Stimulus overselectivity four decades later: a review of the literature and its implications for current research in autism spectrum disorder

Combinatorial Language parent-report Scores Differ Significantly Between Typically Developing Children and Those with Autism Spectrum Disorders

Prefrontal synthesis (PFS) is a component of constructive imagination. It is defined as the process of mentally juxtaposing objects into novel combinations. For example, to comprehend the instruction "put the cat under the dog and above the monkey," it is necessary to use PFS in order to correctly determine the spatial arrangement of the cat, dog, and monkey with relation to one another. The acquisition of PFS hinges on the use of combinatorial language during early childhood development. Accordingly, children with developmental delays exhibit a deficit in PFS, and frequent assessments are recommended for such individuals. In 2018, we developed the Mental Synthesis Evaluation Checklist (MSEC), a parent-reported evaluation designed to assess PFS and combinatorial language comprehension. In this manuscript we use MSEC to identify differences in combinatorial language acquisition between ASD (N = 29,138) and neurotypical (N = 111) children. Results emphasize the utility of the MSEC in distinguishing language deficits in ASD from typical development as early as 2 years of age (p < 0.0001).

Probabilistic Learning of Cue-Outcome Associations is not Influenced by Autistic Traits

According to Bayesian/predictive coding models of autism, autistic individuals may have difficulties learning probabilistic cue-outcome associations, but empirical evidence has been mixed. The target cues used in previous studies were often straightforward and might not reflect real-life learning of such associations which requires learners to infer which cue(s) among many to track. Across two experiments, we compared adult learners with varying levels of autistic traits on their ability to infer the correct cue to learn probabilistic cue-outcome associations when explicitly instructed to do so or when exposed implicitly. We found no evidence for the effect of autistic traits on probabilistic learning accuracy, contrary to the predictions of Bayesian/predictive coding models. Implications for the current Bayesian/predictive coding models are discussed.

Revaluation of overselected stimuli: Emergence of control by underselected stimuli depends on degree of overselectivity

Stimulus overselectivity describes strong control by one stimulus element at the expense of other equally relevant elements. Research suggests that control by underselected stimuli emerges following extinction of the overselected stimulus ("revaluation") and the emergence is larger when overselectivity is greater. We compared such revaluation effects with a control compound or condition in two experiments. Human participants chose between compound S+ and S- stimuli. Then, to assess control by compound-stimulus elements, participants chose between individual elements in a testing phase without feedback. The S+ element chosen most often (the overselected element) underwent revaluation, during which choice of that element was extinguished and choice of a novel element reinforced. Thereafter, participants completed a retesting phase. Revaluation reduced choice of the overselected element. Choice of the underselected element decreased for participants with low overselectivity but increased for participants with high overselectivity. This was not the case for a control compound that did not undergo revaluation (Experiments 1 and 2) or in a control condition in which the overselected element continued to be reinforced during revaluation (Experiment 2). These findings suggest that overselectivity levels may modulate revaluation effects, and they also highlight the importance of the contingency change in postrevaluation changes in stimulus control.

Language evolution is not limited to speech acquisition: a large study of language development in children with language deficits highlights the importance of the voluntary imagination component of language

Did the boy bite the cat or was it the other way around? When processing a sentence with several objects, one has to establish ‘who did what to whom’. When a sentence cannot be interpreted by recalling an image from memory, we rely on the special type of voluntary constructive imagination called Prefrontal synthesis (PFS). PFS is defined as the ability to juxtapose mental visuospatial objects at will. We hypothesised that PFS has fundamental importance for language acquisition. To test this hypothesis, we designed a PFS-targeting intervention and administered it to 6,454 children with language deficiencies (age 2 to 12 years). The results from the three-year-long study demonstrated that children who engaged with the PFS intervention showed 2.2-fold improvement in combinatorial language comprehension compared to children with similar initial evaluations. These findings suggest that language can be improved by training the PFS and exposes the importance of the visuospatial component of language. This manuscript reflects on the experimental findings from the point of view of human language evolution. When used as a proxy for evolutionary language acquisition, the study results suggest a dichotomy of language evolution, with its speech component and its visuospatial component developing in parallel. The study highlights the radical idea that evolutionary acquisition of language was driven primarily by improvements of voluntary imagination rather than by improvements in the speech apparatus.

Cochran's Q Test of Stimulus Overselectivity within the Verbal Repertoire of Children with Autism

Stimulus overselectivity remains an ill-defined concept within behavior analysis, because it can be difficult to distinguish truly restrictive stimulus control from random variation. Quantitative models of bias are useful, though perhaps limited in application. Over the last 50 years, research on stimulus overselectivity has developed a pattern of assessment and intervention repeatedly marred by methodological flaws. Here we argue that a molecular view of overselectivity, under which restricted stimulus control has heretofore been examined, is fundamentally insufficient for analyzing this phenomenon. Instead, we propose the use of the term "overselectivity" to define temporally extended patterns of restrictive stimulus control that have resulted in disproportionate populations of responding that cannot be attributed to chance alone, and highlight examples of overselectivity within the verbal behavior of children with autism spectrum disorder. Viewed as such, stimulus overselectivity lends itself to direct observation and measurement through the statistical analysis of single-subject data. In particular, we demonstrate the use of the Cochran Q test as a means of precisely quantifying stimulus overselectivity. We provide a tutorial on calculation, a model for interpretation, and a discussion of the implications for the use of Cochran's Q by clinicians and researchers.

