The processing-speed theory of adult age differences in cognition

“The proposals for processing deficits in older readers comprise reduced perceptual acuity (Fozard & Gordon-Salant, 2001), increased susceptibility to interference (Hasher & Zacks, 1988), reduced working memory capacity (Dobbs & Rule, 1989; Waters & Caplan, 2005), and slowed processing (Salthouse, 1996).”

“…(crystallised) peaks late in adulthood; tasks such as verbal fluency, reasoning, and long-term memory, which require both crystallised knowledge and fluid ability, peak at intermediate ages (Hartshorne and Germine, 2015; Hedden and Gabrieli, 2004; Salthouse, 1996; Swagerman et al., 2016).”

“The cognitive constructs working memory (WM) and processing speed are fundamental components to general intellectual functioning in humans (Courtney 2004; Salthouse 1996; Salthouse and Coon 1993) and, critically, both WM and processing speed are highly susceptible to disruption following neurological insult.”

“The aims of this study were to: (1) examine the degree of overlap between EC and processing speed at different preschool age points; and (2) determine whether EC uniquely predicts children’s mathematics achievement after accounting for individual differences in processing speed.”

“General slowing has often been put forward as a general account of age-related cognitive impairments (Salthouse, 1996).”

“It has been hypothesized that speed may underlie EF (Salthouse, 1996, 2005); it was an indicator of EF in one latent variable study (McGrath et al., 2016).”

“of personality development, whereas it is more prominent in other fields, such as cognitive aging (e.g., Baltes & Lindenberger, 1997; Martin & Zimprich, 2003; Mascherek & Zimprich, 2011; Salthouse, 1996; Sliwinsky et al., 2003; Zimprich & Martin, 2002).”

“…ability such as elementary perceptual speed, attention, executive function, and episodic memory, whereas measures of crystallized abilities relating to knowledge and expertise exhibit little or no decline during healthy aging (Howard and Howard, 2013; Park et al., 2002; Salthouse, 1996, 2004).”

“N IH -PA Author M anuscript N IH -PA Author M anuscript N IH -PA Author M anuscript empirical predictions that can be distinguished from alternative accounts such as generalized slowing (Madden, 2001;Salthouse, 1996).”

“More specifically, individual differences in processing speed are linked to age-related differences in gf (Fry & Hale, 1996; Salthouse, 1996).”

“Older adults are generally slower than younger adults at most speeded tasks (e.g., Salthouse, 1996), and we replicated this finding with the speeded legibility tasks.”

“Older adults experience declines in processing speed that lead to slower performance in general and lower accuracy on complex cognitive tasks (Salthouse, 1996).”

“…is one of the most common symptoms of neurologic aging, and some groups argue that it is the hallmark of aging underlying all other cognitive changes (Salthouse, 1996, 2000); this is consistent with our finding that individuals who showed the steepest speed declines were in fact the oldest.”

“To adjust for age-related slowing for perceptual, cognitive, and motor processes (Birren, 1970; Salthouse, 1996), older adults were given 50 s to study on each trial, whereas younger adults were given a maximum of 25 s (see Price et al., 2010).”

“On the contrary, PS is an important component of many cognitive domains including WM (Salthouse, 1996).”

“Future research should look at other possible mediators that have yet to be investigated, such as strategy use, speed of processing ( Salthouse, 1996 ), inhibition (Zacks & Hasher, 1994), or degraded transmission of connective information (MacKay & Burke, 1990).”

“We believe that the resulting improvements in brain activation and/or structure delayed the onset or reduced the risk of cognitive slowing, which has been argued to be among the most significant contributors to overall cognitive decline [42,43].”

“It also can be affected more gradually, perhaps via increases in processing speed from youth to adulthood and decreases from adulthood to old age (Kail, 1991; Salthouse, 1996).”

“It has been argued that faster processing speed might provide a foundation for better cognitive performance in higher cognitive domains and for less cognitive decline in them (4, 8, 9).”

“…evidence to support a conclusion that normal aging beyond the mid-1960s is, on average, accompanied by cognitive decline that, although different abilities change at different rates, is largely attributable to slowing of information processing speed (Deary, 2000; Salthouse, 1996; Schaie, 1994).”

