Personality traits predict attitudes toward individuals with intellectual disability.

Background: Explaining individual differences in people's attitudes toward individuals with intellectual disability (ID) is important for increasing social inclusion of people with ID. The aim of the current study was to replicate and extend past research by formulating a single model of attitudes toward individuals with ID with several predictors: personality traits, quality and quantity of contact, perceived knowledge of ID, social desirability, and demographics. Methods: A sample of 221 undergraduate students in the United States completed several surveys in a lab setting: the Mental Retardation Attitude Inventory-Revised, the Big Five Inventory, McManus et al.'s measures of contact with and perceived knowledge of ID, and the Marlowe-Crowne Social Desirability Scale. Results: Results replicated previous findings by showing quality of contact was the strongest predictor of attitudes. Additionally, we found openness to experience and agreeableness remained significant predictors after holding all other variables constant. A follow-up mediation analysis demonstrated that quality of contact mediated the relations from openness and agreeableness to attitudes. Conclusions: Findings suggest personality factors can influence attitudes toward individuals with ID, and further emphasize the importance of quality of contact. Implications for the social inclusion of individuals with ID are discussed.

Wayfinding in Children: A Descriptive Literature Review of Research Methods.

Wayfinding refers to the process of locating unseen destinations in the spatial environment and is an important spatial skill for children. Despite a growing interest in wayfinding development in children, less attention has been focused on documenting the vast methodological heterogeneity of the existing research body, which impacts the ability to synthesize results across different studies. This review aims to systematically catalog and examine the research methods of the wayfinding development literature. We identified a total of 96 studies that examined 4- to 16- year-old children's wayfinding of unfamiliar, large-scale environments and were published between 1965 and 2020. Based on the environments, we grouped these studies into virtual reality (VR) vs. real-life and indoor vs. outdoor. The review revealed a vast diversity in research methods regarding participants, environments, independent variables (IVs), environmental exposure, dependent variables (DVs), and cognitive/behavioral correlates. The field has seen growing research interests in VR environments and atypical development. The most common IVs focused on the environmental features of landmarks and turn information. Relatively less research considered how different cognitive processes such as attention, memory, and learning contribute to wayfinding. Various outcome measures have been used to investigate landmark, route, and survey knowledge regarding DVs. This review showed an imbalance of topic areas in the field, systematic differences between different types of studies, and the need for greater attention on a number of important topics. Finally, we provided targeted, detailed recommendations for future research.

The Acquisition of Survey Knowledge by Individuals With Down Syndrome.

People with Down syndrome often exhibit deficiencies in wayfinding activities, particularly route learning (e.g., Courbois et al., 2013; Davis et al., 2014; Farran et al., 2015). Evidence concerning more sophisticated survey learning has been sparse. In the research reported here, two experiments are reported that evaluated survey learning of youth with DS and typically developing children (TD) matched on mental age. In Experiment 1, participants learned two overlapping routes consisting of three turns each through a virtual environment depicting 9 square city blocks. Following acquisition, they were tested on multiple measures of survey knowledge: finding a shortcut, identifying the direction of landmarks not currently visible from their location in the environment, and recognizing a bird's-eye representation of the overall environment. Under these conditions, which should provide relatively optimal opportunities for survey learning, the participants with DS performed comparably to TD participants matched on non-verbal ability on all of our measures of survey learning. Hence, we concluded that people with DS can acquire some survey knowledge when tasked with learning a small environment and given the opportunity to do so. In Experiment 2, the experimenter navigated participants through a large, relatively complex, virtual environment along a circuitous path, beginning and ending at a target landmark. Then, the participants were placed at a pre-specified location in the environment that they had viewed previously and instructed to navigate to the same target (a door) using the shortest possible path from their current location. They completed the task three times: once after being shown the environment one time, once after three exposures, and once after five exposures. Results indicated that the participants with DS exhibited significantly less skill at identifying the shortcut than did the TD participants, with differences emerging as the number of exposures increased. Participants with DS were also less able to recall landmarks at the end of the experiment. Overall, however, the performance of both groups was relatively poor in both experiments - with the performance of participants with DS being worse as conditions became less optimal. These results were discussed in terms of underlying mechanisms that may account for variations in survey learning as environmental complexity increases.

Children's response, landmark, and metric strategies in spatial navigation.

When interacting with the environment, one can encode spatial information via egocentric or allocentric perspectives. Allocentric processing can include both landmark and geometric information. The current study examined egocentric response-focused, allocentric landmark-focused, and allocentric metric-focused processing strategies in large-scale spatial environments among 38 children aged 6-8 years, 31 children aged 9 and 10 years, and 53 young adults. The current study used a new testing paradigm that made it possible to investigate all three spatial strategies in the same setting. Participants completed a series of experiments in a modified radial arm maze. By systematically changing the starting locations and landmark arrangements, the current study gradually manipulated the reliability and availability of egocentric response and landmark information while maintaining valid metric information. Overall, adults performed better than younger children, with older children performing at an intermediate level. All three groups were able to abandon the egocentric strategy when it became ineffective (Experiment 2) and to apply a landmark strategy flexibly (Experiment 3). Children demonstrated better performance than previous research has indicated. Nevertheless, the adults were more effective in using metric strategies than the two child groups (Experiment 4 and supplemental experiments). Our study suggested that in complex problem-solving situations, metric strategies were more difficult to acquire than the other two strategies and had a longer period of development.

Growth and Decline in Language and Phonological Memory Over Two Years Among Adolescents With Down Syndrome.

Forty-two adolescents with Down syndrome (DS) ages 10 to 21 years completed a battery of language and phonological memory measures twice, 2 years apart. Individual differences were highly stable across two years. Receptive vocabulary scores improved, there was no change in receptive or expressive grammar scores, and nonword repetition scores declined. Digit memory and expressive vocabulary scores improved among younger adolescents, but generally held steady among older adolescents. These patterns may reveal key points in development at which interventions may be best applied. Further research is needed to understand specific processes in tasks that appear to be slowing or declining during adolescence. They may be important for understanding early aging and dementia in DS.

Implicit memory of locations and identities: A developmental study.

Objects in the environment have both location and identity properties. However, it is unclear how these independent properties are processed and combined in the implicit domain. The current study investigated the development of the implicit memory of object locations and object identities, both independently and combined, and the relation between implicit memory and working memory (WM) for these properties. Three age groups participated: 6- and 7-year-old children, 9- and 10-year-old children, and adults. Children and adults completed a repeated search paradigm. In the learning phase, targets' locations were consistently predicted by both the identities and locations of the distracters. In the test phase, either both remained predictive or just the identities or just the locations of the distracters predicted the location of the target. All groups showed significant implicit learning when both the identities and locations of the distracters remained predictive. When only the locations but not the identities of the distracters were predictive, adults and 9- and 10-year-olds showed significant learning, whereas 6- and 7-year-olds did not. When only the identities but not the locations of the distracters were predictive, none of the groups showed significant learning effects. In evaluating the contributions of either visual or spatial WM to implicit learning and memory, we found that children with smaller visual WM exhibited larger implicit memory effects for object identities than did children with larger visual WM. Taken together, the results indicate that children's ability to differentiate identity and location undergoes development even in the implicit domain.

Encouraging top-down attention in visual search:A developmental perspective.

Four experiments are reported in which 60 younger children (7-8 years old), 60 older children (10-11 years old), and 60 young adults (18-25 years old) performed a conjunctive visual search task (15 per group in each experiment). The number of distractors of each feature type was unbalanced across displays to evaluate participants' ability to restrict search to the smaller subset of features. The use of top-down attention processes to restrict search was encouraged by providing external aids for identifying and maintaining attention on the smaller set. In Experiment 1, no external assistance was provided. In Experiment 2, precues and instructions were provided to focus attention on that subset. In Experiment 3, trials in which the smaller subset was represented by the same feature were presented in alternating blocks to eliminate the need to switch attention between features from trial to trial. In Experiment 4, consecutive blocks of the same subset features were presented in the first or second half of the experiment, providing additional consistency. All groups benefited from external support of top-down attention, although the pattern of improvement varied across experiments. The younger children benefited most from precues and instruction, using the subset search strategy when instructed. Furthermore, younger children benefited from blocking trials only when blocks of the same features did not alternate. Older participants benefited from the blocking of trials in both Experiments 3 and 4, but not from precues and instructions. Hence, our results revealed both malleability and limits of children's top-down control of attention.

Sex Differences in Using Spatial and Verbal Abilities Influence Route Learning Performance in a Virtual Environment: A Comparison of 6- to 12-Year Old Boys and Girls.

Previous studies have reported sex differences in wayfinding performance among adults. Men are typically better at using Euclidean information and survey strategies while women are better at using landmark information and route strategies. However, relatively few studies have examined sex differences in wayfinding in children. This research investigated relationships between route learning performance and two general abilities: spatial ability and verbal memory in 153 boys and girls between 6- to 12-years-old. Children completed a battery of spatial ability tasks (a two-dimension mental rotation task, a paper folding task, a visuo-spatial working memory task, and a Piagetian water level task) and a verbal memory task. In the route learning task, they had to learn a route through a series of hallways presented via computer. Boys had better overall route learning performance than did girls. In fact, the difference between boys and girls was constant across the age range tested. Structural equation modeling of the children's performance revealed that spatial abilities and verbal memory were significant contributors to route learning performance. However, there were different patterns of correlates for boys and girls. For boys, spatial abilities contributed to route learning while verbal memory did not. In contrast, for girls both spatial abilities and verbal memory contributed to their route learning performance. This difference may reflect the precursor of a strategic difference between boys and girls in wayfinding that is commonly observed in adults.

Age-related similarities in contextual cueing in the presence of unpredictive distracters.

Contextual cueing effects of 6-8-year-old children, 10-12-year-old-children, and college students were compared under conditions in which some of the distracters in the search displays predicted the location of the target and other distracters did not. More specifically, the percent of distracters that predicted the location of the target varied across three conditions (100%, 67%, and 33%). Previous research had indicated that children are impacted more than adults when the percent of predictive distracters is relatively low. However, that research included new displays as well as repeated displays as participants were implicitly learning the association between the predictive distracters and the target. This re-evaluation did not introduce new display until a separate test phase. Results suggested that all three age groups demonstrated significant and comparable contextual cueing effects across all three signal-to-noise ratio conditions. Hence, children appear to possess the general ability to extract and remember information associated with spatial regularities in the presence of considerable spatial noise. In addition, contextual cueing effects were linked to improvements in search efficiency for all groups in this study, providing another degree of similarity across variations in age.

Response cost to repeated displays--when previous distractors become targets.

A varied-target search task was used to evaluate the response cost of previous distractors becoming current targets in repeated visual search. We compared the relative contributions of distractor identity and location to producing response cost. During an exposure phase, half of the items were possible targets in each repeated display, and the other half were always distractors. Participants searched for a different target from the set of potential targets when the search displays were repeated. In the test phase of Experiments 1a and 1b, the roles of targets and distractors were reversed while the overall configuration was unchanged. Results indicated significant contextual costs after the switch of identities/locations between distractors and targets. In the test phase of Experiments 2a and 2b, target identities were changed again but the target locations remained the same. Less response cost was observed in this condition relative to when both identities and locations were changed. Proximity between target and distractors in the repeated displays also influenced response cost. The mechanisms responsible for the various response cost effects and the interplay between identity, location, and proximity in the production of response cost were discussed.

The impact of signal-to-noise ratio on contextual cueing in children and adults.

Contextual cueing refers to a form of implicit spatial learning where participants incidentally learn to associate a target location with its repeated spatial context. Successful contextual learning produces an efficient visual search through familiar environments. Despite the fact that children exhibit the basic ability of implicit spatial learning, their general effectiveness in this form of learning can be compromised by other development-dependent factors. Learning to extract useful information (signal) in the presence of various amounts of irrelevant or distracting information (noise) characterizes one of the most important changes that occur with cognitive development. This research investigated whether signal-to-noise ratio (S/N) affects contextual cueing differently in children and adults. S/N was operationally defined as the ratio of repeated versus new displays encountered over time. Three ratio conditions were created: high (100%), medium (67%), and low (33%) conditions. Results suggested no difference in the acquisition of contextual learning effects in the high and medium conditions across three age groups (6- to 8-year-olds, 10- to 12-year-olds, and young adults). However, a significant developmental difference emerged in the low S/N condition. As predicted, adults exhibited significant contextual cueing effects, whereas older children showed marginally significant contextual cueing and younger children did not show cueing effects. Group differences in the ability to exhibit implicit contextual learning under low S/N conditions and the implications of this difference are discussed.

The acquisition of contextual cueing effects by persons with and without intellectual disability.

Two experiments were conducted to compare the acquisition of contextual cueing effects of adolescents and young adults with intellectual disabilities (ID) relative to typically developing children and young adults. Contextual cueing reflects an implicit, memory based attention guidance mechanism that results in faster search for target locations that have been previously experienced in a predictable context. In the study, participants located a target stimulus embedded in a context of numerous distracter stimuli. During a learning phase, the location of the target was predictable from the location of the distracters in the search displays. We then compared response times to locating predictable relative to unpredictable targets presented in a test phase. In Experiment 1, all of the distracters predicted the location of the target. In Experiment 2, half of the distracters predicted the location of the target while the other half varied randomly. The participants with ID exhibited significant contextual facilitation in both experiments, with the magnitude of facilitation being similar to that of the typically developing (TD) children and adults. We concluded that deficiencies in contextual cueing are not necessarily associated with low measured intelligence that results in a classification of ID.

Visuo-spatial ability in individuals with Down syndrome: is it really a strength?

Down syndrome (DS) is associated with extreme difficulty in verbal skills and relatively better visuo-spatial skills. Indeed, visuo-spatial ability is often considered a strength in DS. However, it is not clear whether this strength is only relative to the poor verbal skills, or, more impressively, relative to cognitive ability in general. To answer this question, we conducted an extensive literature review of studies on visuo-spatial abilities in people with Down syndrome from January 1987 to May 2013. Based on a general taxonomy of spatial abilities patterned after Lohman, Pellegrino, Alderton, and Regian (1987) and Carroll (1993) and existing studies of DS, we included five different domains of spatial abilities - visuo-spatial memory, visuo-spatial construction, mental rotation, closure, and wayfinding. We evaluated a total of 49 studies including 127 different comparisons. Most comparisons involved a group with DS vs. a group with typical development matched on mental age and compared on a task measuring one of the five visuo-spatial abilities. Although further research is needed for firm conclusions on some visuo-spatial abilities, there was no evidence that visuo-spatial ability is a strength in DS relative to general cognitive ability. Rather, the review suggests an uneven profile of visuo-spatial abilities in DS in which some abilities are commensurate with general cognitive ability level, and others are below.

The impact of distracter-target similarity on contextual cueing effects of children and adults.

Contextual cueing reflects a memory-based attentional guidance process that develops through repeated exposure to displays in which a target location has been consistently paired with a specific context. In two experiments, we compared 20 younger children's (6-7 years old), 20 older children's (9-10 years old), and 20 young adults' (18-21 years old) abilities to acquire contextual cueing effects from displays in which half of the distracters predicted the location of the target and half did not. Across experiments, we varied the similarity between the predictive and nonpredictive distracters and the target. In Experiment 1, the predictive distracters were visually similar to the target and dissimilar from the nonpredictive distracters. In Experiment 2, the nonpredictive distracters were also similar to the target and predictive distracters. All three age groups exhibited contextual cueing in Experiment 1, although the effect was not as strong for the younger children relative to older children and adults. All participants exhibited weaker contextual cueing effects in Experiment 2, with the younger children not exhibiting significant contextual cueing at all. Apparently, when search processes could not be guided to the predictive distracters on the basis of salient stimulus features, younger children in particular experienced difficulty in implicitly identifying and using aspects of the context to facilitate with the acquisition of contextual cueing effects.

Patterns of differences in wayfinding performance and correlations among abilities between persons with and without Down syndrome and typically developing children.

Down syndrome (DS) impacts several brain regions including the hippocampus and surrounding structures that have responsibility for important aspects of navigation and wayfinding. Hence it is reasonable to expect that DS may result in a reduced ability to engage in these skills. Two experiments are reported that evaluated route-learning of youth with DS, youth with intellectual disability (ID) and not DS, and typically developing (TD) children matched on mental age (MA). In both experiments, participants learned routes with eight choice point presented via computer. Several objects were placed along the route that could be used as landmarks. Participants navigated the route once with turn indicators pointing the way and then retraced the route without them. In Experiment 1 we found that the TD children and ID participants performed very similarly. They learned the route in the same number of attempts, committed the same number of errors while learning the route, and recalled approximately the same number of landmarks. The participants with DS performed significantly worse on both measures of navigation (attempts and errors) and also recalled significantly fewer landmarks. In Experiment 2, we attempted to reduce TD and ID vs DS differences by focusing participants' attention on the landmarks. Half of the participants in each group were instructed to identify the landmarks as they passed them the first time. The participants with DS again committed more errors than the participants in the ID and TD groups in the navigation task. In addition, they recalled fewer landmarks. While landmark identification improved landmark memory for both groups, it did not have a significant impact on navigation. Participants with DS still performed more poorly than did the TD and ID participants. Of additional interest, we observed that the performance of persons with DS correlated with different ability measures than did the performance of the other groups. The results the two experiments point to a problem in navigation for persons with DS that exceeds expectations based solely on intellectual level.