What Can We Learn by Treating Perspective Taking as Problem Solving?

Perspective taking has been studied extensively using a wide variety of experimental tasks. The theoretical constructs that are used to develop these tasks and interpret the results obtained from them, most notably theory of mind (ToM), have conceptual shortcomings from a behavior-analytic perspective. The behavioral approach to conceptualizing and studying this class of behavior is parsimonious and pragmatic, but the body of relevant research is currently small. The prominent relational frame theory (RFT) approach to derived perspective taking asserts that "deictic framing" is a core component of this class of behavior, but this proposal also appears to be conceptually problematic. We suggest that in many cases perspective taking is problem solving; when successful, both classes of behavior involve the emission of context-appropriate precurrent behavior that facilitates the appropriate response (i.e., the "solution"). Conceptualizing perspective taking in this way appears to have many advantages, which we explore herein.

The effect of ambient sounds on decision-making and heart rate variability in autism

LAY ABSTRACT

Many autistic people report difficulties making decisions during everyday tasks, such as shopping. To examine the effect of sounds on decision-making, we developed a supermarket task where people watched a film shown from the shopper's perspective and were asked to make decisions between different products. The task was divided into three sections and participants completed each section in a different auditory environment: (1) no sounds, (2) non-social sounds (e.g. fridges humming) and (3) social sounds (e.g. people talking). Thirty-eight autistic and 37 neurotypical adults took part. We measured decision-making by examining how long it took to make a decision and how consistent people were with their decisions. We also measured heart rate variability because this biological response provides a measure of anxiety. After the supermarket shopping task, participants told us in their own words about their experiences. Autistic participants said that they found the non-social and social sound conditions more difficult than the no sound condition, and autistic participants found the social sound condition more negative than neurotypical participants. However, decision-making and heart rate variability were similar for autistic and neurotypical participants across the sound conditions, suggesting that these measures may not have been sensitive enough to reflect the experiences the autistic participants reported. Further research should consider alternative measures to explore the experiences reported by autistic people to help us understand which specific aspects of the environment autistic people are sensitive to. This, in turn, may enable more specific and evidence-based autism-friendly changes to be made.

Genomic selection signatures in autism spectrum disorder identifies cognitive genomic tradeoff and its relevance in paradoxical phenotypes of deficits versus potentialities

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder characterized by paradoxical phenotypes of deficits as well as gain in brain function. To address this a genomic tradeoff hypothesis was tested and followed up with the biological interaction and evolutionary significance of positively selected ASD risk genes. SFARI database was used to retrieve the ASD risk genes while for population datasets 1000 genome data was used. Common risk SNPs were subjected to machine learning as well as independent tests for selection, followed by Bayesian analysis to identify the cumulative effect of selection on risk SNPs. Functional implication of these positively selected risk SNPs was assessed and subjected to ontology analysis, pertaining to their interaction and enrichment of biological and cellular functions. This was followed by comparative analysis with the ancient genomes to identify their evolutionary patterns. Our results identified significant positive selection signals in 18 ASD risk SNPs. Functional and ontology analysis indicate the role of biological and cellular processes associated with various brain functions. The core of the biological interaction network constitutes genes for cognition and learning while genes in the periphery of the network had direct or indirect impact on brain function. Ancient genome analysis identified de novo and conserved evolutionary selection clusters. The de-novo evolutionary cluster represented genes involved in cognitive function. Relative enrichment of the ASD risk SNPs from the respective evolutionary cluster or biological interaction networks may help in addressing the phenotypic diversity in ASD. This cognitive genomic tradeoff signatures impacting the biological networks can explain the paradoxical phenotypes in ASD.

What categorical induction variability reveals about typical and atypical development

Categorical induction abilities are robust in typically developing (TD) preschoolers, while children with Autism Spectrum Disorders (ASD) frequently perform inconsistently on tasks asking for the transference of traits from a known category member to a new example based on shared category membership. Here, TD five-year-olds and six-year-olds with ASD participated in a categorical induction task; the TD children performed significantly better and more consistently than the children with ASD. Concurrent verbal and nonverbal tests were not significant correlates; however, the TD children's shape bias performance at two years of age was significantly positively predictive of categorical induction performance at age five. The shape bias, the tendency to extend a novel label to other objects of the same shape during word learning, appears linked with categorical induction ability in TD children, suggesting a common underlying skill and consistent developmental trajectory. Word learning and categorical induction appear uncoupled in children with ASD.

