Weak Biases Research Articles

Validation of an mHealth System for Monitoring Fundamental Physiological Parameters in the Clinical Setting.

The aim of this work was to validate the measurements of three physiological parameters, namely, body temperature, heart rate, and peripheral oxygen saturation, captured with an out-of-the-lab device using measurements taken with clinically proven devices. The out-of-the-lab specialized device was integrated into a customized mHealth application, e-CoVig, developed within the AIM Health project. To perform the analysis, single consecutive measurements of the three vital parameters obtained with e-CoVig and with the standard devices from patients in an intensive care unit were collected, preprocessed, and then analyzed through classical agreement analysis, where we used Lin's concordance coefficient to assess the agreement correlation and Bland-Altman plots with exact confidence intervals for the limits of agreement to analyze the paired data readings. The existence of possible systematic errors was also addressed, where we found the presence of additive errors, which were corrected, and weak proportional biases. We obtained the mean overall agreement between the measurements taken with the novel e-CoVig device and the reference devices for the measured quantities. Although some limitations in this study were encountered, we present more advanced methods for their further assessment.

Impact of point spread function higher moments error on weak gravitational lensing – II. A comprehensive study

ABSTRACT Weak lensing is one of the most powerful probes for dark matter and dark energy science, although it faces increasing challenges in controlling systematic uncertainties as the statistical errors become smaller. The point spread function (PSF) needs to be precisely modeled to avoid systematic error on the weak lensing measurements. The weak lensing biases induced by errors in the PSF model second moments, i.e. its size and shape, are well-studied. However, Zhang et al. showed that errors in the higher moments of the PSF may also be a significant source of systematics for upcoming weak lensing surveys. Therefore, this work comprehensively investigate the modelling quality of PSF moments from the 3rd to 6th order, and propagate the PSFEx higher moments modelling error in the HSC survey data set to the weak lensing shear–shear correlation functions and their cosmological analyses. The overall multiplicative shear bias associated with errors in PSF higher moments can cause an ∼0.1σ shift on the cosmological parameters for LSST Y10, while the associated additive biases can induce 1σ uncertainties in cosmology parameter inference for LSST Y10, if not accounted. We compare the PSFEx model with PSF in Full FOV, and find similar performance in modelling the PSF higher moments. We conclude that PSF higher moment errors of the future PSF models should be reduced from those in current methods, otherwise needed to be explicitly modeled in the weak lensing analysis.

A Cognitive Bias for Zipfian Distributions? Uniform Distributions Become More Skewed via Cultural Transmission

Abstract There is growing evidence that cognitive biases play a role in shaping language structure. Here, we ask whether such biases could contribute to the propensity of Zipfian word-frequency distributions in language, one of the striking commonalities between languages. Recent theoretical accounts and experimental findings suggest that such distributions provide a facilitative environment for word learning and segmentation. However, it remains unclear whether the advantage found in the laboratory reflects prior linguistic experience with such distributions or a cognitive preference for them. To explore this, we used an iterated learning paradigm—which can be used to reveal weak individual biases that are amplified overtime—to see if learners change a uniform input distribution to make it more skewed via cultural transmission. In the first study, we show that speakers are biased to produce skewed word distributions in telling a novel story. In the second study, we ask if this bias leads to a shift from uniform distributions towards more skewed ones using an iterated learning design. We exposed the first learner to a story where six nonce words appeared equally often, and asked them to re-tell it. Their output served as input for the next learner, and so on for a chain of ten learners (or ‘generations’). Over time, word distributions became more skewed (as measured by lower levels of word entropy). The third study asked if the shift will be less pronounced when lexical access was made easier (by reminding participants of the novel word forms), but this did not have a significant effect on entropy reduction. These findings are consistent with a cognitive bias for skewed distributions that gets amplified over time and support the role of entropy minimization in the emergence of Zipfian distributions.