Contextual cueing effects across the lifespan.

The authors evaluated age-related variations in contextual cueing, which reflects the extent to which visuospatial regularities can facilitate search for a target. Previous research produced inconsistent results regarding contextual cueing effects in young children and in older adults, and no study has investigated the phenomenon across the life span. Three groups (6, 20, and 70 years old) were compared. Participants located a designated target stimulus embedded in a context of distractor stimuli. During exposure, the location of the target could be predicted from the location of the distracters in each display. During test, these predictable displays were intermixed with new displays that did not predict the target location. Response times to locating predictable relative to unpredictable targets were compared. All groups exhibited facilitation effects greater than 0 (95% CIs [.02, .11], d = .4; [.01, .12], d = .4; and [.01, .10], d = .4, for the children, young adults, and older adults, respectively) indicating that contextual cueing is robust across a wide age range. The relative magnitude of contextual cueing effects was essentially identical across the age range tested, F(2, 103) = 1.71, eta rho2 = .02. The authors argue that a mechanism that uses environmental covariation is available to all age ranges, but the expression of the contextual cueing may depend on the way it is measured.

Age-related interference from irrelevant distracters in visual feature search among heterogeneous distracters.

We evaluated age-related variations in the influence of heterogeneous distracters during feature target. Participants in three age groups-6-year-old children, 9-year-old children, and young adults-completed three conditions of search. In a singleton search condition, participants searched for a circle among squares of the same color. In two feature mode search conditions, participants searched for a gray circle or a black circle among gray and black squares. Singleton search was performed at the same level of efficiency for all age groups. In contrast, the two feature mode search conditions yielded age-related performance differences in both conditions. Younger children exhibited a steeper slope than young adults when searching for a gray or black circle. Older children exhibited a steeper slope than young adults when searching for a gray circle but not when searching for a black circle. We concluded that these differences revealed age-related improvements in the relative abilities of adults and children to execute attentional control processes during visual search. In particular, it appears that children found it more difficult to maintain the goal of searching for a circle target than adults and were distracted by the presence of the irrelevant feature dimension of color.

Memory profiles of Down, Williams, and fragile X syndromes: implications for reading development.

The purpose of this review was to understand the types of memory impairments that are associated with intellectual disability (ID, formerly called mental retardation) and the implications of these impairments for reading development. Specifically, studies on working memory, delayed memory and learning, and semantic/conceptual memory in Down syndrome, Williams syndrome, and fragile X syndrome were examined. A distinct memory profile emerged for each of the 3 etiologies of ID. Memory profiles are discussed in relation to strengths and weaknesses in reading skills in these three etiologies. We suggest that reading instruction be designed to capitalize on relatively stronger memory skills while providing extra support for especially challenging aspects of reading.

Asymmetry and performance: toward a neurodevelopmental theory.

Hemispheric asymmetry implies the existence of developmental influences that affect one hemisphere more than the other. However, those influences are poorly understood. One simple view is that asymmetry may exist because of a relationship between a mental process' degree of lateralization and how well it functions. Data scaling issues have largely prevented such investigations, but it is shown that scaling effects are minimized after correction for ceiling and floor effects. After correction, lateralization-performance correlations are pervasive. However, while some correlations are positive, others are negative, with the direction depending on the underlying lateralized process. Two hypotheses are proposed that can account for these relationships by pointing either to individual differences in maturation of the corpus callosum or to developmental limits encountered at different ages of childhood. Their investigation should contribute toward a neurodevelopmental theory of hemispheric asymmetry.

Inhibition of return and negative priming by persons with and without mental retardation.

Persons with and without mental retardation who were matched on CA took part in three tasks: an inhibition of return task, a location negative-priming task, and an identity negative-priming task. Having participants perform all three tasks allowed us to correlate performance among the tasks and assess the various relationships among performance measures on negative priming and inhibition of return. The participants with mental retardation did not exhibit negative priming of identity. However, they did exhibit negative priming of location and inhibition of return. The participants without mental retardation exhibited all three effects. A different pattern of correlations was observed for the participants with and those without mental retardation. Possible reasons for this difference are discussed.