Tracking the acquisition of orthographic skills in developing readers: masked priming effects

A masked priming procedure was used to explore developmental changes in the tuning of lexical word recognition processes. Lexical tuning was assessed by examining the degree of masked form priming and used two different types of prime-target lexical similarity: one letter different (e.g., rlay-->PLAY) and transposed letters (e.g., lpay-->PLAY). The performance of skilled adult readers was compared with that of developing readers in Grade 3. The same children were then tested again two years later, when they were in Grade 5. The skilled adult readers showed no form priming, indicating that their recognition mechanisms for these items had become finely tuned. In contrast, the Grade 3 readers showed substantial form priming effects for both measures of lexical similarity. When retested in Grade 5, the developing readers no longer showed significant one letter different priming, but transposed letter priming remained. In general, these results provide evidence for a transition from more broadly tuned to more finely tuned lexical recognition mechanisms and are interpreted in the context of models of word recognition.     

Knowledge claims and context: loose use

There is abundant evidence of contextual variation in the use of “S knows p.” Contextualist theories explain this variation in terms of semantic hypotheses that refer to standards of justification determined by “practical” features of either the subject’s context (Hawthorne & Stanley) or the ascriber’s context (Lewis, Cohen, & DeRose). There is extensive linguistic counterevidence to both forms. I maintain that the contextual variation of knowledge claims is better explained by common pragmatic factors. I show here that one is variable strictness. “S knows p” is commonly used loosely to implicate “S is close enough to knowing p for contextually indicated purposes.” A pragmatic account may use a range of semantics, even contextualist. I use an invariant semantics on which knowledge requires complete justification. This combination meets the Moorean constraint as well as any linguistic theory should, and meets the intuition constraint much better than contextualism. There is no need for ad hoc error theories. The variation in conditions of assertability and practical rationality is better explained by variably strict constraints. It will follow that “S knows p” is used loosely to implicate that the condition for asserting “p” and using it in practical reasoning are satisfied.     

HIV infection with immunodeficiency presenting with subacute cognitive decline: recent illustrative cases

We describe three recent patients in whom evaluation of subacute, progressive encephalopathy led to the initial diagnosis of human immunodeficiency virus infection. The clinical neurological picture of a predominance of abnormalities of mental function with few elementary neurological deficits, in conjunction with a paucity of systemic symptoms and lack of evidence for prior opportunistic infections preceding the encephalopathy are notable. The cognitive, behavioral, and neuropsychiatric disturbances are described in detail to illustrate the range of manifestations of disordered mental states associated with encephalopathy in individuals with HIV infection. The importance of a comprehensive and broad-minded work-up by brain magnetic resonance imaging, cerebrospinal fluid examination, and specific microbiological tests in delineating the potential multifactorial pathogenesis of the cerebral syndromes in relation to the HIV infection is emphasized. The gratifying long-term clinical improvements in parallel with resolution of neuroimaging and other laboratory abnormalities in response to antiretroviral drug treatment are reported.     

Eighteen rules for writing a code of professional ethics

Most professional societies, scientific associations, and the like that undertake to write a code of ethics do so using other codes as models but without much (practical) guidance about how to do the work. The existing literature on codes is much more concerned with content than procedure. This paper adds to guidance already in the literature what I learned from participating in the writing of an important code of ethics. The guidance is given in the form of "rules" each of which is explained and (insofar as possible) justified. The emphasis is on procedure.     

Match: A program to assist in matching the conditions of factorial experiments

In most experiments that involve between-subjects or between-items factorial designs, the items and/or the participants in the various experimental groups differ on one or more variables, but need to be matched on all other factors that can affect the outcome measure. Matching large groups of items or participants on multiple dimensions is a difficult and time-consuming task, yet failure to match conditions will lead to suboptimal experiments. We describe a computer program, "Match", that automates this process by selecting the best-matching items from larger sets of candidate items. In most cases, the program produces near-optimal solutions in amatter of minutes and selects matches that are typically superior to those obtained using hand matching or other semiautomated processes. We report the results of a case study in which Match was used to generate matched sets of experimental items (words varying in length and frequency) for a published study on language processing. The program was able to come up with better-matching item sets than those hand-selected by the authors of the original study, and in a fraction of the time originally taken up with stimulus matching.     

