Investigating quantity processing and inhibition in ageing with the number Stroop 1Jade E Norris, 2Kevin J Riggs, & 2Julie Castronovo 1Department of Psychology, Swansea University 2Department of Psychology, University of Hull J.E.Norris@Swansea.ac.uk

Ageing and cognition Cognitive decline: processing speed, memory, reasoning, executive functions, inhibition (Hasher & Zacks, 1988; Salthouse, 1996) General knowledge, verbal, & numerical abilities may be preserved (Christensen, 2001) Mathematical problem solving: mixed conclusions- reduced flexibility in choosing effective strategies (Duverne & Lemaire, 2004; Lemaire & Arnaud, 2008) Or, preserved/enhanced maths skills in ageing (Cappelletti et al., 2014; Norris et al., 2015)

Basic numerical processing in ageing Approximate numerical abilities may be preserved in ageing (Cappelletti et al., 2014; Norris et al., 2015) Symbolic and non-symbolic Distance/ratio effect Norris et al. (2015): Higher accuracy & reduced distance effect = more embedded symbolic skills in older age? 67 Norris et al., 2015 4 7 Cappelletti et al., 2014

Number Stroop in ageing Symbolic comparison task: easy? = ceiling effects? Number stroop: Numerical AND physical size Increased interference & preserved distance effects in AD and MCI (Girelli et al., 2001; Kaufmann et al., 2008) Preserved quantity processing (Lambrechts et al., 2013) Older adults-> poorer inhibition (Hasher & Zacks, 1988) -> stronger interference effects, BUT-> nature of interference may be mediated by quantity type 2 7

Quantity processing: shared or unique systems? ‘A Theory of Magnitude’ (ATOM)- links between quantity processes (e.g. number, size, duration) exist due to collective requirement for action (Bueti & Walsh, 2009; Walsh, 2003) Several quantity processes maintained in ageing (Lambrechts et al., 2013) = support for ATOM? Preserved numerical & declined duration processing (Dormal et al., 2012) = evidence of separate systems? Number Stroop simultaneously measures numerical and physical size processing 8

Methods: number Stroop (Cohen Kadosh et al., 2008) Numerical and Physical Distances: 1, 2, and 5 48 trials per congruency condition = 144 trials total Neutral Congruent Incongruent Numerical: 2 7 Physical: 7 7 2 7

Methods 114 younger adults (18-25; Mage = 20, SD = 1.5) 62 older adults (60-75; Mage = 66, SD = 4) Mini-Mental State Exam (MMSE: Folstein et al., 1975) Geriatric Depression Scale (GDS: Yesavage et al., 1982; Kaufmann et al., 2008) Exclusions 8 older adults (2x MMSE <27, 6x GDS >5) 2 younger adults for GDS >5, 2 for failing to complete the testing session, and 1 from the physical task (7% accuracy) = 176 for the numerical task, and 175 for the physical task

Age group x task type x congruency Numerical task fastest Interference effects Task*congruency: F = 50.69, p < .001

Physical task (Age group x distance x congruency) 7 7 Neutral excluded (Henik & Tzelgov, 1982) No main effect of distance Congruency*distance: F = 66.54, p < .001 Distance*age: F = 2.74, p = .066

Numerical task (Age group x distance x congruency) Typical distance effect Congruency*distance: F = 59.131, p < .001 Congruency*age: F = 4.017, p < .05 greater interference in ageing

Numerical task continued… Congruency*distance*age: F = 5.998, p < .001 Young Old

Working interpretations & conclusions Preserved numerical and continuous quantity processing in ageing (ATOM: Walsh, 2003) Stronger interference effects in ageing only during numerical task = increased influence of continuous quantity on numerical judgements (Cappelletti et al., 2014, 2015, Lambrechts et al., 2013) Equalising congruent trials = no facilitation + no neutral distance? (Dixon & Just, 1978; Henik & Tzelgov, 1982) Physical size differences too small? 0.2º 7 2 7 2

Thank you

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Cohen Kadosh et al. (2007): high cognitive load -> numerical & continuous processes activated in parallel = distinct AND shared magnitude systems possible, but mediated by cognitive load