and no-handgrip arousal conditions. Additionally, under immediate handgrip arousal, both high estradiol and progesterone levels attenuated the memory bias for negative over positive images. Follow-up hierarchical linear models revealed consistent effects when accounting for trial-by-trial variability in normative International Affective Picture System valence and arousal ratings. These findings suggest that heightened sympathetic arousal interacts with estradiol and progesterone levels during encoding to increase the mnemonic advantage of negative over positive emotional material.

Stereotype Threat Lowers Older Adults' Self-Reported Hearing Abilities

BACKGROUND

Although stereotype threat is a well-documented phenomenon, previous studies examining it in older adults have almost exclusively focused on objective cognitive outcomes. Considerably less attention has been paid to the impact of stereotype threat on older adults' subjective assessments of their own abilities or to the impact of stereotype threat in noncognitive domains.

OBJECTIVE

Older adults are stereotyped as having experienced not only cognitive declines, but physical declines as well. The current study tested the prediction that stereotype threat can negatively influence older adults' subjective hearing abilities.

METHODS

To test this, 115 adults (mean age 50.03 years, range 41-67) read either a positive or negative description about how aging affects hearing. All participants then answered a questionnaire in which they assessed their own hearing abilities.

RESULTS

The impact of stereotype threat on self-reported hearing was moderated by chronological age. Participants in their 40s and early 50s were unaffected by the stereotype threat manipulation. In contrast, participants in their late 50s and 60s rated their hearing as being subjectively worse when under stereotype threat.

CONCLUSION

The current study provides a clear demonstration that stereotype threat negatively impacts older adults' subjective assessments of their own abilities. It is also the first study to demonstrate an effect of stereotype threat within the domain of hearing. These results have important implications for researchers investigating age-related hearing decline. Stereotype threat can lead to overestimation of the prevalence of age-related hearing decline. It can also serve as a confounding variable when examining the psychosocial correlates of hearing loss. Because of this, researchers studying age-related hearing loss should aim to provide a stereotype threat-free testing environment and also include assessments of stereotype threat within their studies.

How Stereotype Threat Affects Healthy Older Adults' Performance on Clinical Assessments of Cognitive Decline: The Key Role of Regulatory Fit

OBJECTIVES

Stereotype threat can impair older adults' performance on clinical assessments for cognitive decline. We examined why this occurs. Based upon the regulatory focus account of stereotype threat, we predicted that the effects of stereotype threat should depend upon the assessments' reward structure. Stereotype threat should be associated with poor performance when the assessment emphasizes gaining correct answers, but not when it emphasizes avoiding mistakes.

METHOD

Healthy older adults completed a series of mental status examinations. Half of the participants completed these examinations under stereotype threat about their cognitive abilities. Monetary incentives were also manipulated. For half of the participants correct responding led to gains. For the remaining participants incorrect responding/forgetting led to losses.

RESULTS

Consistent with the regulatory focus account, stereotype threat was associated with poor performance when the mental status examinations had a gains-based structure, but not when they had a losses-based structure.

DISCUSSION

Older adults respond to stereotype threat by becoming vigilant to avoid the losses that will make them their worst. Researchers and clinicians can capitalize on this motivational change to combat stereotype threat's negative effects. By using a loss-avoidance frame, stereotype threat's negative effects can be attenuated or even eliminated.

Why two heads apart are better than two heads together: multiple mechanisms underlie the collaborative inhibition effect in memory

