Age dependent effects of early intervention in borderline personality disorder in adolescents.

BACKGROUND: Psychological treatments for young people with sub-threshold or full-syndrome borderline personality disorder (BPD) are found to be effective. However, little is known about the age at which adolescents benefit from early intervention. This study investigated whether age affects the effectiveness of early intervention for BPD. METHODS: N = 626 participants (M age = 15 years, 82.7% female) were consecutively recruited from a specialized outpatient service for early intervention in BPD in adolescents aged 12- to 17-years old. DSM-IV BPD criteria were assessed at baseline, one-year (n = 339) and two-year (n = 279) follow-up. RESULTS: Older adolescents presented with more BPD criteria (χ2(1) = 58.23, p < 0.001) and showed a steeper decline of BPD criteria over the 2-year follow-up period compared with younger adolescents (χ2(2) = 13.53, p = 0.001). In an attempt to disentangle effects of early intervention from the natural course of BPD, a parametrized regression model was used. An exponential decrease (b = 0.10, p < 0.001) in BPD criteria was found when starting therapy over the 2-year follow-up. This deviation from the natural course was impacted by age at therapy commencement (b = 0.06, p < 0.001), although significant across all ages: older adolescents showed a clear decrease in BPD criteria, and young adolescents a smaller decrease. CONCLUSIONS: Early intervention appears effective across adolescence, but manifests differently: preventing the normative increase of BPD pathology expected in younger adolescents, and significantly decreasing BPD pathology in older adolescents. The question as to whether developmentally adapted therapeutic interventions could lead to an even increased benefit for younger adolescents, should be explored in future studies.

Increased virulence due to multiple infection in Daphnia leads to limited growth in 1 of 2 co-infecting microsporidian parasites.

Recent outbreaks of various infectious diseases have highlighted the ever-present need to understand the drivers of the outbreak and spread of disease. Although much of the research investigating diseases focuses on single infections, natural systems are dominated by multiple infections. These infections may occur simultaneously, but are often acquired sequentially, which may alter the outcome of infection. Using waterfleas (Daphnia magna) as a model organism, we examined the outcome of sequential and simultaneous multiple infections with 2 microsporidian parasites (Ordospora colligata and Hamiltosporidium tvaerminnensis) in a fully factorial design with 9 treatments and 30 replicates. We found no differences between simultaneous and sequential infections. However, H. tvaerminnensis fitness was impeded by multiple infection due to increased host mortality, which gave H. tvaerminnensis less time to grow. Host fecundity was also reduced across all treatments, but animals infected with O. colligata at a younger age produced the fewest offspring. As H. tvaerminnensis is both horizontally and vertically transmitted, this reduction in offspring may have further reduced H. tvaerminnensis fitness in co-infected treatments. Our findings suggest that in natural populations where both species co-occur, H. tvaerminnensis may evolve to higher levels of virulence following frequent co-infection by O. colligata.

Understanding the Need for Sleep to Improve Cognition.

The restorative function of sleep is shaped by its duration, timing, continuity, subjective quality, and efficiency. Current sleep recommendations specify only nocturnal duration and have been largely derived from sleep self-reports that can be imprecise and miss relevant details. Sleep duration, preferred timing, and ability to withstand sleep deprivation are heritable traits whose expression may change with age and affect the optimal sleep prescription for an individual. Prevailing societal norms and circumstances related to work and relationships interact to influence sleep opportunity and quality. The value of allocating time for sleep is revealed by the impact of its restriction on behavior, functional brain imaging, sleep macrostructure, and late-life cognition. Augmentation of sleep slow oscillations and spindles have been proposed for enhancing sleep quality, but they inconsistently achieve their goal. Crafting bespoke sleep recommendations could benefit from large-scale, longitudinal collection of objective sleep data integrated with behavioral and self-reported data.

Effects of early foreign language instruction and L1 transfer on vocabulary skills of EFL learners with DLD.