Skeletal and soft tissue completeness of the acanthodian fossil record

AbstractAcanthodians are a poorly understood paraphyletic grade of extinct Palaeozoic fishes. They play an increasingly prominent role in our understanding of vertebrate evolution as part of the chondrichthyan stem‐group even though their evolutionary history is scarce. The limited preservation of their mostly cartilaginous skeleton largely results in a bias towards isolated remains such as fin spines and scales. Here, we quantify the quality of the acanthodian fossil record by using a variation of the Skeletal Completeness Metric (SCM), an approach that calculates how complete the skeletons of individuals are compared to their theoretical complete skeleton. A novel Soft Tissue Completeness Metric (STCM) is introduced to estimate the percentage of soft body tissue preserved as an alternate measurement of completeness. Completeness scores for >1600 specimens comprising >300 taxa obtained from museum collection visits and literature surveys were assembled into a database. Acanthodian completeness peaks in the Lower–Middle Devonian, Pennsylvanian, and earliest Permian. There is no correlation between acanthodian taxonomic richness and completeness. Acanthodians show a significantly lower completeness distribution than many tetrapod groups, but a similarly low distribution to bats. Skeletons deposited in freshwater are significantly more complete than in marine environments where sea level significantly negatively correlates with observed completeness. Our assessment reveals only weak spatial biases influencing the acanthodian fossil record while environmental biases are much higher. This quantified evaluation of acanthodians provides a foundation for further assessments of the likely influence of character absences from morphological datasets on estimates of early chondrichthyan and, therefore, early gnathostome evolution.

Enrolment in clinical research at UCLH and geographically distributed indices of deprivation

Healthcare should be judged by its equity as well as its quality. Both aspects depend not only on the characteristics of service delivery but also on the research and innovation that ultimately shape them. Conducting a fully-inclusive evaluation of the relationship between enrolment in primary research studies at University College London Hospitals NHS Trust and indices of deprivation, here we demonstrate a quantitative approach to evaluating equity in healthcare research and innovation. We surveyed the geographical locations, aggregated into Lower Layer Super Output Areas (LSOAs), of all England-resident UCLH patients registered as enrolled in primary clinical research studies. We compared the distributions of ten established indices of deprivation across enrolled and non-enrolled areas within Greater London and within a distance-matched subset across England. Bayesian Poisson regression models were used to examine the relation between deprivation and the volume of enrolment standardized by population density and local disease prevalence. A total of 54593 enrolments covered 4401 LSOAs in Greater London and 10150 in England, revealing wide geographical reach. The distributions of deprivation indices were similar between enrolled and non-enrolled areas, exhibiting median differences from 0.26% to 8.73%. Across Greater London, enrolled areas were significantly more deprived on most indices, including the Index of Multiple Deprivation; across England, a more balanced relationship to deprivation emerged. Regression analyses of enrolment volumes yielded weak biases, in favour of greater deprivation for most indices, with little modulation by local disease prevalence. Primary clinical research at UCLH has wide geographical reach. Areas with enrolled patients show similar distributions of established indices of deprivation to those without, both within Greater London, and across distance-matched areas of England. We illustrate a robust approach to quantifying an important aspect of equity in clinical research and provide a flexible set of tools for replicating it across other institutions.

Propagating residual biases in masked cosmic shear power spectra

In this paper we derive a full expression for the propagation of weak lensing shape measurement biases into cosmic shear power spectra including the effect of missing data. We show using simulations that terms higher than first order in bias parameters can be ignored and the impact of biases can be captured by terms dependent only on the mean of the multiplicative bias field. We identify that the B-mode power contains information on the multiplicative bias. We find that without priors on the residual multiplicative bias $\delta m$ and stochastic ellipticity variance $\sigma_e$ that constraints on the amplitude of the cosmic shear power spectrum are completely degenerate, and that when applying priors the constrained amplitude $A$ is slightly biased low via a classic marginalisation paradox. Using all-sky Gaussian random field simulations we find that the combination of $(1+2\delta m)A$ is unbiased for a joint EE and BB power spectrum likelihood if the error and mean (precision and accuracy) of the stochastic ellipticity variance is known to better than $\sigma(\sigma_e)\leq 0.05$ and $\Delta\sigma_e\leq 0.01$, or the multiplicative bias is known to better than $\sigma(m)\leq 0.07$ and $\Delta m\leq 0.01$.

Low frequency electrochemical noise in AlGaN/GaN field effect transistor biosensors

