Genetic origins of the Minoans and Mycenaeans.

The origins of the Bronze Age Minoan and Mycenaean cultures have puzzled archaeologists for more than a century. We have assembled genome-wide data from 19 ancient individuals, including Minoans from Crete, Mycenaeans from mainland Greece, and their eastern neighbours from southwestern Anatolia. Here we show that Minoans and Mycenaeans were genetically similar, having at least three-quarters of their ancestry from the first Neolithic farmers of western Anatolia and the Aegean, and most of the remainder from ancient populations related to those of the Caucasus and Iran. However, the Mycenaeans differed from Minoans in deriving additional ancestry from an ultimate source related to the hunter-gatherers of eastern Europe and Siberia, introduced via a proximal source related to the inhabitants of either the Eurasian steppe or Armenia. Modern Greeks resemble the Mycenaeans, but with some additional dilution of the Early Neolithic ancestry. Our results support the idea of continuity but not isolation in the history of populations of the Aegean, before and after the time of its earliest civilizations.

Cognitive adaptation: spatial memory or attentional processing. a comment on Furley and Memmert (2010).

This commentary considers the paper by Furley and Memmert (2010) who sought to test the respective validities of the specific processing and cognitive adaptation hypotheses. That they found no evidence of a difference between experienced basketball players and nonathletes on the Corsi block task, a measure of spatial memory, led them to infer support for the specific processing hypothesis, namely that differences between experts and novices manifest themselves only in processes related specifically to the domain of expertise. An alternative interpretation is offered, indicating possible confounds and referring to recent research that suggests Corsi block and dynamic spatial tasks depend upon different neuronal networks.

Multiple-object tracking: the binding of spatial location and featural identity.

The Multiple-Object Tracking paradigm has most commonly been utilized to investigate how subsets of targets can be tracked from among a set of identical objects. Recently, this research has been extended to examine the function of featural information when tracking is of objects that can be individuated. We report on a study whose findings suggest that, while participants can only hold featural information for roughly two targets this task does not affect tracking performance detrimentally and points to a discontinuity between the cognitive processes that subserve spatial location and featural information.

The influence of visual symmetry on the encoding of objects.

Two experiments examined how symmetry affects the visual encoding of simple flat objects (lamellae). Experiment 1 showed that subjects encode a lamella's shape as both a facsimile and its enantiomorph. In Experiment 2 the errors made when responding to symmetrical and asymmetrical stimuli showed that there were three factors affecting the reproduction of a symmetrical stimulus. These are, in order of decreasing influence, (i) the orientation of the axis of symmetry, (ii) the presence of overall symmetry (irrespective of orientation), and (iii) identity of the orientation of the elements of the response in relation to those of the stimulus. They also show that symmetry is likely to be reproduced even where the reproduction is not of the same shape as the original stimulus. The relevance of these results to representation of objects is discussed.

Anaesthetists' Non-Technical Skills (ANTS): evaluation of a behavioural marker system.

BACKGROUND: Non-technical skills are critical for good anaesthetic practice but are not addressed explicitly in normal training. Realization of the need to train and assess these skills is growing, but these activities must be based on properly developed skills frameworks and validated measurement tools. A prototype behavioural marker system was developed using human factors research techniques. The aim of this study was to conduct an experimental evaluation to establish its basic psychometric properties and usability. METHOD: The Anaesthetists' Non-Technical Skills (ANTS) system prototype comprises four skill categories (task management, team working, situation awareness, and decision making) divided into 15 elements, each with example behaviours. To investigate its experimental validity, reliably and usability, 50 consultant anaesthetists were trained to use the ANTS system. They were asked to rate the behaviour of a target anaesthetist using the prototype system in eight videos of simulated anaesthetic scenarios. Data were collected from the ratings forms and an evaluation questionnaire. RESULTS: The results showed that the system is complete, and that the skills are observable and can be rated with acceptable levels of agreement and accuracy. The internal consistency of the system appeared sound, and responses regarding usability were very positive. CONCLUSIONS: The findings of the evaluation indicated that the ANTS system has a satisfactory level of validity, reliability and usability in an experimental setting, provided users receive adequate training. It is now ready to be tested in real training environments, so that full guidelines can be developed for its integration into the anaesthetic curriculum.

Anaesthetists' attitudes to teamwork and safety.