Research on second language learning by children with DLD has mainly focused on naturalistic L2 acquisition with plenty of exposure. Very little is known about how children with DLD learn foreign languages in classroom settings with limited input. This study addresses this gap and targets English as a foreign language (EFL) learning by Russian-speaking children with DLD. We ask whether learners with DLD benefit from a later onset of EFL instruction because older children are more cognitively mature and have more developed L1 skills. The second aim of this study is to determine whether EFL learners with DLD benefit from positive L1 transfer in vocabulary learning. We administered a receptive vocabulary test to younger (Grade 6, n = 18) and older (Grade 10, n = 15) children with DLD matched on the amount of prior EFL instruction. The younger group started EFL instruction in Grade 2 and the older group in Grade 6. The performance of the two groups was compared after four and a half years of English lessons. Half of the words in the test were English-Russian cognates and half were noncognates. Contra to our hypothesis, the results showed no difference between younger and older children. Both groups equally benefitted from cognate vocabulary suggesting that positive cross-language transfer is available to children with DLD, irrespective of their age and onset of EFL instruction.

The Contributions of Maternal Age Heterogeneity to Variance in Lifetime Reproductive Output.

AbstractVariance among individuals in fitness components reflects both genuine heterogeneity between individuals and stochasticity in events experienced along the life cycle. Maternal age represents a form of heterogeneity that affects both the mean and the variance of lifetime reproductive output (LRO). Here, we quantify the relative contribution of maternal age heterogeneity to the variance in LRO using individual-level laboratory data on the rotifer Brachionus manjavacas to parameterize a multistate age × maternal age matrix model. In B. manjavacas, advanced maternal age has large negative effects on offspring survival and fertility. We used multistate Markov chains with rewards to quantify the contributions to variance in LRO of heterogeneity and of the stochasticity inherent in the outcomes of probabilistic transitions and reproductive events. Under laboratory conditions, maternal age heterogeneity contributes 26% of the variance in LRO. The contribution changes when mortality and fertility are reduced to mimic more ecologically relevant environments. Over the parameter space where populations are near stationarity, maternal age heterogeneity contributes an average of 3% of the variance. Thus, the contributions of maternal age heterogeneity and individual stochasticity can be expected to depend strongly on environmental conditions; over most of the parameter space, the variance in LRO is dominated by stochasticity.

Developmental influences on symptom expression in antipsychotic-naïve first-episode psychosis.

BACKGROUND: The neurodevelopmental model of psychosis was established over 30 years ago; however, the developmental influence on psychotic symptom expression - how age affects clinical presentation in first-episode psychosis - has not been thoroughly investigated. METHODS: Using generalized additive modeling, which allows for linear and non-linear functional forms of age-related change, we leveraged symptom data from a large sample of antipsychotic-naïve individuals with first-episode psychosis (N = 340, 12-40 years, 1-12 visits), collected at the University of Pittsburgh from 1990 to 2017. We examined relationships between age and severity of perceptual and non-perceptual positive symptoms and negative symptoms. We tested for age-associated effects on change in positive or negative symptom severity following baseline assessment and explored the time-varying relationship between perceptual and non-perceptual positive symptoms across adolescent development. RESULTS: Perceptual positive symptom severity significantly decreased with increasing age (F = 7.0, p = 0.0007; q = 0.003) while non-perceptual positive symptom severity increased with age (F = 4.1, p = 0.01, q = 0.02). Anhedonia severity increased with increasing age (F = 6.7, p = 0.00035; q = 0.0003), while flat affect decreased in severity with increased age (F = 9.8, p = 0.002; q = 0.006). Findings remained significant when parental SES, IQ, and illness duration were included as covariates. There were no developmental effects on change in positive or negative symptom severity (all p > 0.25). Beginning at age 18, there was a statistically significant association between severity of non-perceptual and perceptual symptoms. This relationship increased in strength throughout adulthood. CONCLUSIONS: These findings suggest that as maturation proceeds, perceptual symptoms attenuate while non-perceptual symptoms are enhanced. Findings underscore how pathological brain-behavior relationships vary as a function of development.

Effects of Bilateral Cochlear Implantation on Binaural Listening Tasks for Younger and Older Adults.

