The psychophysics of sugar concentration discrimination and contrast evaluation in bumblebees

The capacity to discriminate between choice options is crucial for a decision-maker to avoid unprofitable options. The physical properties of rewards are presumed to be represented on context-dependent, nonlinear cognitive scales that may systematically influence reward expectation and thus choice behavior. In this study, we investigated the discrimination performance of free-flying bumblebee workers (Bombus impatiens) in a choice between sucrose solutions with different concentrations. We conducted two-alternative free choice experiments on two B. impatiens colonies containing some electronically tagged bumblebees foraging at an array of computer-automated artificial flowers that recorded individual choices. We mimicked natural foraging conditions by allowing uncertainty in the probability of reward delivery while maintaining certainty in reward concentration. We used a Bayesian approach to fit psychometric functions, relating the strength of preference for the higher concentration option to the relative intensity of the presented stimuli. Psychometric analysis was performed on visitation data from individually marked bumblebees and pooled data from unmarked individuals. Bumblebees preferred the more concentrated sugar solutions at high stimulus intensities and showed no preference at low stimulus intensities. The obtained psychometric function is consistent with reward evaluation based on perceived concentration contrast between choices. We found no evidence that bumblebees reduce reward expectations upon experiencing non-rewarded visits. We compare psychometric function parameters between the bumblebee B. impatiens and the flower bat Glossophaga commissarisi and discuss the relevance of psychophysics for pollinator-exerted selection pressures on plants.     

Operationalisierte Psychodynamische Diagnostik des Kindes- und Jugendalters

There are only a few studies focusing on the mental structure and its change in children and adolescents with psychiatric disorders. This study aimed at investigating change in the mental structure of children and adolescents over time. At intake 60 inpatients were interviewed with the operationalized psychodynamic diagnostic interview for children and adolescents (OPD-CA). After an average of 27 months 25 patients agreed on participating in the follow-up study. The OPD-CA was conducted again and the Kiddie-Sads present and lifetime version (Kiddie-Sads-PL) as well as parent-based ratings child behaviour checklist (CBCL) and strength and difficulties questionnaire (SDQ) were applied. A consensus rating of the OPD-CA was attained by three researchers well experienced with the use of the OPD-CA. The level of structural integration improved significantly, in particular in the dimensions “control” and “communication skills”. There were no significant changes in the dimension “self-perception/object-perception”. The improvement was also observable in parent-report questionnaires. This study makes a contribution to the idea that changes in the mental structure of children and adolescents can be shown and measured with the OPD-CA.     

Asthma severity, child security, and child internalizing: using story stem techniques to assess the meaning children give to family and disease-specific events

Children with persistent asthma are at increased risk for mental health problems. Although mechanisms of effect are not yet known, it may be that children are less trusting of the family as a source of support and security when they have more severe asthma. This study tested whether asthma severity is related to children's perceptions of insecurity in the family, and whether insecurity is in turn associated with child adjustment. Children (N = 168; mean age = 8 years) completed story stems pertaining to routine family events (e.g., mealtimes) and ambiguous but potentially threatening asthma events such as tightness in the chest. Responses were evaluated for the extent to which appraisals portrayed the family as responding in cohesive, security-provoking ways. Asthma severity was assessed by both objective lung function testing and primary caregiver report. Caregivers reported child symptomatology. Beyond medication adherence, caregiver education, and child age and gender, greater asthma severity predicted more internalizing and externalizing symptoms. Greater asthma severity, assessed using spirometry (but not parent report), was related to less secure child narratives of the family, which in turn related to more child internalizing symptoms. Results suggest that asthma can take a considerable toll on children's feelings of security and mental health. Furthermore, given the difficulty in assessing young children's perceptions, this study helps demonstrate the potential of story stem techniques in assessing children's appraisals of illness threat and management in the family.     

Hangover sensitivity after controlled alcohol administration as predictor of post-college drinking

Predicting continued problematic levels of drinking after the early 20's could help with early identification of persons at risk. This study investigated whether hangover insensitivity could predict postcollege drinking and problems beyond the variance due to drinking patterns. In a preliminary study, 134 college seniors from a laboratory study of hangover (Time 1) were contacted and assessed 1-4 years (M = 2.3) later (Time 2). Hangover severity was studied after controlled alcohol administration to a specific dose while controlling sleep and environmental influences. Hangover severity at Time 1 was used to predict Time 2 drinking volume and problems while controlling for relevant demographics and Time 1 drinking volume. Hangover insensitivity at Time 1 tended to predict a clinical level of alcohol problems with a large statistical effect size. Hangover sensitivity also correlated positively with sensitivity to alcohol intoxication. Hangover severity did not predict future drinking volume. Hangover insensitivity correlates with insensitivity to intoxication and might predict more serious alcohol problems in the future, suggesting that a future larger study is warranted. Hangover insensitivity could result from physiological factors underlying low sensitivity to alcohol or risk for alcoholism.     