Although a group of people working together remembers more than any one individual, they recall less than their predicted potential. This finding is known as collaborative inhibition and is generally thought to arise due to retrieval disruption. However, there is growing evidence that is inconsistent with the retrieval disruption account, suggesting that additional mechanisms also contribute to collaborative inhibition. In the current studies, we examined 2 alternate mechanisms: retrieval inhibition and retrieval blocking. To identify the contributions of retrieval disruption, retrieval inhibition, and retrieval blocking, we tested how collaborative recall of entirely unshared information influences subsequent individual recall and individual recognition memory. If collaborative inhibition is due solely to retrieval disruption, then there should be a release from the negative effects of collaboration on subsequent individual recall and recognition tests. If it is due to retrieval inhibition, then the negative effects of collaboration should persist on both individual recall and recognition memory tests. Finally, if it is due to retrieval blocking, then the impairment should persist on subsequent individual free recall, but not recognition, tests. Novel to the current study, results suggest that retrieval inhibition plays a role in the collaborative inhibition effect. The negative effects of collaboration persisted on a subsequent, always-individual, free-recall test (Experiment 1) and also on a subsequent, always-individual, recognition test (Experiment 2). However, consistent with the retrieval disruption account, this deficit was attenuated (Experiment 1). Together, these results suggest that, in addition to retrieval disruption, multiple mechanisms play a role in collaborative inhibition. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

How retellings shape younger and older adults' memories

The way a story is retold influences the way it is later remembered; after retelling an event in a biased manner people subsequently remember the event in line with their distorted retelling. This study tested the hypothesis that this should be especially true for older adults. To test this, older and younger adults retold a story to be entertaining, to be accurate, or did not complete an initial retelling. Later, all participants recalled the story as accurately as possible. On this final test younger adults were unaffected by how they had previously retold the story. In contrast, older adults had better memory for the story's content and structure if they had previously retold the story accurately. Furthermore, for older adults, greater usage of storytelling language during the retelling was associated with lower subsequent recall. In summary, retellings exerted a greater effect on memory in older, compared with younger, adults.

Stereotype threat can both enhance and impair older adults' memory

Negative stereotypes about aging can impair older adults' memory via stereotype threat; however, the mechanisms underlying this phenomenon are unclear. In two experiments, we tested competing predictions derived from two theoretical accounts of stereotype threat: executive-control interference and regulatory fit. Older adults completed a working memory test either under stereotype threat about age-related memory declines or not under such threat. Monetary incentives were manipulated such that recall led to gains or forgetting led to losses. The executive-control-interference account predicts that stereotype threat decreases the availability of executive-control resources and hence should impair working memory performance. The regulatory-fit account predicts that threat induces a prevention focus, which should impair performance when gains are emphasized but improve performance when losses are emphasized. Results were consistent only with the regulatory-fit account. Although stereotype threat significantly impaired older adults' working memory performance when remembering led to gains, it significantly improved performance when forgetting led to losses.

Stereotype threat can reduce older adults' memory errors

Stereotype threat often incurs the cost of reducing the amount of information that older adults accurately recall. In the current research, we tested whether stereotype threat can also benefit memory. According to the regulatory focus account of stereotype threat, threat induces a prevention focus in which people become concerned with avoiding errors of commission and are sensitive to the presence or absence of losses within their environment. Because of this, we predicted that stereotype threat might reduce older adults' memory errors. Results were consistent with this prediction. Older adults under stereotype threat had lower intrusion rates during free-recall tests (Experiments 1 and 2). They also reduced their false alarms and adopted more conservative response criteria during a recognition test (Experiment 2). Thus, stereotype threat can decrease older adults' false memories, albeit at the cost of fewer veridical memories, as well.

The Collaborative Encoding Deficit is Attenuated with Specific Warnings

Individuals learning together do so less effectively than individuals learning alone, an effect known as the collaborative encoding deficit (Barber, Rajaram, & Aron, 2010). In the present studies we examined whether providing participants with a warning about the collaborative encoding deficit would increase their encoding task performance, and reduce subsequent memory deficits. Across two experiments, specific warnings were beneficial for memory. Collaborating participants who were told about the collaborative encoding deficit, and who received suggestions for how to complete the encoding task, had superior memory than participants who received no warning. This benefit was not due to qualitative changes in encoding task performance, was unrelated to the type of collaboration utilized, was absent when a more general warning was utilized, and was unrelated to self-reported task motivation. Rather, specific warnings appear to protect against the collaborative encoding deficit by increasing time spent on, and attention directed to, the encoding task.

