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Purpose: This study explores whether nativity differences in health care and sociodemographic factors help to account for nativity differences in low birth weight (LBW) when comparing US-born Black women (USBW) to Black Immigrant women (BIW)., Methods: Bivariate analyses and multinomial nested logit (MNL) models were performed using the National Survey of Family Growth (NSFG) dataset., Results: Statistically significant nativity differences between USBW and BIW were found across variables of LBW (p = .009), marital status (p < .001), education level (p < .001), receiving public assistance (p < .001), health care coverage (p < .001), age (p < .001), and poverty level income (p < .001). Results from the MNL models indicated that BIW were 91% less likely to have a LBW baby (p < .001). When accounting for other sociodemographic and health care related variables differing by nativity, although a statistically significant, narrowing gap between BIW and USBW was observed (OR = .12, p < .001), BIW were still less likely to have a LBW baby., Conclusions: Differences between USBW and BIW across sociodemographic variables and health care related factors related to adverse pregnancy outcomes were observed in this study. Controlling for the factors attenuated nativity differences but did not eliminate the differences on LBW. Future research should continue to explore this relationship., (© 2022. W. Montague Cobb-NMA Health Institute.)

Previous studies on how people set and modify decision criteria in old-new recognition tasks (in which they have to decide whether or not a stimulus was seen in a study phase) have almost exclusively focused on properties of the study items, such as presentation frequency or study list length. In contrast, in the three studies reported here, we manipulated the quality of the test cues in a scene-recognition task, either by degrading through Gaussian blurring (Experiment 1) or by limiting presentation duration (Experiment 2 and 3). In Experiments 1 and 2, degradation of the test cue led to worse old-new discrimination. Most importantly, however, participants were more liberal in their responses to degraded cues (i.e., more likely to call the cue "old"), demonstrating strong within-list, item-by-item, criterion shifts. This liberal response bias toward degraded stimuli came at the cost of increasing the false alarm rate while maintaining a constant hit rate. Experiment 3 replicated Experiment 2 with additional stimulus types (words and faces) but did not provide accuracy feedback to participants. The criterion shifts in Experiment 3 were smaller in magnitude than Experiments 1 and 2 and varied in consistency across stimulus type, suggesting, in line with previous studies, that feedback is important for participants to shift their criteria.

Objective: Lack of physical activity participation has been identified as a determinant for negative health outcomes across various ethnicities worldwide and within the USA. We investigated the perceptions of the prospects of promoting dancing within hometown associations as a form for improving physical activity participation for Nigerian Transnational Immigrants (NTIs) in the USA: a migrant cohort subset of individuals who maintain cross-border ties with their indigenous communities of origin., Method: Using PEN-3 cultural model, we conducted semi-structured interviews with 24 transnational African migrants (11 males and 13 females) living in Chicago to explore culturally sensitive strategies to promote physical activity participation among our target population., Results: The findings revealed positive perceptions related to dancing that might help to promote physical activity (PA) among NTI, existential or unique perceptions related to Nigerian parties that may also play a role with PA promotion, and negative perception in the form of limited discussions about PA in Nigerian hometown associations in the USA., Conclusion: Results from this study highlight the need for further investigation on culturally sensitive strategies to improve physical activity and participation in diverse Black immigrant populations, specifically in the form of cultural dance and activities such as parties in which this population frequently participate in. Furthermore, hometown associations may also serve as a platform for the implementation of PA programs due to its large reach to a rather covert group.

