The role of edges in object recognition by pigeons

In three experiments, we explored how pigeons use edges, corresponding to orientation and depth discontinuities, in visual recognition tasks. In experiment 1, we compared the pigeon's ability to recognize line drawings of four different geons when trained with shaded images. The birds were trained with either a single view or five different views of each object. Because the five training views had markedly different appearances and locations of shaded surfaces, reflectance edges, etc, the pigeons might have been expected to rely more on the orientation and depth discontinuities that were preserved over rotation and in the line drawings. In neither condition, however, was there any transfer from the rendered images to the outline drawings. In experiment 2, some pigeons were trained with line drawings and shaded images of the same objects associated with the same response (consistent condition), whereas other pigeons were trained with a line drawing and a shaded image of two different objects associated with the same response (inconsistent condition). If the pigeons perceived any correspondence between the stimulus types, then birds in the consistent condition should have learned the discrimination more quickly than birds in the inconsistent condition. But, there was no difference in performance between birds in the consistent and inconsistent conditions. In experiment 3, we explored pigeons' processing of edges by comparing their discrimination of shaded images or line drawings of four objects. Once trained, the pigeons were tested with planar rotations of those objects. The pigeons exhibited different patterns of generalization depending on whether they were trained with line drawings or shaded images. The results of these three experiments suggest that pigeons may place greater importance on surface features indicating materials, such as food or water. Such substances do not have definite boundaries cued by edges which are thought to be central to human recognition.     

Depression Ein prognostischer Faktor bei koronarer Herzkrankheit

Herzinfarktkranke, die an einer Depression leiden, tragen ein erhöhtes Risiko, in den Folgejahren an einem erneuten Infarkt oder anderen Komplikationen der koronaren Herzkrankheit (KHK) zu sterben. Dass eine Depression, die bei 16–23% der KHK-Patienten auftritt, aber auch schon eine unterschwellige depressive Symptomatik einen unabhängigen prognostischen Faktor der KHK darstellt, konnte in mehreren Studien bestätigt werden. Es ist jedoch noch unklar, ob eine Depression ein kausaler Risikofaktor ist, der den Verlauf der KHK ungünstig beeinflusst, oder lediglich ein Risikoindikator (marker), der zwar eine Vorhersage des Verlaufs erlaubt, diesen aber nicht selbst verändert. Als Bindeglieder zwischen einer Depression und dem Verlauf der KHK werden verhaltensbezogene (verminderte Compliance mit Medikation und risikoreduzierenden Verhaltensempfehlungen) und neurobiologische Mechanismen diskutiert. Am besten untersucht ist die Aktivierung des Hypothalamus-Hypophysen-Nebennierenrinden-Systems und die sympathische Aktivierung (vermehrte Kortisol- und Noradrenalin-Sekretion bei Depression mit der Folge einer erhöhten kardiovaskulären Reaktivität). Weitere potenzielle Bindeglieder umfassen eine verminderte Herzfrequenzvariabilität, stressinduzierte Ischämien, erhöhte Thrombozytenaktivierung und immunologische Dysregulationen. Um die Frage zu klären, ob die Depression ein kausaler Risikofaktor ist, sind Interventionsstudien notwendig, in denen eine depressive Störung erfolgreich behandelt und als Konsequenz auch die Sterblichkeit vermindert wird. Hierzu ist die Befundlage allerdings inkonsistent. Während umfassende, multimodale Interventionsprogramme, die auch eine Modifikation der koronaren Risikofaktoren einschlossen, eine Reduktion von Reinfarktrate und Mortalität demonstrieren konnten, hat eine kürzlich publizierte, große randomisierte Interventionsstudie, in der depressive KHK-Patienten entweder kognitive Verhaltenstherapie oder die übliche Behandlung erhielten, keinen Überlebensvorteil für die Patienten der Behandlungsgruppe zeigen können. Abschließend wird die Befundlage zur Optimierung einer integrierten Versorgung von Patienten mit komorbider Depression dargestellt.     

Fractionating working memory: consolidation and maintenance are independent processes

In the present study, we required subjects to remember simple objects that were masked to interrupt consolidation and allow us to estimate the rate of information accrual in visual working memory. We compared a consolidation-baseline condition with a consolidation-during-maintenance condition in which subjects needed to remember a set of unmasked items and then were shown to-be-remembered masked items. We hypothesized that if the control processes of consolidation and maintenance are performed by common mechanisms, then consolidation should be less efficient when performed during maintenance than when performed alone. However, we found that an identical amount of information was encoded per unit time in the two conditions. These results indicate that working memory consolidation is not slowed by maintenance and suggest a two-step model of encoding in visual working memory.     