Prediction in Autism Spectrum Disorder: A Systematic Review of Empirical Evidence

According to a recent influential proposal, several phenotypic features of autism spectrum disorder (ASD) may be accounted for by differences in predictive skills between individuals with ASD and neurotypical individuals. In this systematic review, we describe results from 47 studies that have empirically tested this hypothesis. We assess the results based on two observable aspects of prediction: learning a pairing between an antecedent and a consequence and responding to an antecedent in a predictive manner. Taken together, these studies suggest distinct differences in both predictive learning and predictive response. Studies documenting differences in learning predictive pairings indicate challenges in detecting such relationships especially when predictive features of an antecedent have low salience or consistency, and studies showing differences in habituation and perceptual adaptation suggest low-level predictive processing differences in ASD. These challenges may account for the observed differences in the influence of predictive priors, in spontaneous predictive movement or gaze, and in social prediction. An important goal for future research will be to better define and constrain the broad domain-general hypothesis by testing multiple types of prediction within the same individuals. Additional promising avenues include studying prediction within naturalistic contexts and assessing the effect of prediction-based intervention on supporting functional outcomes for individuals with ASD. LAY SUMMARY: Researchers have suggested that many features of autism spectrum disorder (ASD) may be explained by differences in the prediction skills of people with ASD. We review results from 47 studies. These studies suggest that ASD may be associated with differences in the learning of predictive pairings (e.g., learning cause and effect) and in low-level predictive processing in the brain (e.g., processing repeated sounds). These findings lay the groundwork for research that can improve our understanding of ASD and inform interventions. Autism Res 2021, 14: 604-630. © 2021 International Society for Autism Research and Wiley Periodicals LLC.

Matrix training to teach tacts using speech generating devices: Replication and extension

Research has shown that training diagonal targets in a matrix may result in correct responses to the nondiagonal targets within the same matrix and novel targets from a separate matrix. This study replicated prior research using matrix training to teach tact noun-verb combinations to 3 male participants with autism who use a speech generating device to communicate. Two matrices were constructed (Matrix 1 and Generalization Matrix), using mastered nouns and verbs. Following baseline, diagonal targets within Matrix 1 were trained. Posttests were conducted for the Generalization Matrix and Matrix 1. Two participants showed recombinative generalization within Matrix 1 and correct responding to all targets within the novel generalization matrix. For the 3rd participant, recombinative generalization was observed within Matrix 1. However, correct responding with the generalization matrix targets was only observed after training with 3 additional matrices. These results replicate and extend previous findings.

Pattern Unifies Autism

Autism is a highly heterogeneous condition, genetically and phenotypically. This diversity of causation and presentation has impeded its definition, recognition, assessment, and treatment. Current diagnostic criteria for autism involve two domains, restricted interests and repetitive behavior (RRBs) and social deficits, whose relationship remains unclear. I suggest that the large suite of traits associated with autism can be usefully conceptualized under the single rubric of "pattern," a term that connects autism with basic brain and cognitive functions and structures its phenotypes within a single theoretical framework. Autism thus involves increases and enhancements to pattern perception, pattern recognition, pattern maintenance, pattern generation, pattern processing, and pattern seeking. RRBs result from increased and imbalanced pattern-related perception and cognition, and social alterations result in part from the usual lack of clear pattern in social interactions, combined with the interference of RRBs with social development. This framework has strong implications for assessment of social and non-social autism-related traits, personalized therapy, and priorities for research.

Blocking of Stimulus Control in Children with Autism

The present study aimed to investigate the blocking of stimulus control in three children with autism. We used a go/no-go procedure in a standard blocking paradigm. In Phase 1, we established one of two sounds or colored squares as a discriminative stimulus for touching a tablet screen. In Phase 2, a colored square was added to the sound or a sound was added to the colored square in a stimulus compound. The discrimination training continued as in Phase 1. We subsequently tested discriminative control by each of the single stimuli separately and by the compounds. Finally, after testing with no programmed consequences, we reestablished the original discrimination and replicated the test of stimulus control. The results support previous experiments by demonstrating that the establishment of discriminative control by a second stimulus by adding it to a previously established discriminative stimulus in a compound was blocked by the earlier discrimination training in all three participants. We discuss procedural details that may be critical to avoid the blocking of stimulus control in the applied field, particularly with respect to the acquisition of skills that involve multiple stimuli, such as joint attention, social referencing, and bidirectional naming.

Imagination in Autism: A Chance to Improve Early Language Therapy

Children with autism often have difficulties in imaginative play, Theory of Mind, and playing out different scenarios in their minds. Research shows that the root of these problems may be the voluntary imagination network that involves the lateral prefrontal cortex and its long frontoposterior connections to the temporal-parietal-occipital area. Previously disconnected visuospatial issues (stimulus overselectivity and tunnel vision) and language issues (lack of comprehension of spatial prepositions and complex recursive sentences) may be explained by the same voluntary imagination deficit. This review highlights the new insights into the mechanism of voluntary imagination, its difference from involuntary imagination, and its unusually strong critical period. Clearer developmental terminology and a better understanding of voluntary imagination have the potential to facilitate communication between therapists and parents, and improve therapy outcomes in children.

