Rich Hypothesis Research Articles

Shifting mammal communities and declining species richness along an elevational gradient on Mount Kenya.

Conservation areas encompassing elevation gradients are biodiversity hotspots because they contain a wide range of habitat types in a relatively small space. Studies of biodiversity patterns along elevation gradients, mostly on small mammal or bird species, have documented a peak in diversity at mid elevations. Here, we report on a field study of medium and large mammals to examine the impact of elevation, habitat type, and gross primary productivity on community structure. Species richness was observed using a camera trap transect with 219 sites situated across different habitat types from 2329 to 4657 m above the sea level on the western slope of Mt Kenya, the second highest mountain in Africa. We found that the lowest elevation natural habitats had the highest species richness and relative abundance and that both metrics decreased steadily as elevation increased, paralleling changes in gross primary productivity, and supporting the energy richness hypothesis. We found no evidence for the mid-domain effect on species diversity. The lowest elevation degraded Agro-Forestry lands adjacent to the National Park had high activity of domestic animals and reduced diversity and abundance of native species. The biggest difference in community structure was between protected and unprotected areas, followed by more subtle stepwise differences between habitats at different elevations. Large carnivore species remained relatively consistent but dominant herbivore species shifted along the elevation gradient. There was some habitat specialization and turnover in species, such that the elevation gradient predicts a high diversity of species, demonstrating the high conservation return for protecting mountain ecosystems for biodiversity conservation.

Finiteness marking in Russian-speaking children with Specific Language Impairment

Much crosslinguistic acquisition research explores finiteness marking in typical development and Specific Language Impairment (SLI). Research into Russian, however, has focused on typical acquisition, not SLI. This article presents a first attempt to investigate finiteness marking in monolingual Russian-speaking children with SLI. We test two competing hypotheses: the Extended Optional Infinitive (EOI) hypothesis and the morphological richness account. The former predicts a large proportion of non-finite forms in the speech of children with SLI crosslinguistically. Due to the rich morphological verbal system of Russian, the latter hypothesis predicts that finiteness marking in Russian SLI will be relatively unimpeded, except for ‘near-miss’ errors. To test these predictions, we analyzed picture-story narrative samples collected from 67 monolingual Russian-acquiring children aged 4;1 to 4;11. All samples are part of the BiSLI corpus created by Tribushinina and colleagues and publicly available through the CHILDES project. We found that, similar to both aged-matched typically developing (TD) controls (N = 24) and younger TD children (N = 23), children with SLI (N = 20) are essentially adultlike in terms of finiteness marking of verbal forms in the matrix clause. The handful of errors observed in the SLI sample involved substitutions in only one inflectional category. These findings provide support for the morphological richness hypothesis over the EOI model of Russian SLI.

Social Networking for Interpersonal Life: A Competence-Based Approach to the Rich Get Richer Hypothesis

Online and offline interactions are thought to draw from separate but complementary skill sets. This explains why individuals who are competent interpersonally tend to get more out of social networking. At least part of what they already know about interacting applies online. But whether computer-based competence has some bearing on real-world interactional capability is still open to debate. The present study tested associations between computer-mediated communication (CMC) competence and interpersonal competence over time. Results indicate that CMC competence was related to interpersonal competence and interpersonal contributed back to CMC competence. The forms of competence become mutually reinforcing. Using Facebook contributed to CMC competence as well, but not to interpersonal competence, at least not directly. Facebook use was related to interpersonal competence indirectly, through increasing CMC competence over time. Social networking is associated with feeling more capable of interacting through computers, and online proficiency has some application in the real world. This is good news for a withdrawn society that has become less competent socially. Developing either form of competence should contribute to its counterpart.

Model Criticism of Growth Curve Models via Posterior Predictive Model Checking

Longitudinal data structures are frequently encountered in a variety of disciplines in the social and behavioral sciences. Growth curve modeling offers a highly extensible framework that allows for the exploration of rich hypotheses. However, owing to the presence of interrelated sources of potential data-model misfit at multiple levels, the matter of model criticism remains challenging for even foundational growth curve models. Through a simulation study and an applied example, the performance of six discrepancy measures was investigated using posterior predictive model checking as the framework for model criticism. The likelihood ratio and the standardized generalized dimensionality discrepancy measure outperformed the other discrepancy measures under consideration and show promise for future study and use.