The quasibinary section of the intermetallic phases MAl 4 and MGa 4 with M=Sr and Ba have been characterised by means of X-ray diffraction (XRD) studies and differential thermal analysis. The binary phases show complete miscibility and form solid solutions M(Al 1-x Ga x ) 4 with M=Sr and Ba. These structures crystallise in the BaAl 4 structure type with four- and five-bonded Al and/or Ga atoms (denoted as Al(4b), Al(5b), Ga(4b), and Ga(5b), respectively) that form a polyanionic Al/Ga sublattice. Solid state 27 Al NMR spectroscopic analysis and quantum mechanical (QM) calculations were applied to study the bonding of the Al centres and the influence of Al/Ga substitution, especially in the regimes with low degrees of substitution. M(Al 1-x Ga x ) 4 with M=Sr and Ba and 0.925≤x≤0.975 can be described as a matrix of the binary majority compound in which a low amount of the Ga atoms has been substituted by Al atoms. In good agreement with the QM calculations, 27 Al NMR investigations and single crystal XRD studies prove a preferred occupancy of Al(4b) for these substitution regimes. Furthermore, two different local Al environments were found, namely isolated Al(4b1) atoms and Al(4b2), due to the formation of Al(4b)-Al(4b) pairs besides isolated Al(4b) atoms within the polyanionic sublattice. QM calculations of the electric field gradient (EFG) using superlattice structures under periodic boundary conditions are in good agreement with the NMR spectroscopic results., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Objective: Dietary behaviors serve as determinants for chronic diseases such as hypertension across various ethnicities worldwide and within the USA. We investigated dietary perspectives specifically for US transnational African migrants, a migrant cohort subset of individuals who maintain cross-border ties with their indigenous communities of origin., Method: Using PEN-3 model, focus group interviews with 14 transnational African migrants (seven males and seven females) were conducted in Chicago to explore the perceptions of dietary behavior in regard to chronic disease risk factors among our target population., Results: The findings underscore that transnational African migrants maintain strong ties with their African community of origin, impacting dietary behaviors and attitudes. Further, transnational African migrants maintain traditional dishes through their connections. Despite the ability to import African traditional foods through personal connections, African migrants face a challenge in maintaining culture yet conforming to norms of acculturation., Conclusion: Results from this study serve to advocate for further exploration of the interaction between African migrant dietary behaviors and risk factors to chronic diseases.

This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of presentation probability on both proportion correct and response times. The effects were moderated by the ubiquitous stimulus position effect. The accuracy and response time data were predicted by an exemplar-based model of perceptual cognition (Kent & Lamberts, 2005). The bow in discriminability was also attenuated when presentation probability for middle items was relatively high, an effect that will constrain future model development. The study provides evidence for item-specific learning in absolute identification. Implications for other theories of absolute identification are discussed. (PsycINFO Database Record, ((c) 2016 APA, all rights reserved).)

We report the first complete characterization of metallycryptates encapsulating Ag(I) cations: carboxylato ligands derived from l-proline and l-alanine chelate and bridge six Cu(II) centres arranged in a slightly distorted octahedral fashion. Eight oxygen atoms of these ligands are disposed in square-prismatic geometry and coordinate the monovalent cation. Two alternative metallacryptates based on alanine have been identified which differ with respect to aggregation: a solid in which pairs of encapsulating sites are formed competes with an infinite chain of M(I) coordinating sites. In contrast, the individual encrypting moieties are arranged as overall neutral and isolated molecular species in the proline-based metallacryptate. This proline derivative can accomodate Ag(I) and Na(I) cations and form a solid solution. Susceptibility measurements confirm ferromagnetic interactions between the Cu(II) within the hexanuclear proline cryptate and thus underline the similarity between solids accommodating Na(I) and Ag(I). Spectroscopic results suggest that these metallacryptates hardly dissociate in methanol solution.