PURPOSE: This study investigated the objective and subjective benefit of a second cochlear implant (CI) on binaural listening tasks of speech understanding in noise and localization in younger and older adults. We aimed to determine if the aging population can utilize binaural cues and obtain comparable benefits from bilateral CI (BIL_CI) when compared to the younger population. METHODS: Twenty-nine adults with severe to profound bilateral sensorineural hearing loss were included. Participants were evaluated in two conditions, better CI (BE_CI) alone and BIL_CI using AzBio and Bamford-Kowal-Bench (BKB) sentence in noise tests. Localization tasks were completed in the BIL_CI condition using a broadband stimulus, low-frequency stimuli, and high-frequency stimuli. A subjective questionnaire was administered to assess satisfaction with CI. RESULTS: Older age was significantly associated with poorer performance on AzBio +5 dB signal-to-noise ratio (SNR) and BKB-speech in noise (SIN); however, improvements from BE_CI to BIL_CI were observed across all ages. In the AzBio +5 condition, nearly half of all participants achieved a significant improvement from BE_CI to BIL_CI with the majority of those occurring in patients younger than 65 years of age. Conversely, the majority of participants who achieved a significant improvement in BKB-SIN were adults >65 years of age. Years of BIL_CI experience and time between implants were not associated with performance. For localization, mean absolute error increased with age for low and high narrowband noise, but not for the broadband noise. Response gain was negatively correlated with age for all localization stimuli. Neither BIL_CI listening experience nor time between implants significantly impacted localization ability. Subjectively, participants report reduction in disability with the addition of the second CI. There is no observed relationship between age or speech recognition score and satisfaction with BIL_CI. CONCLUSION: Overall performance on binaural listening tasks was poorer in older adults than in younger adults. However, older adults were able to achieve significant benefit from the addition of a second CI, and performance on binaural tasks was not correlated with overall device satisfaction. The significance of the improvement was task and stimulus dependent but suggested a critical limit may exist for optimal performance on SIN tasks for CI users. Specifically, older adults require at least a +8 dB SNR to understand 50% of speech postoperatively; therefore, solely utilizing a fixed +5 dB SNR preoperatively to qualify CI candidates is not recommended as this test condition may introduce limitations in demonstrating CI benefit.

How is the distribution of psychological distress changing over time? Who is driving these changes? Analysis of the 1958 and 1970 British birth cohorts.

AIMS: The main objective of this study was to investigate distributional shifts underlying observed age and cohort differences in mean levels of psychological distress in the 1958 and 1970 British birth cohorts. METHODS: This study used data from the 1958 and 1970 British birth cohorts (n = 24,707). Psychological distress was measured by the Malaise Inventory at ages 23, 33, 42 and 50 in the 1958 cohort and 26, 34, 42 and 46-48 in the 1970 cohort. RESULTS: The shifts in the distribution across age appear to be mainly due to changing proportion of those with moderate symptoms, except for midlife (age 42-50) when we observed polarisation in distress- an increase in proportions of people with no symptoms and multiple symptoms. The elevated levels of distress in the 1970 cohort, compared with the 1958 cohort, appeared to be due to an increase in the proportion of individuals with both moderate and high symptoms. For instance, at age 33/34 42.3% endorsed at least two symptoms in the 1970 cohort vs 24.7% in 1958, resulting in a shift in the entire distribution of distress towards the more severe end of the spectrum. CONCLUSIONS: Our study demonstrates the importance of studying not only mean levels of distress over time, but also the underlying shifts in its distribution. Due to the large dispersion of distress scores at any given measurement occasion, understanding the underlying distribution provides a more complete picture of population trends.

[Positive Psychotic Symptoms in Childhood and Adolescence]. / Positiv psychotische Symptome in Kindheit und Jugend.

In both classification systems, DSM-5 and ICD-11, the diagnostic criteria of schizophreniaspectrum disorders in minors are identical to those of adults. Nevertheless, recent studies have emphasized important differences in phenomenology and clinical impact of positive psychotic symptoms between children, adolescents and young adults. Among positive psychotic symptoms, hallucinations have a high prevalence in childhood, where they are often described as vivid, multisensory experiences, that mostly remit spontaneously. In children, these symptoms are not necessarily associated with the emergence of schizophrenia-spectrum disorders. However, they can indicate comorbid psychiatric disorders and cause significant stress or, in other cases, be transient symptoms without any significant pathological value. The article provides a review on recent epidemiological and phenomenological findings on positive psychotic symptoms in children and adolescents and proposes diagnostic and therapeutic strategies on the management of these symptoms in minors.

Beneficial cumulative effects of old parental age on offspring fitness.

Old parental age is commonly associated with negative effects on offspring life-history traits. Such parental senescence effects are predicted to have a cumulative detrimental effect over successive generations. However, old parents may benefit from producing higher quality offspring when these compete for seasonal resources. Thus, old parents may choose to increase investment in their offspring, thereby producing fewer but larger and more competitive progeny. We show that Caenorhabditis elegans hermaphrodites increase parental investment with advancing age, resulting in fitter offspring who reach their reproductive peak earlier. Remarkably, these effects increased over six successive generations of breeding from old parents and were subsequently reversed following a single generation of breeding from a young parent. Our findings support the hypothesis that offspring of old parents receive more resources and convert them into increasingly faster life histories. These results contradict the theory that old parents transfer a cumulative detrimental 'ageing factor' to their offspring.

