Biomedical subjects

Ken McRae

Publications and source records attributed to Ken McRae.

9 recordsLinked to original sources

PubMed2007

Verb aspect and the activation of event knowledge.

The authors show that verb aspect influences the activation of event knowledge with 4 novel results. First, common locations of events (e.g., arena) are primed following verbs with imperfective aspect (e.g., was skating) but not verbs with perfect aspect (e.g., had skated). Second, people generate more locative prepositional phrases as completions to sentence fragments with imperfective than those with perfect aspect. Third, the amplitude of the N400 component to location nouns varies as a function of aspect and typicality, being smallest for imperfective sentences with highly expected locations and largest for imperfective sentences with less expected locations. Fourth, the amplitude of a sustained frontal negativity spanning prepositional phrases is larger following perfect than following imperfective aspect. Taken together, these findings suggest a dynamic interplay between event knowledge and the linguistic stream.

Brain↗

PubMed2006

Isoflavone profiles of red clovers and their distribution in different parts harvested at different growing stages.

The isoflavone compositions and concentrations in the leaf, flower, petiole, and stem of 13 red clover cultivars were studied using high-performance liquid chromatography coupled with a diode array and a mass spectrometric detector with negative electrospray ionization. Different cultivars showed significantly different concentrations of individual and total isoflavones. The leaf contained the highest overall concentration, followed by the stem, petiole, and flower. Biochanin A and formononetin were the predominant isoflavones in all cultivars and all parts, along with eight other minor aglycones, daidzein, genistein, glycitein, irilone, orobol, pratensein, pseudobaptigenin, and prunetin, and four minor malonylglycosides, genistein-7-glucoside-6' '-malonate, orobol-7-glucoside-6' '-malonate, formononetin-7-glucoside-6' '-malonate, and biochanin A-7-glucoside-6' '-malonate. The isoflavone compositions and concentrations were also found to be different between red clover parts harvested at the early bud stage and the late flowering stage. Sample storage and handling prior to analysis were also found to be important. Samples in this study were kept at -5 degrees C for a few days before being freeze-dried and were found to contain mainly the aglycones of isoflavones. This may actually be an advantage in that "natural" and more bioactive isoflavones can be obtained without using chemical hydrolysis. Findings in this study therefore provide important information for developing isoflavone-rich red clovers and for optimizing harvest timing and choosing the right part of the red clover plant.

Chromatography, High Pressure Liquid↗

PubMed2006

Distinctive features hold a privileged status in the computation of word meaning: Implications for theories of semantic memory.

The authors present data from 2 feature verification experiments designed to determine whether distinctive features have a privileged status in the computation of word meaning. They use an attractor-based connectionist model of semantic memory to derive predictions for the experiments. Contrary to central predictions of the conceptual structure account, but consistent with their own model, the authors present empirical evidence that distinctive features of both living and nonliving things do indeed have a privileged role in the computation of word meaning. The authors explain the mechanism through which these effects are produced in their model by presenting an analysis of the weight structure developed in the network during training.

Concept Formation↗

PubMed2005

Meaning through syntax is insufficient to explain comprehension of sentences with reduced relative clauses: comment on McKoon and Ratcliff (2003).

The authors argue that the meaning through syntax (MTS) model proposed by G. McKoon and R. Ratcliff fails to account for the comprehension of sentences with reduced relative clauses. First, the theory's core assumptions regarding verb-based event representations and how they link to constructions are incompatible with well-established analyses from the lexical semantics literature. Second, the MTS theory provides neither a principled nor a consistent account for why some reduced relatives are hard whereas others are easy. Finally, McKoon and Ratcliff's critique of constraint-based models is flawed in that sometimes they tested a nonexistent theory and sometimes they provided evidence for the constraint-based models against which they were arguing.

Humans↗

PubMed2005

Semantic feature production norms for a large set of living and nonliving things.

Semantic features have provided insight into numerous behavioral phenomena concerning concepts, categorization, and semantic memory in adults, children, and neuropsychological populations. Numerous theories and models in these areas are based on representations and computations involving semantic features. Consequently, empirically derived semantic feature production norms have played, and continue to play, a highly useful role in these domains. This article describes a set of feature norms collected from approximately 725 participants for 541 living (dog) and nonliving (chair) basic-level concepts, the largest such set of norms developed to date. This article describes the norms and numerous statistics associated with them. Our aim is to make these norms available to facilitate other research, while obviating the need to repeat the labor-intensive methods involved in collecting and analyzing such norms. The full set of norms may be downloaded from www.psychonomic.org/archive.

Adult↗

PubMed2005

A basis for generating expectancies for verbs from nouns.

We explore the implications of an event-based expectancy generation approach to language understanding, suggesting that one useful strategy employed by comprehenders is to generate expectations about upcoming words. We focus on two questions: (1) What role is played by elements other than verbs in generating expectancies? (2) What connection exists between expectancy generation and event-based knowledge? Because verbs follow their arguments in many constructions (particularly in verb-final languages), deferring expectations until the verb seems inefficient. Both human data and computational modeling suggest that other sentential elements may also play a role in predictive processing and that these constraints often reflect knowledge regarding typical events. We investigated these predictions, using both short and long stimulus onset asynchrony priming. Robust priming obtained when verbs were named aloud following typical agents, patients, instruments, and locations, suggesting that event memory is organized so that nouns denoting entities and objects activate the classes of events in which they typically play a role. These computations are assumed to be an important component of expectancy generation in sentence processing.

Humans↗

PubMed2003

Analyzing the factors underlying the structure and computation of the meaning of chipmunk, cherry, chisel, cheese, and cello (and many other such concrete nouns).

Seven trends regarding the categories that tend to be impaired/preserved in category-specific semantic deficits were identified. The authors hypothesized that these trends arise despite the multiple sources of variation in patient testing because numerous factors that structure semantic memory probabilistically converge to make some categories of knowledge more susceptible to damage than others. Analysis of semantic feature norms and corpus data for 541 concepts revealed that differences in the distribution of knowledge types across categories are sufficient to explain 6 of the trends and are necessary to explain loss of knowledge about nonliving things. Feature informativeness, concept confusability, visual complexity, familiarity, and name frequency contributed to this patterning and provide insight into why knowledge about living things is most often impaired.

Electronic Data Processing↗

PubMed2003

Thematic role focusing by participle inflections: evidence from conceptual combination.

The authors examined how people integrate knowledge of agents and patients of events with the temporal and causal properties of present and past participles to constrain interpretation of isolated participle-noun phrases like arresting cop and arrested crook. Good-agent head nouns were more easily combined with present participles (e.g., arresting cop) than with past participles (e.g., arrested cop), and the reverse was true for good patients. Furthermore, present-participle good-patient phrases (e.g., serving customer) were often interpreted as verb phrases. This research provides further evidence of the interaction between morphosyntactic cues and world knowledge of events in language comprehension.

Analysis of Variance↗

PubMed1999

Further evidence for feature correlations in semantic memory.

The role of feature correlations in semantic memory is a central issue in conceptual representation. In two versions of the feature verification task, participants were faster to verify that a feature (< is juicy >) is part of a concept (grapefruit) if it is strongly rather than weakly intercorrelated with the other features of that concept. Contrasting interactions between feature correlations and SOA were found when the concept versus the feature was presented first. An attractor network model of word meaning that naturally learns and uses feature correlations predicted those interactions. This research provides further evidence that semantic memory includes implicitly learned statistical knowledge of feature relationships, in contrast to theories such as spreading activation networks, in which feature correlations play no role.

Humans↗