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1.  [No title available] 
PMCID: PMC3880565  PMID: 24291266
2.  [No title available] 
PMCID: PMC3883357  PMID: 24291806
3.  [No title available] 
PMCID: PMC3930356  PMID: 24321623
4.  ‘Utilitarian’ judgments in sacrificial moral dilemmas do not reflect impartial concern for the greater good 
Cognition  2015;134:193-209.
•‘Utilitarian’ judgments in moral dilemmas were associated with egocentric attitudes and less identification with humanity.•They were also associated with lenient views about clear moral transgressions.•‘Utilitarian’ judgments were not associated with views expressing impartial altruist concern for others.•This lack of association remained even when antisocial tendencies were controlled for.•So-called ‘utilitarian’ judgments do not express impartial concern for the greater good.
A growing body of research has focused on so-called ‘utilitarian’ judgments in moral dilemmas in which participants have to choose whether to sacrifice one person in order to save the lives of a greater number. However, the relation between such ‘utilitarian’ judgments and genuine utilitarian impartial concern for the greater good remains unclear. Across four studies, we investigated the relationship between ‘utilitarian’ judgment in such sacrificial dilemmas and a range of traits, attitudes, judgments and behaviors that either reflect or reject an impartial concern for the greater good of all. In Study 1, we found that rates of ‘utilitarian’ judgment were associated with a broadly immoral outlook concerning clear ethical transgressions in a business context, as well as with sub-clinical psychopathy. In Study 2, we found that ‘utilitarian’ judgment was associated with greater endorsement of rational egoism, less donation of money to a charity, and less identification with the whole of humanity, a core feature of classical utilitarianism. In Studies 3 and 4, we found no association between ‘utilitarian’ judgments in sacrificial dilemmas and characteristic utilitarian judgments relating to assistance to distant people in need, self-sacrifice and impartiality, even when the utilitarian justification for these judgments was made explicit and unequivocal. This lack of association remained even when we controlled for the antisocial element in ‘utilitarian’ judgment. Taken together, these results suggest that there is very little relation between sacrificial judgments in the hypothetical dilemmas that dominate current research, and a genuine utilitarian approach to ethics.
PMCID: PMC4259516  PMID: 25460392
Moral judgment; Moral dilemmas; Utilitarianism; Psychopathy; Altruism; Impartiality
5.  Thyme to touch: Infants possess strategies that protect them from dangers posed by plants 
Cognition  2013;130(1):44-49.
Plants have been central to human life as sources of food and raw materials for artifact construction over evolutionary time. But plants also have chemical and physical defenses (such as harmful toxins and thorns) that provide protection from herbivores. The presence of these defenses has shaped the behavioral strategies of non-human animals. Here we report evidence that human infants possess strategies that would serve to protect them from dangers posed by plants. Across two experiments, infants as young as eight months exhibit greater reluctance to manually explore plants compared to other entities. These results expand the growing literature showing that infants are sensitive to certain ancestrally recurrent dangers, and provide a basis for further exploration.
PMCID: PMC3896079  PMID: 24161794
6.  Degrading phonetic information affects matching of audiovisual speech in adults, but not in infants 
Cognition  2013;130(1):31-43.
Infants and adults are well able to match auditory and visual speech, but the cues on which they rely (viz. temporal, phonetic and energetic correspondence in the auditory and visual speech streams) may differ. Here we assessed the relative contribution of the different cues using sine-wave speech (SWS). Adults (N=52) and infants (N=34, age ranged in between 5 and 15 months) matched 2 trisyllabic speech sounds (‘kalisu’ and ‘mufapi’), either natural or SWS, with visual speech information. On each trial, adults saw two articulating faces and matched a sound to one of these, while infants were presented the same stimuli in a preferential looking paradigm. Adults’ performance was almost flawless with natural speech, but was significantly less accurate with SWS. In contrast, infants matched the sound to the articulating face equally well for natural speech and SWS. These results suggest that infants rely to a lesser extent on phonetic cues than adults do to match audio to visual speech. This is in line with the notion that the ability to extract phonetic information from the visual signal increases during development, and suggests that phonetic knowledge might not be the basis for early audiovisual correspondence detection in speech.
PMCID: PMC3904288  PMID: 24141035
Audiovisual speech integration; adults; infants; phonetic correspondence; sine-wave speech
7.  Fading Perceptual Resemblance: A Path for Rhesus Macaques (Macaca mulatta) to Conceptual Matching? 
Cognition  2013;129(3):10.1016/j.cognition.2013.08.001.
Cognitive, comparative, and developmental psychologists have long been intrigued by humans’ and animals’ capacity to respond to abstract relations like sameness and difference, because this capacity may underlie crucial aspects of cognition like analogical reasoning. Recently, this capacity has been explored in higher-order, relational matching-to-sample (RMTS) tasks in which humans and animals try to complete analogies of sameness and difference between disparate groups of items. The authors introduced a new paradigm to this area, by yoking the relational-matching cue to a perceptual-matching cue. Then, using established algorithms for shape distortion, the perceptual cue was weakened and eliminated. Humans’ RMTS performance easily transcended the elimination of perceptual support. In contrast, RMTS performance by six macaques faltered as they were weaned from perceptual support. No macaque showed evidence of mature RMTS performance, even given more than 260,000 training trials during which we tried to coax a relational-matching performance from them. It is an important species difference that macaques show so hesitant a response to conceptual relations when humans respond to them so effortlessly. It raises theoretical questions about the emergence of this crucial capacity during humans’ cognitive evolution and during humans’ cognitive development.
PMCID: PMC3809328  PMID: 24076537
same-different; concept learning; relational matching; primate cognition; comparative cognition
8.  Ways of looking ahead: Hierarchical planning in language production 
Cognition  2013;129(3):544-562.
It is generally assumed that language production proceeds incrementally, with chunks of linguistic structure planned ahead of speech. Extensive research has examined the scope of language production and suggests that the size of planned chunks varies across contexts (Ferreira & Swets, 2002; Wagner et al. 2010). By contrast, relatively little is known about the structure of advance planning, specifically whether planning proceeds incrementally according to the surface structure of the utterance, or whether speakers plan according to the hierarchical relationships between utterance elements. In two experiments, we examine the structure and scope of lexical planning in language production using a picture description task. Analyses of speech onset times and word durations show that speakers engage in hierarchical planning such that structurally dependent lexical items are planned together and that hierarchical planning occurs for both direct and indirect dependencies.
PMCID: PMC3909534  PMID: 24045002
Language production; planning scope; hierarchical planning
9.  A disadvantage in bilingual sentence production modulated by syntactic frequency and similarity across languages 
Cognition  2013;129(2):256-263.
Bilingual speakers access individual words less fluently, quickly, and accurately than monolinguals, particularly when accessing low-frequency words. Here we examined whether the bilingual speech production disadvantage would (a) extend to full sentences above and beyond single word retrieval and whether it would be modulated by (b) structural frequency and (c) syntactic properties of the bilingual speakers’ other language. English monolinguals, Spanish-English bilinguals and Mandarin-English bilinguals were tested in a sentence production task conducted exclusively in English. Response times were modulated by bilingualism, structural frequency, and structural similarity across the bilingual speakers’ two languages. These results refine our knowledge regarding the scope of the bilingual disadvantage, demonstrate that frequency effects apply to syntactic structures, and also suggest that syntax is partially shared across bilinguals’ two languages.
PMCID: PMC4241230  PMID: 23948209
Sentence production; Bilingual disadvantage; Frequency effects; Cross-language interactivity
10.  Cognitive constraints on constituent order: Evidence from elicited pantomime 
Cognition  2013;129(1):1-17.
To what extent does human cognition influence the structure of human language? Recent experiments using elicited pantomime suggest that the prevalence of Subject-Object-Verb (SOV) order across the world's languages may arise in part because SOV order is most compatible with how we conceptually represent transitive events (Goldin-Meadow, So, Özyürek, & Mylander, 2008). However, this raises the question as to why non-SOV orders exist. Two recent studies (Meir, Lifshitz, Ilkbasaran, & Padden, 2010; Gibson et al., 2013) suggest that SOV might be suboptimal for describing events in which both the agent and patient are plausible agents (e.g. a woman pushing a boy); we call these “reversible” events. We replicate these findings using elicited pantomime and offer a new interpretation. Meir et al.'s (2010) account is framed largely in terms of constraints on comprehension, while Gibson et al.'s (2013) account involves minimizing the risk of information loss or memory degradation. We offer an alternative hypothesis that is grounded in constraints on production. We consider the implications of these findings for the distribution of constituent order in the world's spoken languages and for the structure of emerging sign languages.