Complete miscibility of the intermetallic phases (IPs) SrGa2 and BaGa2 forming the solid solution Sr(1-x)Ba(x)Ga2 is shown by means of X-ray diffraction, thermoanalytical and metallographic studies. Regarding the distances of Sr/Ba sites versus substitution degree, a model of isolated substitution centres (ISC) for up to 10% cation substitution is explored to study the influence on the Ga bonding situation. A combined application of NMR spectroscopy and quantum mechanical (QM) calculations proves the electric field gradient (EFG) to be a sensitive measure of different bonding situations. The experimental resolution is boosted by orientation-dependent NMR on magnetically aligned powder samples, revealing in first approximation two different Ga species in the ISC regimes. EFG calculations using superlattice structures within periodic boundary conditions are in fair agreement with the NMR spectroscopy data and are discussed in detail regarding their application on disordered IPs., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Completing our reports concerning the reaction products from calcium halides and the amino acid proline, two different solids were found for the reaction of l- and dl-proline with CaI2. The enanti-opure amino acid yields the one-dimensional coordination polymer catena-poly[[aqua-μ3-l-proline-tetra-μ2-l-proline-dicalcium] tetra-iodide 1.7-hydrate], {[Ca2(C5H9NO2)5(H2O)]I4·1.7H2O} n , (1), with two independent Ca(2+) cations in characteristic seven- and eightfold coordination. Five symmetry-independent zwitterionic l-proline mol-ecules bridge the metal sites into a cationic polymer. Racemic proline forms with Ca(2+) cations heterochiral chains of the one-dimensional polymer catena-poly[[di-aquadi-μ2-dl-proline-calcium] diiodide], {[Ca(C5H9NO2)2(H2O)2]I2} n , (2). The centrosymmetric structure is built by one Ca(2+) cation that is bridged towards its symmetry equivalents by two zwitterionic proline mol-ecules. In both structures, the iodide ions remain non-coordinating and hydrogen bonds are formed between these counter-anions, the amino groups, coordinating and co-crystallized water mol-ecules. While the overall composition of (1) and (2) is in line with other structures from calcium halides and amino acids, the diversity of the carboxyl-ate coordination geometry is quite surprising.

In catena-poly[copper(II)-di-μ-chlorido-μ-proline-κ(2)O:O'], [CuCl2(C5H9NO2)]n, two symmetry-independent metal cations adopt distorted octahedral coordination, typical for d(9) Jahn-Teller systems. Each chloride bridge is involved in both a short and a very long interaction with a Cu(II) centre. The centrosymmetric crystal structure contains homochiral chains of opposite handedness which extend along the shortest lattice parameter (i.e. a). The O:O'-bridging coordination mode of proline, although a common motif for such complexes in general, is remarkable for Cu(II); the vast majority of amino acid derivatives of this cation are characterized by N,O-chelation.

Reactions of calcium bromide with enantiopure and racemic proline in aqueous solution lead to two solids in which the zwitterionic amino acid acts as a bridging ligand between neighbouring cations. Depending on the chirality of the amino acid, topologically very different products are obtained. With racemic proline, bromide acts as a simple uncoordinated counter-anion for the cationic heterochiral chains in catena-poly[[aquacalcium(II)]-μ-aqua-μ3-DL-proline-μ2-DL-proline], {[Ca(C5H9NO2)2(H2O)2]Br2}n. In agreement with chemical intuition, only carboxylate and aqua O atoms coordinate the alkaline earth cation in a low-symmetry arrangement. In contrast, L-proline affords the two-dimensional network poly[dibromidobis(μ2-L-proline)calcium(II)], [CaBr2(C5H9NO2)2]n, with an unexpected CaBr2 unit in a more regular coordination sphere.

Under accelerated and controlled evaporation, chain polymers crystallize from aqueous solutions of Ca(II) and Mn(II) halides with enantiopure L-alanine or racemic DL-alanine. In all ten solids thus obtained zwitterionic amino acid ligands bridge neighbouring cations. The exclusively O-donor-based coordination sphere around the metal cations is completed by aqua ligands; the halides remain uncoordinated and act as counter-anions for the cationic strands. Despite the differences in ionic radii and electronic structure between the main group and the transition metal cation, their derivatives with L-alanine share a common structure type. In contrast, the solids derived from DL-alanine differ and adopt structures depending on the metal cation and the halide. Homochiral chains of either chirality or heterochiral chains with different arrangements of crystallographic inversion centres along the polymer strands are encountered. On average, the six-coordinated Ca(II) cations, devoid of any ligand field effect, show more pronounced deviation from idealized octahedral geometry than the d-block cation Mn(II).

Alkali metal triphenylsilyls [Li(12-crown-4)SiPh3]·(thf)0.5 (2), [Na(15-crown-5)SiPh3]·(thf)0.5 (3) and [K(18-crown-6)SiPh3(thf)] (4) were synthesized using 1,1,1-trimethyl-2,2,2-triphenyldisilane (Ph3SiSiMe3) and isolated in high yields. Solid state structures were determined by single crystal X-ray diffraction. These alkali metal silyls catalyzed the regioselective hydrosilylation of 1,1-diphenylethylene to give the anti-Markovnikov product. The presence of crown ethers enhanced the reactivity of the metal silyls in hydrosilylation catalysis.

