Additional Exemplars Research Articles

English-learning preschoolers can correctly parse and interpret negative sentences to guide their interpretations of novel noun and verb meanings

ABSTRACT We studied English-learning children’s ability to learn the meanings of novel words from sentences containing truth-functional negation (Exp1) and to use the semantics of negation to inform word meaning (Exp2). In Exp1, 22-month-olds (n = 21) heard dialogues introducing a novel verb in either negative-transitive (“Mary didn’t blick the baby”) or negative-intransitive (“Mary didn’t blick”) sentences. When then asked to “Find blicking!” while viewing two-participant versus one-participant actions, children who heard negative-transitive sentences looked longer at the two-participant event than children who heard negative-intransitives. Thus, the mere presence of negation does not disrupt sentence processing and word learning in young children. Experiment 2 tested whether 2-to-4-year-olds (n = 20) use the semantics of negation to restrict the meaning of novel nouns when categorizing objects varying along a perceptual continuum (from 10 to 90% exemplars). Children initially heard “These are blickets” paired with certain exemplars (e.g., yellowish creatures, exemplars 10 and 30%). They then saw additional exemplars (e.g., pinkish creatures, 70 and 90%) while hearing either “These are not blickets” (negative condition) or “These are also blickets” (affirmative condition). At test, when seeing two novel exemplars from the continuum (e.g., creatures 20 and 80%) and asked to find “a blicket,” children in the negative condition selected the exemplar from the bottom of the continuum (i.e., the 20%) more often than children in the affirmative condition. Thus, English-learning children as young as 22-months of age correctly parse negative sentences and 2-to-4-year-olds can use negation to understand the boundaries of a word’s meaning.

Silence is Golden: Auditory Preferences in Zoo-housed Gorillas

ABSTRACT Enrichment is presented to improve the welfare of captive animals but sound is frequently presented with the assumption that it is enriching without assessing individuals’ preferences. Typically, presented sounds are unnatural and animals are unable to choose which sounds they can listen to or escape them. We examined preferences of three zoo-housed gorillas for six categories of sound. The gorillas selected unique icons on a computer touchscreen that initiated brief samples of silence, white noise, nature, animal, percussion, and electronic instrumental sounds. Following training, gorillas selected each sound paired with silence (Phase 2), each sound paired with each other sound (Phase 3), and one sound among all other sound categories (Phase 4). Initially, a single sound was associated with each icon, but additional exemplars of the category were added in phases 5–8. Preferences were generally stable and one gorilla showed a strong preference for silence. Although there were individual differences, a surprising general preference for unnatural over natural sounds was revealed. These results indicate the importance of assessing preferences for individuals before introducing auditory stimulation in captive habitats.

Morphological anomalies in Rhipicephalus sanguineus s.s. (Acari: Ixodidae) collected from dogs in steppe and high plateaus regions, Algeria.

The present report describes morphological anomalies in Rhipicephalus sanguineus s.s. collected from dogs between February 2017 and May 2019in the steppic region of Djelfa and high plateau area of Bordj-Bou-Arreridj in Algeria. Out of 1043 ticks from 147infested dogs, four adult ticks (0.38%), collectedfrom four dogs, exhibited local morphological abnormalities. One male displayed ectromely of leg I left, and theother three specimens exhibited multiple associated anomalies in idiosomas and exoskeletons, festoons, stigmas (spiracles), as well as in adanal and accessory plates. This report provides additional exemplars of morphological abnormalities in tick populations of Africa, particularly North Africa.

Sample size, number of categories and sampling assumptions: Exploring some differences between categorization and generalization

Categorization and generalization are fundamentally related inference problems. Yet leading computational models of categorization (as exemplified by, e.g., Nosofsky, 1986) and generalization (as exemplified by, e.g., Tenenbaum and Griffiths, 2001) make qualitatively different predictions about how inference should change as a function of the number of items. Assuming all else is equal, categorization models predict that increasing the number of items in a category increases the chance of assigning a new item to that category; generalization models predict a decrease, or category tightening with additional exemplars. This paper investigates this discrepancy, showing that people do indeed perform qualitatively differently in categorization and generalization tasks even when all superficial elements of the task are kept constant. Furthermore, the effect of category frequency on generalization is moderated by assumptions about how the items are sampled. We show that neither model naturally accounts for the pattern of behavior across both categorization and generalization tasks, and discuss theoretical extensions of these frameworks to account for the importance of category frequency and sampling assumptions.