PMCID: PMC4224279  PMID: 23792806
Word order; SOV; Gesture; Pantomime; Sign language; Production
11.  Rule learning over consonants and vowels in a non-human animal 
Cognition  2012;126(2):307-312.
Perception studies have shown similarities between humans and other animals in a wide array of language-related processes. However, the components of language that make it uniquely human have not been fully identified. Here we show that nonhuman animals extract rules over speech sequences that are difficult for humans. Specifically, animals easily learn rules over both consonants and vowels, while humans do it only over vowels. In Experiment 1, rats learned a rule implemented over vowels in CVCVCV nonsense words. In Experiment 2, rats learned the rule when it was implemented over the consonants. In both experiments, rats generalized such knowledge to novel words they had not heard before. Using the same stimuli, human adults learned the rules over the vowels but not over the consonants. These results suggest differences between humans and animals on speech processing might lie on the constraints they face while extracting information from the signal.
PMCID: PMC4217073  PMID: 23121712
Speech perception; Rule-learning; Consonants and vowels; Animal Cognition
12.  Object-centered representations support flexible exogenous visual attention across translation and reflection 
Cognition  2013;129(2):10.1016/j.cognition.2013.07.001.
Visual attention can be deployed to stimuli based on our willful, top-down goal (endogenous attention) or on their intrinsic saliency against the background (exogenous attention). Flexibility is thought to be a hallmark of endogenous attention, whereas decades of research show that exogenous attention is attracted to the retinotopic locations of the salient stimuli. However, to the extent that salient stimuli in the natural environment usually form specific spatial relations with the surrounding context and are dynamic, exogenous attention, to be adaptive, should embrace these structural regularities. Here we test a non-retinotopic, object-centered mechanism in exogenous attention, in which exogenous attention is dynamically attracted to a relative, object-centered location. Using a moving frame configuration, we presented two frames in succession, forming either apparent translational motion or in mirror reflection, with a completely uninformative, transient cue presented at one of the item locations in the first frame. Despite that the cue is presented in a spatially separate frame, in both translation and mirror reflection, human performance in visual search is enhanced when the target in the second frame appears at the same relative location as the cue location than at other locations. These results provide unambiguous evidence for non-retinotopic exogenous attention and further reveal an object-centered mechanism supporting flexible exogenous attention. Moreover, attentional generalization across mirror reflection may constitute an attentional correlate of perceptual generalization across lateral mirror images, supporting an adaptive, functional account of mirror images confusion.
PMCID: PMC3875404  PMID: 23942348
exogenous attention; non-retinotopic processing; object-centered representation; mirror images
13.  Internal attention to features in visual short-term memory guides object learning 
Cognition  2013;129(2):292-308.
Attending to objects in the world affects how we perceive and remember them. What are the consequences of attending to an object in mind? In particular, how does reporting the features of a recently seen object guide visual learning? In three experiments, observers were presented with abstract shapes in a particular color, orientation, and location. After viewing each object, observers were cued to report one feature from visual short-term memory (VSTM). In a subsequent test, observers were cued to report features of the same objects from visual long-term memory (VLTM). We tested whether reporting a feature from VSTM: (1) enhances VLTM for just that feature (practice-benefit hypothesis), (2) enhances VLTM for all features (object-based hypothesis), or (3) simultaneously enhances VLTM for that feature and suppresses VLTM for unreported features (feature-competition hypothesis). The results provided support for the feature-competition hypothesis, whereby the representation of an object in VLTM was biased towards features reported from VSTM and away from unreported features (Experiment 1). This bias could not be explained by the amount of sensory exposure or response learning (Experiment 2) and was amplified by the reporting of multiple features (Experiment 3). Taken together, these results suggest that selective internal attention induces competitive dynamics among features during visual learning, flexibly tuning object representations to align with prior mnemonic goals.