It is now well established that the time course of perceptual processing influences the first second or so of performance in a wide variety of cognitive tasks. Over the last 20 years, there has been a shift from modeling the speed at which a display is processed, to modeling the speed at which different features of the display are perceived and formalizing how this perceptual information is used in decision making. The first of these models (Lamberts, 1995) was implemented to fit the time course of performance in a speeded perceptual categorization task and assumed a simple stochastic accumulation of feature information. Subsequently, similar approaches have been used to model performance in a range of cognitive tasks including identification, absolute identification, perceptual matching, recognition, visual search, and word processing, again assuming a simple stochastic accumulation of feature information from both the stimulus and representations held in memory. These models are typically fit to data from signal-to-respond experiments whereby the effects of stimulus exposure duration on performance are examined, but response times (RTs) and RT distributions have also been modeled. In this article, we review this approach and explore the insights it has provided about the interplay between perceptual processing, memory retrieval, and decision making in a variety of tasks. In so doing, we highlight how such approaches can continue to usefully contribute to our understanding of cognition.

Introduction. Older African American women are particularly vulnerable to unhealthy lifestyle behaviors such as physical inactivity and the resultant chronic diseases and conditions. This study explored older African American women's perception of physical activity as well as facilitators of and barriers to being physically active in their local environment. Methods. Using a participatory research approach, a total of 7 women aged 65 years and over had their PA level assessed objectively through accelerometry. In addition, physical activity was discussed through the photo-elicitation procedure, which was supplemented by semistructured interviews. Qualitative thematic analysis was used to identify patterns and themes emerging from participants' interview. Results. Participants exhibited low levels of physical activity and viewed "physical activity" to be a broadly defined, nonspecific construct. Interviews revealed that many participants lack important knowledge about physical activity. A variety of personal, social, and environmental facilitators and barriers were reported by the participants. Conclusion. Efforts should be made towards clarifying information on physical activity in this population in order to help them incorporate physical activity into their routines, overcome barriers, and make use of opportunities to be active.

A multifunctional coupler with an ethylene carbonate- and a thiolactone ring was synthesized. As proof of principle the coupler was reacted with four low-molecular weight building blocks to form a multifunctional molecule. The reactivity/selectivity of the coupler towards amines, acrylates and acyl halides was evaluated.

Reactions of manganese(II) chloride, bromide and iodide with proline as an enantiopure and racemic ligand result in six crystalline solids for which diffraction experiments have been performed at 100 K. For two of these compounds, crystal structures at ambient temperature had been reported previously. The most surprising outcome of our systematic comparison lies in the role of chirality: with enantiopure proline three different coordination polymers have been obtained, whereas racemic proline yields isomorphous mononuclear complexes under the same reaction conditions.

The Al(III) complex of 3-cyanopentane-2,4-dionate (acacCN) features peripheric nitrile groups which may coordinate to silver cations. As the Al(acacCN)(3) building block ranges between inertness and lability, its reactivity towards Ag(I) salts depends on the solvent and the weakly or non-coordinating counter anions; an impressive range of different extended structures has been encountered. With AgPF(6), the original building block is retained and hexafluorophosphate remains uncoordinated. A highly symmetric 3D crystalline solid forms in the presence of trichloromethane, and with benzene a tetrasolvate with large solvent-filled voids is obtained. Two different classes of reaction products with silver triflate have been observed. In addition to networks incorporating Al(acacCN)(3), partial solvolysis may lead to a dinuclear methoxide-bridged derivative. The resulting Al(2)(μ-OMe)(2) core may be perceived as a four-connected node in a self-interpenetrating 3D network. Earlier studies reported transmetalation for the reaction of Al(acacCN)(3) with AgNO(3) and we find the same reactivity for silver tetrafluoroborate. Full degradation of the Al(III) building block with formation of [Ag(acacCN)] is observed.

