Category induction from distributional cues in an artificial language

The ability to identify the grammatical category of a word (e.g., noun, verb, adjective) is a fundamental aspect of competence in a natural language. Children show evidence of categorization by as early as 18 months, and in some cases younger. However, the mechanisms that underlie this ability are not well understood. The lexical co-occurrence patterns of words in sentences could provide information about word categories--for example, words that follow the in English often belong to the same category. As a step in understanding the role distributional mechanisms might play in language learning, the present study investigated the ability of adults to categorize words on the basis of distributional information. Forty participants listened for approximately 6 min to sentences in an artificial language and were told that they would later be tested on their memory for what they had heard. Participants were next tested on an additional set of sentences and asked to report which sentences they recognized from the first 6 min. The results suggested that learners performed a distributional analysis on the initial set of sentences and recognized sentences on the basis of their memory of sequences of categories of words. Thus, mechanisms that would be useful in natural language learning were shown to be active in adults in an artificial language learning task.     

Social Constructionism as a Sociological Approach

This essay concerns itself with a detailed presentation of the contents of two works on the construction of reality in society. One is Berger and Luckmann’s well-known book (The social construction of reality. Penguin Book, Harmondsworth, 1966); the other is the somewhat less known book on the same subject by Holzner (Reality construction in society. Schenkman Publishing Company, Cambridge, 1972; orig. 1968). These works deal with the social construction of shared symbolic and cognitive universes of meaning, and partake of the same theoretical sources, namely, Symbolic Interactionism and Schutz’s phenomenological sociology. They differ in their theoretical pursuits, however. Berger and Luckmann deal with what is necessary for the construction of a shared symbolic world, as society is endowed with both an objective and a subjective reality. Holzner is more interested in the social distribution and control of reality construction, and in the different types of reality constructs.     

Motivational Antecedents and Consequences of the Mother–Adolescent Communication

Communication between parents and their children represents an important factor of family socialization. Nevertheless, little is known about why parents communicate in different ways and how these qualitative differences in parent–child communication may affect the child. Building on self-determination theory, the present study focuses on motivational antecedents of need-supportive communication as a function of parental child-related beliefs (i.e., long-term goals that parents have set for their children’s future, and parental child-related behavior expectations in terms of parental dissatisfaction or satisfaction with child behavior). Moreover, the effect of perceived need-supportive communication on children’s prosocial behavior and (externalizing and internalizing) behavioral difficulties will be addressed. Three waves of data from 1125 mothers and adolescents aged between 10 and 17 years were analyzed using growth-curve modeling. We found linearly increasing trajectories in extrinsic parental goals for children and dissatisfaction with child behavior, and decreasing trajectories of need-supportive communication. Individual differences do not vary significantly over time. In addition, holding extrinsic parental goals for children positively predicts parents’ dissatisfaction with their child’s behavior and negatively predicts need-supportive communication. Parents’ dissatisfaction with their child’s behavior also contributes to decreasing need-supportive communication. As expected, need-supportive communication predicts prosocial behavior and externalizing behavioral difficulties. When need-supportive communication decreases over time, both externalizing and internalizing behavioral difficulties increase. Furthermore, the effect of mothers beliefs on adolescents socioemotional development was mediated through perceived mother’s communication quality. These results suggest that parental child-related beliefs are important motivational antecedents of parent–child communication that may prevent behavioral difficulties.     

Parenting Behaviors and Child Externalizing: A Short-Term Investigation of Directionality

Children (N = 404) provided data during 3rd and 4th grades concerning their mothers’ use of punitive discipline and yielding to coercion. Teachers provided data regarding their perceptions of children’s externalizing behaviors at school. We tested a cross-lagged model examining parental disciplinary behaviors as predictors of child externalizing behavior, as well as child externalizing behaviors as a predictor of parental disciplinary behaviors. For boys and for girls, there was over-time stability in all three variables of interest. For boys only, more externalizing behaviors in Grade 3 predicted greater use of punitive discipline by parents and more parental yielding to coercion in Grade 4, over and above Grade 3 levels of these parenting variables. The reverse direction of effects was not observed.     

Using logistic regression to estimate delay-discounting functions

The monetary choice questionnaire (MCQ) and similar computer tasks ask preference questions in order to ascertain indifference, the perceived equivalence of immediate versus larger delayed rewards. Indifference data are then fitted with a hyperbolic function, summarizing the decline in perceived value with delay time. We present a fitting method that estimates the hyperbolic parameterk directly from survey responses. Binary preferences are modeled as a function of time (X₂) and a transformed reward ratio (X ₁), yielding logistic regression coefficients β₂ and β₁. The hyperbolic parameter emerges ask = β₂/β₁, where the logistic predictedp = .5 (the definition of indifference). The MCQ was administered to 1,073 adolescents and was scored using both standard and logistic methods. The means for ln(k) were similar (standard, −4.53; logistic, −4.51), and the results were highly correlated (ρ = .973). Simulated MCQ data showed thatk was unbiased, except where β₁ ≥ −1, indicating a vague survey response. Jackknife standard errors provided excellent coverage.     

Human foraging behavior in a virtual environment

We have developed an experimental platform that allows a large number of human participants to interact in real time within a common virtual world. Within this environment, human participants foraged for resources distributed in two spatially separated pools. In addition to varying the relative replenishment rate for the two pools (50-50, 65-35, or 80-20), we manipulated whether the participants could see each other and the entire resource distribution or had their vision restricted to resources at their own location. Two empirical deviations from an optimal distribution of the participants were found. First, the participants were more scattered within a resource pool than the resources were themselves. Second, there was systematic underutilization of the richer pool. For example, the participants distributed themselves 73% and 27% to resource pools that had replenishment rates of 80% and 20%, respectively. In addition, there were oscillations in the harvesting rate of the pools across time, revealed by a Fourier analysis with prominent power near 50 sec per cycle. The suboptimalities and oscillations were more apparent when the locations of the participants and the food were not visible. Individual participant knowledge thus affects the efficiency with which a population of participants harvests resources.     

Enhanced occipital and anterior cingulate activation in men but not in women during exposure to angry and fearful male faces

Blood-oxygenation-level-dependent signal was measured with functional magnetic resonance imaging in 24 healthy young subjects (12 men and 12 women) during viewing of angry, fearful, and neutral male and female face pictures. Exposure to angry male as opposed to angry female faces activated the visual cortex and the anterior cingulate gyrus significantly more in men than in women. A similar sex-differential brain activation pattern was present during exposure to fearful but not neutral faces. Previous behavioral studies indicate enhanced physiological arousal in men but not in women during exposure to angry male as opposed to female faces, and brain imaging studies have shown that the occipital cortex and the anterior cingulate gyrus are influenced by activity in the autonomic nervous system as well as by visual attention. Hence, we suggest that the elevated occipital and anterior cingulate activation in men during confrontation with other angry and fearful males may reflect enhanced vigilance in a potentially dangerous situation.     

Touchscreen-enhanced visual learning in rats

The efficiency of traditional levers and of modern touchscreen technology for training rats on a computerized visual discrimination was studied in a series of observations. When compared with a lever-based discrimination procedure, the use of touchscreens supported the faster development of signal tracking behavior and acquisition of a two-stimulus simultaneous visual discrimination. It did not affect the final level of accuracy. Factors related to spatial proximity of the responses with the stimuli, sign-tracking, and increased ease of touchscreen motor responses were suggested as possible reasons for the touchscreen training advantage. This increased efficiency allows large numbers of animals to be tested quickly, a necessary requirement for studies involving genetic and physiological interventions.