Dosimetry during intramedullary nailing of the tibia: Patient and occupational exposure

Background Intramedullary nailing under fluoroscopic guidance is a common operation. We studied the intraoperative radiation dose received by both the patient and the personnel

Revealing the mechanisms of human face perception using dynamic apertures

Faces are notoriously hard to perceive when turned upside-down. It is often claimed that perceptual decrements reflect a qualitative switch from parallel whole-face processing, to a serial analysis of individual features. To test this view, we examined observers' ability to categorize faces presented in their entirety, or viewed through a dynamic aperture that moved incrementally across the facial image. Exposing faces region-by-region disrupts holistic processing, but permits serial analysis of local features. In line with the holistic accounts, we predicted that aperture viewing would greatly impair judgements of upright, but not inverted faces. As expected, identity, gender, age, and expression were categorized more precisely when faces were presented upright and in their entirety. Contrary to holistic accounts, however, the detrimental effects of inversion seen in the whole-face condition were no greater than in the aperture condition. Moreover, we found comparable aperture effects for upright and inverted faces; observers exhibited less decision noise when faces were viewed in their entirety, than when viewed through the aperture, irrespective of orientation. We replicate these findings in control experiments and show that the same pattern is seen irrespective of the direction of aperture transition or the nature of the fill used to replace the occluded regions of the to-be-judged image. These results challenge holistic accounts of the face inversion effect and support an alternative interpretation. First, in line with previous findings, they indicate that perceptual decrements when viewing upside-down faces result from impoverished descriptions of local regions, not the loss of whole-face processing. Second, when interpreting inverted faces, access to the wider face context appears to be far more important than currently believed

Double Jeopardy in Inferring Cognitive Processes

Inferences we make about underlying cognitive processes can be jeopardized in two ways due to problematic forms of aggregation. First, averaging across individuals is typically considered a very useful tool for removing random variability. The threat is that averaging across subjects leads to averaging across different cognitive strategies, thus harming our inferences. The second threat comes from the construction of inadequate research designs possessing a low diagnostic accuracy of cognitive processes. For that reason we introduced the systems factorial technology (SFT), which has primarily been designed to make inferences about underlying processing order (serial, parallel, coactive), stopping rule (terminating, exhaustive), and process dependency. SFT proposes that the minimal research design complexity to learn about n number of cognitive processes should be equal to 2n. In addition, SFT proposes that (a) each cognitive process should be controlled by a separate experimental factor, and (b) The saliency levels of all factors should be combined in a full factorial design. In the current study, the author cross combined the levels of jeopardies in a 2 × 2 analysis, leading to four different analysis conditions. The results indicate a decline in the diagnostic accuracy of inferences made about cognitive processes due to the presence of each jeopardy in isolation and when combined. The results warrant the development of more individual subject analyses and the utilization of full-factorial (SFT) experimental designs

Independence of face identity and expression processing: exploring the role of motion

According to the classic Bruce and Young (1986) model of face recognition, identity and emotional expression information from the face are processed in parallel and independently. Since this functional model was published, a growing body of research has challenged this viewpoint and instead support an interdependence view. In addition, neural models of face processing (Haxby, Hoffman & Gobbini, 2000) emphasise differences in terms of the processing of changeable and invariant aspects of faces. This article provides a critical appraisal of this literature and discusses the role of motion in both expression and identity recognition and the intertwined nature of identity, expression and motion processing. We conclude, by discussing recent advancements in this area and research questions that still need to be addressed

Composite faces and Navon letters: Similar global Phenomena different processing mechanisms

The first data set is from a published paper by Fitousi: Fitousi, D. (2019). Global-to-local? Uncovering the temporal dynamics of the composite face illusion using distributional analyses. Frontiers in Psychology ,10, 2331, 1-17. The second data set is new and contains a replication of the classic experiment with Navon's figures (Navon, 1977). The two data sets were modeled with the linear ballistic accumulator model (Brown & Heathcote, 2008). The question of interest was whether global precedence phenomena are governed by similar mechanisms

A signal-detection-based confidence-similarity model of face-matching

The ability to match faces correctly is crucial for efficient face recognition. Face-matchingalso plays an important role in applied setting such as passport control and eyewitnessmemory. However, despite extensive research on face-matching the mechanisms thatgovern this task are still not well understood. Moreover, to-date, many researchers holdon to the belief that match and mismatch responses are governed by two separatesystems, an assumption that thwarted the development of a unified model. The presentstudy outlines a signal-detection-based model of face-matching performance. The modelcan explain a myriad of face-matching phenomena, including the match-mismatchdissociation. The model is also capable of generating new predictions concerning the roleof confidence and similarity and their intricate relations with accuracy, all within theconfines of a single system. The new model was tested against six alternative competitorsmodels (some postulate discrete rather than continuous representations) in threeexperiments. Data analyses consisted of hierarchically-nested model fitting, ROC curveanalyses, and calibration curves analyses. All of the analyses provided substantialsupport in the signal-detection-based confidence-similarity model

From global-to-local? Uncovering the temporal dynamics of the composite face illusion using distributional analyses

The data are the result of an experiment with composite faces. This is a standard composite face task in which a study and test composite faces are presented one after the other. The participant's task is to indicate whether the top half of the test and study faces are 'same' or 'different'. Both RTs and accuracy are measured

From global-to-local? Uncovering the temporal dynamics of the composite face illusion using distributional analyses

The data are the result of an experiment with composite faces. This is a standard composite face task in which a study and test composite faces are presented one after the other. The participant's task is to indicate whether the top half of the test and study faces are 'same' or 'different'. Both RTs and accuracy are measured

How facial aging affects perceived gender: Insights from maximum likelihood conjoint measurement

Conjoint measurement was used to investigate the joint influence of facial gender and facial age on perceived gender (Experiment 1) and perceived age (Experiment 2). A set of 25 faces were created, covarying independently five levels of gender (from very masculine to very feminine) and five levels of age (from very young to very old). Two independent groups of observers were presented with all possible pairs of faces from this set and compared which member of the pair appeared as more feminine (Experiment 1) or older (Experiment 2). Three nested models of the contribution of gender and age to judgment were fit to the data using maximum likelihood. The best fitting model of the three was decided by likelihood ratio tests. Both gender and age contributed to the perceived gender and age of the faces. For judgments of gender, an additive model was rejected in favor of a saturated model in which responses depended on the levels of gender and age. In particular, faces were perceived as less feminine as age increased, but this trend was more pronounced in feminine faces compared to androgynous or male faces. For judgments of age, an additive model was rejected in favor of a saturated model for only half of the observers. For the other half of observers, perceived age increased as the faces become more feminine. Taken together, the results entail that: (a) observers integrate facial gender and age information when judging either of the dimensions, and that (b) cues for masculinity and cues for aging are positively correlated. This correlation exerts stronger influence on female faces, and can explain the success of cosmetics in concealing signs of aging and exaggerating sexually dimorphic features