Little has been studied on how the electrochemical noise impacts the limit of detection of field effect transistor (FET) biosensors. Herein, we investigate low frequency noise associated with phosphate-buffered saline (PBS) solutions at varying ionic strengths (Ni) under both weak and strong gate biases corresponding to saturation and sub-threshold regimes, respectively, in AlGaN/GaN heterojunction FET biosensors. We show that the electrochemical noise is strongly dependent on the ionic strength and gate biasing conditions. In the saturation regime (low bias), varying the ionic strength (a range of 10−6× PBS to PBS 1 × stock solutions used for testing) has little to no effect on the characteristic frequency exponent β(β=1), indicating a predominately diffusion-based process. Conversely, under higher biases (sub-threshold regime), the β parameter varies from 1 to 2 with ionic strength exhibiting both diffusion and drift characteristics, with a “cut point” at approximately 10−5× PBS (Ni≈9×1014/mL). Under a high bias, once the PBS concentration reaches 10−3×, the behavior is then drift dominant. This indicates that the higher bias likely triggers electrochemical reactions and by extension, faradaic effects at most physiologically relevant ionic strengths. The signal-to-noise ratio (SNR) of the device has an inverse linear relationship with the low frequency current noise. The device exhibits a higher SNR in the sub-threshold regime than in the saturation regime. Specifically, within the saturation regime, an inversely proportional relationship between the SNR and the ionic concentration is observed. The electrochemical noise induced from ionic activities is roughly proportional to Ni−1/2.

Media bias against women in music: an empirical analysis of Italian music magazines

The music industry presents a strong gender disparity in all genres and roles (composers, musicians, conductors). The reasons for the disparity discussed in the socio-economic literature regard genetic diversity, socio-cultural differences, and gender discrimination. Discrimination can be aggravated by the negative attitude of the mass media towards the women involved in the music industry. This paper explores the potential media bias in 2022 reviews of pop-rock and jazz albums released internationally between 2003 and 2015, published in two major Italian music magazines. The empirical analysis shows that the reviews of “female” albums consist of fewer words than the “male” albums, but the difference is significant only for a magazine. Within each magazine, the data also reveal two weak qualitative biases (though not significant): the reviews are more positive if no woman appears among the artists and, if the reviewer is a woman, the attitude towards the albums by female artists is, on average, worse.

Attentional bias for alcohol cues in visual search—Increased engagement, difficulty to disengage or both?

Cognitive models emphasise the importance of attentional bias in addiction. However, many attentional bias tasks have been criticised for questionable psychometric properties and inability to differentiate between engagement and disengagement processes. This study therefore examined the suitability of two alternative tasks for assessing attentional bias within the context of alcohol use. Participants were undergraduate students (N = 169) who completed the Visual Search Task and Odd-One-Out Task, the latter of which is designed to differentiate between engagement and disengagement processes of attention, at baseline and one week later. Participants also completed baseline measures of alcohol consumption, craving, and alcohol use problems. Internal consistency was adequate for the Visual Search Task index, and weak for the Odd-One-Out Task indices. Test-retest reliability was weak for both tasks. The Visual Search Task index and the disengagement (but not the engagement) index of the Odd-One-Out Task showed a positive association with alcohol consumption. This study was restricted to a non-clinical student sample. The relatively high error rate of the Odd-One-Out Task might have reduced its sensitivity as an index of attentional bias. Both tasks showed some merit as attentional bias measures, and results suggested that attentional disengagement might be particularly related to alcohol use. However, the reliability of the current measures was inadequate. One potential explanation for the low reliability is that non-clinical samples may have weak and unstable attentional biases to alcohol. Future efforts should be made to improve the psychometric qualities of both tasks and to administer them in a clinical sample.

An Investigation of Large Along-Track Errors in Extratropical Transitioning North Atlantic Tropical Cyclones in the ECMWF Ensemble

Abstract The synoptic evolution and mechanisms for the largest medium-range (72–120 h) along-track errors of tropical cyclones (TC) are investigated. The mean along-track errors (ATEs) of the 51-member European Centre for Medium-Range Weather Forecasts (ECMWF) ensemble are evaluated for 393 forecasts (85 TCs) during the 2008 to 2016 North Atlantic seasons. The 27 unique forecasts within the upper quintile of most negative ATEs (i.e., slow bias greater than 500 km by 72 h) are inherently fast-moving TCs that undergo extratropical transition as they recurve and interact with a 300-hPa upstream trough and a downstream ridge. Both the trough and ridge are underamplified by only 5–10 m ~60 h before the time of largest ATE. The height errors then grow rapidly due to underpredicted 300–200-hPa potential vorticity advection by both the nondivergent wind and the irrotational wind from the TC’s outflow. Both wind components are underpredicted and result in weak biases in the trough’s developing potential vorticity gradient and associated jet streak. The underamplification of the upstream trough is exacerbated by underpredicted 700-hPa cold advection extending from beneath the trough into the TC at 48–36 h before the largest ATE. Standardized differences are consistent with the mean errors and reveal that weaker divergent outflow is driven by underpredicted near-TC precipitation, which corresponds to underpredicted 700-hPa moisture fluxes near the TC at ~108 h before the largest ATE. The ensemble member ATEs at 72–120 h generally show little correlation with their ATEs before 36 h, suggesting that initial position uncertainty is not the primary source of ATE variability later in the forecast.