PMCID: PMC3791170  PMID: 23954925
features and objects; memory encoding; memory retrieval; selective attention; visual short-term memory; visual working memory
14.  Event Segmentation Ability Uniquely Predicts Event Memory 
Cognition  2013;129(2):10.1016/j.cognition.2013.07.002.
Memory for everyday events plays a central role in tasks of daily living, autobiographical memory, and planning. Event memory depends in part on segmenting ongoing activity into meaningful units. This study examined the relationship between event segmentation and memory in a lifespan sample to answer the following question: Is the ability to segment activity into meaningful events a unique predictor of subsequent memory, or is the relationship between event perception and memory accounted for by general cognitive abilities? Two hundred and eight adults ranging from 20 to 79 years old segmented movies of everyday events and attempted to remember the events afterwards. They also completed psychometric ability tests and tests measuring script knowledge for everyday events. Event segmentation and script knowledge both explained unique variance in event memory above and beyond the psychometric measures, and did so as strongly in older as in younger adults. These results suggest that event segmentation is a basic cognitive mechanism, important for memory across the lifespan.
PMCID: PMC3821069  PMID: 23942350
Event cognition; Episodic memory; Cognitive aging
15.  Infant directed speech and the development of speech perception: Enhancing development or an unintended consequence? 
Cognition  2013;129(2):10.1016/j.cognition.2013.07.015.
Infant directed speech (IDS) is a speech register characterized by simpler sentences, a slower rate, and more variable prosody. Recent work has implicated it in more subtle aspects of language development. Kuhl et al. (1997) demonstrated that segmental cues for vowels are affected by IDS in a way that may enhance development: the average locations of the extreme “point” vowels (/a/, /i/ and /u/) are further apart in acoustic space. If infants learn speech categories, in part, from the statistical distributions of such cues, these changes may specifically enhance speech category learning. We revisited this by asking (1) if these findings extend to a new cue (Voice Onset Time, a cue for voicing); (2) whether they extend to the interior vowels which are much harder to learn and/or discriminate; and (3) whether these changes may be an unintended phonetic consequence of factors like speaking rate or prosodic changes associated with IDS. Eighteen caregivers were recorded reading a picture book including minimal pairs for voicing (e.g., beach/peach) and a variety of vowels to either an adult or their infant. Acoustic measurements suggested that VOT was different in IDS, but not in a way that necessarily supports better development, and that these changes are almost entirely due to slower rate of speech of IDS. Measurements of the vowel suggested that in addition to changes in the mean, there was also an increase in variance, and statistical modeling suggests that this may counteract the benefit of any expansion of the vowel space. As a whole this suggests that changes in segmental cues associated with IDS may be an unintended by-product of the slower rate of speech and different prosodic structure, and do not necessarily derive from a motivation to enhance development.
PMCID: PMC3874452  PMID: 23973465
Infant directed speech; Speech categorization; Statistical learning; Phonetic analysis; Vowels; Voices onset time
16.  Competition strength influences individual preferences in an auction game 
Cognition  2014;133(2):480-487.
•We conducted a repeated all-pay auction experiment with real items.•Participants exhibited dynamic bidding strategies.•Bidding dynamics clearly affected preferences for auctioned items.•Preference changes depended on the effort exerted when winning.
Competitive interactions between individuals are ubiquitous in human societies. Auctions represent an institutionalized context for these interactions, a context where individuals frequently make non-optimal decisions. In particular, competition in auctions can lead to overbidding, resulting in the so-called winner’s curse, often explained by invoking emotional arousal. In this study, we investigated an alternative possibility, namely that competitors’ bids are construed as a source of information about the good’s common value thereby influencing an individuals’ private value estimate. We tested this hypothesis by asking participants to bid in a repeated all-pay auction game for five different real items. Crucially, participants had to rank the auction items for their preference before and after the experiment. We observed a clear relation between auction dynamics and preference change. We found that low competition reduced preference while high competition increased preference. Our findings support a view that competitors’ bids in auction games are perceived as valid social signal for the common value of an item. We suggest that this influence of social information constitutes a major cause for the frequently observed deviations from optimality in auctions.
