Side Bias Research Articles

Mapping charge transport effects in thick CCDs with a dithered array of 40,000 stars

We characterize the astrometric distortion at the edges of thick, fully-depleted CCDs in the lab using a bench-top simulation of LSST observing. By illuminating an array of forty thousand pinholes (30μ m diameter) at the object plane of a f/1.2 optical reimager, thousands of PSFs can be imaged over a 4Kx4K pixel CCD. Each high purity silicon pixel, 10μ m square by 100μ m deep, can then be individually characterized through a series of sub-pixel dithers in the X/Y plane. The unique character [response, position, shape] of each pixel as a function of flux, wavelength, back side bias, etc. can be investigated. We measure the magnitude and onset of astrometric error at the edges of the detector as a test of the experimental setup, using a LSST prototype CCD. We show that this astrometric error at the edge is sourced from non-uniformities in the electric field lines that define pixel boundaries. This edge distortion must be corrected in order to optimize the science output of weak gravitational lensing and large scale structure measurements for the LSST.

Scientific impact of MODIS C5 calibration degradation and C6+ improvements

Abstract. The Collection 6 (C6) MODIS (Moderate Resolution Imaging Spectroradiometer) land and atmosphere data sets are scheduled for release in 2014. C6 contains significant revisions of the calibration approach to account for sensor aging. This analysis documents the presence of systematic temporal trends in the visible and near-infrared (500 m) bands of the Collection 5 (C5) MODIS Terra and, to lesser extent, in MODIS Aqua geophysical data sets. Sensor degradation is largest in the blue band (B3) of the MODIS sensor on Terra and decreases with wavelength. Calibration degradation causes negative global trends in multiple MODIS C5 products including the dark target algorithm's aerosol optical depth over land and Ångström exponent over the ocean, global liquid water and ice cloud optical thickness, as well as surface reflectance and vegetation indices, including the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). As the C5 production will be maintained for another year in parallel with C6, one objective of this paper is to raise awareness of the calibration-related trends for the broad MODIS user community. The new C6 calibration approach removes major calibrations trends in the Level 1B (L1B) data. This paper also introduces an enhanced C6+ calibration of the MODIS data set which includes an additional polarization correction (PC) to compensate for the increased polarization sensitivity of MODIS Terra since about 2007, as well as detrending and Terra–Aqua cross-calibration over quasi-stable desert calibration sites. The PC algorithm, developed by the MODIS ocean biology processing group (OBPG), removes residual scan angle, mirror side and seasonal biases from aerosol and surface reflectance (SR) records along with spectral distortions of SR. Using the multiangle implementation of atmospheric correction (MAIAC) algorithm over deserts, we have also developed a detrending and cross-calibration method which removes residual decadal trends on the order of several tenths of 1% of the top-of-atmosphere (TOA) reflectance in the visible and near-infrared MODIS bands B1–B4, and provides a good consistency between the two MODIS sensors. MAIAC analysis over the southern USA shows that the C6+ approach removed an additional negative decadal trend of Terra ΔNDVI ~ 0.01 as compared to Aqua data. This change is particularly important for analysis of vegetation dynamics and trends in the tropics, e.g., Amazon rainforest, where the morning orbit of Terra provides considerably more cloud-free observations compared to the afternoon Aqua measurements.

Face drawing experience is associated with better face recognition performance and reduced left-side bias in face perception

Recent research in computer vision showed that while both analytic (local) and holistic (global) approaches perform well in face recognition, the fusion of the two yields the best performance. Professional face artists/caricaturists mastering both the drawing of individual facial features and whole faces may engage in such fused processing of faces, and thus may excel in face recognition. Zhou et al. (2012) found that art students with face drawing experience showed weaker holistic face processing than non-drawers; nevertheless, the two groups did not differ in sequential face-matching performance. Here we recruited professional face artists, in contrast to art students, in a simultaneous face-matching task with unfamiliar faces that differed in illumination, pose, disguise and expression. In contrast to sequential face-matching, our task reduces the involvement of visual short-term memory, as face artists' advantage is more likely to be in their perceptual ability than in memory. We recruited 15 face artists and 15 non-drawers. Before the experiment, participants drew a face within 15 minutes. An experienced face artist rated participants' expertise according to the drawings. We found that face artists outperformed non-drawers in the simultaneous face-matching task (t(28) = 2.56, p <.05). Face drawing expertise was positively correlated with face recognition performance (r = 0.38, p <.05). In addition, while non-drawers judged a face made from two left half-faces more similar to the original face than one from two right half-faces, i.e., the left side bias (right hemisphere dominance) in face perception, face artists had a reduced bias than non-drawers (t(28) = -2.39, p <.05), suggesting reduced global face processing. Face drawing expertise was negatively correlated with the bias (r = -0.47, p <.05). Together, the results suggest that face drawing expertise may shift attention from global to local, which may help face recognition in challenging tasks. Meeting abstract presented at VSS 2014

Patterns in ritual tooth avulsion at Roonka.