“The CATS Reaction Time task (Davis & Keller, 1998) was used because it includes measures of pure motor speed, processing speed, and conditional inhibition, which have been associated with age-related decline (Lezak et al., 2004; Salthouse, 1996).”

“Salthouse proposed that the reduction with aging in the speed with which many cognitive operations can be executed is a major factor contributing to age-related differences in cognitive functioning [11].”

“Also, previous studies have demonstrated a substantial reduction in age-related cognitive differences after measures of processing speed are factored out of the relationship between cognitive performance and chronological age (Cerella, 1991; Salthouse, 1996, 1999).”

“There is, however, al arge volume of literature documenting progressive slowing of RTs as we age (e.g., Hunter, Thompson, & Roger, 2001; Salthouse, 1991, 1996; Morgan et al., 1994), which may affect an individualʼs quality of lifeby compromisingwork productivity, mobility, and independence.”

“Processing speed is important for its relation, at older ages, to IQ (Detterman, 1987; Jensen, 1987), and for its association with individual differences in various higher level aspects of cognition, including fluid intelligence, reasoning, memory, and executive functioning (Anderson, 2001; Kail, 1986, 1988; Kail & Sa…”

“As shown in Table 1 the younger adults had good hearing and, as would be expected, outperformed the older adults on tests of speed and working memory (e.g., Salthouse, 1991, 1996).”

“Theories that have information leakage (Myerson, Hale, Wagstaff, Poon, & Smith, 1990), slower processing (Cerella, 1985; Salthouse, 1996), and deficits in controlled processing (Jacoby, Bishara, Hessels, & Toth, 2005) have all been proposed, but only the latter has been applied directly to experimental data.”

“The DSST is considered as widely reflecting processing speed (15).”

“…begin with, measures of perceptual speed have superior psychometric properties (e.g., reliability) compared to other cognitive constructs (see Lindenberger, Mayr, & Kliegl, 1993), while loading highly on a factor of general intelligence (Salthouse, 1996; Tucker-Drob, Briley, Starr, & Deary, 2014).”

“It has been argued that processing speed underlies general cognitive abilities (Salthouse, 1996), which suggests that cognitive reserve effects are implemented at some higher level of cognitive processing.”

“The proposed es ntial role of processing speed in senescence-related change in higher-order cognitive functions (Salthouse, 1996) and previously shown transfer of higher-order cognitive training to supporting lower-order cognitive functions (Baniqued et al., 2015; Basak et al., 2008; Mudar et l.,…”

“…that older adults are slower in responding especially when the task requires to select a stimulus (i.e., ink colour/arrow direction) over a more dominantly represented one (i.e., word reading/arrow location), as in the case of Stroop paradigms (Salthouse, 1996; Verhaeghen and De Meersman, 1998).”

“proposed that changes in processing speed could be partially responsible for age-related decline across cognitive processes that rely on processing speed, such as memory [40,41].”

“Because name recognition performance was comparable between groups but reaction time was slower in older adults for the Recent condition, it is also possible that the greater older adult activation here reflects greater difficulty or effort for retrieval processes [51].”

“Finally, the presence of an impairment in storage capacity, albeit in only a portion of the population, may contribute to a higher order impairment in WM tasks (Belleville, Rouleau, & Caza, 1998; Salthouse, 1996).”

“Processing-Speed Theory (Salthouse, 1996) addresses specific assumptions that apply to both views of information processing.”

“However, age-related declines, such as cognitive slowing (Salthouse, 1996) or reduced auditory temporal processing (cf.”

“There was also recognition that processing speed could contribute to performance in other cognitive domains in seronegative adults (Salthouse, 1996a, 1996b).”

