High-probability Sequence Research Articles

The effects of prematurity and socioeconomic deprivation on early speech perception: A story of two different delays.

There is evidence showing that both maturational and environmental factors can impact on later language development. On the one hand, preterm birth has been found to increase the risk of deficits in the preschool and school years. Preterm children show poorer auditory discrimination, reading difficulties, poor vocabulary, less complex expressive language and lower receptive understanding than their matched controls. On the other hand, socioeconomic status (SES) indicators (i.e., income, education and occupation) have been found to be strongly related to linguistic abilities during the preschool and school years. However, there is very little information about how these factors result in lower linguistic abilities. The present study addresses this issue. To do so, we investigated early speech perception in full and preterm infants from families classed as high or low SES. Seventy-six infants were followed longitudinally at 7.5, 9, 10.5 and 12months of age. At each test point, three studies explored infants' phonetic, prosodic and phonotactic development respectively. Results showed no significant differences between the phonetic or the phonotactic development of the preterm and the full-term infants. However, a time-lag between preterm and full-term developmental timing for prosody was found. Socioeconomic status did not have a significant effect on prosodic development. Nonetheless, phonetic and phonotactic development was affected by SES, infants from lower SES showed phonetic discrimination of non-native contrast and a preference for high-probability sequences later than their more advantaged peers. Overall these results suggest that different constraints apply to the acquisition of different phonological subcomponents.

Statistical Learning of Unfamiliar Sounds as Trajectories Through a Perceptual Similarity Space.

In typical statistical learning studies, researchers define sequences in terms of the probability of the next item in the sequence given the current item (or items), and they show that high probability sequences are treated as more familiar than low probability sequences. Existing accounts of these phenomena all assume that participants represent statistical regularities more or less as they are defined by the experimenters-as sequential probabilities of symbols in a string. Here we offer an alternative, or possibly supplementary, hypothesis. Specifically, rather than identifying or labeling individual stimuli discretely in order to predict the next item in a sequence, we need only assume that the participant is able to represent the stimuli as evincing particular similarity relations to one another, with sequences represented as trajectories through this similarity space. We present experiments in which this hypothesis makes sharply different predictions from hypotheses based on the assumption that sequences are learned over discrete, labeled stimuli. We also present a series of simulation models that encode stimuli as positions in a continuous two-dimensional space, and predict the next location from the current location. Although no model captures all of the data presented here, the results of three critical experiments are more consistent with the view that participants represent trajectories through similarity space rather than sequences of discrete labels under particular conditions.

Addressing Feeding Disorders Using High-Probability Sequencing for Children and Adolescents with Developmental Disabilities

Feeding disorders exhibited by children with developmental disabilities, which include limiting food intake or refusing to consume solid foods, often result in poor health consequences. Interventions for feeding disorders vary in terms of their acceptability to children with disabilities and their families. One specific procedure, the high-probability sequence, is a nonrestrictive approach where requests with which a child has a history of compliance are presented prior to requests associated with noncompliance. This article reviewed research concerning the application of high-probability sequencing for feeding disorders among children and adolescents with developmental disabilities. Experimental studies published between 1970 and 2018 in English as either peer-reviewed articles or dissertations were eligible for descriptive review. Identified articles ( N = 15) evaluated high-probability sequencing using various single-case experimental designs. Participants ( N = 21) were generally preschool-aged children (mean age = 5.7 years) diagnosed with autism spectrum disorder (ASD; n = 9) or other developmental disabilities ( n = 12). Subsequent analysis of articles that met quality indicators of the What Works Clearinghouse ( n = 12) suggests that research does not support the effectiveness of the procedure for increasing food acceptance. Implications for practice and future studies involving high-probability sequencing follow a discussion of findings.

Clinical Application of a High-Probability Sequence to Promote Compliance with Vocal Imitation in a Child with Autism Spectrum Disorder.

The current study aimed to evaluate the effects of the high-probability (high-p) instructional procedure involving motor imitation on the levels of compliance with vocal imitation in a 3-year-old boy with autism spectrum disorder (ASD). We used a multiple-baseline design across three stimuli sets to demonstrate effects of the procedure over compliance with vocal imitation responses. Results demonstrated that the high-p procedural sequence was effective in increasing the levels of compliance with vocal imitation. We discuss these finding in terms of the operant mechanisms and clinical applications of increased compliance.