Ensemble data assimilation and prediction of typhoon and associated hazards using TEDAPS: evaluation for 2015–2018 seasons

The initial condition accuracy is a major concern for tropical cyclone (TC) numerical forecast. The ensemble-based data assimilation techniques have shown great promise to initialize TC forecast. In addition to initial condition uncertainty, representing model errors (e.g. physics deficiencies) is another important issue in an ensemble forecasting system. To improve TC prediction from both deterministic and probabilistic standpoints, a Typhoon Ensemble Data Assimilation and Prediction System (TEDAPS) using an ensemble-based data assimilation scheme and a multi-physics approach based on Weather Research and Forecasting (WRF) model, has been developed in Shanghai Typhoon Institute and running realtime since 2015. Performance of TEDAPS in the prediction of track, intensity and associated disaster has been evaluated for the Western North Pacific TCs in the years of 2015–2018, and compared against the NCEP GEFS. TEDAPS produces markedly better intensity forecast by effectively reducing the weak biases and therefore the degree of underdispersion compared to GEFS. The errors of TEDAPS track forecasts are comparative with (slightly worse than) those of GEFS at longer (shorter) forecast leads. TEDAPS ensemble-mean exhibits advantage over deterministic forecast in track forecasts at long lead times, whereas this superiority is limited to typhoon or weaker TCs in intensity forecasts due to systematical underestimation. Four case-studies for three landfalling cyclones and one recurving cyclone demonstrate the capacities of TEDAPS in predicting some challenging TCs, as well as in capturing the forecast uncertainty and the potential threat from TC-associated hazards.

Weak biases emerging from vocal tract anatomy shape the repeated transmission of vowels.

Linguistic diversity is affected by multiple factors, but it is usually assumed that variation in the anatomy of our speech organs plays no explanatory role. Here we use realistic computer models of the human speech organs to test whether inter-individual and inter-group variation in the shape of the hard palate (the bony roof of the mouth) affects acoustics of speech sounds. Based on 107 midsagittal MRI scans of the hard palate of human participants, we modelled with high accuracy the articulation of a set of five cross-linguistically representative vowels by agents learning to produce speech sounds. We found that different hard palate shapes result in subtle differences in the acoustics and articulatory strategies of the produced vowels, and that these individual-level speech idiosyncrasies are amplified by the repeated transmission of language across generations. Therefore, we suggest that, besides culture and environment, quantitative biological variation can be amplified, also influencing language.

Skeletal completeness of the non‐avian theropod dinosaur fossil record

AbstractNon‐avian theropods were a highly successful clade of bipedal, predominantly carnivorous, dinosaurs. Their diversity and macroevolutionary patterns have been the subject of many studies. Changes in fossil specimen completeness through time and space can bias our understanding of macroevolution. Here, we quantify the completeness of 455 non‐avian theropod species using the skeletal completeness metric (SCM), which calculates the proportion of a complete skeleton preserved for a specimen. Temporal patterns of theropod skeletal completeness show peaks in the Carnian, Oxfordian–Kimmeridgian and Barremian–Aptian, and lows in the Berriasian and Hauterivian. Lagerstätten primarily drive the peaks in completeness and observed taxonomic diversity in the Oxfordian–Kimmeridgian and the Barremian–Aptian. Theropods have a significantly lower distribution of completeness scores than contemporary sauropodomorph dinosaurs but change in completeness through time for the two groups shows a significant correlation when conservation Lagerstätten are excluded, possibly indicating that both records are primarily driven by geology and sampling availability. Our results reveal relatively weak temporal sampling biases acting on the theropod record but relatively strong spatial and environmental biases. Asia has a significantly more complete record than any other continent, the mid northern latitudes have the highest abundance of finds, and most complete theropod skeletons come from lacustrine and aeolian environments. We suggest that these patterns result from historical research focus, modern climate dynamics, and depositional transportation energy plus association with conservation Lagerstätten, respectively. Furthermore, we find possible ecological biases acting on different theropod subgroups, but body size does not influence theropod completeness on a global scale.

