197 research outputs found
Social and non-social feedback stimuli lead to comparable levels of reward learning and reward responsiveness in an online probabilistic reward task
Social stimuli seem to be processed more easily and efficiently than non-social stimuli. The current study tested whether social feedback stimuli improve reward learning in a probabilistic reward task (PRT), in which one response option is usually rewarded more often than the other via presentation of non-social reward stimuli. In a pre-registered online study with 305 participants, 75 participants were presented with a non-social feedback stimulus (a star) and information about gains, which is typically used in published PRT studies. Three other groups (with 73â82 participants each) were presented with one of three social feedback stimuli: verbal praise, an attractive happy face, or a âthumbs upâ-picture. The data were analysed based on classical signal detection theory, drift diffusion modelling, and Bayesian analyses of null effects. All PRT variants yielded the expected behavioural preference for the more frequently rewarded response. There was no processing advantage of social over non-social feedback stimuli. Bayesian analyses further supported the observation that social feedback stimuli neither increased nor decreased behavioural preferences in the PRT. The current findings suggest that the PRT is a robust experimental paradigm independent of the applied feedback stimuli. They also suggest that the occurrence of a processing advantage for social feedback stimuli is dependent on the experimental task and design.publishedVersio
Diskurse zu Aspekten afrikanischer Religionen in Tansania seit der UnabhÀngigkeit
In Tansania berufen sich seit dessen UnabhĂ€ngigkeit immer wieder einzelne Personen oder Gruppen auf bestimmte traditionelle religiöse Aspekte. Die Regierung und die fĂŒhrenden Politiker konnten dieses PhĂ€nomen nicht ignorieren, da es Auswirkungen auf zahlreiche Bereiche der Gesellschaft hatte. Aus unterschiedlichen GrĂŒnden, die in der Arbeit diskutiert werden, nahmen Vertreter des Staates Tansania verschiedene Standpunkte gegenĂŒber Vertreter von traditionellen Religionen ein. Durch die Auswahl der gesellschaftlichen Bereiche, Gesundheit, Politik und Recht werden die stattgefundenen Diskurse auszugsweise dargestellt und anhand von Gesetzestexten, Reden von Politikern und Artikel aus Tageszeitungen einerseits und wissenschaftlichen Quellen andererseits analysiert.
Das VerhĂ€ltnis zwischen den traditionellen Vertretern und der Regierung war zumeist durch die Machtposition der letzteren bestimmt. So hatten die Politiker immer die Möglichkeit zu bestimmen, welche traditionell-religiösen Aspekte im Sinne der Entwicklung positiv seien und welche nur ein Hindernis dafĂŒr darstellen wĂŒrden. Problematisch wurde es fĂŒr die Regierung nur, als traditionelle Vertreter staatliche Funktionen ĂŒbernahmen. Durch den Einsatz von gesetzlichen Regelungen zur Kontrolle konnten aber selbst diese Entwicklungen zum Vorteil der Regierung in Tansania genutzt werden
Decision making and feedback processing investigated with event-related potentials
Die Verarbeitung externer Feedbackreize ist essentiell fĂŒr das Treffen von Entscheidungen. Die
aktuelle neurowissenschaftliche Forschung bezĂŒglich Entscheidungsfindung befasste sich bis dato
hauptsÀchlich mit negativem Feedback und seinen Konsequenzen. Die vorliegende Dissertation
beschÀftigte sich mit neuronalen Prozessen in Zusammenhang mit positiven Feedbackreizen und
Persönlichkeitseigenschaften. Zwei Komponenten des ereigniskorrelierten Potentials (EKP), die
Feedback-Related Negativity (FRN) und die P300 Komponente wurden im Kontext von positiven und
negativen, sowie erwarteten und unerwarteten Feedbackreizen untersucht. Es wurden zwei
Elektroenzephalogramm (EEG) Studien durchgefĂŒhrt, in denen eine Spielaufgabe als
Experimentalparadigma vorgegeben wurde. Die Feedbackreize bestanden aus Zahlen, die direkt einen
Geldgewinn oder -verlust andeuteten, sowie aus fröhlichen und Àrgerlichen Gesichtern, die indirekt
einen Geldgewinn oder -verlust anzeigten.
In getrennten Manuskripten wurde der KlÀrung zweier Forschungsfragen nachgegangen. Das erste
Manuskript beschÀftigte sich mit der Frage, ob unerwartetes positives Feedback eine vergleichbare
negative Auslenkung des EKPs hervorruft wie es bei der FRN nach der PrÀsentation von negativem
Feedback zu beobachten ist. Deshalb wurden die Feedbackdimensionen Erwartung und Valenz
experimentell manipuliert. Die daraus resultierenden Ergebnisse deuten darauf hin, dass sowohl
Erwartung als auch Valenz einen vergleichbaren Einfluss auf die Amplitudenmodulation der FRN
haben. Eben diese FRN Amplituden waren erhöht nach unerwartetem und negativem Feedback. P300
Amplituden wurden hingegen nur durch die Erwartung des Reizes moduliert, nicht durch dessen
Valenz. Daraus resultiert die wissenschaftliche Hypothese, die FRN Amplitudenmodulation als Signal
des VerstÀrkungslernens zu betrachten, welches saliente Ereignisse anzeigt.
Das zweite Manuskript beschÀftigt sich mit der Frage ob antisoziale Persönlichkeitseigenschaften die
FRN Amplitudenmodulation in Bezug auf Feedbackerwartung und â valenz beeinflussen. Es wurde der
Einfluss von numerischen im Gegensatz zu emotionalen Feedbackreizen in jenen Versuchspersonen
untersucht, die entweder hohe oder niedrige Werte auf einer psychologischen Skala zur Erfassung von
antisozialen Persönlichkeitseigenschaften aufwiesen. Die Ergebnisse deuten darauf hin, dass es die
Dimension der Feedbackerwartung und nicht der -valenz ist, die zwischen sozialern und antisozialeren
Individuen unterscheidet.
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ZukĂŒnftige Forschung zu Feedbackverarbeitung sollte versuchen die theoretischen AnsĂ€tze mit
aktuellen Forschungsergebnissen in Einklang zu bringen, um das VerstÀndnis zugrunde liegender
Prozesse von Entscheidungsfindung besser verstehen zu können.The processing of external feedback cues is crucial for decision making processes. Recent
neuroscientific research has mainly focused on the processing of negative feedback events. The present
project investigated neuronal processes related to positive feedback cues and personality
characteristics. Two components of the event-related potential (ERP), the Feedback-Related Negativity
(FRN) and the P300 were investigated in the context of positive and negative expected and unexpected
feedback outcomes. Two EEG-studies were conducted applying a gambling paradigm where feedback
stimuli consisted either of numbers indicating direct monetary gain and loss or of happy and angry
faces indicating indirect monetary gain and loss.
Two research questions were addressed in separate scientific manuscripts. The first manuscript
addressed the questions whether unexpected positive feedback elicits a negative ERP deflection in the
latency range of the FRN component. Feedback expectancy and feedback valence were manipulated in
the experimental paradigm. Results indicate that expectancy as well as valence had comparable impact
on FRN amplitude modulation. FRN amplitudes were larger after unexpected compared to expected,
and after negative compared to positive feedback. P300 amplitudes were modulated by expectancy â
unexpected feedback conditions yielding largest P300 amplitudes â but not by valence. Thus, the
proposal is made to interpret FRN amplitude modulation in terms of a reinforcement learning signal
which is indicating motivationally salient outcomes.
The second manuscript addressed the question whether antisocial personality characteristics influence
FRN amplitude modulation related to feedback expectancy and feedback valence. The effect of
numerical versus emotional feedback stimuli was investigated in individuals scoring low and high on a
psychological measure of antisociality. Results indicate that it is the dimension of feedback expectancy
and not of valence that differentiates social from more antisocial individuals.
Future research on feedback processing should try to integrate the different theoretical frameworks and
recent findings to promote the understanding of the underlying cognitive processes
WĂŒrde und Autonomie im Kontext geriatrischer Langzeitpflege
In dieser Dissertation wird das Vorhaben verfolgt, die abstrakten Begriffe der MenschenwĂŒrde und der Autonomie auf der Grundlage einer philosophischen Analyse und der Erfahrungen professionell gepflegter alter Menschen mit real erfahrbaren Inhalten zu fĂŒllen. Damit sollen diese Begriffe fĂŒr die ethische Reflexion und zur Entwicklung von Strategien in der geriatrischen Langzeitpflege zugĂ€nglich gemacht werden.
Zwar sind in der SphĂ€re der Philosophie, des Rechts und in der gesamt-gesellschaftlichen Diskussion zentrale Fragen zur MenschenwĂŒrde und Autonomie schon vielseitig abgehandelt worden, doch wie ein selbstbestimmtes Altern in WĂŒrde konkret realisiert werden kann, ist nach wie vor ein Desiderat der Forschung geblieben. Dies kann auf zwei GrĂŒnde zurĂŒckgefĂŒhrt werden: zum einen darauf, dass Status und Bedeutung dieser Begriffe innerhalb der Moralphilosophie kontrovers diskutiert werden, zum andern darauf, dass das Alter trotz der langen Tradition in der heutigen Philosophie kein wichtiges Thema mehr zu sein scheint. Andererseits sind die AkteuerInnen in der Pflegepraxis damit konfrontiert, dass in Pflegetheorien und -konzepten, in fĂŒr diesen Bereich relevanten Gesetzen und auch in Leitbildern der Organisationen die Achtung der Selbstbestimmung und WĂŒrde immer wieder eingemahnt wird, welche Forderungen mit diesen Prinzipien jedoch verbunden sind, bleibt weitgehend unklar. LĂ€sst man die Idee der menschlichen WĂŒrde undefiniert, bleibt nur das Vertrauen darauf, dass alle AkteurInnen in der geriatrischen Langzeitpflege auch ohne Definition den gleichen Vorstellungen mit diesem Begriff verbinden.
Um die Begriffe stĂ€rker zu konturieren, werden im ersten Schritt dieser Arbeit einflussreiche Konzeptionen von MenschenwĂŒrde und Autonomie kritisch beleuchtet und auf ihre Anwendbarkeit im Kontext der geriatrischen Langzeit-pflege geprĂŒft. Gezeigt wird, inwiefern WĂŒrdekonzeptionen, die auf bestimmten Eigenschaften wie Gottesebenbildlichkeit oder Vernunftbegabung grĂŒnden, mehr Fragen aufwerfen als sie beantworten können. Die in dieser Arbeit vorge-schlagene BedĂŒrfniskonzeption der MenschenwĂŒrde nimmt ihren Ausgang bei einem MoralverstĂ€ndnis, das auf die BedĂŒrftigkeit und Verletzlichkeit der Menschen fokussiert. Die Verletzlichkeit liegt nicht nur in der leiblichen Bedingtheit des Menschen, sondern auch darin, dass das Ausbilden und Aufrecht-erhalten personaler IdentitĂ€t als anthropologische Grundaufgabe des Menschen stets auf die RĂŒckversicherung durch andere angewiesen ist. Dem grundlegenden menschlichen BedĂŒrfnis, sich selbst als achtenswerte und wertgeschĂ€tzte Person wahrnehmen zu können, wird in dieser Konzeption eine zentrale Rolle zugeschrieben. Denn wie gezeigt werden soll, stellt Selbstachtung eine allgemeine und basale Voraussetzung fĂŒr personale IdentitĂ€t und damit fĂŒr ein selbstbestimmtes Gestalten des eigenen Lebensentwurfs dar. Im Gegensatz zu Kant, der davon ausgeht, dass es sich bei der Selbstachtung um eine von sozialen und leiblichen Bedingtheiten unabhĂ€ngige Verfasstheit des Menschen handelt, wird Selbstachtung hier als eine sozial vermittelte Haltung konzipiert, die eng mit unserem Körperselbst verquickt ist. Deshalb ist das ethische Prinzip der MenschenwĂŒrde nur dann fĂŒr wirklichkeitsnahe, problembezogene Ăberlegungen geeignet, wenn es in den Sachverhalten der sozialen Welt fundiert wird.
