Utterances expressing generic kinds (''birds fly'') highlight qualities of a category that are stable and enduring, and thus provide insight into conceptual organization. To explore the role that linguistic input plays in children's production of generic nouns, we observed American and Chinese deaf children whose hearing losses prevented them from…

Comparative behavioral research is important for a number of reasons and can contribute to the understanding of human behavior and development in many different ways. Research with animal models of human behavior and development can be a source not only of general principles and testable hypotheses but also of empirical information that may be…

This review focuses on prenatal stress as a risk factor for psychopathology. Evidence from animal studies is summarized, and the relevance of prenatal stress models in animals for human studies is discussed. In the offspring of prenatally stressed animals, overactivity and impaired negative feedback regulation of the hypothalamic-pituitary-adrenal…

This meta-analysis reviews 208 laboratory studies of acute psychological stressors and tests a theoretical model delineating conditions capable of eliciting cortisol responses. Psychological stressors increased cortisol levels; however, effects varied widely across tasks. Consistent with the theoretical model, motivated performance tasks elicited…

Humans and pigeons were trained to discriminate between 2 views of actual 3-D objects or their photographs. They were tested on novel views that were either within the closest rotational distance between the training views (interpolated) or outside of that range (extrapolated). When training views were 60? apart, pigeons, but not humans,…

Drawing on the theoretical and empirical foundations of two evolutionary models, we argue that, among humans and other mammals, a twofold selection process would parsimoniously account for sex-linked advantages in spatial contexts. In males, a superiority for both solving navigation-related spatial problems and understanding physical principles…

Massive extinctions of animals and the arrival of the first humans in ancient Australia--which occurred 45,000 to 55,000 years ago--may be linked. Researchers at the Carnegie Institution, University of Colorado, Australian National University, and Bates College believe that massive fires set by the first humans may have altered the ecosystem of…

Now, a research team from Virginia Tech and Nanjing Institute of Geology and Paleontology has discovered uniquely well-preserved fossil forms from 550-million-year-old rocks of the Ediacaran Period. The research appears in the Proceedings of the National Academy of Sciences. The discovery of these unusually preserved fossils reveals unprecedented…

Neurological research has demonstrated that brain activity in animals originally dedicated to the production and regulation of physical activity can be decoupled from that physical activity. Furthermore, animals can use the brain activity in this new condition to achieve particular results such as moving a cursor on a screen. These findings are…

We assessed whether exposure to amodal properties in bimodal stimulation (e.g. rhythm, rate, duration) could educate attention to amodal properties in subsequent unimodal stimulation during prenatal development. Bobwhite quail embryos were exposed to an individual bobwhite maternal call under several experimental and control conditions during the…

Growth factor-mediated signaling has emerged as an essential component of memory formation. In this study, we used a phospholipase C gamma 1 (PLC[gamma]1) binding, cell-penetrating peptide to sequester PLC[gamma]1 away from its target, the phosphotyrosine residues within the activated growth factor receptor. Peptides appear to transduce neurons…

We asked whether honeybees, "Apis mellifera," could solve a transitive inference problem. Individual free-flying bees were conditioned with four overlapping premise pairs of five visual patterns in a multiple discrimination task (A+ vs. B-, B+ vs. C-, C+ vs. D-, D+ vs. E-, where + and - indicate sucrose reward or absence of it,…

Recent studies have reported new evidence consistent with the hypothesis that reactivating a memory by re-exposure to a training context destabilizes the memory and induces "reconsolidation." In the present experiments, rats' memory for inhibitory avoidance (IA) training was tested 6 h (Test 1), 2 d (Test 2), and 6 d (Test 3) after training. On…

Operant conditioning of the H-reflex, the electrical analog of the spinal stretch reflex, is a simple model of skill acquisition and involves plasticity in the spinal cord. Previous work showed that the cerebellum is essential for down-conditioning the H-reflex. This study asks whether the cerebellum is also essential for maintaining…

Long-term memory formation is regulated by many distinct molecular mechanisms that control gene expression. An emerging model for effecting a stable, coordinated pattern of gene transcription involves epigenetic tagging through modifications of histones or DNA. In this study, we investigated the regulation of histone phosphorylation in the…