Exploring the role of verbal category labels in flexible cognition

Recent research under the paradigm of the label feedback hypothesis has proposed a causal role for verbal labels in the online learning and processing of categories. Those categories learned along with names are learned faster, and are more robust after learning. The present study seeks to extend this research by considering the relationship between verbal label cues for categories and flexible categorization. Flexibility will be defined as the ability to dynamically activate and modify the cognitive processes of categorization in response to changing task demands. Flexibility is a key trait of human cognitive processes, and flexible categorization is important in creativity, problem solving, and other tasks. In the present study participants must learn to categorize between ‘friendly’ and ‘unfriendly’ aliens either with or without names during training. They then must learn to re-categorize the same stimuli set in one of three different transfer conditions. If labels do indeed act as material anchors upon which to hang categories, and in doing so play a role in maximizing selective attention, labels should also reduce flexibility. While the present study does show a role for selective attention in relearning, no effect of label was found for either category learning or relearning, with one exception; labels facilitated flexibility when a change in selective attention was not involved in the transfer. The inability to replicate previous findings of the role for verbal labels in category learning using similar methodologies raises interesting theoretical issues, questioning the extent to which this relationship applies to linguistic categorization

The Developmental Neurotoxicity of Arsenic: Cognitive and Behavioral Consequences of Early Life Exposure

Background: More than 200 million people worldwide are chronically exposed to arsenic. Arsenic is a known human carcinogen, and its carcinogenic and systemic toxicity have been extensively studied. By contrast, the developmental neurotoxicity of arsenic has been less well described. The aim of this review was to provide a comprehensive review of the developmental neurotoxicity of arsenic. Methods: We reviewed the published epidemiological and toxicological literature on the developmental neurotoxicity of arsenic. Results: Arsenic is able to gain access to the developing brain and cause neurotoxic effects. Animal models link prenatal and early postnatal exposure to reduction in brain weight, reductions in numbers of glia and neurons, and alterations in neurotransmitter systems. Animal and in vitro studies both suggest that oxidative stress may be a mechanism of arsenic neurotoxicity. Fifteen epidemiological studies indicate that early life exposure is associated with deficits in intelligence and memory. These effects may occur at levels of exposure below current safety guidelines, and some neurocognitive consequences may become manifest only later in life. Sex, concomitant exposures, and timing of exposure appear to modify the developmental neurotoxicity of arsenic. Four epidemiological studies failed to show behavioral outcomes of arsenic exposure. Conclusions: The published literature indicates that arsenic is a human developmental neurotoxicant. Ongoing and future prospective birth cohort studies will allow more precise definition of the developmental consequences of arsenic exposure in early life

Glomerular thrombosis in pregnancy: Role of the L-arginine-nitric oxide pathway

Glomerular thrombosis in pregnancy: Role of the L-arginine-nitric oxide pathway. E. coli endotoxin (LPS) and certain cytokines induce synthesis of nitric oxide (NO) from L-arginine, but also promote endothelial injury and intravascular coagulation. NO has vasodilator and antithrombogenic properties. We investigated the relationship between the L-arginine-NO pathway and the susceptibility to LPS-induced glomerular thrombosis in pregnancy. Pregnant rats were given either 0.15 or 0.75 mg/kg/body wt of LPS intraperitoneally. In rats given 0.15 mg/kg/body wt of LPS urinary NO2−/NO3− (end products of NO) increased 200% (P < 0.05), plasma L-arginine did not change, and glomerular thrombosis was minimal. Pregnant rats given 0.75 mg/kg/body wt of LPS developed glomerular thrombosis in 75% of glomeruli (P < 0.05). In these rats plasma L-arginine fell 98%, from 53 ± 4 to 1.4 ± 0.9 mmol/liter (P < 0.05) but the urinary NO2−/NO3− did not increase. Oral administration of L-arginine but not D-arginine increased urinary NO2−/NO3− by 250% and averted glomerular thrombosis in these rats (P < 0.05). Virgin rats given 0.75 mg/kg/body wt of LPS did not contract glomerular thrombosis. In these rats plasma L-arginine decreased only 40% while urinary NO2−/NO3− concomitantly increased over 200% (P < 0.05). Plasma endothelin-1 increased only in rats exhibiting glomerular thrombosis. Thus, limited maternal reserve capability for NO synthesis may underlie, at least in part, the susceptibility for glomerular thrombosis in pregnancy