PMCID: PMC4175410  PMID: 25168161
Social information; All pay auction; Decision-making; Preference formation; Competition
17.  Reasoning about a hidden object after a delay: Evidence for robust representations in 5-month-old infants 
Cognition  2003;88(3):B23-B32.
The present research examined two alternative interpretations of violation-of-expectation findings that young infants can represent hidden objects. One interpretation is that, when watching an event in which an object becomes hidden behind another object, infants form a prediction about the event’s outcome while both objects are still visible, and then check whether this prediction was accurate. The other interpretation is that infants’ initial representations of hidden objects are weak and short-lived and as such sufficient for success in most violation-of-expectation tasks (as objects are typically hidden for only a few seconds at a time), but not more challenging tasks. Five-month-old infants succeeded in reasoning about the interaction of a visible and a hidden object even though (1) the two objects were never simultaneously visible, and (2) a 3- or 4-min delay preceded the test trials. These results provide evidence for robust representations of hidden objects in young infants.
PMCID: PMC4215943  PMID: 12804819
Infant cognition; Object permanence; Memory
18.  Young infants’ reasoning about hidden objects: evidence from violation-of-expectation tasks with test trials only 
Cognition  2004;93(3):167-198.
The present research examined alternative accounts of prior violation-of-expectation (VOE) reports that young infants can represent and reason about hidden objects. According to these accounts, young infants’ apparent success in these VOE tasks reflects only novelty and familiarity preferences induced by the habituation or familiarization trials in the tasks. In two experiments, 4-month-old infants were tested in VOE tasks with test trials only. The infants still gave evidence that they could represent and reason about hidden objects: they were surprised, as indicated by greater attention, when a wide object became fully hidden behind a narrow occluder (Experiment 1) or inside a narrow container (Experiment 2). These and control results demonstrate that young infants can succeed at VOE tasks involving hidden objects even when given no habituation or familiarization trials. The present research thus provides additional support for the conclusion that young infants possess expectations about hidden objects. Methodological issues concerning the use of habituation or familiarization trials in VOE tasks are also discussed.
PMCID: PMC4215956  PMID: 15178376
Infants’ physical reasoning; Violation-of-expectation findings; Novelty and familiarity preferences
19.  Perseverative responding in a violation-of-expectation task in 6.5-month-old infants 
Cognition  2003;88(3):277-316.
In the present research, 6.5-month-old infants perseverated in a violation-of-expectation task designed to examine their reasoning about width information in containment events. After watching a familiarization event in which a ball was lowered into a wide container, the infants failed to detect the violation in a test event in which the same ball was lowered into a container only half as wide as the ball (narrow-container test event). This negative result (which was replicated in another experiment) was interpreted in terms of a recent problem-solving account of infants’ perseverative errors in various means-end tasks (Aguiar, A., & Baillargeon, R. (2000). Perseveration and problem solving in infancy. In H. W. Reese (Ed.), Advances in child development and behavior (Vol. 27, pp. 135–180). San Diego, CA: Academic Press). It was assumed that the infants in the present experiments (1) did not attend to the relative widths of the ball and container in their initial analysis of the narrow-container test event, (2) categorized the event as similar to the familiarization event shown on the preceding trials, and (3) retrieved the expectation they had formed for that event (“the ball will fit into the container”), resulting in a perseverative error. This interpretation was supported by additional experiments in which different modifications were introduced that led to non-perseverative responding, indicating that 6.5-month-old infants could detect the violation in the narrow-container test event. The present findings are important for several reasons. First, they provide the first demonstration of perseverative responding in a violation-of-expectation task. Second, they make clear the breadth and usefulness of the problem-solving account mentioned above. Finally, they add to the evidence for some degree of continuity between infants’ and adults’ problem-solving abilities.
PMCID: PMC4212222  PMID: 12804814
Infant cognition; Physical reasoning; Violation-of-expectation task; Perseveration
20.  Connecting Numbers to Discrete Quantification: A Step in the Child’s Construction of Integer Concepts 
Cognition  2013;129(1):31-41.