Cognitive Empathy as Imagination: Evidence From Reading the Mind in the Eyes in Autism and Schizotypy

How is cognitive empathy related to sociality, imagination, and other psychological constructs? How is it altered in disorders of human social cognition? We leveraged a large data set (1,168 students, 62% female) on the Reading the Mind in the Eyes test (RMET), the Autism Quotient (AQ), and the Schizotypal Personality Questionnaire (SPQ-BR) to test the hypotheses that the RMET, as a metric of cognitive empathy, reflects mainly social abilities, imagination, or both. RMET showed the expected female bias in performance, though only for eyes that expressed emotions and not for neutral expressions. RMET performance was significantly, and more strongly, associated with the AQ and SPQ subscales that reflect aspects of imagination (AQ-Imagination and SPQ-Magical Ideation) than aspects of social abilities (AQ-Social, AQ-Communication, and SPQ-Interpersonal subscales). These results were confirmed with multiple regression analysis, which also implicated increased attention (AQ-Attention Switching and, marginally non-significantly, AQ-Attention to Detail) in RMET performance. The two imagination-related correlates of RMET performance also show the strongest sex biases for the AQ and SPQ: male biased in AQ-Imagination, and female biased in SPQ-Magical Ideation, with small to medium effect sizes. Taken together, these findings suggest that cognitive empathy, as quantified by the RMET, centrally involves imagination, which is underdeveloped (with a male bias) on the autism spectrum and overdeveloped (with a female bias) on the schizotypy spectrum, with optimal emotion-recognition performance intermediate between the two. The results, in conjunction with previous studies, implicate a combination of optimal imagination and focused attention in enhanced RMET performance.

An Evaluation of Two Tact-Training Procedures on Acquired Tacts and Tacting During Play

A common practice in tact training is to include a supplemental verbal stimulus (e.g., "What is it?") in addition to the presentation of a nonverbal discriminative stimulus. Previous literature has suggested that this supplemental verbal stimulus can impede acquisition and generalization relative to the presentation of the object alone, as it may establish faulty stimulus control or decrease spontaneous tacting. Research has yet to compare these 2 training methods on the generalization of learned tacts to more naturalistic, play-based environments. The present study evaluated the use of "What is it?" compared to the presentation of only the nonverbal discriminative stimulus on tact acquisition among 3 children with autism spectrum disorder and the extent to which these training procedures led to tacting in a play-based setting following discrete-trial training. Overall, participants learned to tact stimuli under both conditions, and all participants demonstrated generalization of tacts in a play-based setting. Recommendations for the development and evaluation of naturalistic posttraining assessment are discussed.

Novel Prefrontal Synthesis Intervention Improves Language in Children with Autism

Prefrontal synthesis (PFS) is defined as the ability to juxtapose mental visuospatial objects at will. Paralysis of PFS may be responsible for the lack of comprehension of spatial prepositions, semantically-reversible sentences, and recursive sentences observed in 30 to 40% of individuals with autism spectrum disorder (ASD). In this report we present data from a three-year-long clinical trial of 6454 ASD children age 2 to 12 years, which were administered a PFS-targeting intervention. Tablet-based verbal and nonverbal exercises emphasizing mental-juxtaposition-of-objects were organized into an application called Mental Imagery Therapy for Autism (MITA). The test group included participants who completed more than one thousand exercises and made no more than one error per exercise. The control group was selected from the rest of participants by a matching procedure. Each test group participant was matched to the control group participant by age, gender, expressive language, receptive language, sociability, cognitive awareness, and health score at first evaluation using propensity score analysis. The test group showed a 2.2-fold improvement in receptive language score vs. control group (p < 0.0001) and a 1.4-fold improvement in expressive language (p = 0.0144). No statistically significant change was detected in other subscales not targeted by the exercises. These findings show that language acquisition improves after training PFS and that a further investigation of the PFS-targeting intervention in a randomized controlled study is warranted.

Perceptual category learning in autism spectrum disorder: Truth and consequences

The ability to categorize is fundamental to cognitive development. Some categories emerge effortlessly and rapidly while others can take years of experience to acquire. Children with autism spectrum disorder (ASD) are often able to name and sort objects, suggesting that their categorization abilities are largely intact. However, recent experimental work shows that the categories formed by individuals with ASD may diverge substantially from those that most people learn. This review considers how atypical perceptual category learning can affect cognitive development in children with ASD and how atypical categorization may contribute to many of the socially problematic symptoms associated with this disorder. Theoretical approaches to understanding perceptual processing and category learning at both the behavioral and neural levels are assessed in relation to known alterations in perceptual category learning associated with ASD. Mismatches between the ways in which children learn to organize perceived events relative to their peers and adults can accumulate over time, leading to difficulties in communication, social interactions, academic performance, and behavioral flexibility.