“Several hypotheses have recently emerged to explain cognitive de-differentiation in late life (Ghisletta & de Ribaupierre, 2005): general slowing (Salthouse, 1996), physiological and nervous system functioning decline (Lindenberger & Baltes, 1994), increased bihemispheric (rather than unilateral)…”

“According to Salthouse (1996), reduction in speed leads to impairments in cognitive functioning because relevant operations cannot be successfully executed (the limited time mechanism) and because the products of early processing may no longer be available when later processing is complete (the…”

“…attentional capacity (for a similar view but with miniature golf experts, see Molander & Bäckman, 1996; for reviews on attention and ageing, see Allen, Ruthruff, & Lien, 2007; Hartley, 1992) or processing capacity (for reviews on speed of processing and ageing, see Hartley, 2006; Salthouse, 1996).”

“Advanced age is associated with decrements across multiple cognitive domains, including speed of perceptual processing, working memory and executive abilities, fluid reasoning and episodic memory (Horn and Cattell, 1967; Lindenberger, 2014; Salthouse, 1996).”

“A vast literature shows that as adults age, many domains of cognitive function decline, including speed of processing, working memory, long-term memory, and reasoning (Hertzog, Dixon, Hultsch, & MacDonald, 2003; Park & Reuter-Lorenz, 2009; Salthouse, 1996), all of which decline at similar rates (Park et al.”

“On a more general level, these findings are consistent with the general role of processing speed (Salthouse, 1996, 2001) as the mediator of the relationship between age and performance of complex cognitive tasks.”

“Importantly, volumetric brain reduction was associated with deteriorated cognitive perfor- mance in older adults (Fleischman et al., 2014; Kramer et al., 2007; Salthouse, 1996).”

“A common reason for an older adult to move to an assisted living facility is because they, due in part to age-related changes in cognition (Parasuraman and Nestor, 1991; Salthouse, 1996; Tracy and DeYoung, 2004), can no longer carry out everyday activities such as driving.”

“Prior work suggests that non-pathologic (i.e., “normal”) aging is associated with declines in executive function and processing speed, and that when these factors are taken into account, the relationship between normal aging and memory performance is greatly reduced (Salthouse, 1996).”

“Study 1: Task To test the model, it was essential to have the participants perform an information processing task (Salthouse 1996, 2016).”

“Therefore, we hypothesized that: i) poorer cognitive function will be associated with wider sulcal span and lower g-SI; ii) the sulcus–performance associations are only partially mediated by age, that is correlations between cognitive functions and sulcal features will be present after correcting for age effects; iii)…”

“The box completion task ( Salthouse, 1996 ) consisted of a 5 � 7 array of three-sided, 2-D boxes (e.g., that contained a left, top, and right side), 1.9 cm on each side, printed on a letter-sized sheet of paper.”

“…speed changes in middle age, processing speed appears to decline and may be related to other age-related declines in cognitive functions in older-adult populations (Salthouse, 1996; Salthouse & Ferrer-Caja, 2003, Silwinski & Buschke, 1999; Sternäng, Wahlin, & Nilsson, 2008; Zimprich & Kurtz, 2013).”

“Our use of this term is certainly consistent with accounts of slowing in cognitive aging (Salthouse, 1996) and with many characterizations of older adults as having slowed language processing abilities (e.”

“Strengths of this study include use of a nationally representative sample; availability of a wide range of prospectively-obtained potential confounders, including childhood cognition to rule out selection by prior ability; a detailed assessment of lifestyle behaviors in midlife, including 5-day diet diaries; estimatio…”

“As suggested by Salthouse (1996), in order to properly isolate the effect of age-related inhibition, general slowing must be taken into account.”

“…because previous research has demonstrated that age, education and gender are related to aspects of cognition (Buckner 2004; Coffey et al. 2001; Salthouse 1996), and age is also related to gray matter volume (Blatter et al. 1995; Good et al. 2001; Lemaitre et al. 2005; Murphy et al. 1992;…”

“First, a dominant theory in cognitive aging posits that capacity differences between age groups arise from differences in basic processing speed (Salthouse, 1996; Verhaeghen & Salthouse, 1997), although the inverse position has been argued as well (Hasher & Zacks, 1988).”

“1991; Cerella & Hale 1994), and the comprehension deficits observed in the oldest participants may have occurred because new information in the passages was presented before older participants had an opportunity to encode and integrate previous material (Salthouse 1996).”