Disseminating a smokeless tobacco cessation intervention model to dental hygienists: a randomized comparison of personalized instruction and self-study methods.

This study evaluated 2 methods of disseminating an empirically validated smokeless tobacco intervention delivered during routine dental care. Twenty cities within 12 states were stratified and then randomized to 1 of 3 groups: personalized instruction (PI), self-study (SS), or delayed training (DT) control. Dental hygienists in the SS condition were sent a manual and video. Those in the PI condition were recruited to attend a workshop. Thirty-seven percent of eligible hygienists agreed to participate. At 12 months postenrollment, hygienists in the SS and PI conditions significantly increased their "Assist" behaviors (discuss cessation techniques, help patient set a quit date, and provide cessation materials) and reported fewer perceived barriers to delivering the intervention as compared with hygienists in DT. An economic analysis suggests that SS is more cost-effective than PI.     

Assessing aggression in adolescent romantic relationships: can we do it better?

Almost all research on aggression in adolescent romantic relationships makes use of 1-time, retrospective assessment methods. In the present research, the authors compared data on the experience of adolescent relationship aggression (physical aggression and threatening behavior) collected from 125 high school students via 2 methods: (a) a 1-time, 2-month retrospective assessment and (b) a cumulative method based on four 2-week retrospective assessments, each spaced 2 weeks apart. For the cumulative method, data from the 4 assessments were aggregated to cover the same time period as the single, 2-month retrospective assessment. A greater proportion of the sample (48.0%) reported experiencing physical aggression using the cumulative method compared with the single, 2-month retrospective method (27.0%). The prevalence of threatening behavior was also higher using the cumulative method (48.8% vs. 24.8%). Adolescent trauma and anxiety symptoms correlated more strongly with physical aggression data derived from the cumulative method than from the 1-time assessment method.     

New approaches to demystifying insight

After a person has become stuck on a problem, they sometimes achieve a clear and sudden solution through insight--the so-called Aha! experience. Because of its distinctive experience, the origins and characteristics of insight have received considerable attention historically in psychological research. However, despite considerable progress in characterizing insight, the underlying mechanisms remain mysterious. We argue that research on insight could be greatly advanced by supplementing traditional insight research, which depends on a few complex problems, with paradigms common in other domains of cognitive science. We describe a large set of mini-insight problems to which multiple methods can be applied, together with subjective reports to identify insight problem-solving. Behavioral priming and neuroimaging methods are providing evidence about what, where, and how neural activity occurs during insight. Such evidence constrains theories of component processes, and will help to demystify insight.     

Toward a taxonomy of attention shifting: Individual differences in fMRI during multiple shift types

Although task switching is often considered one of the fundamental abilities underlying executive functioning and general intelligence, there is little evidence that switching is a unitary construct and little evidence regarding the relationship between brain activity and switching performance. We examined individual differences in multiple types of attention shifting in order to determine whether behavioral performance and fMRI activity are correlated across different types of shifting. The participants (n=39) switched between objects and attributes both when stimuli were perceptually available (external) and when stimuli were stored in memory (internal). We found that there were more switchrelated activations in many regions associated with executive control—including the dorsolateral and medial prefrontal and parietal cortices—when behavioral switch costs were higher (poor performance). Conversely, activation in the ventromedial prefrontal cortex (VMPFC) and the rostral anterior cingulate was consistently correlated with good performance, suggesting a general role for these areas in efficient attention shifting. We discuss these findings in terms of a model of cognitive-emotional interaction in attention shifting, in which reward-related signals in the VMPFC guide efficient selection of tasks in the lateral prefrontal and parietal cortices.     

Negative Affect in Victimized Children: The Roles of Social Withdrawal, Peer Rejection, and Attitudes Toward Bullying

This study evaluated the validity of mediating pathways in predicting self-assessed negative affect from shyness/social withdrawal, peer rejection, victimization by peers (overt and relational), and the attitude that aggression is legitimate and warranted. Participants were 296 3rd through 5th graders (156 girls, 140 boys) from 10 elementary schools. Self-report measures of victimization, attitudes, and negative affect, and a teacher-report measure of shyness/social withdrawal and peer rejection were completed during the spring semesters of 2 consecutive years. Hierarchical regression analyses supported the mediational model in predicting negative affect at Time 2. However, an increase in negative affect over the 12-month study period was best accounted for by direct effects of increased victimization and changes in attitudes/attributions regarding aggression. Implications for the planning of school interventions designed to interrupt these victimization-maladjustment pathways are discussed.