Consonant Age of Acquisition Reveals Nonlinear Effects in Nonword Repetition Performance.

Recent work has shown significant sublexical effects of long-term memory in nonword repetition (NWR) using a dichotomous consonant age of acquisition (CAoA) variable (Moore, 2018; Moore, Fiez, and Tompkins, 2017). Performance consistently decreased when stimuli comprised consonants acquired later versus earlier in speech development. To address potential confounds related to stimulus design and linearity, the purpose of this study was to test whether performance decreases as the CAoA value of stimuli increases in various linguistic tasks using a continuous CAoA variable. Thirty-one college students completed NWR and other linguistic tasks in which the stimuli varied in average CAoA values. Data were analyzed using multilevel modeling. After accounting for phonotactic probability, CAoA was a statistically significant predictor of performance across the models reported. The relationship was more complex in some of the models in which CAoA showed a statistically significant nonlinear relationship with the outcome measure. Results from this study support previous work showing that CAoA affects performance on NWR and other linguistic tasks that vary in their memory, auditory perceptual, and articulatory demands. Importantly, this line of work was extended here by demonstrating that the CAoA effect is robust across novel stimulus sets and study designs, and may be more complex than previously understood when using a dichotomous CAoA variable. Quadratic results suggest that the CAoA variable has a differential effect on performance for low to moderate CAoA values, but for higher CAoA values the effect is similarly negative. The nonlinear relationship between CAoA and measures of speed and accuracy on some of the tasks warrants further study into the complex relationship between various predictive factors that contribute to language performance.

Differential return on investment: Academic growth in mathematics and reading based on initial performance.

BACKGROUND: Students vary in their initial achievement when they enter school and their rate of academic growth as they move through school. These differences have implications for classroom instruction and educational policy. Although previous research has examined initial achievement and growth differences, a gap remains in understanding how initial level of achievement interacts with subsequent growth as children move through school. AIM: Using Vygotsky's zone of proximal development (ZPD) and return on investment as theoretical grounding, this registered report examined how students' initial academic performance relative to their school predicts their subsequent academic achievement. The stage 1 accepted registered report is available at https://osf.io/9zmak/. Specifically, we tracked the achievement of a cohort of students who started at or above their school's mean at the beginning of third grade and tested a range of hypotheses regarding their achievement and growth as well as which students showed the greatest gains from their time in school. SAMPLE: Using a large database of student academic achievement in the United States, this registered report included de-identified data from all students from fall 2014 to spring 2017 in grades three through five from the ten US states with the highest participation for the Northwest Evaluation Association's Measures of Academic Progress (MAP®) - a computer adaptive test of academic achievement in mathematics and reading. Because the MAP is taken at least twice per school year, up to six scores were included on mathematics and reading achievement for effective samples of approximately 220,000 students. METHOD: We built separate reading and mathematics three-level piecewise longitudinal hierarchical linear models (student repeated measures, nested within students, nested within schools) to model student growth from the beginning of third grade to the end of fifth grade (i.e., three academic years and two summers). RESULTS: For both mathematics and reading, average student achievement growth slowed as they progressed from third through fifth grade. From there, the findings diverged. In mathematics, student growth was mostly similar across achievement levels and grades from third through fifth. However, in reading, above-average students demonstrated slower growth than average students during the school year but faster growth during the summer. Also of note, at the beginning of third grade, the highest achieving students outscored average students in their school by more than 2 years in mathematics and 3 years in reading. CONCLUSIONS: Our results may be able to be explained via a ZPD model, which posits development only occurs when students are placed in appropriately challenging environments. In mathematics, the observed pattern of relatively consistent growth across achievement levels suggests average students were just as likely to be in their ZPD as higher achieving students. In reading, as initial achievement increased, student reading growth slowed, which suggests the higher the initial achievement, the less likely students were to be in their ZPD. If a goal of education is for students to learn new things, our results suggest existing school offerings in reading are not meeting that goal equitably for students across the performance spectrum. Differential growth patterns should be considered when designing learning experiences for students who enter with a wide range of prior mastery.