Im Anschluss an die theoretische Untersuchung soll eine in der wissenschaftlichen und öffentlichen Debatte gleichsam vernachlĂ€ssigte Perspektive aufgenommen werden â die des betroffenen Menschen. Anhand leitfadengestĂŒtzter Interviews wird dargestellt, wie pflegebedĂŒrftige alte Menschen und betroffene Angehörige die Möglichkeiten der Selbstbestimmung im Kontext der Langzeitpflege erleben und was nach ihrem Empfinden zur Bewahrung der WĂŒrde beitrĂ€gt. Dabei soll der Begriff der WĂŒrde weiter ausdifferenziert und Autonomie in jenen Aspekten sichtbar gemacht werden, welche aus der Sicht der Betroffenen elementare Bedeutung fĂŒr die IdentitĂ€tsbewahrung und -bewĂ€hrung haben. Die in der Dissertation gewonnenen mehrschichtigen Perspektiven bilden eine Grundlage fĂŒr konkrete Fragen der Pflegepraxis: Welchen Verhaltens und welcher Haltungen bedarf es seitens der Pflege- und Betreuungspersonen? Und welche institutionellen und gesellschaftlichen Voraussetzungen sind notwendig, um die WĂŒrde und Selbstbestimmung alter pflegebedĂŒrftiger Menschen zu schĂŒtzen und zu sichern?This dissertation aims to charge the abstract terms of human dignity and autonomy with contents experienced in real life and based on the experience of elderly people which are professionally cared for. More over, these terms shall be made approachable to ethical reflection and the development of strategies in geriatric long term care.
Central questions on human dignity and autonomy have been subject to a lot of research in the sphere of philosophy, law and sociology, but the question remains how an autonomous and dignified life for the elderly can be practically realised. There are two reasons for this: One is, that the status and importance of these terms has been discussed controversially within moral philosophies and second that the focus on age, aging and death, which are important themes of philosophical traditions, have vanished in modern times.
Professional care takers however, are faced with a constant claim for respect regarding autonomy and dignity of the care receivers. Care theories and care concepts, relevant jurisdiction and mission statements of organisations emphasise the importance of autonomy and dignity, while not explaining their respective understanding of these terms. It remains unclear even now, what the resulting claims from these principles are. If the idea of human dignity remains undefined, we necessarily presuppose that all acting individuals in long term care share a common understanding even without definition.
In analysing the terms, the first part of the analysis critically reviews important concepts of human dignity and autonomy and their application in the context of geriatric long term care. This raises the point of whether specific concepts of dignity that rely on characteristics such as âImago deiâ or the human capacity for self determination, eventually raise more questions than they answer. This study proposes a concept of dignity which is based on specific basic needs of human beings. It starts with an understanding of morality which is focussing on the vulnerability of human beings. Vulnerability is not created by the physical conditions alone but is also based on the nexus between image of the self and the approval of others. The very human need to perceive itself as respected and valued is of central importance for this concept. The study shows that self respect is a common and basic prerequisite for personal identity and creating an autonomous conception of the good. By way of contrast to Kant who assumes that self respect is not dependent on social and physical conditions, self respect is understood here as a socially transferred approach, which is closely connected to our body image. According to this concept of dignity, problems of daily life can be tackled in an adequate way and be brought to practical solutions for care takers.