Explanation-based learning in infancy.

In explanation-based learning (EBL), domain knowledge is leveraged in order to learn general rules from few examples. An explanation is constructed for initial exemplars and is then generalized into a candidate rule that uses only the relevant features specified in the explanation; if the rule proves accurate for a few additional exemplars, it is adopted. EBL is thus highly efficient because it combines both analytic and empirical evidence. EBL has been proposed as one of the mechanisms that help infants acquire and revise their physical rules. To evaluate this proposal, 11- and 12-month-olds (n = 260) were taught to replace their current support rule (that an object is stable when half or more of its bottom surface is supported) with a more sophisticated rule (that an object is stable when half or more of the entire object is supported). Infants saw teaching events in which asymmetrical objects were placed on a base, followed by static test displays involving a novel asymmetrical object and a novel base. When the teaching events were designed to facilitate EBL, infants learned the new rule with as few as two (12-month-olds) or three (11-month-olds) exemplars. When the teaching events were designed to impede EBL, however, infants failed to learn the rule. Together, these results demonstrate that even infants, with their limited knowledge about the world, benefit from the knowledge-based approach of EBL.

Facelikeness matters: A parametric multipart object set to understand the role of spatial configuration in visual recognition

ABSTRACTThere is a view that faces and objects are processed by different brain mechanisms. Different factors may modulate the extent to which face mechanisms are used for objects. To distinguish these factors, we present a new parametric multipart three-dimensional object set that provides researchers with a rich degree of control of important features for visual recognition such as individual parts and the spatial configuration of those parts. All other properties being equal, we demonstrate that perceived facelikeness in terms of spatial configuration facilitated performance at matching individual exemplars of the new object set across viewpoint changes (Experiment 1). Importantly, facelikeness did not affect perceptual discriminability (Experiment 2) or similarity (Experiment 3). Our findings suggest that perceptual resemblance to faces based on spatial configuration of parts is important for visual recognition even after equating physical and perceptual similarity. Furthermore, the large parametrically controlled object set and the standardized procedures to generate additional exemplars will provide the research community with invaluable tools to further understand visual recognition and visual learning.

The effect of scene category distinctiveness on memory performance

Previous studies showed a remarkable capacity to memorize large number of scenes (Konkle et al., 2010). Same study showed exemplar effect (higher number of exemplars per category led to decreased performance). Can images of similar gist from different categories also impair the performance? Alternatively, people are trained to deal with these similarities: when they encounter a scene coming from the class of scenes of similar gist and mixed categories, they are more sensitive when encoding it. We used a set of 2048 grayscale scenes (64 categories). We evaluated the pairwise scene similarity using gist metric (Oliva & Torralba, 2001). For each image we inspected the most proximate 32 images and calculated its category distinctiveness as the proportion of the images of the same category. The distinctiveness was later averaged over categories. To each participant (N=29) we presented 320 unique scenes (5 per category) and additional 2x40 scenes for repeat detection. In the second part, the participants were making old/new judgments with 256 images (128 new, 128 old, 2+2 per category). We pooled the categories into four groups based on the distinctiveness and evaluated its effect on memory performance. We found no effect of category distinctiveness on d’. In two subsequent experiments, we found no effect in a more difficult version (12 scenes per category) or in a color version. Our experiments suggest there is no benefit in memorizing visually distinct categories (with lower gist similarity to other scene categories). The images with similar global characteristics (gist) from different categories did not serve as additional exemplars and their presence did not decrease the memory performance. Meeting abstract presented at VSS 2015

Pancultural nostalgia: prototypical conceptions across cultures.