The crystal structure of dl-alanine hydro-iodide (1-carb-oxy-ethanaminium iodide), C(3)H(8)NO(2) (+)·I(-), is that of an organic salt consisting of N-protonated cations and iodide anions. The compound features homochiral helices of N-H⋯O hydrogen-bonded cations in the [010] direction; neighbouring chains are related by crystallographic inversion centers and hence show opposite chirality. The iodide counter-anions act as hydrogen-bond acceptors towards H atoms of the ammonium and carb-oxy groups, and cross-link the chains along [100]. Thus, an overall two-dimensional network is formed in the ab plane. No short contacts occur between iodide anions.

It is well established that visual search becomes harder when the similarity between target and distractors is increased and the similarity between distractors is decreased. However, in models of visual search, similarity is typically treated as a static, time-invariant property of the relation between objects. Data from other perceptual tasks (e.g., categorization) demonstrate that similarity is dynamic and changes as perceptual information is accumulated (Lamberts, 1998). In three visual search experiments, the time course of target-distractor similarity effects and distractor-distractor similarity effects was examined. A version of the extended generalized context model (EGCM; Lamberts, 1998) provided a good account of the time course of the observed similarity effects, supporting the notion that similarity in search is dynamic. Modeling also indicated that increasing distractor homogeneity influences both perceptual and decision processes by (respectively) increasing the rate at which stimulus features are processed and enabling strategic weighting of stimulus information.

In three experiments, the effects of selective attention on perceptual processes in a complex multidimensional object categorization task were investigated. In each experiment, participants completed a perceptual-matching task to gain estimates of the perceptual salience of each stimulus dimension, then a categorization task using the same stimuli. In Experiments 1 and 2, the perceptual processing of stimulus dimensions was faster when dimensions were more diagnostic of category membership, regardless of their perceptual salience. Experiment 3 demonstrated that this prioritization of perceptual processing was evident even when stimuli were presented in unpredictable locations during categorization, indicating that the physical characteristics of the stimulus guide selective attention to diagnostic stimulus dimensions.

Aim: The aim of this study was to investigate the prevalence of eating problems and their association with neurological and behavioural disabilities and growth among children born extremely preterm (EPC) at age 6 years., Method: A standard questionnaire about eating was completed by parents of 223 children (125 males [56.1%], 98 females [43.9%]) aged 6 years who were born at 25 weeks' gestation or earlier (mean 24.5 wks, SD 0.7 wks; mean birthweight 749.1 g, SD 116.8 g), and parents of 148 classmates born at term (66 males [44.6%], 82 females [55.4%]). All children underwent neurological, cognitive, and anthropometric assessment, and parents and teachers completed a behaviour scale., Results: Eating problems were more common among the EPC than the comparison group (odds ratio [OR] 3.6, 95% confidence interval [CI] 2.1-6.3), including oral motor (OR 5.2, 95% CI 2.8-9.9), hypersensitivity (OR 3.0, 95% CI 1.6-5.6), and behavioural (OR 3.8, 95% CI 1.9-7.6) problems. Group differences were reduced after adjustment for cognitive impairment, neuromotor disability, and other behaviour problems. EPC with eating problems were shorter, lighter, and had lower mid-arm circumference and lower body mass index (BMI) even after adjusting for disabilities, gestational age, birthweight, and feeding problems at 30 months., Interpretation: Eating problems are still frequent in EPC at school age. They are only partly related to other disabilities but make an additional contribution to continued growth failure and may require early recognition and intervention.

It has previously been shown that moving images are remembered better than static ones. In two experiments, we investigated the basis for this dynamic superiority effect. Participants studied scenes presented as a single static image, a sequence of still images, or a moving video clip, and 3 days later completed a recognition test in which familiar and novel scenes were presented in all three formats. We found a marked congruency effect: For a given study format, accuracy was highest when test items were shown in the same format. Neither the dynamic superiority effect nor the study-test congruency effect was affected by encoding (Experiment 1) or retrieval (Experiment 2) manipulations, suggesting that these effects are relatively impervious to strategic control. The results demonstrate that the spatio-temporal properties of complex, realistic scenes are preserved in long-term memory.

