Genes Matter So What Brian Byrne, Katrina Grasby and William Coventry University of New England

Some personal reflections A single learning theory Initial hypothesis: Letters represent morphemes The phonetic module is buried in the cognitive unconscious Learning print-speech pairs that reveal letter- phoneme relations ≠ discovery of alphabetic principle Therefore, design and delivery of instruction is the main source of variance

WRONG!!!

Colorado Learning Disabilities Research Center and Institute for Behavioral Genetics

Twin designs Identical (MZ) twins: 100% genes in common Fraternal (DZ) twins: Average 50% genes in common

Classic twin design When twins are reared within a family (that is, not separated at birth), variance can be partitioned thus: genetic varianceenvironmental variance shared environmentunique environment total variance

Genetic, shared environment and unique environment influences on a trait can be estimated from the degree of similarity between twins as a function of zygosity A = 2(r MZ – r DZ ) C = r MZ – A E = 1 - r MZ

Reading (from International Twin Study of Literacy) Kindergarten (words) Grade 2 (words) Grade 1 (words) Grade 2 (text)

Extremes analysis Heritability of low- and high-ability reading GradeAbility-1 SD-1.5 SD 1Low.58.35* High Low.63.40* High * N = 90, small for twin model, wide confidence intervals

All in all… …genes really matter when it comes to understanding sources of differences among school students in literacy (and numeracy) in Australian schools This includes low-end scores, though evidence for more environmental influence at very low ability levels

An important observation Kvaale, Haslam, Gottdeiner, Clinical Psychology Review, 2013 “We found that biogenetic explanations reduce blame…but induce pessimism (about recovery)… Promoting biogenetic explanations to alleviate blame may induce pessimism and set the stage for self-fulfilling prophecies that could hamper recovery from psychological problems.”

A menu for Implications Individuals hampered by literacy difficulties Practitioners and teachers Researchers Policy-makers Politicians

Implications: For teachers and teacher training Differences among teachers are not nearly as substantial as public opinion holds and the press promotes. Basing teacher rewards on student achievement is unsound and could have unfortunate consequences (such as teachers’ reluctance to work in schools with poor NAPLAN results). Nevertheless, because academic achievement is about means as well as variances, teaching and teacher training need to be as evidence-based as possible (e.g., the phonics/whole language issue).

Implications: For the educational system as a whole The practice of comparing “like” schools on the basis of NAPLAN results is invidious because the comparator (ICSEA) is a distant proxy for student characteristics, including genetic endowment

Implications: For the educational system as a whole Any additional funding flowing from NAPLAN testing should be directed towards individual students, not to schools for school-level changes (e.g., smaller class sizes, more computers….)

Implications: For the educational system as a whole As the curriculum moves to be “national,” that is more uniform across the country, genetic influence will increase as environmental variance in the form of curriculum differences decreases.

Introduction to Psycholinguistics Brian Byrne University of New England Thank you to Sally Larsen, Dipti McGowan The families of the twins and the twins themselves The Australian Research Council The Australian Twin Registry