Condition-dependent foraging strategies in a coastal seabird: evidence for the rich get richer hypothesis

Abstract The degree to which foraging individuals are able to appropriately modify their behaviors in response to dynamic environmental conditions and associated resource availability can have important fitness consequences. Despite an increasingly refined understanding of differences in foraging behavior between individuals, we still lack detailed characterizations of within-individual variation over space and time, and what factors may drive this variability. From 2014 to 2017, we used GPS transmitters and accelerometers to document foraging movements by breeding adult Brown Pelicans (Pelecanus occidentalis) in the northern Gulf of Mexico, where the prey landscape is patchy and dynamic at various scales. Assessments of traditional foraging metrics such as trip distance, linearity, or duration did not yield significant relationships between individuals. However, we did observe lower site fidelity and less variation in energy expenditure in birds of higher body condition, despite a population-level trend of increased fidelity as the breeding season progressed. These findings suggest that high-quality individuals are both more variable and more efficient in their foraging behaviors during a period of high energetic demand, consistent with a “rich get richer” scenario in which individuals in better condition are able to invest in more costly behaviors that provide higher returns. This work highlights the importance of considering behavioral variation at multiple scales, with particular reference to within-individual variation, to improve our understanding of foraging ecology in wild populations.

Fine motor skills enhance lexical processing of embodied vocabulary: A test of the nimble-hands, nimble-minds hypothesis.

Research suggests that fine motor skills (FMS) are linked to aspects of cognitive development in children. Additionally, lexical processing advantages exist for words implying a high body-object interaction (BOI), with initial findings indicating that such words in turn link to children's FMS-for which we propose and evaluate four competing hypotheses. First, a maturational account argues that any links between FMS and lexical processing should not exist once developmental variables are controlled for. Second, functionalism posits that any link between FMS and lexical processing arises due to environmental interactions. Third, the semantic richness hypothesis argues that sensorimotor input improves lexical processing, but predicts no links between FMS and lexical processing. A fourth account, the nimble-hands, nimble minds (NHNM) hypothesis, proposes that having greater FMS improves lexical processing for high-BOI words. In two experiments, the response latencies of preschool children (n = 90, n = 76, ages = 5;1) to 45 lexical items encompassing high-BOI, low-BOI, and less imageable words were measured, alongside measures of FMS, reasoning, and general receptive/expressive vocabulary. High-BOI words appeared to show unique links to FMS, which remained after accounting for low-BOI and less imageable words, general vocabulary, reasoning, and chronological age. Although further work is needed, the findings provide initial support for the NHNM hypothesis.

Online learning of symbolic concepts

Learning complex symbolic concepts requires a rich hypothesis space, but exploring such spaces is intractable. We describe how sampling algorithms can be brought to bear on this problem, leading to the prediction that humans will exhibit the same failure modes as sampling algorithms. In particular, we show that humans get stuck in “garden paths”—initially promising hypotheses that turn out to be sub-optimal in light of subsequent data. Susceptibility to garden paths is sensitive to the availability of cognitive resources. These phenomena are well-explained by a Bayesian model in which humans stochastically update a sample-based representation of the posterior over a compositional hypothesis space. Our model provides a framework for understanding “bounded rationality” in symbolic concept learning.

Parameters of Poor Pronoun Systems

The world’s smallest pronoun systems can eschew any of the following contrasts: (a) author-nonauthor, (b) participant-nonparticipant, (c) singular-nonsingular. This supports the view that features are mutually independent parameters ( Harbour 2011a , 2014a , 2016 ), but is problematic for Koeneman and Zeijlstra’s (2014) reworking of the Rich Agreement Hypothesis, which is predicated on the claim that (a)–(c) are universally obligatory. The facts necessitate revision of Koeneman and Zeijlstra’s proposal.