This study places the emphasis on care receivers and their families while at the same time not forgetting the difficulties of care takers. Based on structured interviews the study demonstrates how people in geriatric long term care and their relatives experience the options of autonomy and what they consider to be necessary to pursue dignity. In so doing, the term dignity is to be further evaluated and autonomy is going to be made visible in aspects that are of elementary importance for the preservation and defence of identity. The study presents a multi-layered-perspective that presents three main questions: one concerning specific individual questions, one concerning institutional presuppositions and the last regarding social conditions of the society.
This dissertation aims to charge the abstract terms of human dignity and autonomy with contents experienced in real life and based on the experience of elderly people which are professionally cared for. More over, these terms shall be made approachable to ethical reflection and the development of strategies in geriatric long term care.
Central questions on human dignity and autonomy have been subject to a lot of research in the sphere of philosophy, law and sociology, but the question remains how an autonomous and dignified life for the elderly can be practically realised. There are two reasons for this: One is, that the status and importance of these terms has been discussed controversially within moral philosophies and second that the focus on age, aging and death, which are important themes of philosophical traditions, have vanished in modern times.
Professional care takers however, are faced with a constant claim for respect regarding autonomy and dignity of the care receivers. Care theories and care concepts, relevant jurisdiction and mission statements of organisations emphasise the importance of autonomy and dignity, while not explaining their respective understanding of these terms. It remains unclear even now, what the resulting claims from these principles are. If the idea of human dignity remains undefined, we necessarily presuppose that all acting individuals in long term care share a common understanding even without definition.
In analysing the terms, the first part of the analysis critically reviews important concepts of human dignity and autonomy and their application in the context of geriatric long term care. This raises the point of whether specific concepts of dignity that rely on characteristics such as âImago deiâ or the human capacity for self determination, eventually raise more questions than they answer. This study proposes a concept of dignity which is based on specific basic needs of human beings. It starts with an understanding of morality which is focussing on the vulnerability of human beings. Vulnerability is not created by the physical conditions alone but is also based on the nexus between image of the self and the approval of others. The very human need to perceive itself as respected and valued is of central importance for this concept. The study shows that self respect is a common and basic prerequisite for personal identity and creating an autonomous conception of the good. By way of contrast to Kant who assumes that self respect is not dependent on social and physical conditions, self respect is understood here as a socially transferred approach, which is closely connected to our body image. According to this concept of dignity, problems of daily life can be tackled in an adequate way and be brought to practical solutions for care takers.
This study places the emphasis on care receivers and their families while at the same time not forgetting the difficulties of care takers. Based on structured interviews the study demonstrates how people in geriatric long term care and their relatives experience the options of autonomy and what they consider to be necessary to pursue dignity. In so doing, the term dignity is to be further evaluated and autonomy is going to be made visible in aspects that are of elementary importance for the preservation and defence of identity. The study presents a multi-layered-perspective that presents three main questions: one concerning specific individual questions, one concerning institutional presuppositions and the last regarding social conditions of the society
Geschlechtsspezifische Verteilung der Fotorezeptoren im Auge der westlichen Honigbiene Apis mellifera L., 1758 (Apidae, Hymenoptera)
Spektrale HeterogenitĂ€t scheint ein verbreitetes Bauprinzip der Komplexaugen von Insekten zu sein. So sind auch bei der Arbeiterin der Honigbiene Apis mellifera die drei Fotorezeptortypen, welche ihr Absorptionsmaximum im ultravioletten (UV), blauen bzw. grĂŒnen WellenlĂ€ngenbereich haben, unterschiedlich hĂ€ufig in verschiedenen Ommatidien zu finden. Es gibt drei Ommatidientypen welche neben sechs GrĂŒn-Rezeptoren mit zwei UV -, einem UV- und einem Blau- oder zwei Blau-Rezeptoren ausgestattet sind. Die spektralen Eigenschaften der neunten und nur basal am Rhabdom teilhabenden Zelle sind bis heute nicht eindeutig geklĂ€rt. Die HeterogenitĂ€t im Auge der Drohnen wurde bis heute nicht auf Zellebene untersucht bzw. beschrieben. Bekannt ist aufgrund morphologischer, physiologischer und molekularbiologischer Untersuchungen, dass das Drohnenauge in zwei sich stark unterscheidende Regionen unterteilt ist. Auch fĂŒr die dorsale Randregion (DRA), welche bei beiden Geschlechtern vorkommt und dem Polarisationssehen dient, gibt es Evidenzen, dass sich die Zusammensetzung der Fotorezeptoren unterscheidet.