The present study asks when young children understand that number words quantify over sets of discrete individuals. For this study, two- to four-year-old children were asked to extend the number word five or six either to a cup containing discrete objects (e.g., blocks) or to a cup containing a continuous substance (e.g., water). In Experiment 1, only children who knew the exact meanings of the words one, two and three extended higher number words (five or six) to sets of discrete objects. In Experiment 2, children who only knew the exact meaning of one extended higher number words to discrete objects under the right conditions (i.e., when the problem was first presented with the number words one and two). These results show that children have some understanding that number words pertain to discrete quantification from very early on, but that this knowledge becomes more robust as children learn the exact, cardinal meanings of individual number words.
PMCID: PMC3742655  PMID: 23831562
Word Learning; Number Concepts; Discrete Quantification
21.  Greater learnability is not sufficient to produce cultural universals 
Cognition  2013;129(1):70-87.
Looking across human societies reveals regularities in the languages that people speak and the concepts that they use. One explanation that has been proposed for these “cultural universals” is differences in the ease with which people learn particular languages and concepts. A difference in learnability means that languages and concepts possessing a particular property are more likely to be accurately transmitted from one generation of learners to the next. Intuitively, this difference could allow languages and concepts that are more learnable to become more prevalent after multiple generations of cultural transmission. If this is the case, the prevalence of languages and concepts with particular properties can be explained simply by demonstrating empirically that they are more learnable. We evaluate this argument using mathematical analysis and behavioral experiments. Specifically, we provide two counter-examples that show how greater learnability need not result in a property becoming prevalent. First, more learnable languages and concepts can nonetheless be less likely to be produced spontaneously as a result of transmission failures. We simulated cultural transmission in the laboratory to show that this can occur for memory of distinctive items: these items are more likely to be remembered, but not generated spontaneously once they have been forgotten. Second, when there are many languages or concepts that lack the more learnable property, sheer numbers can swamp the benefit produced by greater learnability. We demonstrate this using a second series of experiments involving artificial language learning. Both of these counter-examples show that simply finding a learnability bias experimentally is not sufficient to explain why a particular property is prevalent in the languages or concepts used in human societies: explanations for cultural universals based on cultural transmission need to consider the full set of hypotheses a learner could entertain and all of the kinds of errors that can occur in transmission.
PMCID: PMC3752284  PMID: 23831566
cultural universals; iterated learning; learnability bias; cultural evolution; vowel harmony
22.  How children perceive fractals: Hierarchical self-similarity and cognitive development 
Cognition  2014;133(1):10-24.
•Visual recursion becomes available around the same age as iteration (9–10 years-old).•Acquisition of visual recursion is facilitated by previous experience with iteration.•Both visual recursion and iteration correlate with grammar comprehension.•Representing hierarchies recursively improves detection of nested mistakes.•Recursion in vision follows learning constraints similar to language.
The ability to understand and generate hierarchical structures is a crucial component of human cognition, available in language, music, mathematics and problem solving. Recursion is a particularly useful mechanism for generating complex hierarchies by means of self-embedding rules. In the visual domain, fractals are recursive structures in which simple transformation rules generate hierarchies of infinite depth. Research on how children acquire these rules can provide valuable insight into the cognitive requirements and learning constraints of recursion.
Here, we used fractals to investigate the acquisition of recursion in the visual domain, and probed for correlations with grammar comprehension and general intelligence. We compared second (n = 26) and fourth graders (n = 26) in their ability to represent two types of rules for generating hierarchical structures: Recursive rules, on the one hand, which generate new hierarchical levels; and iterative rules, on the other hand, which merely insert items within hierarchies without generating new levels. We found that the majority of fourth graders, but not second graders, were able to represent both recursive and iterative rules. This difference was partially accounted by second graders’ impairment in detecting hierarchical mistakes, and correlated with between-grade differences in grammar comprehension tasks. Empirically, recursion and iteration also differed in at least one crucial aspect: While the ability to learn recursive rules seemed to depend on the previous acquisition of simple iterative representations, the opposite was not true, i.e., children were able to acquire iterative rules before they acquired recursive representations. These results suggest that the acquisition of recursion in vision follows learning constraints similar to the acquisition of recursion in language, and that both domains share cognitive resources involved in hierarchical processing.
