457 research outputs found
Uneven integration for perception and action cues in children’s working memory
We examined the development of visual cue integration in a desktop working-memory task using boxes with different visual action cues (opening actions) and perceptual surface cues (colours, monochromatic textures, or images of faces). Children had to recall which box held a hidden toy, based on (a) the action cue, (b) the surface cue, or (c) a conjunction of the two. Results from three experiments show a set of asymmetries in children's integration of action and surface cues. The 18–24-month-olds disregarded colour in conjunction judgements with action; 30–36-month-olds used colour but disregarded texture. Images of faces were not disregarded at either age. We suggest that 18–24-month-olds' disregard of colour, seen previously in reorientation tasks (Hermer & Spelke, 1994), may represent a general phenomenon, likened to uneven integration between the dorsal and ventral streams in early development
Cortical Processing of Global Form, Motion and Biological Motion Under Low Light Levels
Advances in potential treatments for rod and cone dystrophies have increased the need to understand the contributions of rods and cones to higher-level cortical vision. We measured form, motion and biological motion coherence thresholds and EEG steady-state visual evoked potentials (SSVEP) responses under light conditions ranging from photopic to scotopic. Low light increased thresholds for all three kinds of stimuli; however, global form thresholds were relatively more impaired than those for global motion or biological motion. SSVEP responses to coherent global form and motion were reduced in low light, and motion responses showed a shift in topography from the midline to more lateral locations. Contrast sensitivity measures confirmed that basic visual processing was also affected by low light. However, comparison with contrast sensitivity function (CSF) reductions achieved by optical blur indicated that these were insufficient to explain the pattern of results, although the temporal properties of the rod system may also play a role. Overall, mid-level processing in extra-striate areas is differentially affected by light level, in ways that cannot be explained in terms of low-level spatiotemporal sensitivity. A topographical shift in scotopic motion SSVEP responses may reflect either changes to inhibitory feedback mechanisms between V1 and extra-striate regions or a reduction of input to the visual cortex. These results provide insight into how higher-level cortical vision is normally organised in absence of cone input, and provide a basis for comparison with patients with cone dystrophies, before and after treatments aiming to restore cone function
Masculinity as Governance: police, public service and the embodiment of authority, c. 1700-1850
About the book: Public Men offers an introduction to an exciting new field: the history of masculinities in the political domain and will be essential reading for students and specialists alike with interests in gender or political culture. By building upon new work on gender and political culture, these new case studies explore the gendering of the political domain and the masculinities of the men who have historically dominated it. As such, Public Men is a major contribution to our understanding of the history of Britain between the Eighteenth and the Twentieth centuries
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Development of the spatial contrast sensitivity function (CSF) during childhood: Analysis of previous findings and new psychophysical data
While the contrast sensitivity function (CSF) changes markedly during infancy, there is no consensus regarding whether, how, and why it continues to develop in later childhood. Here we analyzed previously published data (N = 1,928 CSFs), and present new psychophysical findings from 98 children (4.7–14.8 years) and 50 adults (18.1–29.7 years), in order to establish: (1) Does the CSF change during childhood? (2) How large is the developmental effect size? (3) Are any changes uniform across the CSF, or frequency-specific? (4) Can some or all of the changes be explained by ‘non-visual’ (i.e., procedural/cognitive) factors, such as boredom or inattentiveness? The new data were collected using a four-alternative forced-choice [4AFC] Gabor-detection task, with two different psychophysical procedures (Weighted Staircase; QUEST+), and suprathreshold (false-negative) catch trials to quantify lapse rates. It is shown that from 4—18 years, the CSF improves (at an exponentially decaying rate) by approximately 0.3 log10 units (a doubling of CS), with 90% of this change complete by 12 years. The size of the effect was small relative to individual variability, with age alone explaining less than one sixth of variability (16%), and most children performing as well as some adults (i.e., falling within the 90% population limits for adults). Development was frequency-specific, with changes occurring primarily around or below the CSF peak (≤ 4 cpd). At least half --- and potentially all --- of the changes observed could be explained by ‘non-visual’ factors (e.g., lapses in concentration), though possible biological mechanisms are discussed
Bimanual strategies for object retrieval in infants and young children