Tooth avulsion is the intentional removal of one or more teeth for ritual or aesthetic reasons, or to denote group affiliation. Typically the maxillary incisors are the teeth most often selected for removal. Previous authors have discussed the presence of tooth avulsions in several individuals recovered from Roonka, but those papers did not examine any patterns in those removals that might be present. Analysis of the tooth avulsions at Roonka reveals a change in the practice over time, with the older burials from phase II typically showing removal of both maxillary central incisors with a left side bias when only one tooth is removed, and the more recent phase III burials showing only one incisor avulsed and a right side bias for removal. Frequencies in the practice also changed over time, with avulsions being much more common in the older phase II burials. Historical evidence suggests that any particular regional or social group would have its own particular pattern of tooth avulsion, so these changes in tooth avulsions at Roonka suggest that the site was either used by multiple groups of people for burials, or that there was significant cultural change during the occupation of the site.

Color and side preferences in Palestine sunbirds (Nectarinia osea)

Floral color is an important cue that converged in many ornithophilous flowers and can be used by nectarivorous birds to make foraging decisions. Wild ornithophilous flowers are frequently red, although they are more often yellow in Israel. The Palestine sunbird (Nectarinia osea) is the only nectarivorous bird in Israel and surrounding Mediterranean areas. Given the prevalence of yellow flowers in their habitats (along with sunbirds' expected sensitivity increase in this region of color vision), we predicted that Palestine sunbirds prefer yellow food sources over red. We examined sunbird foraging behavior when they were presented simultaneously with a yellow and red feeder, each containing the same quantity and quality of food. We investigated whether sunbirds had a side bias in the color preference experiment, but also in a separate experiment where both feeders were white. Sunbirds did not exhibit a significant color bias, while they did have a significant preference for a particular side of the cage. Location appears to be a more important cue than color to Palestine sunbirds, likely because location can offer information on the most rewarding plants and recently depleted flowers. However, color may still provide useful information that could influence foraging decisions in different contexts.

Exploring the Emergence of Side Biases and Familiarity–Novelty Preferences from the Real‐Time Dynamics of Infant Looking

This study examined how look dynamics contribute to infants’ emerging novelty preferences. Time‐series analyses were used to study the temporal nature of looking displayed by 3‐ to 5‐month‐old infants during a serial paired‐comparison task. Evidence was found only for short‐term stability: Novelty preferences and side biases were not stable from one visit to the next, but looking was consistent from one moment to the next producing stability within trials and temporarily across trials leading to the formation of behavioral runs. Persistence in looking left or right across multiple trials did not change from one visit to the next, but persistence in looking at familiar stimuli declined with age. By Visit 3, familiarity runs occurred less often than did novelty runs. Frequent but highly variable runs, including surprisingly late familiarity preferences, suggest that overall side biases and novelty preferences found during visual preference tasks are emergent phenomena affected by moment‐to‐moment changes in looking.

Initial investigations into preschoolers’ mirror-style versus transposed bodily imitation.

In typical development, imitation plays a key role in sociocognitive competence. The current study investigated a hypothesised developmental trajectory in face-to-face full body imitation style in 91 preschoolers, as well as a relation between imitation style and theory of mind (ToM). Children's response style to 8 lateralized action prompts was recorded as either "mirror" or "transposed." Overall, mirror-style response increased with age, and was predominant for children and an adult comparison group. Imitation style varied depending on the prompt given, with certain actions showing a side bias regardless of prompt viewed. Mirror-style response was correlated with ToM performance after controlling for language ability, but not after controlling for age. Findings are discussed regarding the hypothesised relation between postural synchrony and larger perspective-taking competence.

Right Side Bias in Aesthetic Arrangement in Viewing Pictures

Right Side Bias in Aesthetic Arrangement in Viewing Pictures

Behavioural Lateralization in Budgerigars Varies with the Task and the Individual

Handedness/footedness and side biases are a well-known phenomenon in many animals, including humans. However, these so-called biases have mostly been studied at the population level - individual biases have received less attention, especially with regard to consistency over different tasks. Here we investigate behavioral lateralization in 12 male Budgerigars, Melopsittacus undulatus, a social parrot inhabiting the Australian bushlands. We performed 5 types of experiments to investigate lateralization, in tasks that involved climbing onto a perch, or landing on perches arranged in various configurations. The birds displayed highly significant, individually varying biases. The bias displayed by any particular individual varied with the task, in strength as well as polarity. Analysis of the data revealed that the preferred foot used for climbing did not coincide with the foot that was used while landing. Thus, landing choices are probably not determined by foot bias. Furthermore, these individual preferences were overridden completely when a bird had to perform a task simultaneously with another bird.

