Cumulative estrogen exposure and prospective memory in older women

This study looked at cumulative lifetime estrogen exposure, as estimated with a mathematical index (Index of Cumulative Estrogen Exposure (ICEE)) that included variables (length of time on estrogen therapy, age at menarche and menopause, postmenopausal body mass index, time since menopause, nulliparity and duration of breastfeeding) known to influence estrogen levels across the life span, and performance on prospective and retrospective memory measures in a group of 50 postmenopausal women (mean age=69.3years) who, if they were current or former users of estrogen therapy, had started therapy within 5years of menopause. The ICEE was found to be a significant predictor of performance on the Prospective Memory task (F(1)=4.21, p=.046, η(p)(2)=.084). No significant relationship was noted between the ICEE and performance on measures of retrospective memory. The results suggest that the level of cumulative lifetime exposure to estrogen a woman has influences her prospective memory performance later in life and that the influence of reproductive and biological markers of endogenous estrogen exposure are relevant factors to consider when studying the effect of estrogen therapy on cognitive functioning in postmenopausal women. In addition, the finding that performance on a measure of prospective memory, but not performance on measures of retrospective memory, was associated with the ICEE adds further support to the theory that the frontal cortex may be especially sensitive to estrogen.     

Processing prefixes and suffixes in handwriting production

Previous research showed that handwriting production is mediated by linguistically oriented processing units such as syllables and graphemes. The goal of this study was to investigate whether French adults also activate another kind of unit that is more related to semantics than phonology, namely morphemes. Experiment 1 revealed that letter duration and inter-letter intervals were longer for suffixed words than for pseudo-suffixed words. These results suggest that the handwriting production system chunks the letter components of the root and suffix into morpheme-sized units. Experiment 2 compared the production of prefixed and pseudo-prefixed words. The results did not yield significant differences. This asymmetry between suffix and prefix processing has also been observed in other linguistic tasks. In suffixed words, the suffix would be processed on-line during the production of the root, in an analytic fashion. Prefixed words, in contrast, seem to be processed without decomposition, as pseudo-affixed words.     

The role of novelty in early word learning

What mechanism implements the mutual exclusivity bias to map novel labels to objects without names? Prominent theoretical accounts of mutual exclusivity (e.g., Markman, 1989, 1990 ) propose that infants are guided by their knowledge of object names. However, the mutual exclusivity constraint could be implemented via monitoring of object novelty (see Merriman, Marazita, & Jarvis, 1995 ). We sought to discriminate between these contrasting explanations across two preferential looking experiments with 22‐month‐olds. In Experiment 1, infants viewed three objects: one name‐known, two name‐unknown. Of the two name‐unknown objects, one was novel, and the other had been previously familiarized. The infants responded to hearing a novel label by increasing attention only to the novel, name‐unknown object. In a second experiment in which the name‐known object was absent, a novel label increased infants’ attention to a novel object beyond baseline preference for novelty. The experiments provide clear evidence for a novelty‐based mechanism. However, differences in the time course of disambiguation across experiments suggest that novelty processing may be influenced by contextual factors.     

Producing Pronouns and Definite Noun Phrases: Do Speakers Use the Addressee’s Discourse Model?

We report two experiments that investigated the widely held assumption that speakers use the addressee's discourse model when choosing referring expressions (e.g., Ariel, 1990; Chafe, 1994; Givón, 1983; Prince, 1985), by manipulating whether the addressee could hear the immediately preceding linguistic context. Experiment 1 showed that speakers increased pronoun use (and decreased noun phrase use) when the referent was mentioned in the immediately preceding sentence compared to when it was not, even though the addressee did not hear the preceding sentence, indicating that speakers used their own, privileged discourse model when choosing referring expressions. The same pattern of results was found in Experiment 2. Speakers produced more pronouns when the immediately preceding sentence mentioned the referent than when it mentioned a referential competitor, regardless of whether the sentence was shared with their addressee. Thus, we conclude that choice of referring expression is determined by the referent's accessibility in the speaker's own discourse model rather than the addressee's.     

Cue effectiveness in communicatively efficient discourse production

Recent years have seen a surge in accounts motivated by information theory that consider language production to be partially driven by a preference for communicative efficiency. Evidence from discourse production (i.e., production beyond the sentence level) has been argued to suggest that speakers distribute information across discourse so as to hold the conditional per-word entropy associated with each word constant, which would facilitate efficient information transfer (Genzel & Charniak, 2002). This hypothesis implies that the conditional (contextualized) probabilities of linguistic units affect speakers' preferences during production. Here, we extend this work in two ways. First, we explore how preceding cues are integrated into contextualized probabilities, a question which so far has received little to no attention. Specifically, we investigate how a cue's maximal informativity about upcoming words (the cue's effectiveness) decays as a function of the cue's recency. Based on properties of linguistic discourses as well as properties of human memory, we analytically derive a model of cue effectiveness decay and evaluate it against cross-linguistic data from 12 languages. Second, we relate the information theoretic accounts of discourse production to well-established mechanistic (activation-based) accounts: We relate contextualized probability distributions over words to their relative activation in a lexical network given preceding discourse.     