Work Values, Gender, and Expectations About Work Commitment and Pay: Laying the Groundwork for the “Motherhood Penalty”?

The gender pay gap most seriously affects women with children—a situation labeled the motherhood penalty. One common explanation is that mothers value family more than employment, leading to reduced work commitment and hence to lower pay. Using a questionnaire, we examined the relationship between endorsement of two work-related values (family and power), anticipated work commitment, and expected peak pay among 229 undergraduates at a southeastern U.S. university. Men expected higher peak salaries, valued power more and family less than women. For both genders, valuing power predicted higher expected peak salary and valuing family predicted lower anticipated work commitment. For women, reduced work commitment, in turn, predicted lower anticipated peak pay. For men, valuing family predicted higher peak pay expectations.     

When similarity leads to sparing: probing mechanisms underlying the attentional blink

When two targets are embedded in a temporal stream of distractors, second-target identification is initially impaired and then gradually improves as inter-target interval lengthens (attentional blink; AB). Notably, in about half of the published studies, this deficit is partially ameliorated when the targets follow one another directly, a condition known as “lag-1 sparing”. Here, we probe the impact of target-distractor similarity on lag-1 sparing, with the surprising finding that while high similarity impairs second-target accuracy at all subsequent lags, it actually improves accuracy when the targets follow one another directly. We suggest that this improvement reflects the positive influence of over-committing resources to target processing in the AB.     

Learning representations of wordforms with recurrent networks: comment on sibley, kello, plaut, & elman (2008)

Sibley et al. (2008) report a recurrent neural network model designed to learn wordform representations suitable for written and spoken word identification. The authors claim that their sequence encoder network overcomes a key limitation associated with models that code letters by position (e.g., CAT might be coded as C‐in‐position‐1, A‐in‐position‐2, T‐in‐position‐3). The problem with coding letters by position (slot‐coding) is that it is difficult to generalize knowledge across positions; for example, the overlap between CAT and TOMCAT is lost. Although we agree this is a critical problem with many slot‐coding schemes, we question whether the sequence encoder model addresses this limitation, and we highlight another deficiency of the model. We conclude that alternative theories are more promising.     

Dramatic Increase in Heritability of Cognitive Development From Early to Middle Childhood: An 8-Year Longitudinal Study of 8,700 Pairs of Twins

ABSTRACT— The generalist genes hypothesis implies that general cognitive ability ( g ) is an essential target for understanding how genetic polymorphisms influence the development of the human brain. Using 8,791 twin pairs from the Twins Early Development Study, we examine genetic stability and change in the etiology of g assessed by diverse measures during the critical transition from early to middle childhood. The heritability of a latent g factor in early childhood is 23%, whereas shared environment accounts for 74% of the variance. In contrast, in middle childhood, heritability of a latent g factor is 62%, and shared environment accounts for 33%. Despite increasing importance of genetic influences and declining influence of shared environment, similar genetic and shared environmental factors affect g from early to middle childhood, as indicated by a cross-age genetic correlation of .57 and a shared environmental correlation of .65. These findings set constraints on how genetic and environmental variation affects the developing brain.     

Wild chimpanzees (Pan troglodytes schweinfurthii) distinguish between different scream types: evidence from a playback study

When experiencing aggression from group members, chimpanzees commonly produce screams. These agonistic screams are graded signals and vary acoustically as a function of the severity of aggression the caller is facing. We conducted a series of field playback experiments with a community of wild chimpanzees in the Budongo Forest, Uganda, to determine whether individuals could meaningfully distinguish between screams given in different agonistic contexts. We compared six subjects’ responses to screams given in response to severe and mild aggression. Subjects consistently discriminated between the two scream types. To address the possibility that the response differences were driven directly by the screams’ peripheral acoustic features, rather than any attached social meaning, we also tested the subjects’ responses to tantrum screams. These screams are given by individuals that experienced social frustration, but no physical threat, yet acoustically they are very similar to screams of victims of severe aggression. We found chimpanzees looked longer at severe victim screams than either mild victim screams or tantrum screams. Our results indicate that chimpanzees attend to the informational content of screams and are able to distinguish between different scream variants, which form part of a graded continuum.