Lateralization of agonistic and vigilance responses in Przewalski horses (Equus przewalskii)

Eye and limb preferences were scored in the closest undomesticated relative of Equus caballus using the same methods as used previously to study laterality in feral horses. Observations were made of 33 Przewalski horses (Equus ferus przewalskii) (male N=20, female N=13) living under natural social conditions on a large reserve in France. Significant left-eye/side biases were found in agonistic interactions within harem bands (M±SE bias to left 58%±0.01 for threats, P<0.001; 68%±0.05 for attacks; P<0.001) and in stallion fights (threats, 52%±0.01 left, P<0.001; attacks, 63%±0.02 left, P<0.001): as many as 80% of the horses were significantly lateralized in attack responses within harem bands. Laterality of vigilance was measured as lifting up the head from grazing and turning it to the left or right side: a directional bias to the left was found (M±SE 53%±0.02 left, P<0.001). Side bias in reactivity was calculated as the percent of head lifts above the level of the withers on the left or right side and this was also left side biased (M±SE 73%±0.03 left, P<0.001). These results indicate right-hemisphere specialization for control of aggression and responses to novelty. The left bias in attack scores within harem bands was stronger in males than females (P=0.024) and in immature than adult horses (P=0.032). Immature horses were also more strongly lateralized than adults in vigilance scores (P=0.022), which may suggest that experience reduces these side biases. Our results show that Przewalski horses exhibit left eye preferences, as do feral horses, and do so even more strongly than feral horses. Considering feral and Przewalski horses together, we deduce that ancestral horses had similar lateral biases. Also similar to feral horses, the Przewalski horses showed no significant forelimb preference at the group level or in the majority of horses at the individual level, confirming the hypothesis that previously reported limb preferences in domestic breeds are entrained or generated by breed-specific selection.

Laterality Influences Schooling Position in Rainbowfish, Melanotaenia spp

Cerebral lateralization is a widespread trait among animals, is often manifested as side biases in behaviour (laterality) and has been suggested to provide fitness benefits. Here we examined the influence of laterality on the organisation of fish schools using rainbowfish (Melanotaenia spp) as model species. The pattern and strength of laterality for each individual was determined by examining eye preferences whilst examining their reflection in a mirror. Schools of four fish of known laterality were then created and the preferred position for each fish within the school was repeatedly observed in a flume. Fish which showed right eye preferences in the mirror test preferentially adopted a position on the left side of the school. Conversely, fish that showed left eye preferences in the mirror test or where non-lateralised preferentially adopted a position slightly to the right side of the school. However, this general pattern varied depending on the species and sex of the school. Our results strongly implicate individual laterality in the geometry of school formation.

Lateralization of spatial relationships between wild mother and infant orcas, Orcinus orca

Cooperative interactions have been argued to be a powerful factor mediating the evolution of lateralization in animals. Mother−infant asymmetric spatial relationships represent a case of social coordination among organisms. Although lateralized interactions between mothers and infants have been found in beluga whales, Delphinapterus leucas, whether this is the case in other cetaceans remains unknown. In the current study, we investigated mother–infant spatial laterality, more specifically, the lateral biases in an infant's position near its mother in wild orcas, Orcinus orca. Distances between the research boat and whales were categorized into three groups to test the influence of a potential threat on laterality expression. Observations on travelling individually identified mother–infant pairs showed group-level preference for the infant to be on the mother's right side when far from the boat. This bias reversed at close distance. At an intermediate distance, no significant side bias was found; however, when we considered only cases of apparent mother−calf pair avoidance of the boat for analysis, the left-sided bias was again observed. In contrast, when infants were socializing near mothers or when they followed older calves, the infants preferred the right side. We argue that these preferences are associated with right-hemispheric advantage in social responses, while the shift from right-sided to left-sided bias in potentially threatening situations is caused by role reversal between mother and infant in determining their relative position in the dyad. Cetaceans seem to share with primates the pronounced lateralization of parent−offspring relationships.

