Spatial relational learning in rufous hummingbirds (Selasphorus rufus)

There is increasing evidence that animals can learn abstract spatial relationships, and successfully transfer this knowledge to novel situations. In this study, rufous hummingbirds (Selasphorus rufus) were trained to feed from either the lower or the higher of two flowers. When presented with a test pair of flowers, one of which was at a novel height, they chose the flower in the appropriate spatial position rather than the flower at the correct height. This response may also have been influenced by a preference for taller flowers as acquisition of the task during experimental training occurred more readily when the reward flower was the taller of the pair. Thus, it appears that although learning abstract relationships may be a general phenomenon across contexts, and perhaps across species, the ease with which they are learned and the context in which they are subsequently used may not be the same.     

Adolescent depression and externalizing problems: testing two models of comorbidity in an inpatient sample

Differentiating between additive (quantitative) and interactive (qualitative) effects of comorbidity has important treatment implications. This study illustrates the heuristic superiority of a multifactorial approach over simple group comparisons in testing quantitative versus qualitative models of comorbidity. Analysis of variance was used to compare 266 adolescent inpatients identified as depressed, externalizing, both, or neither on self-report measures of personality, school problems, and substance abuse. The results support quantitative rather than qualitative models of comorbidity. Depressed status related most strongly to group differences in interpersonal and self-critical concerns. Externalizing status related most strongly to group differences in school problems and drug use. Main effects for the two statuses together explained especially elevated levels of reactance and alcohol abuse among the comorbid adolescents.     

Untreated recovery from eating disorders

This retrospective study explored the experience of recovery from anorexia nervosa and bulimia nervosa without professional treatment. A nine-question open-ended electronic survey was posted for a period of four months at a mid-western university. Sixteen female and two male respondents reported recovery from adolescent-onset full syndrome anorexia nervosa or bulimia nervosa. All respondents reported onset factors supporting a sociocultural etiology. Recovery was initiated through the empathic, participatory efforts of parents and friends, or was self-initiated. Respondents with the shortest disorder duration and most complete recovery reported early parental intervention. Onset factors similar to those in research with a clinically treated population were found. Implications of the findings are discussed.     

Six does not just mean a lot: preschoolers see number words as specific

This paper examines what children believe about unmapped number words - those number words whose exact meanings children have not yet learned. In Study 1, 31 children (ages 2-10 to 4-2) judged that the application of five and six changes when numerosity changes, although they did not know that equal sets must have the same number word. In Study 2, 15 children (ages 2-5 to 3-6) judged that six plus more is no longer six, but that a lot plus more is still a lot. Findings support the hypothesis that children treat number words as referring to specific, unique numerosities even before they know exactly which numerosity each word refers to.     

Relations between Big Five personality characteristics and perceived support in adolescents' families

The authors investigated the longitudinal relations between family members' Big Five personality factors and perceived support. Members of 285 two-parent families with 2 adolescent children judged their own and other family members' Big Five factors and the support perceived from the other members on 3 occasions at 12-month intervals. The Big Five factor Agreeableness was particularly related to perceived support. Changes in individuals' Big Five factors were linked to changes in the support they perceived themselves but even more to changes in the support that other family members perceived from them. Results are consistent with the parallel continuities hypothesis: Individual characteristics will be stable when there is stability in the supportive environment, but when the environment is changing, personality tends to change in the same direction, and vice versa.     

Defense mechanisms and self-reported violence toward partners and strangers

We examined the relationship between defense mechanisms and self-reported violence toward partners and toward strangers in a sample of college student men. Fifty men completed the Thematic Apperception Test (TAT; Murray, 1943) and the Conflict Tactics Scale (CTS; Straus, 1979), a self-report measure of strategies (including violence) for resolving conflicts with partners and strangers. The TAT responses were coded for defense mechanisms with the Defense Mechanisms Manual (Cramer, 1991b). The relative use of identification was negatively correlated (r = -.49, p <.001), and the relative use of projection was positively correlated (r =.49, p <.001) with the most extreme CTS report of violence toward partners. The relative use of identification was negatively correlated with the most extreme CTS report of violence toward strangers (r = -.34, p <.05). The relative use of denial was positively correlated with the most extreme CTS report of violence toward strangers (r =.32, p <.05).     

The effects of behavioral history on response acquisition with immediate and delayed reinforcement

Effects of prior exposure to the experimental chamber with levers present or absent and variable-time (VT) 60-s water deliveries arranged during one, five, or no 1-hr sessions were examined in rats during a 6-hr response-acquisition session in which presses on one lever produced water delivery immediately or after a 15-s resetting delay, and presses on the other lever canceled scheduled water deliveries. Response acquisition was (a) slower to occur when water deliveries were delayed, (b) most consistent in groups that had received five VT sessions, and (c) impaired by the presence of levers only when there had been five VT sessions and water deliveries were delayed during the acquisition session.     

Sleep quality, sleep propensity and academic performance

We examined associations between measures of sleep propensity on the Epworth Sleepiness Scale, sleep quality on the Pittsburgh Sleep Quality Index and academic performance by GPA and grades in introductory psychology for 414 students. In the total sample, neither sleep propensity nor sleep quality correlated with GPA or introductory psychology grades. However, among students carrying a full course load, those reporting poor sleep quality performed less well on academic measures than those reporting a better quality of sleep. Further research is needed to assess the moderating influence of overall demands of daytime functioning on the association between sleep quality and academic performance.     

Crime, Social Capital, and Community Participation

Social disorganization at the neighborhood and community levels has been consistently linked to various forms of criminal activity. However, a very much smaller body of literature addresses the effects of crime on community organizations. In some studies, crime appears to energize communities while in others, crime leads to withdrawal from community life. Using department of health crime victimization data and interviews with 2,985 low-income inner city residents living in 487 multi-family dwellings, a multi-level model examined the relationships among crime victimization, social organization, and participation in neighborhood organizations. Social organization at the individual and building levels was measured using recent formulations of social capital theory. Findings regarding crime suggested more signs of a chilling effect on participation than of an energizing effect, especially at the building level. Social capital at the building level was more strongly and consistently related to participation in community organizations than was crime.