The influence of forgetting rate on complex span and academic performance Debbora Hall, Chris Jarrold, John Towse and Amy Zarandi

Complex span and academic achievement Complex span is predictive of academic performance (Swanson & Beebe-Frankenburger, 2004) Storage and processing are also related to academic performance (e.g. Bull et al., 2008) Complex span itself is a better predictor than its component parts (Bayliss et al., 2003) There is residual variance left when STM and speed of processing is partialled out… (Bayliss et al., 2003).

Residual variance is not just measurement error Residual variance is related to academic performance (Bayliss et al., 2003). It is also related to the rate at which information is forgotten (Bayliss & Jarrold, 2014).

What is complex span? Short- term memory Residual Variance Speed of Processing Rehearsal? Complex span Forgetting? Memory Scanning?

Exploring residual variance in complex span and academic achievement 107 children aged between 5 and 8 years old. Reading ▫NFER group reading test; sentence comprehension and word reading Mathematics ▫Progress in Maths 6 & 8; ‘Maths Age’ derived to equate across tests. Complex span, short-term memory, speed of processing, forgetting, rehearsal (articulation), and memory scanning.

Complex span Two complex span tasks (age partialled correlation r (105) =.714, p <.01. Simple span measured using digit span Both complex span tasks harder than simple span, p <.01 Verbal- verbal complex span performance poorer than verbal-visual complex span performance, p<.01. Verbal and visual baseline processing tasks measured independently (comparable speed, p>.10; significantly correlated, r (105) =.710).

Calculating residual variance in complex span Verbal baseline processing Visual baseline processing Simple span The unstandardised residuals were saved for each participant to create a ‘verbal residual’. The same predictors were used in a linear regression with verbal-visual complex span to create a ‘visual residual’ Verbal- verbal complex span Both baseline processing measures used to gain estimate of general speed of processing.

Does the residual variance relate to academic performance? Bivariate correlations shown. With age partialled, storage remains significantly related to reading and maths, processing to maths, and the residuals to reading, all ps <.01.

Measuring speed of rehearsal Single word, e.g. ‘cat cat cat cat cat’ Word pairs, e.g. ‘rug bin rug bin rug bin rug bin rug bin’ Six single words and six word pairs; average time taken to articulate 5 utterances of a single word & average time taken to articulate 5 word pair utterances. ‘Articulation time’

Measuring forgetting Preloaded with digits, calibrated to individual span level + 1 item to avoid ceiling levels of performance. Then given 1s, 2.5s, 4s, 7s, and 10s of either the verbal or visual processing task Recall digits in correct serial order. This was very difficult and the responses were scored with partial credit for list items in any order. Sample was truncated to N = 65; only individuals scoring above 50% at baseline included.

Forgetting task performance

Measuring memory scanning To index memory scanning: Sternberg scanning task. Lists of between 1 and 6 items ?

Do the novel measures correlate with the components of complex span? Articulation (single word) Articulation (word pair) Verbal Forgetting Visual Forgetting Memory scanning Storage Factor-.28*-.38* * Processing Factor.10.25* * Verbal Residual *-.08 Visual Residual *-.08 Full sample for all variables excluding forgetting, for which data is presented for the truncated sample only (N = 65).

Do the novel measures correlate with reading and maths? Regression models have shown only articulation to have a unique contribution in predicting reading after storage and processing have been taken into account.

Conclusions Forgetting is related to the residual variance in complex span (see also Bayliss & Jarrold, 2014; & further replication). Forgetting, articulation time, and memory scanning did not account for the relationship between the residual variance and academic performance. Complex span itself remains the best predictor of academic performance, and is greater than the sum of storage and processing, with independent contributions from articulation. What is the link between residual variance and academic performance?