Clinical Equipoise and Adaptive Clinical Trials

Ethically permissible clinical trials must not expose subjects to risks that are unreasonable in relation to anticipated benefits. In the research ethics literature, this moral requirement is typically understood in one of two different ways: (1) as requiring the existence of a state of clinical equipoise, meaning a state of honest, professional disagreement among the community of experts about the preferred treatment; or (2) as requiring an equilibrium between individual and collective ethics. It has been maintained that this second interpretation makes it mandatory to minimize the number of patients receiving the treatment that will eventually be shown to be inferior by the trial. This requirement has led to the development of adaptive trials, i.e., trials in which treatment allocation is determined by data accumulated during interim analysis. Many statisticians argue that in some circumstances—typically with potentially high benefits, as in the much discussed ECMO trial—adaptive design is the only ethically permissible experimental design. Nevertheless, some proponents of clinical equipoise argue that adaptive trials are neither ethically required nor permissible. More specifically, they argue that clinical trials using adaptive designs fail to meet the moral requirement of clinical equipoise, since these trials presuppose an epistemic state that is incompatible with a physician’s duty of care to her subjects. This paper emphasizes that the debate is to a large extent resting on an epistemological confusion. Specifically, I argue that this response conflates two different conceptions of statistical evidence (i.e., frequentist and Bayesian), and that recognizing this distinction elucidates an epistemological framework in which adaptive trials are both consistent with and recommended by the moral requirement of clinical equipoise.

     

Towards a Better Understanding of Cognitive Deficits in Absence Epilepsy: a Systematic Review and Meta-Analysis

Neuropsychology Review - Cognition in absence epilepsy (AE) is generally considered undisturbed. However, reports on cognitive deficits in AE in recent years have suggested otherwise. This review...     

Face processing is enhanced in the left and upper visual hemi-fields

We tested whether two known hemi-field asymmetries would affect visual search with face stimuli. Holistic processing of spatial configurations is better in the left hemi-field, reflecting a right hemisphere specialization, and object recognition is better in the upper visual field, reflecting stronger projections into the ventral stream. Faces tap into holistic processing and object recognition at the same time, which predicts better performance in the left and upper hemi-field, respectively. In the first experiment, participants had to detect a face with a gaze direction different from the remaining faces. Participants were faster to respond when targets were presented in the left and upper hemi-field. The same pattern of results was observed when only the eye region was presented. In the second experiment, we turned the faces upside-down, which eliminated the typical spatial configuration of faces. The left hemi-field advantage disappeared, showing that it is related to holistic processing of faces, whereas the upper hemi-field advantage related to object recognition persisted. Finally, we made the search task easier by asking observers to search for a face with open among closed eyes or vice versa. The easy search task eliminated the need for complex object recognition and, accordingly, the advantage of the upper visual field disappeared. Similarly, the left hemi-field advantage was attenuated. In sum, our findings show that both horizontal and vertical asymmetries affect the search for faces and can be selectively suppressed by changing characteristics of the stimuli.     

An eye movement corpus study of the age-of-acquisition effect

In the present study, we investigated the effects of word-level age of acquisition (AoA) on natural reading. Previous studies, using multiple language modalities, showed that earlier-learned words are recognized, read, spoken, and responded to faster than words learned later in life. Until now, in visual word recognition the experimental materials were limited to single-word or sentence studies. We analyzed the data of the Ghent Eye-tracking Corpus (GECO; Cop, Dirix, Drieghe, & Duyck, in press), an eyetracking corpus of participants reading an entire novel, resulting in the first eye movement megastudy of AoA effects in natural reading. We found that the ages at which specific words were learned indeed influenced reading times, above other important (correlated) lexical variables, such as word frequency and length. Shorter fixations for earlier-learned words were consistently found throughout the reading process, in both early (single-fixation durations, first-fixation durations, gaze durations) and late (total reading times) measures. Implications for theoretical accounts of AoA effects and eye movements are discussed.     

Using Automated Learning Devices for Monkeys (ALDM) to study social networks

Social network analysis has become a prominent tool to study animal social life, and there is an increasing need to develop new systems to collect social information automatically, systematically, and reliably. Here we explore the use of a freely accessible Automated Learning Device for Monkeys (ALDM) to collect such social information on a group of 22 captive baboons (Papio papio). We compared the social network obtained from the co-presence of the baboons in ten ALDM testing booths to the social network obtained through standard behavioral observation techniques. The results show that the co-presence network accurately reflects the social organization of the group, and also indicate under which conditions the co-presence network is most informative. In particular, the best correlation between the two networks was obtained with a minimum of 40 days of computer records and for individuals with at least 500 records per day. We also show through random permutation tests that the observed correlations go beyond what would be observed by simple synchronous activity, to reflect a preferential choice of closely located testing booths. The use of automatized cognitive testing therefore presents a new way of obtaining a large and regular amount of social information that is necessary to develop social network analysis. It also opens the possibility of studying dynamic changes in network structure with time and in relation to the cognitive performance of individuals.     