Sensitivity to Changing Environmental Conditions across Individuals with Subtype 2 Automatically Reinforced and Socially Reinforced Self-injury

Automatically reinforced Subtype 2 self-injurious behavior (ASIB) has been characterized as showing insensitivity to competing reinforcement contingencies in the contexts of both functional analyses and in treatment using reinforcement alone (Hagopian, Rooker, &Yenokyan, 2018). One question is whether this insensitivity is specific to Subtype 2 ASIB as response class in these contexts or whether it is represents a generalized response tendency of the individual that is evident across other response classes. To examine this question, we compared responding on a single-operant task under changing reinforcement schedules for three individuals with Subtype 2 ASIB, relative to a comparison group of three individuals with socially reinforced SIB (which is characterized by sensitivity to changes in reinforcement contingencies). As hypothesized, all individuals showed sensitivity to changes in contingencies. These results provide preliminary support that the insensitivity of Subtype 2 ASIB is a property specific to that response class in these contexts rather than a generalized response tendency of the individual.

Systematic Review of Verbal Operants in Speech Generating Device Research from Skinner's Analysis of Verbal Behavior

Skinner's (1957) book Verbal Behavior is a critical tool in designing effective communication programs for individuals with limited speech. The purpose of this systematic review was to analyze the speech generating device (SGD) research literature from Skinner's taxonomy of primary verbal operants. An extraction procedure yielded 56 studies published between 1995 and 2018, with a total of 221 participants, most of whom had autism spectrum disorder (ASD) or an intellectual and developmental disability (IDD). The large majority of SGD studies (42) targeted multiply controlled mands, whereas only a handful of studies targeted verbal operants that were not mands. Few studies employed procedures for fading contrived sources of stimulus control to promote spontaneous responding, and few studies targeted more sophisticated, topography-based responses (e.g., typing, speech). Results of the review highlight the need for better dissemination of Skinner's Verbal Behavior, the need for research to evaluate effects of SGD in teaching a greater variety of spontaneous verbal operants, and the need to focus on application of SGD with populations beyond individuals with ASD and IDD.

Novel linguistic evaluation of prefrontal synthesis (LEPS) test measures prefrontal synthesis acquisition in neurotypical children and predicts high-functioning versus low-functioning class assignment in individuals with autism

In order to grasp the difference between "the cat on the mat" and "the mat on the cat," understanding the words and the grammar is not enough. Rather it is essential to visualize the cat and the mat together to appreciate their relations. This type of imagination, which involves juxtaposition of mental objects is conducted by the prefrontal cortex and is therefore called Prefrontal Synthesis (PFS). PFS acquisition has a strong experience-dependent critical period putting children with language delay in danger of never acquiring PFS and, consequently, not mastering complex language comprehension. In typical children, the timeline of PFS acquisition correlates with vocabulary expansion. Conversely, atypically developing children may learn many words but never acquire PFS. In these individuals, intelligence tests based on vocabulary assessment may miss the profound deficit in PFS. Accordingly, we developed a test specific for PFS - Linguistic Evaluation of Prefrontal Synthesis or LEPS - and administered it to 50 neurotypical children, age 4.1 ± 1.3 years and to 23 individuals with impairments, age 16.4 ± 3.0 years. All neurotypical children older than 4 years received the LEPS score 7/10 or greater indicating good PFS ability. Among individuals with impairments only 39% received the LEPS score 7/10 or greater. LEPS was 90% correct in predicting high-functioning vs. low-functioning class assignment in individuals with impairments.

Comparative psychopharmacology of autism and psychotic-affective disorders suggests new targets for treatment

The first treatments showing effectiveness for some psychiatric disorders, such as lithium for bipolar disorder and chlorpromazine for schizophrenia, were discovered by accident. Currently, psychiatric drug design is seen as a scientific enterprise, limited though it remains by the complexity of brain development and function. Relatively few novel and effective drugs have, however, been developed for many years. The purpose of this article is to demonstrate how evolutionary biology can provide a useful framework for psychiatric drug development. The framework is based on a diametrical nature of autism, compared with psychotic-affective disorders (mainly schizophrenia, bipolar disorder and depression). This paradigm follows from two inferences: (i) risks and phenotypes of human psychiatric disorders derive from phenotypes that have evolved along the human lineage and (ii) biological variation is bidirectional (e.g. higher vs lower, faster vs slower, etc.), such that dysregulation of psychological traits varies in two opposite ways. In this context, the author review the evidence salient to the hypothesis that autism and psychotic-affective disorders represent diametrical disorders in terms of current, proposed and potential psychopharmacological treatments. Studies of brain-derived neurotrophic factor, the PI3K pathway, the NMDA receptor, kynurenic acid metabolism, agmatine metabolism, levels of the endocannabinoid anandamide, antidepressants, anticonvulsants, antipsychotics, and other treatments, demonstrate evidence of diametric effects in autism spectrum disorders and phenotypes compared with psychotic-affective disorders and phenotypes. These findings yield insights into treatment mechanisms and the development of new pharmacological therapies, as well as providing an explanation for the longstanding puzzle of antagonism between epilepsy and psychosis. Lay Summary: Consideration of autism and schizophrenia as caused by opposite alterations to brain development and function leads to novel suggestions for pharmacological treatments.