Mit Hilfe immunohistochemischer, molekularbiologischer und ultrastruktureller Techniken wurden die geschlechtsspezifischen Unterschiede der Augenregionen beschrieben. Dabei wurden in der gesamten Arbeiterinnenretina die drei bekannten Ommatidientypen gefunden. Diese konnten auch in der Ventralregion der Drohnenretina nachgewiesen werden. In der Dorsalregion wurden drei weitere Ommatidientypen entdeckt, welche sich in der Anzahl der UV-Rezeptoren (zwei, einem oder keinem) unterscheiden. AuĂerdem sind im Gegensatz zu den bekannten Typen in allen Ommatidien Blau-, jedoch keine GrĂŒn-Rezeptoren enthalten. Es ist anzunehmen, dass es sich bei diesen dorsalen Modifikationen des Drohnenauges um Anpassungen an das Paarungsverhalten handelt. Weiters wurden in der Retina beider Geschlechter Hinweise darauf gefunden, dass in der DRA mehr UV-Rezeptoren pro Ommatidium vorhanden sind.Spectral heterogeneity seems to be a common design of the insect compound eye. In honeybee workers of Apis mellifera, three photoreceptor types - with absorption maximum in the UV, blue and green range of wavelength spectrum - are distributed heterogeneously in the ommatidia. The three known types of ommatidia each contain six green receptors and either two UV, two blue or one UV and one blue receptor. The spectral quality of the short ninth cell at the base of the ommatidium remains unclear. The spectral heterogeneity in dronesâ eyes has not yet been examined on the cellular level. Based on morphological, physiological and molecular biological data, it is known that the eye is divided in two distinct areas, which are used in different contexts. Likewise, in the dorsal rim area (DRA), a region used for polarization vision in both sexes, there is strong evidence that the photoreceptor distribution differs from the main retina.
The sex-specific differences of photoreceptor distribution in different eye areas of workers and drones were examined with immunohistochemical, molecular biological and ultrastructural techniques. In the main retina of workers, the three known ommatidia types were found. The same three types were found in the ventral area of the droneâs eye. In the dorsal area three new ommatidia types with respect to the number of UV-receptors (none, one or two) were identified. Additionally, they contain, in contrast to the known types, blue receptors in all ommatidia while green receptors are absent. It can be assumed that these dorsal modifications are adaptations for mating behavior. Additionally, there is evidence that the DRA of both sexes contains more UV receptors in each ommatidium than in the main retina
Hungry for compliments? Ghrelin is not associated with neural responses to social rewards or their pleasantness
The stomach-derived hormone ghrelin motivates food search and stimulates food consumption, with highest plasma concentrations before a meal and lowest shortly after. However, ghrelin also appears to affect the value of non-food rewards such as interaction with rat conspecifics, and monetary rewards in humans. The present pre-registered study investigated how nutritional state and ghrelin concentrations are related to the subjective and neural responses to social and non-social rewards. In a cross-over feed-and-fast design, 67 healthy volunteers (20 women) underwent functional magnetic resonance imaging (fMRI) in a hungry state and after a meal with repeated plasma ghrelin measurements. In task 1, participants received social rewards in the form of approving expert feedback, or non-social computer reward. In task 2, participants rated the pleasantness of compliments and neutral statements. Nutritional state and ghrelin concentrations did not affect the response to social reward in task 1. In contrast, ventromedial prefrontal cortical activation to non-social rewards was reduced when the meal strongly suppressed ghrelin. In task 2, fasting increased activation in the right ventral striatum during all statements, but ghrelin concentrations were neither associated with brain activation nor with experienced pleasantness. Complementary Bayesian analyses provided moderate evidence for a lack of correlation between ghrelin concentrations and behavioral and neural responses to social rewards, but moderate evidence for an association between ghrelin and non-social rewards. This suggests that ghrelinâs influence may be restricted to non-social rewards. Social rewards implemented via social recognition and affirmation may be too abstract and complex to be susceptible to ghrelinâs influence. In contrast, the non-social reward was associated with the expectation of a material object that was handed out after the experiment. This may indicate that ghrelin might be involved in anticipatory rather than consummatory phases of reward