Complementarity and linguistic divergence in collaborative dialogue

Language is fundamental to the human ability to work collaboratively on shared tasks. Current theories of dialogue, the format in which language use is shared and coordinated, emphasize cognitive processes that bring conversational partners’ talk into alignment. Driven by automatic priming of linguistic representation and the synchronization of embodied actions, the success of an interacting pair is ascribed to the degree to which the two converge. Such convergence, however, cannot explain how language use allows dyads to extend their abilities beyond those at the individual level, nor how a dyad might produce a novel idea. Instead, a new theory of dialogue must be developed, one that takes into account both convergent processes as well as processes that support divergence and complementarity. Borrowing a theoretical framing from dynamical systems and extended cognition, such a model is described as an interpersonal synergy. The role of divergence in supporting collaboration is tested across three domains in which collaboration has been previously tested. In Experiment 1, we test whether linguistic divergence supports joint decision making in a perceptual task, replicating and extending previous work that found that indiscriminate alignment negatively correlates with collective benefit. In Experiment 2, dyads engage in a creative humor production task together and alone. Here we correlate turn-by-turn divergence with collaborative success. In Experiment 3 we explore the extent to which overlapping or complementary contributions assist in the construction of a collaborative memory over repeated conversational rehearsals. Across these three domains different methods for measuring conversational divergence are established. We find that turn-by-turn progressivity predicts the extent to which pairs produce more humorous and creative jokes. However, we fail to correlate measures of conversational divergence with collaborative benefit in the decision-making and memory tasks. These studies and new methods represent a first step in developing a fuller theory of dialogue as the basis for the coordination of distinct information and contributions, such that both convergent and divergent processes may benefit the ability of conversational partners to engage in socially extended cognitive activities

A study of social interactions and web dynamics in the spider Anelosimus sp., (Theriidae) in Monteverde, Costa Rica

Sociality in spiders represents serious evolutionary drawbacks, yet persists in some 20 species. Sociality of an undescribed species of spider, Anelosimus sp. (Theriidae), was studied in Monteverde, Costa Rica. The social interactions that were considered were: prey capture, kin recognition and web dynamics. I observed prey capture, whether adults or juveniles were attacking, and how long it took to first contact the prey. Adults preferentially attacked larger prey, while juveniles preferentially attacked smaller prey (p = 0.001, 2 = 10.517, df = 1, n = 23). There was also a trend showing that spiders in multiple-spider webs contacted prey faster than those in single-spider webs (p = 0.09). These results suggest that an increase in efficiency and a sharing of the prey-capture burden act as mechanisms to help make social living beneficial. A second part of the study consisted of introducing foreign spiders, both juveniles and adults, to webs and recording the reaction. The introduced adults were almost always shown aggression, while introduced juveniles were never shown aggression. This suggests the presence of kin recognition, as foreigners were recognized; smaller juveniles were largely ignored, while large foreigners were attacked and chased off. Size could be the mechanism for determining when juveniles finally disperse from the natal web. Finally, I found a positive relation between web volume and number of spiders (p = 0.001) and number of smaller webs within 50 cm (p = 0.08). This indicates that the web must increase proportionally with each additional spider in a brood. My study suggests possible mechanisms for making social living beneficial despite the serious evolutionary drawbacks. La sociabilidad en las arañas representa serias desventajas evolucionarías, encontrándose en alrededor de 20 especies. El comportamiento social no descrito en las especies de Anelosimus sp. (Theriidae), fue estudiado en Monteverde, Costa Rica. Las interacciones sociales que fueron consideradas son: la captura de presas, el reconocimiento de parentela y la dinámica de la tela.https://digitalcommons.usf.edu/tropical_ecology/1506/thumbnail.jp