Longitudinal evidence that older parents produce offspring with longer telomeres in a wild social bird.

As telomere length (TL) often predicts survival and lifespan, there is considerable interest in the origins of inter-individual variation in TL. Cross-generational effects of parental age on offspring TL are thought to be a key source of variation, but the rarity of longitudinal studies that examine the telomeres of successive offspring born throughout the lives of parents leaves such effects poorly understood. Here, we exploit TL measures of successive offspring produced throughout the long breeding tenures of parents in wild white-browed sparrow weaver (Plocepasser mahali) societies, to isolate the effects of within-parent changes in age on offspring TLs. Our analyses reveal the first evidence to date of a positive within-parent effect of advancing age on offspring TL: as individual parents age, they produce offspring with longer telomeres (a modest effect that persists into offspring adulthood). We consider the potential for pre- and post-natal mechanisms to explain our findings. As telomere attrition predicts offspring survival to adulthood in this species, this positive parental age effect could impact parent and offspring fitness if it arose via differential telomere attrition during offspring development. Our findings support the view that cross-generational effects of parental age can be a source of inter-individual variation in TL.

Crossover Interference, Crossover Maturation, and Human Aneuploidy.

A striking feature of human female sexual reproduction is the high level of gametes that exhibit an aberrant number of chromosomes (aneuploidy). A high baseline observed in women of prime reproductive age is followed by a dramatic increase in older women. Proper chromosome segregation requires one or more DNA crossovers (COs) between homologous maternal and paternal chromosomes, in combination with cohesion between sister chromatid arms. In human females, CO designations occur normally, according to the dictates of CO interference, giving early CO-fated intermediates. However, ≈25% of these intermediates fail to mature to final CO products. This effect explains the high baseline of aneuploidy and is predicted to synergize with age-dependent cohesion loss to explain the maternal age effect. Here, modern advances in the understanding of crossing over and CO interference are reviewed, the implications of human female CO maturation inefficiency are further discussed, and areas of interest for future studies are suggested.

Normative video head impulse test data in subjects with and without vascular risk factors.

PURPOSE: There is a paucity of age- and vascular risk factor-stratified video head impulse test (vHIT) vestibulo-ocular reflex (VOR) data in the literature. The aim of this study was to investigate the vHIT VOR properties in healthy subjects of different ages and subjects with vascular risk factors. METHODS: This was a prospective observational single-center study at a tertiary referral university hospital in northern Sweden. Healthy participants and subjects with vascular risk factors were investigated with a floor standing external camera vHIT device. Age-stratified mean VOR gain among healthy adults and between group gain and gain asymmetry differences were calculated. RESULTS: We included eighty-eight healthy adults with a mean (range) age of 50 (22-85) years and n = 48 stroke ward patients with vascular risk factors (but without vestibular disease) with a mean (range) age of 74 (42-92) years. The mean VOR gain of horizontal canals decreased at higher ages in healthy subjects (r = - 0.32, p < 0.01, n = 167 canals). The age-stratified mean (SD) VOR gains were < 30 years: 0.98 (0.07), 30-39 years: 0.97 (0.07), 40-49 years: 0.98 (0.06), 50-59 years: 0.99 (0.06), 60-69 years: 0.93 (0.08), ≥ 70 years: 0.89 (0.15). No consistent differences between healthy subjects and subjects with vascular risk factors were seen except for a trend towards more pronounced gain asymmetries in the latter group. CONCLUSIONS: Age, but not vascular risk factors influence VOR gain. Age-adjusted vHIT-measurements may be useful in acute vertigo stroke risk differentiation.

Transgenerational maternal age effects in nature: Lessons learnt from Asian elephants.

IN FOCUS: Reichert, S., Berger, V., Jackson, J., Chapman, S. N., Htut, W., Mar, K. U., & Lummaa, V. (2019). Maternal age at birth shapes offspring life-history trajectory across generations in long-lived Asian elephants. Journal of Animal Ecology, 89, 996-1007. Parental age can have strong effects on offspring life history, but the prevalence and magnitude of such effects in natural populations remain poorly understood. Using a multigenerational dataset of semi-captive Asian elephants, Reichert et al. (2019) studied the effects of maternal and grandmaternal age on offspring performance and found that offspring from old mothers have lower survival, but higher body condition and reproductive success than offspring from younger mothers. Importantly the observed consequences on survival are long-lasting and span more than one generation, with grand-offspring of old grandmothers also showing reduced survival. These findings suggest that persistent transgenerational effects of maternal age on fitness can shape the individual variation in ageing patterns in nature and ultimately the evolution of life histories.