Language evolution to revolution: the leap from rich-vocabulary non-recursive communication system to recursive language 70,000 years ago was associated with acquisition of a novel component of imagination, called Prefrontal Synthesis, enabled by a mutation that slowed down the prefrontal cortex maturation simultaneously in two or more children – the Romulus and Remus hypothesis

There is an overwhelming archeological and genetic evidence that modern speech apparatus was acquired by hominins by 600,000 years ago. On the other hand, artifacts signifying modern imagination, such as (1) composite figurative arts, (2) bone needles with an eye, (3) construction of dwellings, and (4) elaborate burials arose not earlier than 70,000 years ago. It remains unclear (1) why there was a long gap between acquisition of modern speech apparatus and modern imagination, (2) what triggered the acquisition of modern imagination 70,000 years ago, and (3) what role language might have played in this process. Our research into evolutionary origin of modern imagination has been driven by the observation of a temporal limit for the development of a particular component of imagination. Modern children not exposed to recursive language in early childhood never acquire the type of active constructive imagination called Prefrontal Synthesis (PFS). Unlike vocabulary and grammar acquisition, which can be learned throughout one’s lifetime, there is a strong critical period for the development of PFS and individuals not exposed to recursive language in early childhood can never acquire PFS as adults. Their language will always lack understanding of spatial prepositions and recursion that depend on the PFS ability. In a similar manner, early hominins would not have been able to learn recursive language as adults and, therefore, would not be able to teach recursive language to their children. Thus, the existence of a strong critical period for PFS acquisition creates an evolutionary barrier for behavioral modernity. An evolutionary mathematical model suggests that a synergistic confluence of three events (1) a genetic mutation that extended the critical period by slowing down the prefrontal cortex development simultaneously in two or more children, (2) invention of recursive elements of language, such as spatial prepositions, by these children and (3) their dialogic communications using these recursive elements, resulted in concurrent conversion of a non-recursive communication system of their parents to recursive language and acquisition of PFS around 70,000 years ago.

The effects of concurrent cognitive task load on recognising faces displaying emotion

Two independent experiments (N = 30 and N = 24) investigated the effects of concurrent task loads on the recognition of faces displaying emotions. The study aimed to explore a possible resolution for an apparently discrepant finding in the literature regarding the impact of such loads on recognition of facial emotions. Faces displaying different emotions were presented, with or without a concurrent load, until the facial stimuli were correctly labelled to criterion in terms of the displayed emotion. Participants were then presented with elements from the faces (i.e. eyebrows, eyes, and mouth). When participants had to complete the concurrent task as well as the facial recognition task, they did not respond equally to the separate facial elements, and over-selected to the mouth when recognising facial expressions of emotion. The findings relating to the impact of the concurrent load tasks on correct labelling of the facial elements with respect to the emotional faces are discussed in terms of the impact of cognitive load on the production of over-selectivity and the recognition of faces displaying emotions in complex situations, and the implications for those with a developmental disability.

Generalization of content and emotional prosody across speakers varying in gender in youth with Autism Spectrum Disorder

AIMS

We employed a discrimination-choice procedure, embedded in a custom-made videogame, to evaluate whether youth with Autism Spectrum Disorder (ASD), including nonverbal individuals, distinguish sentences on the basis of emotional tone-of-voice and generalize linguistic information across speaker gender.

METHODS AND PROCEDURES

Thirteen youth with ASD (7-21 years) and 13 age-matched typical controls heard pairs of pre-recorded sentences varying in lexical content and prosody (e.g., enthusiastic "Dave rode a bike'' vs. grouchy "Mark held a key''). After training to select a target sentence, participants heard test probes comprising re-combinations of the content and prosodic features of the sentences. Interspersed generalization trials used a voice opposite in gender to the voice used in training.

OUTCOMES AND RESULTS

Youth with ASD were less accurate than controls in discriminating sentences based on emotional tone-of-voice. Nonverbal and verbal youth did not differ in this regard. The ASD group showed only slight decrements in generalizing to the opposite-gender voice.

CONCLUSIONS AND IMPLICATIONS

The finding of intact generalization of linguistic information across male/female speakers contrasts with the widely held view that autism is characterized by deficits in generalization. This suggests the need to test generalization under varying task demands to identify limits on performance.

Diametric effects of autism tendencies and psychosis proneness on attention control irrespective of task demands

Our capacity to attend a target while ignoring irrelevant distraction impacts our ability to successfully interact with our environment. Previous reports have sometimes identified excessive distractor interference in both autism and schizophrenia spectrum disorders and in neurotypical individuals with high subclinical expressions of these conditions. Independent of task, we show that the direction of the effect of autism or psychosis traits on the suppression or rejection of a non-target item is diametrical. In Study 1, in which the presence of a salient non-target item hindered performance, higher autism traits were associated with better performance, while higher psychosis traits were associated with worse performance. In Study 2, in which the presence of a salient non-target item facilitated performance, a complete reversal of effects was observed. Future clinical interventions may be informed by the context-specific advantages we observed for the autism and psychosis spectra, and by the need to consider the diametric effects they yield.