Conducting behavioral research on Amazon’s Mechanical Turk

Amazon’s Mechanical Turk is an online labor market where requesters post jobs and workers choose which jobs to do for pay. The central purpose of this article is to demonstrate how to use this Web site for conducting behavioral research and to lower the barrier to entry for researchers who could benefit from this platform. We describe general techniques that apply to a variety of types of research and experiments across disciplines. We begin by discussing some of the advantages of doing experiments on Mechanical Turk, such as easy access to a large, stable, and diverse subject pool, the low cost of doing experiments, and faster iteration between developing theory and executing experiments. While other methods of conducting behavioral research may be comparable to or even better than Mechanical Turk on one or more of the axes outlined above, we will show that when taken as a whole Mechanical Turk can be a useful tool for many researchers. We will discuss how the behavior of workers compares with that of experts and laboratory subjects. Then we will illustrate the mechanics of putting a task on Mechanical Turk, including recruiting subjects, executing the task, and reviewing the work that was submitted. We also provide solutions to common problems that a researcher might face when executing their research on this platform, including techniques for conducting synchronous experiments, methods for ensuring high-quality work, how to keep data private, and how to maintain code security.     

Ontogenese des Verhaltens von Totenkopf-Affen (Saimiri sciureus)

Zusammenfassung Zehn Totenkopf-Affenkinder, die in gemischten Gruppen aufwuchsen, wurden in einer Verlaufsuntersuchung über 1200 Std beobachtet. Die Ontogenese des Verhaltens von der Geburt bis ins vierte Lebensjahr hinein wird in sieben Phasen beschrieben. Neben der Mutter-Kind-Beziehung wird vor allem die Beziehung zwischen Kind und Gruppe berücksichtigt.Während des ersten Lebensmonats ist die Mutter-Kind-Beziehung überwiegend taktil gelenkt. Interaktionen des Säuglings mit Gruppenmitgliedern gibt es schon vom ersten Lebenstag an. Von der dritten Woche an entsteht die sog. Tante-Kind-Beziehung, eine enge, meist vielseitige Bindung zwischen dem Kind und einem Weibchen.Wenn das Kind im zweiten Lebensmonat motorisch selbständig wird, entwickelt sich eine stärker visuell orientierte Beziehung zur Mutter. Zugleich setzt die Entwöhnung ein, und das Kind erweitert die schon bestehenden sozialen Bindungen um die Spielpartner-Beziehung. Ein großer Teil der arttypischen Verhaltensweisen ist bis zu diesem Zeitpunkt aufgetreten.Mit 5 und mit 9 Monaten lockert sich die Mutter-Kind-Beziehung jeweils stufenweise. Gleichzeitig treten neue Verhaltensmuster auf, und andere Verhaltensweisen verändern sich in der Häufigkeit und im Kontext ihres Auftretens.Im letzten Entwöhnungsabschnitt vom 9. bis zum 14. Monat tritt das junge Männchen in Beziehung zum ranghöchsten Tier der Gruppe; diese Beziehung umfaßt Kampfspiele und allmählich zunehmende Unterdrückung während des zweiten und dritten Jahres, bis sie mit Erreichen der Geschlechtsreife im Alter von 2 Jahren und 9 Monaten in Rivalenkämpfe übergeht.Das Verhalten entwickelt sich aus angeborenen Elementen, die in phasenspezifischen Interaktionen mit den Gruppenmitgliedern durch Lernprozesse geformt werden. Protrahierte und progressive Entwöhnung, Partnerspiele, Abweisung und Unterdrückung sind die wesentlichen Vorgänge, die den sozialen Reifungsprozeß bestimmen.Die Gesetzmäßigkeiten der Entwicklung werden am Säuglings- und Mutterverhalten, an den Formen der Selbstbehauptung und der Unterordnung sowie an der Differenzierung der beiden Sexualrollen aufgezeigt und mit biologischen Reifungskriterien, wie Gewicht, Zahnen, motorische Entwicklung und Spermatogenese, korreliert.

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Summary The behavioral ontogeny of ten infant squirrel monkeys (Saimiri sciureus) raised in mixed groups was studied during more than 1200 hours of protracted observation, comprising a life span from birth to the third and parts of the fourth year. The complete development is divided into seven phases and emphasis is placed on infant-group rather than on mother-infant relationships.For the first month of life the most prominent type of interaction between mother and infant is tactile. Acoustic, tactile and visual interaction with group mates starts as early as the first day of life. From about two weeks on a strong social bond is established between the infant and a female group mate, the so-called aunt. Aunt-infant interactions show greater variation than mother-infant interactions.As the infant gains motor independence during its second month, motherinfant visual interaction increases and weaning starts. The infant begins to play with other juveniles. Most of the species-specific behavioral elements are already present.During the 5th and 9th months the mother-infant detachment progresses gradually. During these two periods new behavior patterns develop and others change in frequency and in context of occurrence.At the beginning of the second year, during final weaning, the juvenile male establishes a closer relationship to the alpha-animal. Play fighting and progressive suppression during the second and third year lead to severe fighting. The young male becomes sexually mature at 33 months.The behavior, based on innate elements, is developed further through learning during stage-specific interaction with group mates. Prolonged and progressive weaning, social play and various forms of rejective and suppressive behavior strongly influence the maturation of social behavior.The rules which govern behavioral development are exemplified by the mothernewborn behavior, dominant-submissive behavior, and the sexual role differentiation. The various periods are correlated with physical developmental criteria such as weight, toothing, motor development, and spermatogenesis.

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Herrn Professor Dr. Dr. h. c. Heinrich Klüver, Sewell L. Avery Distinguished Service Professor of Biological Psychology, University of Chicago, zum 70. Geburtstag gewidmet.

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Für die unermüdliche Hilfe beim Beobachten, Protokollieren und Auswerten der Resultate danken wir unseren technischen Assistentinnen Roswitha Koschnick, Helga Krohn, Ilse Kutschera und Sigrid Schürmann, für die aufopfernde Pflege der Tiere Herrn Erasmus Soiderer.