Genes MatterSo What

Brian Byrne, Katrina Grasby and William CoventryUniversity 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 designWhen twins are reared within a family (that is, not separated at birth), variance can be partitioned thus:

genetic variance environmental variance

shared environment unique 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(rMZ – rDZ)

C = rMZ – A

E = 1 - rMZ

Reading (from International Twin Study of Literacy)

Kindergarten (words)

Grade 2 (words)

Grade 1 (words)

Grade 2 (text)

Extremes analysisHeritability of low- and high-ability reading

Grade Ability -1 SD -1.5 SD1 Low .58 .35*

High .69 .812 Low .63 .40*

High .76 .67

* 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 ImplicationsIndividuals 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 PsycholinguisticsBrian Byrne

University of New EnglandThank you to

Sally Larsen, Dipti McGowan

The families of the twins and the twins themselves

The Australian Research Council

The Australian Twin Registry