Solar Irradiance Forecasts by Mesoscale Numerical Weather Prediction Models with Different Horizontal Resolutions

This study examines the performance of radiation processes (shortwave and longwave radiations) using numerical weather prediction models (NWPs). NWP were calculated using four different horizontal resolutions (5, 2 and 1 km, and 500 m). Validation results on solar irradiance simulations with a horizontal resolution of 500 m indicated positive biases for direct normal irradiance dominate for the period from 09 JST (Japan Standard Time) to 15 JST. On the other hand, after 15 JST, negative biases were found. For diffused irradiance, weak negative biases were found. Validation results on upward longwave radiation found systematic negative biases of surface temperature (corresponding to approximately −2 K for summer and approximately −1 K for winter). Downward longwave radiation tended to be weak negative biases during both summer and winter. Frequency of solar irradiance suggested that the frequency of rapid variations of solar irradiance (ramp rates) from the NWP were less than those observed. Generally, GHI distributions between the four different horizontal resolutions resembled each other, although horizontal resolutions also became finer.

Low survival of strongly footed pheasants may explain constraints on lateralization

Brain lateralization is considered adaptive because it leads to behavioral biases and specializations that bring fitness benefits. Across species, strongly lateralized individuals perform better in specific behaviors likely to improve survival. What constrains continued exaggerated lateralization? We measured survival of pheasants, finding that individuals with stronger bias in their footedness had shorter life expectancies compared to individuals with weak biases. Consequently, weak, or no footedness provided the highest fitness benefits. If, as suggested, footedness is indicative of more general brain lateralization, this could explain why continued brain lateralization is constrained even though it may improve performance in specific behaviors.

Systematicity, but not compositionality: Examining the emergence of linguistic structure in children and adults using iterated learning

Recent work suggests that cultural transmission can lead to the emergence of linguistic structure as speakers’ weak individual biases become amplified through iterated learning. However, to date no published study has demonstrated a similar emergence of linguistic structure in children. The lack of evidence from child learners constitutes a problematic gap in the literature: if such learning biases impact the emergence of linguistic structure, they should also be found in children, who are the primary learners in real-life language transmission. However, children may differ from adults in their biases given age-related differences in general cognitive skills. Moreover, adults’ performance on iterated learning tasks may reflect existing (and explicit) linguistic biases, partially undermining the generality of the results. Examining children’s performance can also help evaluate contrasting predictions about their role in emerging languages: do children play a larger or smaller role than adults in the creation of structure? Here, we report a series of four iterated artificial language learning studies (based on Kirby, Cornish & Smith, 2008) with both children and adults, using a novel child-friendly paradigm. Our results show that linguistic structure does not emerge more readily in children compared to adults, and that adults are overall better in both language learning and in creating linguistic structure. When languages could become underspecified (by allowing homonyms), children and adults were similar in developing consistent mappings between meanings and signals in the form of structured ambiguities. However, when homonimity was not allowed, only adults created compositional structure. This study is a first step in using iterated language learning paradigms to explore child-adult differences. It provides the first demonstration that cultural transmission has a different effect on the languages produced by children and adults: While children were able to develop systematicity, their languages did not show compositionality. We focus on the relation between learning and structure creation as a possible explanation for our findings and discuss implications for children’s role in the emergence of linguistic structure.

Weak lensing shear calibration with simulations of the HSC survey

We present results from a set of simulations designed to constrain the weak lensing shear calibration for the Hyper Suprime-Cam (HSC) survey. These simulations include HSC observing conditions and galaxy images from the Hubble Space Telescope (HST), with fully realistic galaxy morphologies and the impact of nearby galaxies included. We find that the inclusion of nearby galaxies in the images is critical to reproducing the observed distributions of galaxy sizes and magnitudes, due to the non-negligible fraction of unrecognized blends in ground-based data, even with the excellent typical seeing of the HSC survey (0.58" in the $i$-band). Using these simulations, we detect and remove the impact of selection biases due to the correlation of weights and the quantities used to define the sample (S/N and apparent size) with the lensing shear. We quantify and remove galaxy property-dependent multiplicative and additive shear biases that are intrinsic to our shear estimation method, including a $\sim 10$ per cent-level multiplicative bias due to the impact of nearby galaxies and unrecognized blends. Finally, we check the sensitivity of our shear calibration estimates to other cuts made on the simulated samples, and find that the changes in shear calibration are well within the requirements for HSC weak lensing analysis. Overall, the simulations suggest that the weak lensing multiplicative biases in the first-year HSC shear catalog are controlled at the 1 per cent level.

