scholarly journals Personality-specific carry-over effects on breeding

2020 ◽  
Vol 287 (1940) ◽  
pp. 20202381
Author(s):  
Stephanie M. Harris ◽  
Sébastien Descamps ◽  
Lynne U. Sneddon ◽  
Milena Cairo ◽  
Philip Bertrand ◽  
...  
Keyword(s):  
Individual Differences ◽  
Reproductive Success ◽  
Individual Variability ◽  
Breeding Phenology ◽  
Breeding Performance ◽  
Subsequent Performance ◽  
Breeding Activity ◽  
Pace Of Life ◽  
Carry Over

Carry-over effects describe the phenomenon whereby an animal's previous conditions influence its subsequent performance. Carry-over effects are unlikely to affect individuals uniformly, but the factors modulating their strength are poorly known. Variation in the strength of carry-over effects may reflect individual differences in pace-of-life: slow-paced, shyly behaved individuals are thought to favour an allocation to self-maintenance over current reproduction, compared to their fast-paced, boldly behaved conspecifics (the pace-of-life syndrome hypothesis). Therefore, detectable carry-over effects on breeding should be weaker in bolder individuals, as they should maintain an allocation to reproduction irrespective of previous conditions, while shy individuals should experience stronger carry-over effects. We tested this prediction in black-legged kittiwakes breeding in Svalbard. Using miniature biologging devices, we measured non-breeding activity of kittiwakes and monitored their subsequent breeding performance. We report a number of negative carry-over effects of non-breeding activity on breeding, which were generally stronger in shyer individuals: more active winters were followed by later breeding phenology and poorer breeding performance in shy birds, but these effects were weaker or undetected in bolder individuals. Our study quantifies individual variability in the strength of carry-over effects on breeding and provides a mechanism explaining widespread differences in individual reproductive success.

Inter-individual variation shapes the human microbiome

2019 ◽  
Vol 42 ◽  
Author(s):  
Emily F. Wissel ◽  
Leigh K. Smith
Keyword(s):  
Individual Differences ◽  
Individual Variation ◽  
Human Microbiome ◽  
Individual Variability ◽  
Microbiota Composition ◽  
Target Article ◽  
Microbiome Research

Abstract The target article suggests inter-individual variability is a weakness of microbiota-gut-brain (MGB) research, but we discuss why it is actually a strength. We comment on how accounting for individual differences can help researchers systematically understand the observed variance in microbiota composition, interpret null findings, and potentially improve the efficacy of therapeutic treatments in future clinical microbiome research.

scholarly journals Temporal changes in reproductive success and optimal breeding decisions in a long-distance migratory bird

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cynthia Reséndiz-Infante ◽  
Gilles Gauthier
Keyword(s):  
Reproductive Success ◽  
Clutch Size ◽  
Environmental Changes ◽  
Migratory Bird ◽  
Laying Date ◽  
Negative Consequences ◽  
Breeding Phenology ◽  
Additional Time ◽  
Long Distance ◽  
Seasonal Decline

AbstractMany avian migrants have not adjusted breeding phenology to climate warming resulting in negative consequences for their offspring. We studied seasonal changes in reproductive success of the greater snow goose (Anser caerulescens atlantica), a long-distance migrant. As the climate warms and plant phenology advances, the mismatch between the timing of gosling hatch and peak nutritive quality of plants will increase. We predicted that optimal laying date yielding highest reproductive success occurred earlier over time and that the seasonal decline in reproductive success increased. Over 25 years, reproductive success of early breeders increased by 42%, producing a steeper seasonal decline in reproductive success. The difference between the laying date producing highest reproductive success and the median laying date of the population increased, which suggests an increase in the selection pressure for that trait. Observed clutch size was lower than clutch size yielding the highest reproductive success for most laying dates. However, at the individual level, clutch size could still be optimal if the additional time required to acquire nutrients to lay extra eggs is compensated by a reduction in reproductive success due to a delayed laying date. Nonetheless, breeding phenology may not respond sufficiently to meet future environmental changes induced by warming temperatures.

scholarly journals Letter transpositions and morphemic boundaries in the second language processing of derived words: An exploratory study of individual differences