Development of the Mental Synthesis Evaluation Checklist (MSEC): A Parent-Report Tool for Mental Synthesis Ability Assessment in Children with Language Delay

Mental synthesis is the conscious purposeful process of synthesizing novel mental images from objects stored in memory. Mental synthesis ability is essential for understanding complex syntax, spatial prepositions, and verb tenses. In typical children, the timeline of mental synthesis acquisition is highly correlated with an increasing vocabulary. Children with Autism Spectrum Disorder (ASD), on the other hand, may learn hundreds of words but never acquire mental synthesis. In these individuals, tests assessing vocabulary comprehension may fail to demonstrate the profound deficit in mental synthesis. We developed a parent-reported Mental Synthesis Evaluation Checklist (MSEC) designed to assess mental synthesis acquisition in ASD children. The psychometric quality of MSEC was tested with 3715 parents of ASD children. Internal reliability of the 20-item MSEC was good (Cronbach's alpha >0.9). MSEC exhibited adequate test⁻retest reliability; good construct validity, supported by a positive correlation with the Autism Treatment Evaluation Checklist (ATEC) Communication subscale; and good known group validity reflected by the difference in MSEC scores for children of different ASD severity levels. The MSEC questionnaire is copyright-free and can be used by researchers as a complimentary subscale for the ATEC evaluation. We hope that the addition of MSEC will make the combined assessment more sensitive to small steps in a child's development. As MSEC does not rely on productive language, it may be an especially useful tool for assessing the development of nonverbal and minimally verbal children.

Neurobiological mechanisms for nonverbal IQ tests: implications for instruction of nonverbal children with autism

Traditionally, the neurological correlates of IQ test questions are characterized qualitatively in terms of ‘control of attention’ and ‘working memory.’ In this report we attempt to characterize each IQ test question quantitatively by two factors: a) the number of disparate objects that have to be imagined in concert in order to solve the problem and, b) the amount of recruited posterior cortex territory. With such a classification, an IQ test can be understood on a neuronal level and a subject’s IQ score could be interpreted in terms of specific neurological mechanisms available to the subject.

Here we present the results of an analysis of the three most popular nonverbal IQ tests: Test of Nonverbal Intelligence (TONI-4), Standard Raven's Progressive Matrices, and Wechsler Intelligence Scale for Children (WISC-V). Our analysis shows that approximately half of all questions (52±0.02%) are limited to mental computations involving only a single object; these easier questions are found towards the beginning of each test. More difficult questions located towards the end of each test rely on mental synthesis of several disparate objects and the number of objects involved in computations gradually increases with question difficulty. These more challenging questions require the organization of wider posterior cortex networks by the lateral prefrontal cortex (PFC). This conclusion is in line with neuroimaging studies showing that activation level of the lateral PFC and the posterior cortex positively correlates with task difficulty. This analysis has direct implications for brain pathophysiology and, specifically, for therapeutic interventions for children with language impairment, most notably for children with Autism Spectrum Disorder (ASD) and other developmental disorders.

Over-Selectivity is Related to Autism Quotient and Empathizing, But not to Systematizing

The relationships of autism quotient (AQ), systematizing (SQ), and empathizing (EQ), with over-selectivity were explored to assess whether over-selectivity is implicated in complex social skills, which has been assumed, but not experimentally examined. Eighty participants (aged 18–60) were trained on a simultaneous discrimination task (AB+CD−), and tested in extinction on the degree to which they had learned about both elements of the reinforced (AB) compound. Higher AQ and lower EQ scorers demonstrated greater over-selectivity, but there was no relationship between SQ and over-selectivity. These results imply that high AQ scorers perform similarly to individuals with ASD on this cognitive task, and that over-selectivity may be related to some complex social skills, like empathy.

Autism Tendencies and Psychosis Proneness Interactively Modulate Saliency Cost

Atypical responses to salient information are a candidate endophenotype for both autism and psychosis spectrum disorders. The present study investigated the costs and benefits of such atypicalities for saliency-based selection in a large cohort of neurotypical adults in whom both autism and psychosis expressions were assessed. Two experiments found that autism tendencies and psychosis proneness interactively modulated the cost incurred in the presence of a task-irrelevant salient distractor. Specifically, expressions of autism and psychosis had opposing effects on responses to salient information such that the benefits associated with high expressions for autism offset costs associated with high expressions for psychosis. The opposing influences observed on saliency cost may be driven by distinct attentional mechanisms that are differentially affected by expressions for autism and psychosis.

Association testing of vasopressin receptor 1a microsatellite polymorphisms in non-clinical autism spectrum phenotypes