Nostalgia is a frequently experienced complex emotion, understood by laypersons in the United Kingdom and United States of America to (a) refer prototypically to fond, self-relevant, social memories and (b) be more pleasant (e.g., happy, warm) than unpleasant (e.g., sad, regretful). This research examined whether people across cultures conceive of nostalgia in the same way. Students in 18 countries across 5 continents (N = 1,704) rated the prototypicality of 35 features of nostalgia. The samples showed high levels of agreement on the rank-order of features. In all countries, participants rated previously identified central (vs. peripheral) features as more prototypical of nostalgia, and showed greater interindividual agreement regarding central (vs. peripheral) features. Cluster analyses revealed subtle variation among groups of countries with respect to the strength of these pancultural patterns. All except African countries manifested the same factor structure of nostalgia features. Additional exemplars generated by participants in an open-ended format did not entail elaboration of the existing set of 35 features. Findings identified key points of cross-cultural agreement regarding conceptions of nostalgia, supporting the notion that nostalgia is a pancultural emotion.

Family-level relationships of the spittlebugs and froghoppers (Hemiptera: Cicadomorpha: Cercopoidea)

The spittlebug superfamily Cercopoidea (Hemiptera: Cicadomorpha) comprises approximately 3000 phytophagous species (including some economically important pests of grass crops) classified among the families Cercopidae, Aphrophoridae, Epipygidae, Clastopteridae and Machaerotidae. However, the monophyly of these taxa has never been tested and the evolutionary relationships among these major lineages are unknown. Presented here are the results of the first ever phylogenetic investigation of the higher-level relationships within Cercopoidea, based on DNA nucleotide sequence data from six loci (18S rDNA, 28S rDNA, histone 3, wingless, cytochrome oxidase I and cytochrome oxidase II) generated from exemplars of 109 spittlebug species representing all five described families, seven of eight subfamilies and 61 genera (eight additional exemplars, representing a selection of other Auchenorrhyncha taxa, were included as outgroups). The resulting topologies are used to evaluate the monophyly of each cercopoid family, and further to calculate divergence date estimates to examine the chronological origins and historical diversification of Cercopoidea. The results of this investigation suggest that: (i) four of the five described families are monophyletic; Epipygidae was recovered consistently as originating within Aphrophoridae; (ii) the exclusively Old World Machaerotidae is the most anciently diversified family of extant spittlebugs; (iii) New World Cercopidae (i.e. Ischnorhininae) constitute a derived monophyletic lineage; (iv) the genus Microsargane Fowler, classified currently within Aphrophoridae, actually belongs within Cercopidae; and (v) the origins of the major spittlebug lineages probably coincided with the breakup of Pangaea and, subsequently, Gondwana, as well as major floristic diversification such as the rise of angiosperms.

Generic language and speaker confidence guide preschoolers’ inferences about novel animate kinds.

We investigated the influence of speaker certainty on 156 four-year-old children's sensitivity to generic and nongeneric statements. An inductive inference task was implemented, in which a speaker described a nonobvious property of a novel creature using either a generic or a nongeneric statement. The speaker appeared to be confident, neutral, or uncertain about the information being relayed. Preschoolers were subsequently asked if a second exemplar shared the same property as the first. Preschoolers consistently extended properties to additional exemplars only when properties were described in a generic form by a confident or neutral speaker. If a speaker appeared to be uncertain or if statements were made in a nongeneric form, properties were not consistently extended beyond the first exemplar. The findings demonstrate that children integrate the inductive cues provided by generic language with social cues when reasoning about abstract kinds.