All about the Money â External Performance Monitoring is Affected by Monetary, but Not by Socially Conveyed Feedback Cues in More Antisocial Individuals
This study investigated the relationship between feedback processing and antisocial personality traits measured by the PSSI questionnaire (Kuhl and KazĂ©n, 1997) in a healthy undergraduate sample. While event-related potentials [feedback related negativity (FRN), P300] were recorded, participants encountered expected and unexpected feedback during a gambling task. As recent findings suggest learning problems and deficiencies during feedback processing in clinical populations of antisocial individuals, we performed two experiments with different healthy participants in which feedback about monetary gains or losses consisted either of socialâemotional (facial emotion displays) or non-social cues (numerical stimuli). Since the FRN and P300 are both sensitive to different aspects of feedback processing we hypothesized that they might help to differentiate between individuals scoring high and low on an antisocial trait measure. In line with previous evidence FRN amplitudes were enhanced after negative and after unexpected feedback stimuli. Crucially, participants scoring high on antisocial traits displayed larger FRN amplitudes than those scoring low only in response to expected and unexpected negative numerical feedback, but not in response to socialâemotional feedback â irrespective of expectancy. P300 amplitudes were not modulated by antisocial traits at all, but by subjective reward probabilities. The present findings indicate that individuals scoring high on antisociality attribute higher motivational salience to monetary compared to emotionalâsocial feedback which is reflected in FRN amplitude enhancement. Contrary to recent findings, however, no processing deficiencies concerning socialâemotional feedback stimuli were apparent in those individuals. This indicates that stimulus salience is an important aspect in learning and feedback processes in individuals with antisocial traits which has potential implications for therapeutic interventions in clinical populations
Hungry for compliments? Ghrelin is not associated with neural responses to social rewards or their pleasantness
The stomach-derived hormone ghrelin motivates food search and stimulates food consumption, with highest plasma concentrations before a meal and lowest shortly after. However, ghrelin also appears to affect the value of non-food rewards such as interaction with rat conspecifics, and monetary rewards in humans. The present pre-registered study investigated how nutritional state and ghrelin concentrations are related to the subjective and neural responses to social and non-social rewards. In a cross-over feed-and-fast design, 67 healthy volunteers (20 women) underwent functional magnetic resonance imaging (fMRI) in a hungry state and after a meal with repeated plasma ghrelin measurements. In task 1, participants received social rewards in the form of approving expert feedback, or non-social computer reward. In task 2, participants rated the pleasantness of compliments and neutral statements. Nutritional state and ghrelin concentrations did not affect the response to social reward in task 1. In contrast, ventromedial prefrontal cortical activation to non-social rewards was reduced when the meal strongly suppressed ghrelin. In task 2, fasting increased activation in the right ventral striatum during all statements, but ghrelin concentrations were neither associated with brain activation nor with experienced pleasantness. Complementary Bayesian analyses provided moderate evidence for a lack of correlation between ghrelin concentrations and behavioral and neural responses to social rewards, but moderate evidence for an association between ghrelin and non-social rewards. This suggests that ghrelinâs influence may be restricted to non-social rewards. Social rewards implemented via social recognition and affirmation may be too abstract and complex to be susceptible to ghrelinâs influence. In contrast, the non-social reward was associated with the expectation of a material object that was handed out after the experiment. This may indicate that ghrelin might be involved in anticipatory rather than consummatory phases of reward.publishedVersio
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