The implicit cognition of reciprocal exchange: automatic retrieval of positive and negative experiences with partners in a prisoner's dilemma game

Models of reciprocity imply that cheater detection is an important prerequisite for successful social exchange. Considering the fundamental role of memory in reciprocal exchange, these theories lead to the prediction that memory for cheaters should be preferentially enhanced. Here, we examine whether information of a partner's previous behaviour in an interaction is automatically retrieved when encountering the face of a partner who previously cheated or cooperated. In two studies, participants played a sequential prisoner's dilemma game with cheaters and cooperative partners. Alternating with the game blocks, participants were asked to classify the smiling or angry facial expressions of cooperators and cheaters. Both experiments revealed congruence effects, reflecting faster identification of the smiles of cooperators (Experiments 1 and 2) and faster identification of the angry facial expressions of cheaters (Experiment 2). Our study provides evidence for the automatic retrieval of the partner's behaviour in the game, regardless of whether partners cheated or cooperated, and thus provides further evidence against the cheater detection hypothesis.     

Similarity and Helping Behavior on the Web: The Impact of the Convergence of Surnames Between a Solicitor and a Subject in a Request Made by E‐Mail1

Similarity between a solicitor and a subject traditionally enhances helping behavior. An experiment was carried out in a computer‐mediated context. Fifty students received an e‐mail containing a 40‐question survey on their food habits, which required 15 to 20 min of their time to respond. This questionnaire came from a hypothetical student of the university in which the participants were registered. In half of the cases, the surname of the solicitor, which appeared in his or her electronic address, was the same as the surname of the target. Results show that compliance to the request was significantly higher in the same‐sumame condition than in the different‐surname condition. The response delay was significantly shorter in the same‐surname condition than in control condition.     

Social Comparison, Perceived Control, and Occupational Burnout

Deux études transversales ont porté sur 72 officiers des douanes (recherche no. 1) et sur cent officiers de police (recherche no. 2) dans le but d’approfondir la relation entre la direction de la comparaison sociale et des variables comme le burnout, des plaintes relatives à la santé ou la satisfaction liée au travail. La comparaison sociale a été mesurée par la fréquence avec laquelle les sujets disaient se comparer avec des salariés mieux et moins bien lotis sur plusieurs dimensions professionnelles. On a mené des analyses de corrélation plusieurs et de médiation pour mettre à l’épreuve deux hypothèses complémentaires. Premièrement, la comparaison ascendante était supposée être positivement liée au contrôle perçu et à la satisfaction professionnelle, et négativement aux ennuis de santé et au burnout. Deuxièmement, le contrôle perçu devait avoir un impact sur la relation entre la direction de la comparaison et des variables comme le burnout, les plaintes relatives à la santé ou la satisfaction liée au travail. Les résultats des deux études ont partiellement validé ces attentes et montré que seule la composante émotionnelle du burnout, l’épuisement émotionnel, était affectée par la direction de la comparaison sociale et médiatisée par le contrôle perçu. Two cross‐sectional studies were conducted among 72 customs officers (Study 1) and 100 police officers (Study 2) to examine the relationship between the direction of social comparison and outcomes such as occupational burnout, health complaints, and job satisfaction. Social comparison was measured by the frequency at which participants reported that they compared themselves with better‐off and worse‐off employees on several work‐related dimensions. Correlation and mediation analyses were conducted to test two complementary hypotheses. Firstly, upward comparison was expected to be positively related to perceived control and job satisfaction, and negatively related to health complaints and occupational burnout. Secondly, perceived control was expected to mediate the relationship between comparison direction and psychological outcomes such as burnout, health complaints, and job satisfaction. The results of both studies partially supported these predictions and showed that only the emotional component of burnout—emotional exhaustion—was affected by social comparison direction and mediated by perceived control.     

Hierarchy of interactive functions in father‐mother‐baby three‐way games

In developmental research, the family has mainly been studied through dyadic interaction. Three‐way interactions have received less attention, partly because of their complexity. This difficulty may be overcome by distinguishing between four hierarchically embedded functions in three‐way interactions: (1) participation (inclusion of all participants), (2) organization (partners keeping to their roles), (3) focalization (sharing a common focus) and (4) affective contact (being in tune). We document this hierarchical model on a sample of 80 families observed in the Lausanne Trilogue Play situation across four different sites. Hierarchy between functions was demonstrated by means of Guttman scalability coefficient. Given the importance of the child's development in a threesome, the pertinence of this model for family assessment is discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

Bridging the gap on Facebook: assessing intergroup contact and its effects for intergroup relations

In line with Allport's contact hypothesis, previous research showed that direct intergroup contact can reduce prejudices. However, establishing face-to-face contact is not always feasible. We postulate that Facebook-groups are a setting where direct and observed intergroup contact can develop, reducing prejudices and increasing mutual acceptance. Analyzing the comments of nine Facebook-groups with the destructive and constructive conflict scale, our results indicated that the expression of prejudices decreased and that of mutual acceptance increased over time, both for in- and outgroup members of the Facebook-groups. Only the expression of less prejudices, but not that of more mutual acceptance was predicted by intergroup contact. The influence of group-based motivations on the engagement in intergroup contact is discussed, and the overall findings are integrated in Steele and Brown's process model of media practices.