Background: Participant drop-out occurs in all longitudinal studies, and if systematic, may lead to selection biases and erroneous conclusions being drawn from a study., Aims: We investigated whether drop out in the Avon Longitudinal Study of Parents And Children (ALSPAC) was systematic or random, and if systematic, whether it had an impact on the prediction of disruptive behaviour disorders., Method: Teacher reports of disruptive behaviour among currently participating, previously participating and never participating children aged 8 years in the ALSPAC longitudinal study were collected. Data on family factors were obtained in pregnancy. Simulations were conducted to explain the impact of selective drop-out on the strength of prediction., Results: Drop out from the ALSPAC cohort was systematic and children who dropped out were more likely to suffer from disruptive behaviour disorder. Systematic participant drop-out according to the family variables, however, did not alter the association between family factors obtained in pregnancy and disruptive behaviour disorder at 8 years of age., Conclusions: Cohort studies are prone to selective drop-out and are likely to underestimate the prevalence of psychiatric disorder. This empirical study and the simulations confirm that the validity of regression models is only marginally affected despite range restrictions after selective drop-out.

The time course of perception and retrieval of object features was investigated. Participants completed a perceptual matching task and 2 recognition tasks under time pressure. The recognition tasks imposed different retention loads. A stochastic model of feature sampling with a Bayesian decision component was used to estimate the rate of feature perception and the rate of retrieval of feature information. The results demonstrated that retrieval rates did not differ among object features if only a single object was held in memory. If 2 objects were retained in memory, differences among retrieval rates of features emerged, indicating that features that were quickly perceived were also quickly retrieved. The results from the 2-object retention condition are compatible with process reinstatement models of retrieval.

There is increasing evidence to suggest that mental simulations underlie many cognitive processes. We review results from three rapidly developing research areas suggesting that simulations underlie information retrieval. First, neuroimaging work indicates that cortical circuits that were activated during encoding are reactivated during retrieval. Second, retrieval is aided by behavioural re-enactment of processes involved in encoding, including re-enactment of encoding eye movements. Third, the time courses of encoding of visual features and the retrieval of information about those features are related. Overall, the evidence suggests that the often observed interactions between encoding and retrieval result from a cognitive system that, at least partially, reactivates processes that were involved in encoding to retrieve information.

The study of list length effects (adding items to a list affects memory for the other items) and list strength effects (strengthening some items in a list affects memory for the nonstrengthened items) is important to constrain models of memory. In recognition memory, a list length effect is generally found, whereas a list strength effect is not. Using the switched-plurality procedure in an old-new recognition task (e.g., study banana; test bananas), we found the opposite pattern. Length manipulations caused no change in memory performance, whereas strength manipulations did. The list strength effect was found when recollection was likely to operate at test (with switched-plurality lures). When recollection was unlikely to operate (with unrelated lures), the strength effect disappeared. The result was observed using both a size judgement task (which has previously produced positive list strength effects) and a pleasantness judgement task (which has not yielded list strength effects before).

The inverse base-rate effect in categorization (Medin & Edelson, 1988) arises when participants assign an ambiguous stimulus to a category that occurred less frequently than an alternative category, against the principles of Bayesian decision making. In the experiment reported in this article, rule-based and attention-shifting accounts of the inverse base-rate effect were evaluated. Participants completed a categorization task, known to produce the inverse base-rate effect, under standard conditions, under time pressure, and with a secondary task load. The inverse base-rate effect persisted under severe time pressure and under secondary task load. The results provided no evidence for the role of rule-based processes in producing the inverse base-rate effect. The data from the experiment are compatible with an attention-shifting account.

A four-part experiment was carried out to study the relationship between the time course of object-feature perception and the time course of retrieval of object information from memory. The experiment consisted of 2 perceptual matching tasks, and 2 perceptual recognition tasks. In all 4 tasks, participants provided speeded judgments of the identity of 2 objects. A stochastic feature-sampling model was used to estimate the time needed for feature perception and the time needed for retrieval of feature information. No evidence was found for a systematic relationship between perception times and retrieval times for individual features. Indeed, the model applications indicated that retrieval times were constant for different features, whereas perception rates varied across the features., (((c) 2006 APA, all rights reserved).)