Social Capital on Facebook

Online relationship formation through social networking sites helps to meet the developmental need for intimacy in emerging adults. Through the use of the rich get richer and the social compensation hypotheses, it is evident that personality characteristics such as extraversion and introversion impact online relationship formation. However, there is a lack of research on the amount of relational benefits, in terms of social capital, accrued from these relationships. This study addressed this issue by examining how the online communication styles of extraverts and introverts mediate the relationship between the personality variables and the accumulation of online social capital. Support for the rich get richer hypothesis was found, with extraversion leading to the accumulation of bonding social capital. This relationship was mediated by the active communication behaviors of extraverts.

Weighted species richness outperforms species richness as predictor of biotic resistance.

The species richness hypothesis, which predicts that species-rich communities should be better at resisting invasions than species-poor communities, has been empirically tested many times and is often poorly supported. In this study, we contrast the species richness hypothesis with four alternative hypotheses with the aim of finding better descriptors of invasion resistance. These alternative hypotheses state that resistance to invasions is determined by abiotic conditions, community saturation (i.e., the number of resident species relative to the maximum number of species that can be supported), presence/absence of key species, or weighted species richness. Weighted species richness is a weighted sum of the number of species, where each species' weight describes its contribution to resistance. We tested these hypotheses using data on the success of 571 introductions of four freshwater fish species into lakes throughout Sweden, i.e., Arctic char (Salvelinus alpinus), tench (Tinca tinca), zander (Sander lucioperca), and whitefish (Coregonus lavaretus). We found that weighted species richness best predicted invasion success. The weights describing the contribution of each resident species to community resistance varied considerably in both strength and sign. Positive resistance weights, which indicate that species repel invaders, were as common as negative resistance weights, which indicate facilitative interactions. This result can be contrasted with the implicit assumption of the original species richness hypothesis, that all resident species have negative effects on invader success. We argue that this assumption is unlikely to be true in natural communities, and thus that we expect that weighted species richness is a better predictor of invader success than the actual number of resident species.

Terms of the debate on the format and structure of visual memory.

Our ability to actively maintain information in visual memory is strikingly limited. There is considerable debate about why this is so. As with many questions in psychology, the debate is framed dichotomously: Is visual working memory limited because it is supported by only a small handful of discrete "slots" into which visual representations are placed, or is it because there is an insufficient supply of a "resource" that is flexibly shared among visual representations? Here, we argue that this dichotomous framing obscures a set of at least eight underlying questions. Separately considering each question reveals a rich hypothesis space that will be useful for building a comprehensive model of visual working memory. The questions regard (1) an upper limit on the number of represented items, (2) the quantization of the memory commodity, (3) the relationship between how many items are stored and how well they are stored, (4) whether the number of stored items completely determines the fidelity of a representation (vs. fidelity being stochastic or variable), (5) the flexibility with which the memory commodity can be assigned or reassigned to items, (6) the format of the memory representation, (7) how working memories are formed, and (8) how memory representations are used to make responses in behavioral tasks. We reframe the debate in terms of these eight underlying questions, placing slot and resource models as poles in a more expansive theoretical space.

Different relationships between galling and non-galling herbivore richness and plant species richness: a meta-analysis

The plant richness hypothesis (PRH) is used to explain herbivorous insect richness based on the number of plant species, predicting a positive relationship. However, the influence of plant richness on insect distribution can become stronger with greater levels of specialization of herbivores. In this meta-analysis, I tested whether there is any difference in the correlation force recorded between studies that investigated endophagous versus exophagous herbivores, and galling versus non-galling guilds, in order to determine whether more specialized groups have a stronger relationship. Furthermore, I calculated whether effect sizes were homogeneous between galling studies carried out at local and regional scales, and between tropical and temperate regions. A total of 52 correlations were analyzed between plant species richness and herbivore species richness, with 18 correlations derived from galling herbivores and 34 from non-galling herbivores. The effect sizes were significant and positive in all studies, being higher for endophages than for exophages, and for galling than for non-galling studies. These results provide evidence that groups of insects with a higher level of host specialization and specificity (e.g., endophagous and galling) exhibit a greater dependence on plant richness. There was no difference in effect sizes for galling studies between the local and regional level or between tropical and temperate groups. Despite the large variability found for galling studies, effect sizes were consistent independently of climatic region and latitudinal variation. These results suggest that the PRH for galling insects can be generalized to most ecosystem and vegetation types.