Conditioned place preference or aversion as animal welfare assessment tools: Limitations in their application

Conditioned place preference (CPP) or aversion (CPA) methods are potentially useful tools in animal welfare assessment because they permit measurement of the reinforcing properties of a stimulus in the absence of the stimulus itself. We used CPP/CPA techniques in a series of experiments to assess the preference of food restricted broiler breeders for increased food quantities or avoidance of aversive stimuli. In all experiments, 6–10 week old Ross308 pairs of broiler breeders were housed in pens divided in half. Pen sides were visually differentiated and birds were trained with different stimuli on each pen side, correcting for possible side biases, either different food amounts for CPP or aversive stimuli on one pen side and none, or ‘neutral’, on the other, for CPA. To test if a preference for a pen side had been formed, the pen divider was removed when no stimulus was present and the amount of time birds spent on each pen side was recorded. Each experiment had a factorial treatment structure (n=10 replicate pens per treatment combination) and the proportions of time spent by birds on the ‘positive’ pen side (i.e. increased food amount for CPP or ‘neutral’ for CPA) were analysed. In experiment 1 on CPP (180 birds forming 90 pairs), three different training regimes in combination with three different testing methods were trialled: whilst during training of all birds, on one pen side the birds received the commercially recommended, restricted amount of food (R) and on the other pen side they received twice that amount (2R) (no food was present during testing). In experiment 2 (110 birds forming 40 pairs and 10 individually housed) and 3 (80 birds forming 40 pairs), further refinements were made to the experimental methods and birds were allocated to CPP treatments with food amounts 2R or 3R (vs. R) or to CPA treatments, ‘social isolation’ or ‘unpredictable wind’. Overall, there was no evidence of aversion at testing to the pen sides with aversive stimuli during training and little evidence of preference at testing for the pen sides with increased food amounts during training. Furthermore, where statistical significance was achieved for CPP the preferences shown were very small. The most consistent result was a strong preference for the pen side birds were not previously housed on immediately before each test (P<0.001 in all experiments). It appeared that birds were motivated to explore a location where they had not just been housed in an attempt to find food and this motivation seemed to overshadow other effects. This series of experiments demonstrates some limitations of CPP/CPA techniques for welfare assessment and the learning problems experienced by chronically food restricted animals.

JUDGING BIAS IN COMPETITIVE ACADEMIC DEBATE: THE EFFECTS OF REGION, SIDE, AND SEX

Debate is a “mind sport” that requires fair and impartial judging. This study examines debate rounds at the Tournament of Champions from 2004 to 2009. We use a binomial choice model to estimate the marginal effects of regional bias, sex bias, and side bias, using transitive predictions to control for idiosyncratic quality. We find evidence of region and side bias but not sex bias. These factors may explain the significant number of nontransitive outcomes in the data. Finally, we suggest some policy remedies to mitigate the impact of biases and further applications of our methodology. (JEL C25, J16, J52, J71, L83)

Increased behavioural lateralization in parasitized coral reef fish

Preferential use of one side of the body for cognitive or behavioural tasks (lateralization) is common in many animals, including humans. However, few studies have demonstrated whether lateralization is phenotypically plastic, and varies depending on the ecological context. We studied lateralization (measured as a turning preference) in the bridled monocle bream (Scolopsis bilineatus). This coral reef fish is commonly infected by a large, ectoparasitic isopod (Anilocra nemipteri) that attaches to the left or right side of its host’s head. Fish that were parasitized showed no turning bias with respect to the side on which the parasite had attached. On average, however, parasitised fish were significantly more lateralized (i.e. had a strong side bias) than unparasitized fish. The extent of lateralization declined significantly when we experimentally removed the parasite. Our results indicate that lateralization can vary with the ecological context. One possible explanation is that lateralization shortens the response time until fish flee after encountering a predator. A stronger side bias might be advantageous for parasitized individuals to overcome their recently documented lower maximum swimming speed.

Primate laterality and the biology and evolution of human handedness: a review and synthesis

We review evidence for and against lateralization of manual control, communication, visual processing, and auditory processing in nonhuman primates. Compared to humans and some other vertebrate species, manual specialization in nonhuman primates is relatively weak. A right-bias in chimpanzees may exist, but is so weak that many studies using simple tasks fail to reveal it. Slightly stronger biases may exist in baboons and chimpanzees for communicative signals in the manual and facial domains. Several studies have found robust visual side biases that depend on the object being viewed, in primates including chimpanzees. Evidence for lateralization of auditory processing remains inconclusive. We conclude that the robust, species-wide lateralization that exists in humans is unusual, and perhaps unique among primates, and discuss several possible evolutionary explanations for this strong asymmetry. In particular, we consider the hypothesis that preexisting hemispheric asymmetry for perception and language processing drove the evolution of human handedness.