PMCID: PMC4148595  PMID: 24955884
Recursion; Iteration; Hierarchy; Language evolution; Development; Visuo-spatial
23.  Open questions and a proposal: A critical review of the evidence on infant numerical abilities 
Cognition  2013;128(3):331-352.
Considerable research has investigated infants’ numerical capacities. Studies in this domain have used procedures of habituation, head turn, violation of expectation, reaching, and crawling to ask what quantities infants discriminate and represent visually, auditorily as well as intermodally. The concensus view from these studies is that infants possess a numerical system that is amodal and aplicable to the quantification of any kind of entity and that this system is fundamentally separate from other systems that represent continuous magnitude. Although there is much evidence consistent with this view, there are also inconsistencies in the data. This paper provides a broad review of what we know, including the evidence suggesting systematic early knowledge as well as the peculiarities and gaps in the empirical findings with respect to the concensus view. We argue, from these inconsistencies, that the concensus view cannot be entirely correct. In light of the evidence, we propose a new hypothesis, the Signal Clarity hypothesis, that posits a developmental role for dimensions of continuous quantity within the discrete quantity system and calls for a broader research agenda that considers the covariation of discrete and continuous quantities not simply as a problem for experimental control but as information that developing infants may use to build more precise and robust representations of number.
PMCID: PMC3708991  PMID: 23748213
number; quantity discrimination; infant
24.  The effect of word predictability on reading time is logarithmic 
Cognition  2013;128(3):302-319.
It is well known that real-time human language processing is highly incremental and context-driven, and that the strength of a comprehender’s expectation for each word encountered is a key determinant of the difficulty of integrating that word into the preceding context. In reading, this differential difficulty is largely manifested in the amount of time taken to read each word. While numerous studies over the past thirty years have shown expectation-based effects on reading times driven by lexical, syntactic, semantic, pragmatic, and other information sources, there has been little progress in establishing the quantitative relationship between expectation (or prediction) and reading times. Here, by combining a state-of-the-art computational language model, two large behavioral data-sets, and non-parametric statistical techniques, we establish for the first time the quantitative form of this relationship, finding that it is logarithmic over six orders of magnitude in estimated predictability. This result is problematic for a number of established models of eye movement control in reading, but lends partial support to an optimal perceptual discrimination account of word recognition. We also present a novel model in which language processing is highly incremental well below the level of the individual word, and show that it predicts both the shape and time-course of this effect. At a more general level, this result provides challenges for both anticipatory processing and semantic integration accounts of lexical predictability effects. And finally, this result provides evidence that comprehenders are highly sensitive to relative differences in predictability – even for differences between highly unpredictable words – and thus helps bring theoretical unity to our understanding of the role of prediction at multiple levels of linguistic structure in real-time language comprehension.
PMCID: PMC3709001  PMID: 23747651
Psycholinguistics; Expectation; Probabilistic models of cognition; Information theory; Reading
25.  Voxel-based lesion-parameter mapping: Identifying the neural correlates of a computational model of word production 
Cognition  2013;128(3):380-396.
The dual-route interactive two-step model explains the variation in the error patterns of aphasic speakers in picture naming, and word and nonword repetition tasks. The model has three parameters that can vary across individuals: the efficiency of the connections between semantic and lexical representations (s-weight), between lexical and phonological representations (p-weight), and between representations of auditory input and phonological representations (nl-weight). We determined these parameter values in 103 participants with chronic aphasia from left hemisphere stroke whose lesion locations had been determined. Then, using voxel-based lesion-parameter mapping, we mapped the parameters onto the brain, thus determining the neural correlates of the model’s mechanisms. The maps and the behavioral findings supported the model’s central claim that word repetition is affected by both the p and nl parameters. We propose that these two parameters constitute the model’s analogue of the “dorsal stream” component of neurocognitive models of language processing.
PMCID: PMC3709005  PMID: 23765000
Aphasia; Language production; Computational models; Voxel-based Lesion Parameter Mapping

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