Narratives of criminal action and forensic psychology

Purpose. In commenting on Youngs and Canter's (2011) study, Ward (2011) raises concerns about offenders’ personal narratives and their link to self‐concepts and identity. His comments relate to explorations of personal life stories rather than the narratives of actual crimes that are the focus of Youngs and Canter's (2011) study. The elaboration of this different focus helps to allay many of Ward's (2011) concerns and reveals further possibilities for developing the narrative approach within forensic psychology.Methods. The focus on offenders’ accounts of a particular crime allows the development of a standard pro forma, the Narrative Role Questionnaire (NRQ), which deals with the roles a person thinks they played when committing a crime. These roles act as a summary of the criminal's offence narrative. Multivariate analysis of the NRQ clarifies the specific narrative themes explored by Youngs and Canter (2011).Results. The examination of the components of the NRQ indicates that offence narratives encapsulate many psychological processes including thinking styles, self‐concepts, and affective components. This allows the four narrative themes identified by Youngs and Canter to provide the basis for rich hypotheses about the interaction between the dynamics of personal stories and identity. The four narratives of criminal action also offer a foundation for understanding the particular, detailed styles of offending action and the immediate, direct processes that act to instigate and shape these.Conclusion. These developments in our understanding of offence narratives generate fruitful research questions that bridge the concerns of investigative and correctional applications of narrative theory.

Social compensation or rich-get-richer? The role of social competence in college students’ use of the Internet to find a partner

Online dating continues to grow rapidly in popularity every day, yet the role of social competence in online dating behavior remains unclear. This study was designed to expand previous research and conduct a comprehensive investigation on how social competence is associated with college students’ online dating behaviors, perceptions, and attitudes. Two hypotheses were tested: The social compensation hypothesis (SCH) —socially incompetent individuals would engage in more online dating, and the rich- get- richer hypothesis (RGRH)—socially competent individuals would use online dating more than their incompetent counterparts. The results showed that incompetent individuals, despite their ability to see benefits in online dating, did not show a favorable attitude towards online dating. They indicated a more frequent use of and a stronger preference for face-to-face dating compared to online dating, which contradicted the SCH. There were weak associations between competence traits and online dating behavior. Socially competent individuals perceived less benefit and showed less interest in online dating, which disconfirmed the RGRH.

Galling arthropod diversity in the subtropical neotropics: Espinilho savannah and riparian forests compared

Xeric sites with scleromorphic vegetation appear to have higher gall-inducing arthropod richness as revealed in studies of local faunas across the world, and the harsh environment hypothesis (HEH) was proposed to explain this. However, plant richness also seems to influence galling arthropod richness positively, which appears paradoxical on a biogeographical scale. To test the HEH in southern Brazil, a sampling regime distinct from the usual local survey was adopted: eight transects were sampled during 90 min counting all galls; this was repeated three times over one year for the same transects. Xeric espinilho savannah (five transects) and mesic Uruguay River riparian forests (three transects) in subtropical Brazil were compared. Fifty-nine gall morphotypes on 15 host families were recognized out of 12,355 individual galls. Riparian forests were richer (individual-based rarefaction) and had higher gall equitabilities (bootstrapped 95% CIs); this contradicted the HEH. The plant richness hypothesis was generally supported because forests were recorded as richer in both plants and host plants. Vegetation types had different galling and host plant compositions; the latter may drive the former. Species pools appear distinct among environments, even adjacent ones, given the low similarities found. This further negates the ecological process of preference for xeric sites proposed in the HEH.

The syntax/morphology interface in Spanish L2 acquisition: Focus on quantified DPs

AbstractThis article examines whether L2 acquisition of morphology and syntax develops independently (the Separation Hypothesis) or not (the Rich Agreement Hypothesis), focusing on the acquisition of Number specification on certain Spanish quantifiers by French speakers. In Spanish, some quantifiers are specified for Number and directly precede the head noun, in contrast to their French counterparts where a dummy prepositiondemust appear inside the DP. Results from a grammaticality judgement task and a production task show that intermediate and advanced learners perform poorly on plural inflection with some quantifiers, and reject the use ofde. This suggests that they have acquired Number specification on these quantifiers, which allows Case marking on the following noun, but do not produce the appropriate morphology. These results support the Separation Hypothesis, but not the Rich Agreement Hypothesis.

An unbiased sensitivity analysis reveals important parameters controlling periodicity of circadian clock

To assess the importance of model parameters in kinetic models, sensitivity analysis is generally employed to provide key measures. However, it is quite often that no information is available for a significant number of parameters in biochemical models. Therefore, the results of sensitivity analysis that heavily rely on the accuracy of parameters are largely ambiguous. In this study, we propose a computational approach to determine the relative importance of parameters controlling the performance of the circadian clock in Drosophila. While previous attempts to sensitivity analysis largely depend on the knowledge of model parameters which are generally unknown, our study depicts a consistent picture of sensitivity assessment for a large number of parameters, even when the values of these parameters are not available in vivo. The resulting parametric sensitivity analysis suggests that PER/TIM negative loop is critical to maintain the stable periodicity of the circadian clock, which is consistent to the previously experimental and computational findings. Furthermore, our analysis generates a rich hypothesis of important parameters in the circadian clock that can be further tested experimentally. This approach can also be extended to assess the sensitivity of parameters in any biochemical system where a large number of parameters have unknown values.

Temporal changes in species diversity and composition in abandoned fields in a trans-Himalayan landscape, Nepal

Secondary succession is an increasing phenomenon due to global changes in agriculture policies and practices. The empirical findings are biased towards the temperate zone. Abandonment of agriculture fields is less frequent in the subtropical and tropical zones where agriculture areas are, in general, expanding. But there are exceptions; a rapid rate of abandonment of agricultural fields have taken place in the arid trans-Himalayan region, due to today’s globalization of economy. We analysed agriculture fields that were abandoned between 1950 and 2003 in a large u-valley in central Nepal (3400 m a.s.l.). The potential forest vegetation is dominated by Pinus wallichina and shrubs of junipers and cotoneaster species. We tested the intermediate richness hypothesis in relation to vegetation cover, soil development and whether old-field succession is convergent or divergent with species data from 242 1 m2 plots in 5 age-classes. The main species compositional turnover expressed by Detrended Correspondence Analyses (DCA) correlated, as expected, with time after abandonment. Fields that were abandoned a long time ago are closer to forest at the periphery of the agricultural landscape. Moisture of the soil significantly increased with age of abandonment, but total vegetation cover and pH were negatively related to age. Beta diversity expressed in DCA SD-units showed an increasing trend with age of abandonment, supporting the divergence pattern in old-field succession. The reason why the succession is not converging may be due to browsing by domestic animals that prevent a closed canopy of pines and juniper to develop. There was a significant hump-shaped pattern in species richness along the temporal gradient, which agrees with the intermediate species-richness hypothesis. There was a rapid increase in species richness in plots close to the villages that were used for haymaking which increased the seed input significantly.

Customized classification learning based on query projections

We develop a customized classification learning method QPL, which is based on query projections. Given an instance to be classified (query instance), QPL explores the projections of the query instance (QPs), which are essentially subsets of attribute values shared by the query and training instances. QPL investigates the associated training data distribution of a QP to decide whether it is useful. The final prediction for the query is made by combining some statistics of the selected useful QPs. Unlike existing instance-based learning, QPL does not need to compute a distance measure between instances. The utilization of QPs for learning can explore a richer hypothesis space and achieve a balance between precision and robustness. Another characteristic of QPL is that the target class may vary for different query instances in a given data set. We have evaluated our method with synthetic and benchmark data sets. The results demonstrate that QPL can achieve good performance and high reliability.

Customized Generalization of Support Patterns for Classification

We propose a novel classification learning method called customized support pattern learner (CSPL). Given an instance to be classified, CSPL explores and discovers support patterns (SPs), which are essentially attribute value subsets of the instance to be classified. The final prediction of the class label is performed by combining some statistics of the discovered useful SPs. One advantage of the CSPL method is that it can explore a richer hypothesis space and discover useful classification patterns involving attribute values with almost indistinguishable information gain. The customized learning characteristic also allows that the target class can vary for different instances to be classified. It facilitates extremely easy training instance maintenance and updates. We have evaluated our method with real-world problems and benchmark data sets. The results demonstrate that CSPL can achieve good performance and high reliability.