Perceptual simulation in developing language comprehension

We tested an embodied account of language proposing that comprehenders create perceptual simulations of the events they hear and read about. In Experiment 1, children (ages 7–13 years) performed a picture verification task. Each picture was preceded by a prerecorded spoken sentence describing an entity whose shape or orientation matched or mismatched the depicted object. Responses were faster for matching pictures, suggesting that participants had formed perceptual-like situation models of the sentences. The advantage for matching pictures did not increase with age. Experiment 2 extended these findings to the domain of written language. Participants (ages 7–10 years) of high and low word reading ability verified pictures after reading sentences aloud. The results suggest that even when reading is effortful, children construct a perceptual simulation of the described events. We propose that perceptual simulation plays a more central role in developing language comprehension than was previously thought.     

Assessment of working memory components at 6years of age as predictors of reading achievements a year later

The ability of working memory skills (measured by tasks assessing all four working memory components), IQ, language, phonological awareness, literacy, rapid naming, and speed of processing at 6 years of age, before reading was taught, to predict reading abilities (decoding, reading comprehension, and reading time) a year later was examined in 97 children. Among all working memory components, phonological complex memory contributed most to predicting all three reading abilities. A capacity measure of phonological complex memory, based on passing a minimum threshold in those tasks, contributed to the explained variance of decoding and reading comprehension. Findings suggest that a minimal ability of phonological complex memory is necessary for children to attain a normal reading level. Adding assessment of phonological complex memory, before formal teaching of reading begins, to more common measures might better estimate children’s likelihood of future academic success.     

Age differences in understanding precedent-setting decisions and authorities' responses to violations of deontic rules

Oral narrative skills are assumed to develop through parent-child interactive routines. One such routine is shared reading. A causal link between shared reading and narrative knowledge, however, has not been clearly established. The current research tested whether an 8-week shared reading intervention enhanced the fictional narrative skills of children entering formal education. Dialogic reading, a shared reading activity that involves elaborative questioning techniques, was used to engage children in oral interaction during reading and to emphasize elements of story knowledge. Participants were 40 English-speaking 5- and 6-year-olds who were assigned to either the dialogic reading group or an alternative treatment group. Analysis of covariance results found that the dialogic reading children’s posttest narratives were significantly better on structure and context measures than those for the alternative treatment children, but results differed for produced or retold narratives. The dialogic reading children also showed expressive vocabulary gains. Overall, this study concretely determined that aspects of fictional narrative construction knowledge can be learned from interactive book reading.     

Learning to learn: From within-modality to cross-modality transfer during infancy

One critical aspect of learning is the ability to apply learned knowledge to new situations. This ability to transfer is often limited, and its development is not well understood. The current research investigated the development of transfer between 8 and 16 months of age. In Experiment 1, 8- and 16-month-olds (who were established to have a preference to the beginning of a visual sequence) were trained to attend to the end of a sequence. They were then tested on novel visual sequences. Results indicated transfer of learning, with both groups changing baseline preferences as a result of training. In Experiment 2, participants were trained to attend to the end of a visual sequence and were then tested on an auditory sequence. Unlike Experiment 1, only older participants exhibited transfer of learning by changing baseline preferences. These findings suggest that the generalization of learning becomes broader with development, with transfer across modalities developing later than transfer within a modality.     

Modulation of N400 in chronic non-fluent aphasia using low frequency Repetitive Transcranial Magnetic Stimulation (rTMS)

Low frequency Repetitive Transcranial Magnetic Stimulation (rTMS) has previously been applied to language homologues in non-fluent populations of persons with aphasia yielding significant improvements in behavioral language function up to 43 months post stimulation. The present study aimed to investigate the electrophysiological correlates associated with the application of rTMS through measurement of the semantic based N400 Event-related brain potentials (ERP) component. Low frequency (1 Hz) rTMS was applied to the anterior portion of the homologue to Broca’s area (pars triangularis), for 20 min per day for 10 days, using a stereotactic neuronavigational system. Twelve non-fluent persons with aphasia, 2-6 years post stroke were stimulated. Six participants were randomly assigned to receive real stimulation and six participants were randomly assigned to receive a blind sham control condition. ERP measures were recorded at baseline, 1 week and 2 months subsequent to stimulation. The findings demonstrate treatment related changes observed in the stimulation group when compared to the placebo control group at 2 months post stimulation indicating neuromodulation of N400 as a result of rTMS. No treatment related changes were identified in the stimulation group, when compared to the sham group from baseline to 1 week post stimulation. The electrophysiological results represent the capacity of rTMS to modulate neural language networks and measures of lexical-semantic function in participants with non-fluent aphasia and suggest that time may be an important factor in brain reorganization subsequent to rTMS.