2021 ◽  
Vol 42 (2) ◽  
pp. 417-446
Author(s):  
Hasibe Kahraman ◽  
Bilal Kırkıcı
Keyword(s):  
Individual Differences ◽  
Language Processing ◽  
Exploratory Study ◽  
Reading Proficiency ◽  
Individual Variability ◽  
Morphological Processing ◽  
Group Level ◽  
Priming Effects ◽  
Second Language Processing ◽  
Morphological Priming

AbstractResearch into nonnative (L2) morphological processing has produced largely conflicting findings. To contribute to the discussions surrounding the contradictory findings in the literature, we examined L2 morphological priming effects along with a transposed-letter (TL) methodology. Critically, we also explored the potential effects of individual differences in the reading networks of L2 speakers using a test battery of reading proficiency. A masked primed lexical decision experiment was carried out in which the same target (e.g., ALLOW) was preceded by a morphological prime (allowable), a TL-within prime (allwoable), an substituted letter (SL)-within prime (allveable), a TL-across prime (alloawble), an SL-across prime (alloimble), or an unrelated prime (believable). The average data yielded morphological priming but no significant TL priming. However, the results of an exploratory analysis of the potential effects of individual differences suggested that individual variability mediated the group-level priming patterns in L2 speakers. TL-within and TL-across priming effects were obtained only when the performance of participants on nonword reading was considered, while the magnitude of the morphological priming effects diminished as the knowledge of vocabulary expanded. The results highlight the importance of considering individual differences while testing L2 populations.

Individual Variation in the Strength of Territory Defense in Male Song Sparrows: Correlates of Age, Territory Tenure, and Neighbor Aggressiveness

Behaviour ◽  
2004 ◽  
Vol 141 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Jeremy Hyman ◽  
Melissa Hughes ◽  
Stephen Nowicki ◽  
William Searcy
Keyword(s):  
Individual Differences ◽  
Reproductive Success ◽  
Extrinsic Factors ◽  
Territory Defense ◽  
Intrinsic Factors ◽  
Territorial Aggression ◽  
Male Song ◽  
Song Sparrows ◽  
Territory Owner ◽  
Older Males

AbstractIn many species, the ability to defend a territory is essential for a male to obtain any reproductive success at all, and even among territorial individuals, variation in the strength of territory defense could have a significant impact on how much reproductive success is obtained. Previous studies have documented consistent individual differences in the vigor with which male song sparrows (Melospiza melodia) defend their territories, as measured by the strength of their reactions to territorial intrusions simulated through song playback. Variation in the strength of defense could reflect intrinsic differences among individuals in their resource holding potential (RHP), or variation in extrinsic factors. In this study, we examined whether variation in the strength of territory defense corresponds to differences in intrinsic factors such as the age or experience of the territory owner, the extrinsic factor of the level of aggression shown by neighbours, or both. Results indicate that males that previously held territories on the study site, regardless of whether they were holding the same territory as the previous year, show higher levels of territory defense than males that are new to the study site, and, assuming that returning males are older males, suggest that age is more important than experience on a specific territory in determining strength of territory defense. In addition, we found evidence that males with high levels of territorial aggression tend to be spatially clustered. The pattern observed suggests that a combination of intrinsic and extrinsic factors contribute to the expression of individual differences in territorial aggression.

scholarly journals Right Ventrolateral Prefrontal Cortex Mediates Individual Differences in Conflict-driven Cognitive Control

2011 ◽  
Vol 23 (12) ◽  
pp. 3903-3913 ◽  
Author(s):  
Tobias Egner
Keyword(s):  
Conflict Resolution ◽  
Individual Differences ◽  
Cognitive Control ◽  
Inferior Frontal Gyrus ◽  
Group Analysis ◽  
Individual Variability ◽  
Primary Role ◽  
Conflict Adaptation ◽  
Traditional Group ◽  
Behavioral Expression