Creating illusions of knowledge: learning errors that contradict prior knowledge

Most people know that the Pacific is the largest ocean on Earth and that Edison invented the light bulb. Our question is whether this knowledge is stable, or if people will incorporate errors into their knowledge bases, even if they have the correct knowledge stored in memory. To test this, we asked participants general-knowledge questions 2 weeks before they read stories that contained errors (e.g., "Franklin invented the light bulb"). On a later general-knowledge test, participants reproduced story errors despite previously answering the questions correctly. This misinformation effect was found even for questions that were answered correctly on the initial test with the highest level of confidence. Furthermore, prior knowledge offered no protection against errors entering the knowledge base; the misinformation effect was equivalent for previously known and unknown facts. Errors can enter the knowledge base even when learners have the knowledge necessary to catch the errors.

Learning and Remembering with Others: The Key Role of Retrieval in Shaping Group Recall and Collective Memory

People frequently collaborate to learn and remember information, and this may help groups create a shared representation of the world (i.e., collective memories). However, contrary to intuitions, collaboration also lowers group recall levels. Such impairment occurs regardless of whether people collaborate when first experiencing, or encoding, an event (the collaborative encoding deficit), or when retrieving, or remembering, the event (the collaborative inhibition effect). In understanding how collaboration impairs group recall and enhances collective or shared memories it remains unknown as to where collaboration exerts the greatest influence - at encoding or at retrieval - to shape these distinct phenomena. The current study simultaneously compared collaboration at these two stages and revealed the power of collaborative retrieval. Collaboration impaired the group recall product at both time points, but especially so at retrieval. Furthermore, only collaborative retrieval played a significant role in the formation of collective memories.

Exploring the relationship between retrieval disruption from collaboration and recall

When people recall together in a collaborative group they recall less than their potential. This phenomenon of collaborative inhibition is explained in terms of retrieval disruption. However, collaborative recall also re-exposes individuals to items recalled by others that they themselves might otherwise have forgotten. This re-exposure produces post-collaborative benefits in individual recall. The current study examined whether reduced retrieval disruption during group recall is related not only to less collaborative inhibition, but also to greater post-collaborative recall benefits. To test this we devised a paradigm to calculate the extent to which each individual experienced retrieval disruption during group recall. We also included two types of collaborative groups, one of which was expected to experience greater retrieval disruption than the other. Results suggest that the relationship between retrieval disruption and recall performance depends on the level at which retrieval disruption is measured. When retrieval disruption was assessed at the individual level, then minimising retrieval disruption was associated with higher recall (i.e., less collaborative inhibition and greater post-collaborative individual recall). However, when retrieval disruption was assessed at the group level there was no relationship with recall. Furthermore, the findings from this design suggest a role of cross-cueing in modulating group recall levels.

Collaborative memory and part-set cueing impairments: the role of executive depletion in modulating retrieval disruption

When people are exposed to a subset of previously studied list items they recall fewer of the remaining items compared to a condition where none of the studied items is provided during recall. This occurs both when the subset of items is provided by the experimenter (i.e., the part-set cueing deficit in individual recall) and when they are provided during the course of a collaborative discussion (i.e., the collaborative inhibition effect in group recall). Previous research has identified retrieval disruption as a common mechanism underlying both effects; however, less is known about the factors that may make individuals susceptible to such retrieval disruption. In the current studies we tested one candidate factor: executive control. Using an executive depletion paradigm we directly manipulated an individual's level of executive control during retrieval. Results revealed no direct role of executive depletion in modulating retrieval disruption. In contrast, executive control abilities were indirectly related to retrieval disruption through their influence at encoding. Together these results suggest that executive control des not directly affect retrieval disruption at the retrieval stage, and that the role of this putative mechanism may be limited to the encoding stage.

Higher social intelligence can impair source memory

Source monitoring is made difficult when the similarity between candidate sources increases. The current work examines how individual differences in social intelligence and perspective-taking abilities serve to increase source similarity and thus negatively impact source memory. Strangers first engaged in a cooperative storytelling task. On each trial, a single word was shown to both participants, but only 1 participant was designated to add a story sentence, using this assigned word. As predicted, social intelligence negatively predicted performance in a subsequent source-monitoring task. In a 2nd study, preventing participants from being able to anticipate their partner's next contribution to the story eliminated the effect.