People with autism have consistently been found to outperform controls on visuo-spatial tasks such as block design, embedded figures, and visual search tasks. Plaisted, O'Riordan, and others (Bonnel et al., 2003; O'Riordan & Plaisted, 2001; O'Riordan, Plaisted, Driver, & Baron-Cohen, 2001; Plaisted, O'Riordan, & Baron-Cohen, 1998a, 1998b) have suggested that these findings might be explained in terms of reduced perceptual similarity in autism, and that reduced perceptual similarity could also account for the difficulties that people with autism have in making generalizations to novel situations. In this study, high-functioning adults with autism and ability-matched controls performed a low-level categorization task designed to examine perceptual similarity. Results were analysed using standard statistical techniques and modelled using a quantitative model of categorization. This analysis revealed that participants with autism required reliably longer to learn the category structure than did the control group but, contrary to the predictions of the reduced perceptual similarity hypothesis, no evidence was found of more accurate performance by the participants with autism during the generalization stage. Our results suggest that when all participants are attending to the same attributes of an object in the visual domain, people with autism will not display signs of enhanced perceptual similarity.

The extended generalized context model for response times (K. Lamberts, 2000) was designed to account for choice proportions and response times in perceptual categorization. In this article, the hypothesis that the model also offers an account of accuracy and response times in absolute identification was investigated. The model was applied to the data from 2 absolute identification experiments and provided a good account of the bow and the set-size effects in accuracy and response time data from individual participants, including the response time distributions for individual stimuli. The model applications demonstrated that exemplar-based process models offer a viable account of absolute identification data.

The orthographic uniqueness point (OUP) of a word is the position of the first letter from the left that distinguishes a word from all other words. In 2 recent studies (P. J. Kwantes & D. J. K. Mewhort, 1999a; A. K. Lindell, M. E. R. Nicholls, & A. E. Castles, 2003), it has been observed that words with an early OUP were processed more quickly than words with a late OUP. This has been taken to suggest that observers process the letters of words sequentially in a left-to-right order. In this article, it is shown that the OUP results do not provide selective evidence for left-to-right sequential processing in visual word recognition because the data are also compatible with an account in which letter processing occurs in random order.

In two experiments, the response signal technique (Reed, 1973) was combined with the DRM paradigm (e.g., McDermott & Roediger, 1998) to investigate the time course of false recognition memory--in particular, how this effect varies along the time course of generating a recognition judgment. Across the experiments, in addition to standard instructions, there were forewarning instructions encouraging the participants to avoid this effect, as well as inclusion instructions intended to enhance this tendency. It was found that the false memory effect was at its strongest at earlier response signals, diminishing when more time was given to make a recognition judgment. The forewarning instructions led to a more conservative overall response bias, rather than to a reduction of the effect. However, the participants were able to exaggerate this effect in the inclusion condition. The results are discussed in terms of the role of strategic processing in recognition memory.

Traditional process models of old-new recognition have not addressed differences in accuracy and response time between individual stimuli. Two new process models of recognition are presented and applied to response time and accuracy data from 3 old-new recognition experiments. The 1st model is derived from a feature-sampling account of the time course of categorization, whereas the 2nd model is a generalization of a random-walk model of categorization. In the experiments, a new technique was used, which yielded reliable individual-stimulus data through repeated presentation of structurally equivalent items. The results from the experiments showed reliable differences in accuracy and response times between stimuli. The random-walk model provided the better account of the results from the 3 experiments. The implications of the results for process models of recognition are discussed.

An experiment was conducted to investigate people's ability to vary a response criterion strategically, in a recognition memory task, as a function of the length of time given to process the test stimuli (from 100 to 1,500 msec). The experiment used the response signal procedure, in which the participants responded after a signal that came at a variable time delay from stimulus onset. The proportion of new versus old test items was varied systematically with the time of the response signal, with the proportion of new test items rising, falling, or staying constant at later signals. It was found that the participants' response biases changed adaptively, becoming more conservative at later signals in the rising condition, becoming less conservative in the falling condition, and not changing significantly in the constant condition. Theoretical and methodological implications for recognition memory research are discussed.