When learning goes beyond statistics: Infants represent visual sequences in terms of chunks

Much research has documented infants’ sensitivity to statistical regularities in auditory and visual inputs, however the manner in which infants process and represent statistically defined information remains unclear. Two types of models have been proposed to account for this sensitivity: statistical models, which posit that learners represent statistical relations between elements in the input; and chunking models, which posit that learners represent statistically-coherent units of information from the input. Here, we evaluated the fit of these two types of models to behavioral data that we obtained from 8-month-old infants across four visual sequence-learning experiments. Experiments examined infants’ representations of two types of structures about which statistical and chunking models make contrasting predictions: illusory sequences (Experiment 1) and embedded sequences (Experiments 2–4). In all four experiments, infants discriminated between high probability sequences and low probability part-sequences, providing strong evidence of learning. Critically, infants also discriminated between high probability sequences and statistically-matched sequences (illusory sequences in Experiment 1, embedded sequences in Experiments 2–3), suggesting that infants learned coherent chunks of elements. Experiment 4 examined the temporal nature of chunking, and demonstrated that the fate of embedded chunks depends on amount of exposure. These studies contribute important new data on infants’ visual statistical learning ability, and suggest that the representations that result from infants’ visual statistical learning are best captured by chunking models.

Rapid infectious disease identification by next-generation DNA sequencing

Currently, there is a critical need to rapidly identify infectious organisms in clinical samples. Next-Generation Sequencing (NGS) could surmount the deficiencies of culture-based methods; however, there are no standardized, automated programs to process NGS data. To address this deficiency, we developed the Rapid Infectious Disease Identification (RIDI™) system. The system requires minimal guidance, which reduces operator errors. The system is compatible with the three major NGS platforms. It automatically interfaces with the sequencing system, detects their data format, configures the analysis type, applies appropriate quality control, and analyzes the results. Sequence information is characterized using both the NCBI database and RIDI™ specific databases. RIDI™ was designed to identify high probability sequence matches and more divergent matches that could represent different or novel species. We challenged the system using defined American Type Culture Collection (ATCC) reference standards of 27 species, both individually and in varying combinations. The system was able to rapidly detect known organisms in <12h with multi-sample throughput. The system accurately identifies 99.5% of the DNA sequence reads at the genus-level and 75.3% at the species-level in reference standards. It has a limit of detection of 146cells/ml in simulated clinical samples, and is also able to identify the components of polymicrobial samples with 16.9% discrepancy at the genus-level and 31.2% at the species-level. Thus, the system's effectiveness may exceed current methods, especially in situations where culture methods could produce false negatives or where rapid results would influence patient outcomes.

USING HIGH‐PROBABILITY FOODS TO INCREASE THE ACCEPTANCE OF LOW‐PROBABILITY FOODS

Studies have evaluated a range of interventions to treat food selectivity in children with autism and related developmental disabilities. The high-probability instructional sequence is one intervention with variable results in this area. We evaluated the effectiveness of a high-probability sequence using 3 presentations of a preferred food on increasing acceptance in a child with autism who refused a few specific foods. The high-probability sequence increased acceptance of 3 foods. We then systematically faded the intervention for 2 foods.

Momentum versus extinction effects in the treatment of self-injurious escape behavior.

An individual's self-injurious escape behavior was treated using a high-probability instructional sequence with and without extinction. When presented alone, the high-probability sequence did not reduce self-injurious behavior. When escape extinction was implemented either alone or in combination with the high-probability sequence, self-injury decreased and compliance increased, suggesting that extinction may be a necessary component of the treatment for behavior problems maintained by escape.

Effects of high-probability requests on the acquisition and generalization of responses to requests in young children with behavior disorders.

The failure to respond to requests in young children often is maintained by the reactions of the adults that encounter this behavior. This failure to respond to requests has been identified as a primary reason for the children's exclusion from community, social, and instructional opportunities. Numerous interventions that target the failure to respond have consisted of punishment and reinforcement procedures. More recently, antecedent interventions have focused on changing the context in which a request is delivered. In the current study, high-probability requests were provided as an antecedent to delivering a low-probability request. The requests were delivered by multiple trainers in an attempt to produce generalized appropriate responding to adults who did not use the high-probability sequence. Results showed an immediate increase in appropriate responding in 2 children when the intervention was delivered. In addition, when the intervention was implemented by more than one adult, spontaneous increases in responding also were observed toward adults who had never implemented the request sequence. Improvements in responding to requests were maintained after the intervention was discontinued.