Inhibition deficits are modulated by age and CGG repeat length in carriers of the FMR1 premutation allele who are mothers of children with fragile X syndrome.

Individuals who carry a premutation (PM) allele on the FMR1 gene may experience executive limitations associated with their genetic status, including inhibition deficits. However, poor understanding of individualized risk factors has limited clinical management of this group, particularly in mothers who carry the PM allele who have children with fragile X syndrome (FXS). The present study examined CGG repeat length and age as factors that may account for variable expressivity of inhibition deficits. Participants were 134 carriers of the PM allele who were mothers of children with FXS. Inhibition skills were measured using both self-report and direct behavioral assessments. Increased vulnerability for inhibition deficits was observed at mid-range CGG lengths of approximately 80-100 repeats, with some evidence of a second zone of vulnerability occurring at approximately 130-140 CGG repeats. Risk associated with the genotype also became more pronounced with older age. This study identifies personalized risk factors that may be used to tailor the clinical management of executive deficits in carriers of the PM allele. Inhibition deficits may contribute to poor outcomes in carriers of the PM allele and their families, particularly in midlife and early old age, and clinical monitoring may be warranted.

Molecular genetic classification in Prader-Willi syndrome: a multisite cohort study.

BACKGROUND: Prader-Willi syndrome (PWS) is due to errors in genomic imprinting. PWS is recognised as the most common known genetic cause of life-threatening obesity. This report summarises the frequency and further characterises the PWS molecular classes and maternal age effects. METHODS: High-resolution microarrays, comprehensive chromosome 15 genotyping and methylation-specific multiplex ligation probe amplification were used to describe and further characterise molecular classes of maternal disomy 15 (UPD15) considering maternal age. RESULTS: We summarised genetic data from 510 individuals with PWS and 303 (60%) had the 15q11-q13 deletion; 185 (36%) with UPD15 and 22 (4%) with imprinting defects. We further characterised UPD15 findings into subclasses based on the presence (size, location) or absence of loss of heterozygosity (LOH). Additionally, significantly older mothers (mean age=32.5 years vs 27.7 years) were found in the UPD15 group (n=145) compared with the deletion subtype (n=200). CONCLUSIONS: We report on molecular classes in PWS using advanced genomic technology in the largest cohort to date. LOH patterns in UPD15 may impact the risk of having a second genetic condition if the mother carries a recessive mutant allele in the isodisomic region on chromosome 15. The risk of UPD15 may also increase with maternal age.

Apparent and standardised ileal digestibility of amino acids in wheat, triticale and barley for broiler chickens at two different ages.

1. The influence of the age of broiler chickens on ileal amino acid (AA) digestibilities in three cereals was examined. The digestibility estimates, including both apparent (AID) and standardised (SID) coefficients, for wheat, triticale and barley samples were determined using 14 and 28 d old broilers of mixed sex, fed diets containing the test grains as the only source of protein.2. Each assay diet was offered to five replicate cages of 14 and eight birds respectively, for the 14 and 28 day samplings. On both sampling days, the contents from the lower half of the ileum were collected for determination of the AID coefficients. The SID coefficients were calculated using ileal endogenous amino acid (EAA) losses previously determined from birds fed an N-free diet.3. The average AID for essential AA (EAA) in triticale and barley were significantly higher at 28 day compared to those at 14 days. In contrast, the magnitude of AID coefficients of AA in wheat was found to be in larger in the younger chickens.4. Correction of AID for EAA losses increased the values of digestibility coefficients by an average of about 7%. The SID values of AA in wheat was not influenced by the age of broilers. The SID of most AA in triticale, and of all the AA in barley, were higher in 28-day-old chickens compared with their 14-day-old counterparts. The results suggested that the SID coefficients of EAA in wheat determined at day 28 could be applied to feed formulations for 14-day-old broilers, but in the case of triticale and barley, the values obtained in older chickens were not applicable in younger birds and vice versa.

