Effect of social organisation on interspecific differences in overmarking behaviour of foals in African equids

Animal Cognition - Overmarking remains an unstudied topic in juvenile mammals. We have previously documented a very high rate of overmarking by foals in four captive African equid species: mountain...     

Do dogs rescue their owners from a stressful situation? A behavioral and physiological assessment

Animal Cognition - Rescue behavior is considered a type of pro-social response, defined as a voluntary action directed to benefit another individual who is in a stressful or dangerous situation. In...     

The Spotlight Effect Revisited: Overestimating the Manifest Variability of Our Actions and Appearance

Three studies examined people's estimates of the perceived variability of their appearance and behavior in the eyes of others. Whether assessing the manifest variability of their physical appearance (Studies 1a, 1b, and 1c), their athletic accomplishments (Study 2), or their performance on a popular videogame (Study 3), participants consistently overestimated the extent to which their ups and downs would be noted by observers. The results of Study 3 suggest that this bias stems in part from a failure to appreciate the extent to which observers are preoccupied with managing their own actions. Discussion focuses on how this corollary of the “spotlight effect” can contribute to social anxiety and gnawing regrets of inaction.     

Exploring the mental health of Mexican migrant farm workers in the Midwest: psychosocial predictors of psychological distress and suggestions for prevention and treatment

The purposes of the present study were threefold: (a) to assess the prevalence levels of anxiety and depression in a sample of Mexican migrant farm workers in the midwestern United States; (b) to explore the relationships among acculturative stress, anxiety, and depression; and (c) to examine the variables that best predict anxiety and depression. The overall sample revealed elevated levels of anxiety and depression. Migrant farm workers with heightened levels of acculturative stress were more likely to report high levels of anxiety and depression. Family dysfunction, ineffective social support, low self-esteem, lack of agreement with the decision to migrate, high education levels, high levels of acculturative stress, and high levels of anxiety were significantly associated with high depression levels. The overall findings suggest that migrant farm workers who experience elevated levels of acculturative stress may be at risk for experiencing high levels of anxiety and depression. The findings highlight the importance of establishing prevention and treatment services for migrant farm workers that aim to increase levels of emotional support, self-esteem, and coping skills.     

Satisfiability Testing for Boolean Formulas Using Δ-trees

The tree-based data structure of -tree for propositional formulas is introduced in an improved and optimised form. The -trees allow a compact representation for negation normal forms as well as for a number of reduction strategies in order to consider only those occurrences of literals which are relevant for the satisfiability of the input formula. These reduction strategies are divided into two subsets (meaning- and satisfiability-preserving transformations) and can be used to decrease the size of a negation normal form A at (at most) quadratic cost. The reduction strategies are aimed at decreasing the number of required branchings and, therefore, these strategies allow to limit the size of the search space for the SAT problem.     

Action-based and vision-based selection of input: Two sources of control

In the first part of this paper we review evidence suggesting that there exists a mechanism that selects input on the basis of its similarity to the required action. This response-based input selection differs from the more established space- and object-based input selection in that it is not constrained by the structure of the input. Our evidence suggests that the two-choice Stroop effect is caused by this response-based selection mechanism. By contrast, it is known that the flanker effect is determined by the space- and object- based selection mechanisms. We explore whether the conflict resolution of the Stroop and flanker tasks is different as well by embedding these two tasks in a PRP (Psychological Refractory Period) paradigm. We show that the Stroop and the PRP effects are additive whereas the flanker and the PRP effects are underadditive, suggesting that the processes in charge of the conflict resolution in the Stroop and the flanker tasks are indeed different. We discuss possible reasons for this difference, and discuss possible ways in which the response-based mechanism can be implemented in information processing models.     

Psychosocial predictors of anxiety among immigrant Mexican migrant farmworkers: implications for prevention and treatment

This study examined predictors of anxiety symptomatology among immigrant Mexican migrant farmworkers in the Midwest. Its purposes were to assess the prevalence of anxiety symptoms, to examine the relationship between acculturative stress and anxiety, and to determine the variables that best predict anxiety. Heightened levels were found for overall anxiety and in the cognitive, affective, and physiological expressions of anxiety. Elevated acculturative stress, low self-esteem, ineffective social support, lack of control and choice in living a migrant farmworker lifestyle, low religiosity, and high education were significantly related to high anxiety. Findings suggest that migrant farmworkers who experience elevated acculturative stress are susceptible to the development of anxiety-related disorders and highlight the importance of establishing prevention and treatment services for migrant farmworkers.     

Win-shift and win-stay learning in the short-beaked echidna (<Emphasis Type="Italic">Tachyglossus aculeatus</Emphasis>)

Numerous previous investigators have explained species differences in spatial memory performance in terms of differences in foraging ecology. In three experiments we attempted to extend these findings by examining the extent to which the spatial memory performance of echidnas (or "spiny anteaters") can be understood in terms of the spatio-temporal distribution of their prey (ants and termites). This is a species and a foraging situation that have not been examined in this way before. Echidnas were better able to learn to avoid a previously rewarding location (to "win-shift") than to learn to return to a previously rewarding location (to "win-stay"), at short retention intervals, but were unable to learn either of these strategies at retention intervals of 90 min. The short retention interval results support the ecological hypothesis, but the long retention interval results do not. Electronic Publication