Outsourcing to an Unknown Workforce: Exploring Opensurcing as a Global Sourcing Strategy

This paper presents a psychological contract perspective on the use of the open source development model as a global sourcing strategy-opensourcing, as we term it here-whereby commercial companies and open source communities collaborate on development of software of commercial interest to the company. Building on previous research on information systems outsourcing, a theoretical framework for exploring the opensourcing phenomenon is derived. The first phase of the research concerned qualitative case studies involving three commercial organizations (IONA Technologies, Philips Medical Systems, and Telefonica) that had liberated what had hitherto been proprietary software and sought to grow a global open source community around their product. We followed this with a large-scale survey involving additional exemplars of the phenomenon. The study identifies a number of symmetrical and complementary customer and community obligations that are associated with opensourcing success. We also identify a number of tension points on which customer and community perceptions tend to vary. Overall the key watchwords for opensourcing are openness, trust, tact, professionalism, transparency, and complementariness: The customer and community need to establish a trusted partnership of shared responsibility in building an overall opensourcing ecosystem. The study reveals an ongoing shift from OSS as a community of individual developers to OSS as a community of commercial organizations, primarily small to medium-sized enterprises. It also reveals that opensourcing provides ample opportunity for companies to headhunt top developers, hence moving from outsourcing to a largely unknown OSS workforce toward recruitment of developers from a global open source community whose talents have become known as a result of the opensourcing experience.

Beyond fast mapping: young children's extensions of novel words and novel facts.

L. Markson and P. Bloom (1997) concluded that there was evidence against a dedicated system for word learning on the basis of their finding that children remembered a novel word and a novel fact equally well. However, a word-learning system involves more than recognition memory; it must also provide a means to guide the extension of words to additional exemplars, and words and facts may differ with regard to extendibility. Two studies are reported in which 2-4-year-old children learned novel words and novel facts for unfamiliar objects and then were asked to extend the words and facts to additional exemplars of the training objects. In both studies, children extended the novel word to significantly more category members than they extended the novel fact. The results show that by 2 years of age, children honor the necessary extendibility of novel count nouns but are uncertain about the extendibility of arbitrary facts.

Pitch Identification in Children and Adults: Naming and Discrimination

Elementary school children and adults selected for significant pitch identification ability, so called "absolute pitch", were given two tasks to determine some of the characteristics of this skill. In a pitch-naming task, participants gave the note names for tones randomly selected from the chromatic scale either with a conventional piano or pure tone timbre. Naming accuracy was higher among the adults, on trials having the piano timbre, and for certain pitch categories (note names), reflecting more accurate identification of "white key" pitches. Analysis of errors indicated a strong bias towards certain pitch categories, again primarily the "white key" pitches, in both children and adults. Comparison subjects having similar musical training, but no absolute pitch, also showed these biases. In a pitch recognition task, participants were asked to detect additional exemplars of a target tone in an extended series of tones varying in pitch. While those with significant pitch naming skill were quite adept at this task as well, biases associated with pitch category were less apparent. These results suggest a distinction between pitch encoding and naming in those who excel in pitch identification.

Effects of Hypothesis Saliency on the Use of Positive and Diagnostic Test Strategies

The situation-centered model of inference under conditions of uncertainty (McDonald, 1990) is expanded to account for changes in test strategy employment over problems. Basic concepts regarding the transfer of learning between problems are incorporated into the model and lead to the prediction that diagnostic test strategy, rather than positive test strategy, will be the norm on problems presented after subjects have learned to access sets of hypotheses for which there is no identifiable salient (obvious) hypothesis. Two experiments were conducted to test this prediction. Both utilized a set of category discovery problems in which subjects were given an exemplar and were asked to discover the correct category to which the exemplar belonged by testing the membership status of additional exemplars. In Experiment 1, 83% of subjects solved a target problem in which the set of learned hypotheses was comprised of subsets of the correct category. This is a condition in which positive test strategy is completely ineffective, suggesting that most subjects employed diagnostic test strategy. In Experiment 2, 89% of subjects who listed an analyzable best guess tested exemplars that were not members of their best-guess category, behavior which is wholly inconsistent with the use of positive test strategy. The results of both experiments refute the idea that people have a bias toward using positive test strategy and specify some of the conditions under which positive test strategy and diagnostic test strategy will be employed.