Variation in the AVPR1a gene, which codes for a receptor for the neurohormone vasopressin, has been found to relate to autism risk. Interestingly, variation in this gene also relates to differences in social behaviour in non-clinical populations. Variation in this gene may affect expression of AVPR1a receptors in brain areas involved in social behaviour. Here, we tested whether AVPR1a variation was associated with Autism Quotient (AQ) scores, a questionnaire that measures non-clinical manifestations of autism, in a population of 873 healthy university students. The AVPR1a RS1 and RS3 microsatellites were examined, and variants were categorized as "long" or "short". The RS3 long/long genotype was significantly associated with a higher AQ score (i.e., a more autistic-like phenotype) for the combined population and for females only. Further examination showed that this relationship was due to a specific RS3 variant, termed the "target allele", which previous research has linked to reduced altruism and increased marital problems in healthy individuals. We also observed that the relationship between RS3 genotype and AQ score was mainly due to the "attention switching" (the ability to shift attention from one task to another) component of the questionnaire; this ability is commonly impaired in autism spectrum disorders. Overall, our study establishes continuity between the existing AVPR1a research in clinical and non-clinical populations. Our results suggest that vasopressin may exert its effects on social behaviour in part by modulating attentional focus between social and non-social cues. Autism Res 2017, 10: 750-756. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Reducing overselective stimulus control with differential observing responses

Overselective stimulus control refers to discriminative control in which the number of controlling stimuli is too limited for effective behavior. Experiment 1 included 22 special-education students who exhibited overselective stimulus control on a two-sample delayed matching task. An intervention added a compound identity matching opportunity within the sample observation period of the matching trials. The compound matching functioned as a differential observing response (DOR) in that high accuracy verified observation and discrimination of both sample stimuli. Nineteen participants learned to perform the DOR and two-sample delayed matching accuracy increased substantially for 16 of them. When the DOR was completely withdrawn after 10 sessions, accuracy declined. In Experiment 2, a more gradual withdrawal of DOR requirements showed that highly accurate performance could be maintained with the DOR on only a proportion of trials for most participants. The results show that DOR training may lead to a general improvement in observing behavior.

Autism As a Disorder of High Intelligence

A suite of recent studies has reported positive genetic correlations between autism risk and measures of mental ability. These findings indicate that alleles for autism overlap broadly with alleles for high intelligence, which appears paradoxical given that autism is characterized, overall, by below-average IQ. This paradox can be resolved under the hypothesis that autism etiology commonly involves enhanced, but imbalanced, components of intelligence. This hypothesis is supported by convergent evidence showing that autism and high IQ share a diverse set of convergent correlates, including large brain size, fast brain growth, increased sensory and visual-spatial abilities, enhanced synaptic functions, increased attentional focus, high socioeconomic status, more deliberative decision-making, profession and occupational interests in engineering and physical sciences, and high levels of positive assortative mating. These findings help to provide an evolutionary basis to understanding autism risk as underlain in part by dysregulation of intelligence, a core human-specific adaptation. In turn, integration of studies on intelligence with studies of autism should provide novel insights into the neurological and genetic causes of high mental abilities, with important implications for cognitive enhancement, artificial intelligence, the relationship of autism with schizophrenia, and the treatment of both autism and intellectual disability.

Factors producing over-selectivity in older individuals

Stimulus over-selectivity describes a phenomenon where only a subset of the relevant stimuli present in the environment, control an individual's behavior. The current experiment explored the degree to which over-selectivity increases in old age. The level of over-selectivity in a visual discrimination task in 60 individuals aged 60-89 years was assessed, as well as the degree to which this reflected attentional control. In addition, the intellectual functioning and cognitive flexibility of the participants were assessed. Results showed that, as age increased, three effects were revealed: levels of stimulus over-selectivity increased, IQ scores decreased, and cognitive flexibility decreased. However, over-selectivity was not related to IQ or cognitive flexibility, and appeared related most to attentional impairments. Thus, ageing is related to significant declines in effective stimulus control. These effects can have a serious impact on the physical and psychological health of old adults, as well as their quality of life, and, therefore, this area of research warrants further exploration. The results are discussed in relation to the attention-deficit and comparator theory of over-selectivity.

Stimulus Overselectivity in Autism, Down Syndrome, and Typical Development

Stimulus overselectivity refers to maladaptive narrow attending that is a common learning problem among children with intellectual disabilities and frequently associated with autism. The present study contrasted overselectivity among groups of children with autism, Down syndrome, and typical development. The groups with autism and Down syndrome were matched for intellectual level, and all three groups were matched for developmental levels on tests of nonverbal reasoning and receptive vocabulary. Delayed matching-to-sample tests presented color/form compounds, printed words, photographs of faces, Mayer-Johnson Picture Communication Symbols, and unfamiliar black forms. No significant differences among groups emerged for test accuracy scores. Overselectivity was not statistically overrepresented among individuals with autism in contrast to those with Down syndrome or typically developing children.

Naturalistic Developmental Behavioral Interventions: Empirically Validated Treatments for Autism Spectrum Disorder

Earlier autism diagnosis, the importance of early intervention, and development of specific interventions for young children have contributed to the emergence of similar, empirically supported, autism interventions that represent the merging of applied behavioral and developmental sciences. “Naturalistic Developmental Behavioral Interventions (NDBI)” are implemented in natural settings, involve shared control between child and therapist, utilize natural contingencies, and use a variety of behavioral strategies to teach developmentally appropriate and prerequisite skills. We describe the development of NDBIs, their theoretical bases, empirical support, requisite characteristics, common features, and suggest future research needs. We wish to bring parsimony to a field that includes interventions with different names but common features thus improving understanding and choice-making among families, service providers and referring agencies.