A questionnaire survey was conducted with 222 anaesthetists from 11 Scottish hospitals to measure their attitudes towards human and organisational factors that can have an impact on effective team performance and consequently on patient safety. A customised version of the Operating Room Management Attitude Questionnaire (ORMAQ) was used. This measures attitudes to leadership, communication, teamwork, stress and fatigue, work values, human error and organisational climate. The respondents generally demonstrated positive attitudes towards the interpersonal aspects of their work, such as team behaviours and they recognised the importance of communication skills, such as assertiveness. However, the results suggest that some anaesthetists do not fully appreciate the debilitating effects of stress and fatigue on performance. Their responses were comparable with (and slightly more favourable than) those reported in previous ORMAQ surveys of anaesthetists and surgeons in other countries.

The role of left-right symmetry in the encodement of spatial orientations.

Three experiments investigated a hypothesis, suggested by studies of the difficulties of discriminating between shapes forming symmetrical pairs, that spatial orientations of thin flat plates (lamellae) may be encoded in a plane, the encodement consisting of two enantiomorphs. The results indicated that participants encoded the spatial orientation of lamellar stimuli in terms of the difference in cogency between their two enantiomorphic elements (Expt 1). The difference in the cogency of the two enantiomorphs is related to the orientation of the plane containing the lamellar stimulus with respect to the participant's fronto-parallel plane (Expt 2). The two possible orientations of a lamella which yield the same difference of cogency, but which differ in spatial orientation (e.g. lamella 'b' set at 30 degrees or set at 150 degrees) are distinguished by the manner in which the two enantiomorphic elements are arranged with respect to their axis of symmetry (Expt 3). The results suggest that the orientation of a lamella may be encoded as a two-dimensional representation and hence that three dimensions may be encoded by two by means of enantiomorphs. Implications of this finding for the encodements of three-dimensional solids, wherein pronounced contours may fulfil the same role as do the edges of lamella, are discussed briefly.

The role of typical contours in the encodement of objects in three-dimensional arrays.

Two experiments are reported in which the relationship between the orientation of the typical contour of a lamella in relation to the observer, and the ability of the observer to learn the correct position and orientation of sets of lamellae in three-dimensional arrays, was examined. For lamellae presented with their typical contour in a plane other than the observer's frontoparallel plane, the results of both experiments indicated that participants encoded lamellae in such a way that their typical contour appeared to be closer to the observer's frontoparallel plane than the respective stimulus. The relationship of the present findings to previous results on children's drawings and to the concept of the picture plane are considered.

Perceived similarity of shapes is an asymmetrical relationship: a study of typical contours.

Two experiments are reported in which the relationship between perceived similarity amongst simple geometric solids and the set of projections arising from rotation of the typical contour of the solids about a vertical axis in its plane are examined. The results indicate (1) that judgments of similarity are affected by pronouncedness of typical contours, (2) similarity of simple geometrical solids is an asymmetrical attribute, in that where a set of possible projections of model X contains a set of possible projections of model Y, then model Y is judged as more similar to model X than X is to Y. The implications of this asymmetry for perceptual constancy and theories of object recognition are discussed.

Base rate data on the abnormality of subtest scatter for WAIS-R short-forms.

Tables are presented which permit clinicians to determine the abnormality of a WAIS-R subtest profile when one of nine different short-forms has been administered. The tables record the discrepancy, between each subtest and the individual's mean subtest score, which must be exceeded to occur in less than 15 per cent or 5 per cent of the healthy population. Two tables are provided; the first uses a statistical formula developed by Silverstein (1984a) to estimate the discrepancies from the US standardization sample. The second presents empirically derived discrepancies based on a sample of 326 healthy individuals which was representative of the adult UK population in terms of age, sex and social class distributions. The UK sample was also used to generate base rate data on the cumulative number of abnormal subtest deviations exhibited by healthy individuals.

The relationships between psychometric intelligence and learning in an explicit and an implicit task.

An experiment is reported examining the relation of implicit grammar learning and series completion tasks to a standard measure of psychometric intelligence, the Wechsler Adult Intelligence Scale-Revised (WAIS-R; D. Wechsler, 1981). The results replicate and extend an earlier study by A. S. Reber, F. F. Walkenfeld, and R. Hernstadt (1991) and provide the following support for the differences between explicit and implicit tasks: (a) The implicit task was less strongly related to Full Scale IQ, and (b) the implicit task appeared to be independent of age. The implicit and explicit tasks exhibited a quite different pattern of relations to the factors known to underlie WAIS-R performance. Although both tasks showed significant links with a Perceptual Organization factor, only the series completion task showed a significant link with the Attention factor.