Genetic and environmental influences on functional connectivity within and between canonical cortical resting-state networks throughout adolescent development in boys and girls.

The human brain is active during rest and hierarchically organized into intrinsic functional networks. These functional networks are largely established early in development, with reports of a shift from a local to more distributed organization during childhood and adolescence. It remains unknown to what extent genetic and environmental influences on functional connectivity change throughout adolescent development. We measured functional connectivity within and between eight cortical networks in a longitudinal resting-state fMRI study of adolescent twins and their older siblings on two occasions (mean ages 13 and 18 years). We modelled the reliability for these inherently noisy and head-motion sensitive measurements by analyzing data from split-half sessions. Functional connectivity between resting-state networks decreased with age whereas functional connectivity within resting-state networks generally increased with age, independent of general cognitive functioning. Sex effects were sparse, with stronger functional connectivity in the default mode network for girls compared to boys, and stronger functional connectivity in the salience network for boys compared to girls. Heritability explained up to 53% of the variation in functional connectivity within and between resting-state networks, and common environment explained up to 33%. Genetic influences on functional connectivity remained stable during adolescent development. In conclusion, longitudinal age-related changes in functional connectivity within and between cortical resting-state networks are subtle but wide-spread throughout adolescence. Genes play a considerable role in explaining individual variation in functional connectivity with mostly stable influences throughout adolescence.

Health-related quality of life in long-term disease-free breast cancer survivors versus female population controls in Germany.

PURPOSE: Little is known about breast cancer (BC) survivors' health-related quality of life (HRQoL) > 5 or even > 10 years past diagnosis. It is of interest whether, in the long run, survivors' HRQoL aligns with that of the general population. Study objectives were to (1) compare disease-free BC survivors' HRQoL to that of non-cancer controls, and (2) compare long-term survivors (LTS, 5-9 years post-diagnosis), very long-term survivors (VLTS, ≥ 10 years post-diagnosis), and controls with respect to their HRQoL. METHODS: The samples of 2647 disease-free BC survivors (5-16 years post-diagnosis) and 1005 population controls were recruited in German multi-regional population-based studies. HRQoL was assessed by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30). Differences in HRQoL were assessed with multiple regression, controlling for age and education. RESULTS: Disease-free BC survivors < 80 years (at survey) reported overall global health status/quality of life comparable to controls, but statistically significant lower physical, role, emotional, social, and cognitive functioning. They also indicated more fatigue, insomnia, dyspnoea, and financial difficulties. However, differences were only of trivial or small clinical relevance. At age 80-89, no differences between BC survivors and controls were observed. Deficits in emotional and cognitive functioning and some symptoms (e.g. insomnia and fatigue) persist, as both LTS and VLTS reported more detriments than controls. CONCLUSIONS: In view of the persistent, small but significant detriments in disease-free BC survivors' cognitive and emotional functioning and higher symptom burden, possibilities to prevent detriments from becoming chronic should be explored.

Northward range expansion in spring-staging barnacle geese is a response to climate change and population growth, mediated by individual experience.

All long-distance migrants must cope with changing environments, but species differ greatly in how they do so. In some species, individuals might be able to adjust by learning from individual experiences and by copying others. This could greatly speed up the process of adjustment, but evidence from the wild is scarce. Here, we investigated the processes by which a rapidly growing population of barnacle geese (Branta leucopsis) responded to strong environmental changes on spring-staging areas in Norway. One area, Helgeland, has been the traditional site. Since the mid-1990s, an increasing number of geese stage in another area 250 km further north, Vesterålen. We collected data on goose numbers and weather conditions from 1975 to 2017 to explore the extent to which the increase in population size and a warmer climate contributed to this change in staging area use. During the study period, the estimated onset of grass growth advanced on average by 0.54 days/year in each of the two areas. The total production of digestible biomass for barnacle geese during the staging period increased in Vesterålen but remained stable in Helgeland. The goose population has doubled in size during the past 25 years, with most of the growth being accommodated in Vesterålen. The observations suggest that this dramatic increase would not have happened without higher temperatures in Vesterålen. Records of individually marked geese indicate that from the initial years of colonization onwards, especially young geese tended to switch to Vesterålen, thereby predominating in the flocks at Vesterålen. Older birds had a lower probability of switching to Vesterålen, but over the years, the probability increased for all ages. Our findings suggest that barnacle geese integrate socially learned behaviour with adjustments to individual experiences, allowing the population to respond rapidly and accurately to global change.