Modeling the Early Stages of Phase Separation in Disordered Elastin-like Proteins

Elastin-like proteins (ELPs) are known to undergo liquid-liquid phase separation reversibly above a concentration-dependent transition temperature. Previous studies suggested that, as temperature increases, ELPs experience an increased propensity for type II β-turns. However, how the ELPs behave below the phase transition temperature itself is still elusive. Here, we investigate the importance of β-turn formation during the early stages of ELP self-association. We examined the behavior of two ELPs, a 150-repeat construct that had been investigated previously (ELP[V5G3A2-150] as well as a new 40-repeat construct (ELP40) suitable for nuclear magnetic resonance measurements. Structural analysis of ELP40 reveals a disordered conformation, and chemical shifts throughout the sequence are insensitive to changes in temperature over 20°C. However, a low population of β-turn conformation cannot be ruled out based on chemical shifts alone. To examine the structural consequences of β-turns in ELPs, a series of structural ensembles of ELP[V5G3A2-150] were generated, incorporating differing amounts of β-turn bias throughout the chain. To mimic the early stages of the phase change, two monomers were paired, assuming preferential interaction at β-turn regions. This approach was justified by the observation that buried hydrophobic turns are commonly observed to interact in the Protein Data Bank. After dimerization, the ensemble-averaged hydrodynamic properties were calculated for each degree of β-turn bias, and the results were compared with analytical ultracentrifugation experiments at various temperatures. We find that the temperature dependence of the sedimentation coefficient (s20,wo) can be reproduced by increasing the β-turn content in the structural ensemble. This analysis allows us to estimate the presence of β-turns and weak associations under experimental conditions. Because disordered proteins frequently exhibit weak biases in secondary structure propensity, these experimentally-driven ensemble calculations may complement existing methods for modeling disordered proteins generally.

Chick cranial neural crest cells use progressive polarity refinement, not contact inhibition of locomotion, to guide their migration

To move directionally, cells can bias the generation of protrusions or select among randomly generated protrusions. Here we use 3D two-photon imaging of chick branchial arch 2 directed neural crest cells to probe how these mechanisms contribute to directed movement, whether a subset or the majority of cells polarize during movement, and how the different classes of protrusions relate to one another. We find that, in contrast to Xenopus, cells throughout the stream are morphologically polarized along the direction of overall stream movement and do not exhibit contact inhibition of locomotion. Instead chick neural crest cells display a progressive sharpening of the morphological polarity program. Neural crest cells have weak spatial biases in filopodia generation and lifetime. Local bursts of filopodial generation precede the generation of larger protrusions. These larger protrusions are more spatially biased than the filopodia, and the subset of protrusions that are productive for motility are the most polarized of all. Orientation rather than position is the best correlate of the protrusions that are selected for cell guidance. This progressive polarity refinement strategy may enable neural crest cells to efficiently explore their environment and migrate accurately in the face of noisy guidance cues.

The most stable adsorption geometries of two chiral modifiers on Pt(111)

The molecular description of chirality transfer on chirally modified metal surfaces is unclear due to the complexity of the systems and the weak energetic biases favoring specific enantioselective pathways. In order to move to an enhanced level of molecular understanding it is critical to define the chemisorption geometries of the modifiers responsible for enantiodifferentiation. Model surface science studies of chiral molecules on single crystals provide an indirect method to probe catalytic chirality transfer molecular mechanisms. Apart from the great difference between ultrahigh vacuum (UHV) and reaction conditions, the extent to which such studies can inform the interpretation of data obtained under reaction conditions depends on the degree to which the model systems are correctly defined. The same holds true for any comparison of UHV surface spectroscopy data to spectroscopic measurements made at the catalyst-solution interface under either in-situ or operando conditions.We present detailed reflection absorption infrared spectroscopy (RAIRS) data on (R)-1-(1-naphthyl)ethylamine, (R)-NEA, and its simple derivative, (R)-1-(8-methyl-1-naphthyl)ethylamine, on Pt(111). Various conflicting proposals for the structure of NEA and analogous modifiers on Pt catalyst particles and extended Pt surfaces are found in the literature. Here, we find that below high sub-monolayer coverages on Pt(111), (R)-NEA adopts a chemisorption geometry where the entire naphthyl group is π-bonded to the surface and the amine group forms a dative bond to the surface. The same general adsorption geometry is found for the methyl-substituted derivative. The study provides reference spectra for these chiral modifiers and confirms the molecular structures described in our previous studies of diastereomeric complexes formed by the (R)-NEA/Pt(111) system.