Social learning drives handedness in nectar-robbing bumblebees

Bumblebees have been found to observe and copy the behaviour of others with regard to floral choices, particularly when investigating novel flower types. They can also learn to make nectar-robbing holes in flowers as a result of encountering them. Here, we investigate handedness in nectar-robbing bumblebees feeding on Rhinanthus minor, a flower that can be robbed from either the right-hand side or the left-hand side. We studied numerous patches of R. minor spread across an alpine landscape; each patch tended to be robbed on either the right or the left. The intensity of side bias increased through the season and was strongest in the most heavily robbed patches. We suggest that bees within patches learn robbing strategies (including handedness) from one another, either by direct observation or from experience with the location of holes, leading to rapid frequency-dependent selection for a common strategy. Primary robbing was predominantly carried out not only by a specialist robbing species, Bombus wurflenii, but also by Bombus lucorum, a widespread generalist. Both species adopted the same handedness within particular flower patches, providing the first evidence for social learning crossing the species boundary in wild insects.

Frequency of intron loss correlates with processed pseudogene abundance: a novel strategy to test the reverse transcriptase model of intron loss

BackgroundAlthough intron loss in evolution has been described, the mechanism involved is still unclear. Three models have been proposed, the reverse transcriptase (RT) model, genomic deletion model and double-strand-break repair model. The RT model, also termed mRNA-mediated intron loss, suggests that cDNA molecules reverse transcribed from spliced mRNA recombine with genomic DNA causing intron loss. Many studies have attempted to test this model based on its predictions, such as simultaneous loss of adjacent introns, 3'-side bias of intron loss, and germline expression of intron-lost genes. Evidence either supporting or opposing the model has been reported. The mechanism of intron loss proposed in the RT model shares the process of reverse transcription with the formation of processed pseudogenes. If the RT model is correct, genes that have produced more processed pseudogenes are more likely to undergo intron loss.ResultsIn the present study, we observed that the frequency of intron loss is correlated with processed pseudogene abundance by analyzing a new dataset of intron loss obtained in mice and rats. Furthermore, we found that mRNA molecules of intron-lost genes are mostly translated on free cytoplasmic ribosomes, a feature shared by mRNA molecules of the parental genes of processed pseudogenes and long interspersed elements. This feature is likely convenient for intron-lost gene mRNA molecules to be reverse transcribed. Analyses of adjacent intron loss, 3'-side bias of intron loss, and germline expression of intron-lost genes also support the RT model.ConclusionsCompared with previous evidence, the correlation between the abundance of processed pseudogenes and intron loss frequency more directly supports the RT model of intron loss. Exploring such a correlation is a new strategy to test the RT model in organisms with abundant processed pseudogenes.

Self-Portraits: Smartphones Reveal a Side Bias in Non-Artists

According to surveys of art books and exhibitions, artists prefer poses showing the left side of the face when composing a portrait and the right side when composing a self-portrait. However, it is presently not known whether similar biases can be observed in individuals that lack formal artistic training. We collected self-portraits by naïve photographers who used the iPhone™ front camera, and confirmed a right side bias in this non-artist sample and even when biomechanical constraints would have favored the opposite. This result undermines explanations based on posing conventions due to artistic training or biomechanical factors, and is consistent with the hypothesis that side biases in portraiture and self-portraiture are caused by biologically- determined asymmetries in facial expressiveness.

Intercellular calcium signaling in a gap junction-coupled cell network establishes asymmetric neuronal fates in C. elegans

The C. elegans left and right AWC olfactory neurons specify asymmetric subtypes, one default AWC(OFF) and one induced AWC(ON), through a stochastic, coordinated cell signaling event. Intercellular communication between AWCs and non-AWC neurons via a NSY-5 gap junction network coordinates AWC asymmetry. However, the nature of intercellular signaling across the network and how individual non-AWC cells in the network influence AWC asymmetry is not known. Here, we demonstrate that intercellular calcium signaling through the NSY-5 gap junction neural network coordinates a precise 1AWC(ON)/1AWC(OFF) decision. We show that NSY-5 gap junctions in C. elegans cells mediate small molecule passage. We expressed vertebrate calcium-buffer proteins in groups of cells in the network to reduce intracellular calcium levels, thereby disrupting intercellular communication. We find that calcium in non-AWC cells of the network promotes the AWC(ON) fate, in contrast to the autonomous role of calcium in AWCs to promote the AWC(OFF) fate. In addition, calcium in specific non-AWCs promotes AWC(ON) side biases through NSY-5 gap junctions. Our results suggest a novel model in which calcium has dual roles within the NSY-5 network: autonomously promoting AWC(OFF) and non-autonomously promoting AWC(ON).