Breeder hen dietary L-carnitine affects progeny carcase traits

(1) Ross 308 broiler breeder hens were given diets containing 0 or 25 mg L-carnitine/kg from 21 weeks of age. (2) Hens were inseminated with semen from Ross broiler breeder males and subsequent growth performance and carcase traits, of progeny obtained from hatches at 30, 35 and 37 weeks of age, were evaluated. (3) Progeny were hatched in a common facility and separated by gender. Experimental treatments employed for the 30-, 35- and 37-week hatches, respectively, were: hen diet and progeny gender (16 replications with two subplots); hen diet, progeny diet (0 and 50 mg L-carnitine/kg of diet) and progeny gender (16 replications with 4 subplots); and hen diet and progeny diet (high and low density; 16 replications with two subplots). (4) Females had lower growth rate and less breast meat, but greater proportions of carcase fat and breast meat than males. Growth performance measurements of progeny were not affected by hen L-carnitine, but hen L-carnitine decreased abdominal fat in progeny. Increasing diet density in the chick diets increased growth and carcase weights. Hen and progeny dietary L-carnitine interacted to increase male mortality. However, dietary hen L-carnitine decreased carcase fat and increased breast meat in progeny fed on high nutrient density diets. (5) In conclusion, L-carnitine in the diet of hens affected carcase traits of their progeny.

Broiler breeder semen quality as affected by trace minerals in vitro

Research has shown that trace elements, such as Se, Mn, and Zn, can alter reproductive functions. The aim of the current study was to evaluate the sperm quality index (SQI) and sperm viability as affected by various levels and sources of Se, Mn, and Zn when added in vitro to broiler breeder semen. In vitro treatments consisted of the following sources and levels of minerals: Control, no minerals added to sperm; seleno L-methionine, 4 levels ranging from 8.78 to 7,896 microg/L; sodium selenite, 4 levels ranging from 8.78 to 7,896 microg/L; MnSO4, 8 levels ranging from 6,500 to 65,000 mg/L; Zn 180 (Zinpro Corporation), 4 levels ranging from 0.65 to 650 mg/L; and ZnSO4, 4 levels ranging from 0.65 to 650 mg/L. The addition of 7,896 microg of sodium selenite/L to semen was detrimental to sperm motility. Also, MnSO4 adversely affected SQI and sperm viability at concentrations of 6,500 mg/L and greater. Sperm viability was decreased when 650 mg/L of Zn 180 was added to semen. Sperm motility was depressed by exposure to Zn 180 at 650 mg/L and ZnSO4 at 65 and 650 mg/L. Our results suggest that these trace minerals must act at the reproductive tissue level during spermatogenesis to improve semen quality. Direct in vitro application of these elements to semen appears to be detrimental to spermatozoa.

Isoleucine needs of thirty- to forty-two-day-old female chickens: growth and carcass responses

Two experiments were conducted to evaluate Ile responses in female broilers. In experiment 1, dietary Ile was 0.42 or 0.72% total of diet. Diets were fed to 3 broiler strains: multipurpose Arbor Acres+, high-yield Ross 508, and high-yield Ross 708. In experiment 2, dietary Ile dose responses (0.42 to 0.82% total of diet in 0.08% increments) were evaluated. A corn-soybean meal control (0.70%) diet was used in experiment 2 (6 replications). No Ile x strain interactions occurred. Feeding broilers 0.42% Ile suppressed (P < 0.05) BW gain, feed intake, feed conversion, and breast and thigh yields. Arbor Acres+ strain had a higher BW gain and feed intake (P < 0.05) than the Ross 508 and 708 strains. Differences (P < 0.05) among strains were observed in breast and drumstick yields; Ross 708 broilers had increased breast and drumstick yields in comparison to birds from the Arbor Acres+ and Ross 508 strains. Birds fed surfeit Ile in the titration diets grew as well as (P < 0.05) the birds fed the control diet. Quadratic responses (P < 0.05; 95% of response) were obtained for BW gain (0.67%), feed intake (0.66%), feed conversion (0.68%), and breast meat yield (0.63%). The 30- to 42-d Ile need for female broilers is between 0.63 and 0.68% of total diet (0.59 to 0.64% digestible Ile).

Threonine needs of broiler chickens with different growth rates

The Thr needs in 3 commercial broiler strains (A, multipurpose; B, high yield; C, high yield) known to differ in terms of feed intake, growth rate, and breast yield were evaluated. Birds were randomized across 96 floor pens (12 birds/pen), received a common diet from d 1 to 20, and were fed graduations of Thr (0.52 to 0.87% total Thr in 0.07% increments) from d 21 to 42. Treatments (3 x 6 factorial) were replicated 5 or 6 times. The corn, soybean meal, and peanut meal test diet contained 0.43 and 0.96% digestible Thr and Lys, respectively. An additional group of strain C birds (6 pens) was maintained on a corn-soybean meal diet containing surfeit Thr (0.73% of diet). Birds fed the corn and soybean meal diet performed similarly (P < or = 0.05) to birds fed peanut meal diets. A feed conversion interaction (P < or = 0.05) occurred indicating that strain C was more sensitive to Thr deficiency than strains A and B. The abdominal fat interaction (P < or = 0.05) indicated that strain A had more relative abdominal fat than strains B and C. All strains differed (P < or = 0.05) in terms of BW gain (A, 78.2; B, 75.1; C, 72.9 g/d). Strain C had the lowest (P < or = 0.05) feed intake, which resulted in the lowest (P < 0.05) Thr intake, but it had the highest (P < or = 0.05) breast meat yield. Most parameters tested yielded quadratic (P < or = 0.05) models whereby Thr estimates could be predicted. Namely, BW gain and breast meat yield resulted in total Thr estimates (95% of maximum response) of 0.74 and 0.71%, respectively, which are in close agreement with the 1994 NRC (0.74%). The plasma Thr sigmoid response verified the former estimates. Analysis of strain intercepts and slopes as affected by Thr differed (P < or = 0.05) in terms of feed intake but not BW gain or breast meat yield. The 21 to 42 d Thr need across strains was estimated as 0.74% total or 0.65% digestible. Because dietary Lys was not in excess of the bird's needs, the former digestibility estimate equated to a Thr/Lys of 0.68.

Immune system and cardiac functions of progeny chicks from dams fed diets differing in zinc and manganese level and source

This research was conducted to evaluate immunity (experiments 1 to 3), cardiac function, and ascities resistance (experiment 4) of progeny chicks from broiler breeders fed diets differing in trace metal level and source. Broiler breeders received a control diet (75 mg of Zn and 83 mg of Mn added/kg of diet), the control diet supplemented with inorganic Zn (75 mg/kg of diet) and Mn (80 mg/kg of diet), the control diet supplemented with organic Zn (75 mg/kg of diet) and inorganic Mn (80 mg/kg of diet), or the control diet supplemented with organic Zn (75 mg/kg of diet) and Mn (80 mg/kg of diet) in experiments 1, 2, and 3. In experiment 4, the control diet and diet supplemented with organic sources of Zn and Mn were fed to broiler breeders. Immune organ weights, circulating granulocytes vs. agranulocytes, CD4 and CD8 positive T cells, cutaneous basophil hypersensitivity, and antibody titers to SRBC and breeder vaccinations were measured in progeny. Some supplemental mineral treatments increased (P < or = 0.05) cutaneous basophil hypersensitivity and relative bursa weight. All supplemental mineral treatments increased (P < or = 0.05) relative thymus weight. In experiment 4, electrocardiograph, pulse oximetry, heart rate, hematocrits, ventricle weights, and ascites incidence were measured in progeny reared in a cold-stress environment. The supplemental organic minerals increased (P < or = 0.05) left ventricle plus septum and total ventricular weights. Although progeny ascites incidence did not differ between breeder mineral treatments, breeders fed supplemental Zn and Mn sired progeny with improved cardiac functional capacity and some improvements in immunity.