A Simple, Test-Based Method to Control the Overestimation Bias in the Analysis of Potential Prognostic Tumour Markers

The early evaluation of prognostic tumour markers is commonly performed by comparing the survival of two groups of patients identified on the basis of a cut-off value. The corresponding hazard ratio (HR) is usually estimated, representing a measure of the relative risk between patients with marker values above and below the cut-off. A posteriori methods identifying an optimal cut-off are appropriate when the functional form of the relation between the marker distribution and patient survival is unknown, but they are prone to an overestimation bias. In the presence of a small sample size, which is typical of rare diseases, the external validation sets are hardly available and internal cross-validation could be unfeasible. We describe a new method to obtain an unbiased estimate of the HR at an optimal cut-off, exploiting the simple relation between the HR and the associated p-value estimated by a random permutation analysis. We validate the method on both simulated data and set of gene expression profiles from two large, publicly available data sets. Furthermore, a reanalysis of a previously published study, which included 134 Stage 4S neuroblastoma patients, allowed for the identification of E2F1 as a new gene with potential oncogenic activity. This finding was confirmed by an immunofluorescence analysis on an independent cohort.

Slow motion bias: Exploring the relation between time overestimation and increased perceived intentionality

Recent research on time perception has revealed that actions which are replayed in slow motion are perceived to take longer and rated to be more intentional (e.g., foul plays). Interestingly, the bias on duration estimations seems to disappear when information on the slow motion factor (i.e., the degree the video was slowed down) was provided. Here, we scrutinize the question whether also the intentionality bias disappears when explicit information about the slow motion factor is provided. To this end, two groups watched the same video clips, all displaying foul situations in a basketball match, in different video speeds. While the uninformed group saw the videos without further information, the informed group received additional information about the current slow motion factor. This study replicated the overestimation of original duration with increasing slow motion and indicated that this effect might be reduced when information about the slow motion factor is provided. However, despite generally lower intentionality ratings in the informed group, video speed information was not able to reduce the rise in intentionality ratings with increasing slow motion. Potential reasons and open questions regarding the nature and mechanisms behind these perceptual temporal biases (e.g., different time processing systems) are discussed.

The humble estimate: Humility predicts higher self-assessment accuracy

Humility is thought to be associated with greater accuracy in self-assessment. However, clear evidence is lacking. Two studies tested this central proposition. In Study 1 (N = 258), participants completed a task on logical reasoning before estimating both their raw and relative performance. Study 2 (N = 214) was aimed at replicating Study 1 with a task on English fluency. Results from both studies were consistent. There was evidence of overestimation bias across each sample in which participants' estimated performance was higher than their actual performance. More importantly, humility was associated with less overestimation bias, such that the difference in estimated and actual performance was smaller or non-existent among those higher in humility. We also replicated the Dunning-Kruger effect in which participants of lower ability in these skills (i.e., lower actual scores) were most likely to overestimate their performance. Further analyses found that the negative relationship between humility and overestimation bias was not moderated by actual performances. However, the same analyses revealed that the Dunning-Kruger effect was also not moderated by humility. Hence, there is strong replicable evidence that humility is associated with less overestimation bias, supporting the view that greater accuracy in self-assessment is an attribute of humility, and that this relationship is independent of actual ability, but humility does not affect the robust Dunning-Kruger effect.

Why Do Actions in Slow Motion Appear to Last Longer? On the Effect of Video Speed Information

When displayed in slow motion, actions are often perceived longer compared with original speed. However, it remains to be determined why this bias exists. Is it possible that the bias emerges because participants underestimate the factor by which a video was slowed down and hence arrive at erroneous conclusions about the original duration? If true, providing explicit information about the respective video speed should eliminate this slow motion effect. To scrutinize the nature of this bias, participants rated the original duration of sports actions displayed at original speed or slow motion. Results revealed the expected overestimation bias consisting in longer ratings with increasing slow motion. However, the bias disappeared when information about the current video speed was provided. The observations suggest an influence of knowledge about video playback speed on cognitive-evaluative processes which may hold important implications for future research and practice.

Biology Teachers' Worldviews on the Global Distribution and Loss of Biodiversity: A GIS-Based Mental-Mapping Approach

This paper explores (1) student teachers' mental maps of the global distribution and loss of biodiversity and (2) their perception of threatened biodiversity at the national, transnational and global levels. Data was collected from a questionnaire study of student biology teachers from Germany (n = 868) and Costa Rica (n = 284). Student teachers' mental maps matched quite well with the scientific view. Nevertheless, they clearly showed a "brazilisation bias," meaning that the first and foremost country associated with high and threatened biodiversity was Brazil. Industrialized countries were often misconceived to have a particularly threatened biodiversity. Except for Brazil (and Costa Rica in the Costa Rican sample), most students neglected a connection between a country's high biodiversity and its high threat as proposed by the biodiversity hotspots concept. Despite this common ground, major ethnocentric distortions merged in the composite mental maps for each sample: German students had a more global perspective on biodiversity and its loss, whereas Costa Ricans students had a more localized view. Student teachers from both countries have largely overestimated the percentage of threatened plant species on a national, transnational and global level ("overestimation bias"). In addition, the estimated percentage of threatened plant species have correspondingly increased with a greater distance from the students' home country ("spatial optimism bias"). Results will be discussed in terms of educational implications.