An investigation into the use of CCTV footage to improve likeness in facial composites

Facial composites are an important investigative tool and have been used in numerous high-profile cases (e.g. Yorkshire Ripper). Despite this, a great deal of research has indicated that composites often portray very poor facial resemblance to the suspect/target. While some of the difficulties with the older composite systems (e.g. Photofit and Identikit) were due to system design (see e.g. Ellis, Shepherd & Davies, 1975; Davies, Ellis & Shepherd, 1978; Laughery & Fowler (1980), the hit rate for composites constructed with more modern systems (e.g. E-FIT and PROfit) can still be very low (e.g. Frowd et al. 2005). While research has indicated that composite likeness can be improved at test by combining composites from multiple witnesses (e.g. Bennet, Brace, Pike, & Kemp 1999; Bruce, Ness, Hancock, Newman, & Rarity, 2002; Ness, 2003) research on improving composites during construction has produced mixed results

You must see the point: Automatic processing of cues to the direction of social attention

Four experiments explored the processing of pointing gestures comprising hand and combined head and gaze cues to direction. The cross-modal interference effect exerted by pointing hand gestures on the processing of spoken directional words, first noted by S. R. H. Langton, C. O'Malley, and V. Bruce (see record 1996-06577-002), was found to be moderated by the orientation of the gesturer's head-gaze (Experiment 1). Hand and head cues also produced bidirectional interference effects in a within-modalities version of the task (Experiment 2). These findings suggest that both head-gaze and hand cues to direction are processed automatically and in parallel up to a stage in processing where a directional decision is computed. In support of this model, head-gaze cues produced no influence on nondirectional decisions to social emblematic gestures in Experiment 3 but exerted significant interference effects on directional responses to arrows in Experiment 4. It is suggested that the automatic analysis of head, gaze, and pointing gestures occurs because these directional signals are processed as cues to the direction of another individual's social attention

The use of pigmentation and shading information in recognising the sex and identities of faces

An investigation of what can be learned about representational processes in face recognition from the independent and combined effects of inverting and negating facial image is reported. In experiment 1, independent effects of inversion and negation were observed in a task of identifying famous faces. In experiments 2 through 4 the question of whether effects of negation were still obtained when effects due to the reversal of pigmentation in negative image were eliminated was examined. By the use of images of the 3-D surfaces of faces measured by laser, and displays as smooth surfaces devoid of pigmentation, only effects of inversion were obtained reliably, suggesting that the effects observed in experiment 8 arose largely through the inversion of pigmentation values in normal images of faces. The results of experiment 5 suggested that the difference was not due to the different task demands of experiments 2 - 4 compared with those of experiment 1. When normally pigmented face images were used in a task making similar demands to that of experiment 4, independent effects of inversion and negation were again observed. When a task of sex classification was used in experiment 6 and 7, clear effects of negation as well as inversion were observed on latencies, though not accuracies, of responding. The results are interpreted in terms of the information content of pigmentation relative to shape from shading in different face-classification tasks. Tbe results also reinforce other recent evidence demonstrating the importance of image intensity as well as spatial layout of face 'features'

Reflexive visual orienting in response to the social attention of others

Four experiments investigate the hypothesis that cues to the direction of another's social attention produce a reflexive orienting of an observer's visual attention. Participants were asked to make a simple detection response to a target letter which could appear at one of four locations on a visual display. Before the presentation of the target, one of these possible locations was cued by the orientation of a digitized head stimulus, which appeared at fixation in the centre of the display. Uninformative and to-be-ignored cueing stimuli produced faster target detection latencies at cued relative to uncued locations, but only when the cues appeared 100 msec before the onset of the target (Experiments 1 and 2). The effect was uninfluenced by the introduction of a to-be-attended and relatively informative cue (Experiment 3), but was disrupted by the inversion of the head cues (Experiment 4). It is argued that these findings are consistent with the operation of a reflexive, stimulus-driven or exogenous orienting mechanism which can be engaged by social attention signals

Item-writing Rules: Collective Wisdom

In student assessment, teachers place the greatest weight on tests they have constructed themselves and have an equally great interest in the quality of those tests. To increase the validity of teacher-made tests, many item-writing rules-of-thumb are available in the literature, but few rules have been tested experimentally. In light of the paucity of empirical studies, the validity of any given guideline might best be established by relying on experts. This study analyzed twenty classroom assessment textbooks to identify a consensus list of item-writing rules. Forty rules for which there was agreement among textbook authors are presented. The rules address four different validity concerns-potentially confusing wording or ambiguous requirements, the problem of guessing, test-taking efficiency, and controlling for testwiseness

Complexities of face perception and categorisation

We amplify possible complications to the tidy division between early vision and later categorisation which arise when we consider the perception of human faces. Although a primitive face-detecting system, used for social attention, may indeed be integral to “early vision,” the relationship between this and diverse other uses made of information from faces is far from clear

Do the eyes have it? Cues to the direction of social attention

The face communicates an impressive amount of visual information. We use it to identify its owner, how they are feeling and to help us understand what they are saying. Models of face processing have considered how we extract such meaning from the face but have ignored another important signal - eye gaze. In this article we begin by reviewing evidence from recent neurophysiological studies that suggests that the eyes constitute a special stimulus in at least two senses. First, the structure of the eyes is such that it provides us with a particularly powerful signal to the direction of another person's gaze, and second, we may have evolved neural mechanisms devoted to gaze processing. As a result, gaze direction is analysed rapidly and automatically, and is able to trigger reflexive shifts of an observer's visual attention. However, understanding where another individual is directing their attention involves more than simply analysing their gaze direction. We go on to describe research with adult participants, children and non-human primates that suggests that other cues such as head orientation and pointing gestures make significant contributions to the computation of another's direction of attention

Vegetation dieback as a proxy for temperature within a wet pyroclastic density current: A novel experiment and observations from the 6th of August 2012 Tongariro eruption

The 6th of August 2012 eruption of Te Maari (Mt Tongariro, New Zealand) generated wet pyroclastic density currents (PDCs) which caused widespread dieback of vegetation (singed, brown foliage) in their path. An absence of significant charcoal formation suggests that PDC temperatures were mostly below 250 °C. Textural evidence for liquid water being present in the matrices during emplacement (vesicles) suggests that temperatures were b100 °C. We determined a probable minimum PDC temperature using an experiment replicating the critical temperatures required to induce foliar browning in seven species affected by the eruption. In locations where all species exhibited browned foliage (or were defoliated), temperatures were probably ≥64 °C assuming a PDC duration of 60 s. In the more distal areas, where only the most susceptible species were browned while others remained healthy and unaffected, temperatures were probably around 51–58 °C. These results have relevance to volcanic hazard mitigation and risk assessment, especially on the popular Tongariro Alpine Crossing