Age differences in goal-directed bimanual coordination were studied in typically developing infants aged 9 – 29 months, compared to a group of children aged 4-6 years and a group of adults, using an object retrieval task. This task required one hand to open and hold the lid of a transparent box, while the second hand retrieved a small toy from inside the box. Well-coordinated retrieval strategies with differentiated use of the two hands were not established in the majority of infants until 18 months of age. Temporal analysis of the hand actions revealed that, unlike adults who perform the task with close synchronization of the hands at the start, the infants performed the task sequentially and did not activate the second hand until the first hand had started to lift the lid. The children’s hand preferences for the two hand actions also contrasted with those of adults. In children aged 27-29 months and 4-6 years there was a preference for using the right hand to lift the lid while in right-handed adults the reverse pattern was observed. The results suggest that although bimanual coordination starts to develop in the second year of life, the adult pattern of performance on this task is not observed before 6 years of age. It is likely that further maturation of the brain networks involved in bimanual coordination, and in particular functional interhemispheric transfer via the corpus callosum, is required before automatization of bimanual hand actions is achieved
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Default perception of high-speed motion
When human observers are exposed to even slight motion signals followed by brief visual transients—stimuli containing no detectable coherent motion signals—they perceive large and salient illusory jumps. This novel effect, which we call “high phi”, challenges well-entrenched assumptions about the perception of motion, namely the minimal-motion principle and the breakdown of coherent motion perception with steps above an upper limit. Our experiments with transients such as texture randomization or contrast reversal show that the magnitude of the jump depends on spatial frequency and transient duration, but not on the speed of the inducing motion signals, and the direction of the jump depends on the duration of the inducer. Jump magnitude is robust across jump directions and different types of transient. In addition, when a texture is actually displaced by a large step beyond dmax, a breakdown of coherent motion perception is expected, but in the presence of an inducer observers again perceive coherent displacements at or just above dmax. In sum, across a large variety of stimuli, we find that when incoherent motion noise is preceded by a small bias, instead of perceiving little or no motion, as suggested by the minimal-motion principle, observers perceive jumps whose amplitude closely follows their own dmax limits
Early detection of multiple myeloma in primary care using blood tests: a case-control study in primary care
This is the final version. Available on open access from Royal College of General Practitioners via the DOI in this recordBACKGROUND: Multiple myeloma is a haematological cancer characterised by numerous non-specific symptoms leading to diagnostic delay in a large proportion of patients. AIM: To identify which blood tests are useful in suggesting or excluding a diagnosis of myeloma. DESIGN AND SETTING: A matched case-control study set in UK primary care using routinely collected data from the Clinical Practice Research Datalink. METHOD: Symptom prevalence and blood tests were analysed up to 5 years before diagnosis in 2703 cases and 12 157 matched controls. Likelihood ratios (LR) were used to classify tests or their combinations as useful rule-in tests (LR+ = ≥5), or rule-out tests (LR- = ≤0.2). RESULTS: Raised plasma viscosity (PV) had an LR+ = 2.0, 95% confidence interval [CI] = 1.7 to 2.3; erythrocyte sedimentation rate (ESR) 1.9, 95% CI = 1.7 to 2.0; and C-reactive protein (CRP) 1.2, 95% CI = 1.1 to 1.4. A normal haemoglobin had an LR- = 0.42, 95% CI = 0.39 to 0.45; calcium LR- = 0.81, 95% CI = 0.78 to 0.83; and creatinine LR- = 0.80, 95% CI = 0.77 to 0.83. The test combination with the lowest LR- was all normal haemoglobin with calcium and PV, which had an LR- = 0.06, 95% CI = 0.02 to 0.18, though the LR- for normal haemoglobin and PV together was 0.12 (95% CI = 0.07 to 0.23). CONCLUSION: Plasma viscosity and ESR are better for both ruling in and ruling out the disease compared with C-reactive protein. A combination of a normal ESR or PV and normal haemoglobin is a simple rule-out approach for patients currently being tested in primary care.This manuscript presents work carried out as part of a DPhil scholarship awarded to Constantinos Koshiaris funded by the Primary Care Research Trust, the University of Oxford, and National Institute for Health Research (NIHR) Oxford CLAHRC. This article presents independent research funded by the NIHR
Impaired perception of facial motion in autism spectrum disorder
Copyright: © 2014 O’Brien et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This article has been made available through the Brunel Open Access Publishing Fund.Facial motion is a special type of biological motion that transmits cues for socio-emotional communication and enables the discrimination of properties such as gender and identity. We used animated average faces to examine the ability of adults with autism spectrum disorders (ASD) to perceive facial motion. Participants completed increasingly difficult tasks involving the discrimination of (1) sequences of facial motion, (2) the identity of individuals based on their facial motion and (3) the gender of individuals. Stimuli were presented in both upright and upside-down orientations to test for the difference in inversion effects often found when comparing ASD with controls in face perception. The ASD group’s performance was impaired relative to the control group in all three tasks and unlike the control group, the individuals with ASD failed to show an inversion effect. These results point to a deficit in facial biological motion processing in people with autism, which we suggest is linked to deficits in lower level motion processing we have previously reported
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