Conflict adaptation—a conflict-triggered improvement in the resolution of conflicting stimulus or response representations—has become a widely used probe of cognitive control processes in both healthy and clinical populations. Previous fMRI studies have localized activation foci associated with conflict resolution to dorsolateral PFC (dlPFC). The traditional group analysis approach employed in these studies highlights regions that are, on average, activated during conflict resolution, but does not necessarily reveal areas mediating individual differences in conflict resolution, because between-subject variance is treated as noise. Here, we employed a complementary approach to elucidate the neural bases of variability in the proficiency of conflict-driven cognitive control. We analyzed two independent fMRI data sets of face–word Stroop tasks by using individual variability in the behavioral expression of conflict adaptation as the metric against which brain activation was regressed while controlling for individual differences in mean RT and Stroop interference. Across the two experiments, a replicable neural substrate of individual variation in conflict adaptation was found in ventrolateral PFC (vlPFC), specifically, in the right inferior frontal gyrus, pars orbitalis (BA 47). Unbiased regression estimates showed that variability in activity in this region accounted for ∼40% of the variance in behavioral expression of conflict adaptation across subjects, thus documenting a heretofore unsuspected key role for vlPFC in mediating conflict-driven adjustments in cognitive control. We speculate that vlPFC plays a primary role in conflict control that is supplemented by dlPFC recruitment under conditions of suboptimal performance.

Rhythmic Activity and Individual Variability in Recognition Memory: Theta Oscillations Correlate with Performance whereas Alpha Oscillations Correlate with ERPs

2017 ◽  
Vol 29 (1) ◽  
pp. 183-202 ◽  
Author(s):  
Yvonne Y. Chen ◽  
Jeremy B. Caplan
Keyword(s):  
Individual Differences ◽  
Recognition Memory ◽  
Memory Task ◽  
Rhythmic Activity ◽  
Individual Variability ◽  
Theta Oscillations ◽  
Alpha Oscillations ◽  
Alpha Oscillation ◽  
Familiarity And Recollection ◽  
Visual Inattention

During study trials of a recognition memory task, alpha (∼10 Hz) oscillations decrease, and concurrently, theta (4–8 Hz) oscillations increase when later memory is successful versus unsuccessful (subsequent memory effect). Likewise, at test, reduced alpha and increased theta activity are associated with successful memory (retrieval success effect). Here we take an individual-differences approach to test three hypotheses about theta and alpha oscillations in verbal, old/new recognition, measuring the difference in oscillations between hit trials and miss trials. First, we test the hypothesis that theta and alpha oscillations have a moderately mutually exclusive relationship; but no support for this hypothesis was found. Second, we test the hypothesis that theta oscillations explain not only memory effects within participants, but also individual differences. Supporting this prediction, durations of theta (but not alpha) oscillations at study and at test correlated significantly with d′ across participants. Third, we test the hypothesis that theta and alpha oscillations reflect familiarity and recollection processes by comparing oscillation measures to ERPs that are implicated in familiarity and recollection. The alpha-oscillation effects correlated with some ERP measures, but inversely, suggesting that the actions of alpha oscillations on memory processes are distinct from the roles of familiarity- and recollection-linked ERP signals. The theta-oscillation measures, despite differentiating hits from misses, did not correlate with any ERP measure; thus, theta oscillations may reflect elaborative processes not tapped by recollection-related ERPs. Our findings are consistent with alpha oscillations reflecting visual inattention, which can modulate memory, and with theta oscillations supporting recognition memory in ways that complement the most commonly studied ERPs.

Depression as a Consequence of Inadequate Neurochemical Adaptation in Response to Stressors

1992 ◽  
Vol 160 (S15) ◽  
pp. 36-43 ◽  
Author(s):  
Hymie Anisman ◽  
Robert M. Zacharko
Keyword(s):  
Individual Differences ◽  
Pharmacological Treatment ◽  
Individual Variability ◽  
Symptoms Of Depression ◽  
Symptom Profile ◽  
Behavioural Effects ◽  
Neurochemical Changes ◽  
Strain Variability

Stressors induce behavioural disturbances and neurochemical changes in animals, some of which are reminiscent of the symptoms and presumed neurochemical concomitants of depression in humans. Just as in humans, where considerable inter-individual variability is evident in the symptom profile of depression, there is marked inter-individual and inter-strain variability in the behavioural effects of stressors in animals. It is proposed that stressors induce adaptive neurochemical changes, failure of which may engender behavioural disturbances. Variability in the symptoms of depression and in the efficacy of its pharmacological treatment may reflect the biochemical heterogeneity of the illness. Inter-individual differences in vulnerability to stressor-provoked neurochemical changes may contribute to the behavioural profiles observed.

Sign in / Sign up

Export Citation Format

Share Document