Investigating looking and social looking measures as an index of infant violation of expectation

Accumulated looking time has been widely used to index violation of expectation (VoE) response in young infants. But there is controversy concerning the validity of this measure, with some interpreting infant looking behaviour in terms of perceptual preferences (Cohen & Marks, 2002; Haith, 1998). The current study aimed to compare the use of looking time with a recently used measure of social looking (Walden et al., 2007) in distinguishing between 6-month-old infants’ response to novelty/familiarity and a condition in which the object was illegitimately switched for a different object. Following habituation, infants showed more social looking in response to the object-switch condition that the novel object change whereas the more commonly-used accumulated looking time measure did not distinguish between the two, showing an increase for both. Thus, social looking is a more valid measure of infant VoE than looking time

Limits of object persistence:young infants perceive continuity of vertical and horizontal trajectories, but not 45-degree oblique trajectories

Previous research indicated that 4-month-old infants perceive continuity of objects moving on horizontal trajectories but appear to have difficulty processing occlusion events involving oblique trajectories. However, because perception of continuity of vertical trajectories has not been tested, it is uncertain whether this indicates a specific deficit for oblique trajectories or a specific advantage for horizontal trajectories. We evaluated the contribution of trajectory orientation and the form of occlusion in three experiments with 144 4-month-olds. Infants perceived continuity of horizontal and vertical trajectories under all conditions presented. However, they did not perceive continuity of an oblique (45˚) trajectory under any condition. Thus 4-month-olds appear unable to process continuity of a 45˚ trajectory. In a fourth experiment with 48 6- and 8-month-old infants, we demonstrated that by 6 months infants' difficulty with oblique trajectories is overcome. We suggest that young infants’ difficulty with oblique trajectories likely relates to immature eye movement control

Perception of Size and Mass Relationships of Moving and Stationary Object in Collision Events in 10-to-11-Month-Old Infants

Around 5.5–6.5 months of age, infants first attend to object size and perceive its mass cues in simple collision events. Infants attend to the size of the moving object and expect a greater displacement following a collision with a large object and stationary object, and lesser displacement following a collision with a small object and stationary object. It has been proposed that infants of 6-to-7 months of age can differentiate between sizes of moving objects but do not perceive the size and mass relationships in simple collision events. The present two investigations aimed to investigate whether infants 10-to-11 months of age (N = 16) could perceive this relationship (experiment 1) and the reverse of this relationship (experiment 2) utilising the looking time paradigm. The reverse of this relationship entailed the circumstances in which the moving object size was kept constant, but the stationary object size varied (small or large). Results from these experiments revealed that infants did not differ in their looking times for size congruent and size incongruent distances in both conditions. Infants did not look longer at the incongruent test events that violated expectation. For that reason, we conclude infants of 10-to-11 months of age were unable to perceive size and mass associations in collision events in either direction (moving object or stationary object size)

Young infants' visual fixation patterns in addition and subtraction tasks support an object tracking account

Investigating infants' numerical ability is crucial to identifying the developmental origins of numeracy. Wynn (1992) Nature, 358, 749-750, claimed that 5-month-old infants understand addition and subtraction as indicated by longer looking at outcomes that violate numerical operations (i.e., 1 + 1 = 1, or 2 – 1 = 2). However, her claim is contentious, with others suggesting that her results might reflect a familiarity preference for the initial array, or that they could be explained in terms of object tracking. To cast light on this controversy, Wynn’s conditions were replicated with conventional looking time supplemented with eye tracker data. In the incorrect outcome of 2 in a subtraction event (2 – 1 = 2) infants looked selectively at the incorrectly present object, a finding that is not predicted by an initial array preference account or a symbolic numerical account, but which is consistent with a perceptual object tracking account. It appears that young infants can track at least one object over occlusion, and this may form the precursor of numerical ability

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

Investigating the social environment of the A-not-B search task

Abstract Controversy exists concerning the origins of object permanence, with different measures suggesting different conclusions. Looking measures have been interpreted as evidence for early understanding (Baillargeon, 1987, Developmental Psychology, 23:655), while Piaget (The construction of reality in the child, 1954) interpreted perseverative reaching behaviour on his AB search task to be indicative of limited understanding. However, looking measures are often reported to be an unreliable index of infant expectation (Haith, 1998, Infant Behaviour and Development, 21:167) and reaching behaviour has been explained by many alternative processes (e.g. Smith et al., 1999, Psychological Review, 106:235; Topál et al., 2008, Science, 321:1831). We aimed to investigate whether social looking (Dunn Walden et al., 2007, Developmental Science, 10:654) can be used as a valid measure of infant expectation of object location during the Piagetian AB search task. Furthermore, we aimed to test the social accounts of perseverative reaching by investigating how the direction of experimenter gaze would affect infant search and social behaviour. Infant search and social behaviour was compared on B trials across three different conditions, namely experimenter gaze to midline, location A and location B. Search performance significantly improved when the experimenter looked to location B. Infant social looking indicated that infants expect the object to be found in the location in which they search and are actively seeking information about object location from the experimenter. We conclude that social looking is a valid index of infant expectation that has provided support for the importance of the social environment on the AB search task. This casts doubt on the potential for this task to provide information related to the development of object permanence in infancy

The effect of encouraging self evaluation on children's ability to transfer the use of mnemonic strategy

84 children divided into 3 age groups (5 yrs to 6 yrs 9 mo, 8 yrs 1 mo to 9 yrs 10 mo, and 10 yrs 11 mo to 11 yrs 11 mo) were tested on a memory task before and after being given training in the use of a mnemonic strategy. Half of them were asked a series of questions aimed at making them evaluate their improved performance when using the strategy. All age groups improved their performance after strategy training. However, in the younger groups, only those Ss given performance evaluation questions used the strategy in a subsequent task. On the other hand, 11-yr-olds in the evaluation and nonevaluation groups transferred the strategy to the new task. It is argued that older children spontaneously evaluate their performance, whereas younger children need help. (9 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved