The processing-speed theory of adult age differences in cognition

“It is well established that as people age; they experience declining cognitive function [16–18] and more difficulty remembering medical information [19].”

“Younger adults were faster on two tests of perceptual speed ( Salthouse, 1996 ), Pattern Comparison, t (70) = 8.”

“Another general cognitive theory that has been proposed for explaining cognitive decline in aging posits that performance changes in older adults results from general decreases in the processing speeds of cognitive operations (Salthouse, 1996).”

“First, this issue is theoretically important and could be linked with processing speed theory of healthy cognitive aging [40], one of the major contemporary theories of healthy aging.”

“General factor theories of cognitive aging view this impairment as a by-product of a more basic deficit, general mental slowing in older age (Fisk & Warr, 1996; Salthouse, 1996 ).”

“The young group (557 ms) was faster than the older group (853 ms), consistent with a general cognitive slowing typically found (Salthouse, 1996).”

“This finding supports numerous findings in the literature that have shown age-related reductions in the speed of executing many cognitive processes (Birren & Fischer, 1995; Hartley et al., 1994; Salthouse, 1996).”

“, 1995), working memory (Nicholas, Connor, Obler, & Albert, 1998; Tun & Wingfield, 1997), reasoning (Cronin-Golomb, 1990; Denney & Denney, 1982), visuospatial perception (Benton, Eslinger, & Damasio, 1981; Salthouse, 1992; Wasserstein, Thompson, Sorman, & Barr, 1982), construction (Ben-Yishay, Diller, Mandelberg, Gord…”

“Slowing of processing speed is generally acknowledged as a hallmark of cognitive aging (Salthouse, 1996), but a large body of evidence also proposes that executive functions are particularly sensitive to normal aging (Bherer, Belleville, & Hudon, 2004).”

“This suggests that the age-related decline in adult L2 learning is primarily due to the age-related decline in fluid intelligence (Raz, Millman, & Sarpel, 1990; Salthouse, 1996), whereas processes relying on verbal working memory capacity appear to be less affected by age.”

“Aging itself can also be associated with several comorbid conditions that by themselves can result in an increased risk of cognitive impairment and slower reaction times ( Salthouse, 1996 ).”

“…brings special challenges for speech comprehension due to age-related declines in episodic memory (Wingfield and Kahana, 2002), processing speed (Salthouse, 1996), and working memory resources (Salthouse, 1994), all of which can have a negative impact on comprehension of spoken sentences (see…”

“For example, Salthouse (1996) proposed a theory that age-related changes in fluid intelligence are mediated by changes in processing speed.”

“A further explanation for age-related computer performance differences is the decline in cognitive, psychomotor and sensory functioning over the lifespan [13, 14, 15, 16, 17].”

“There is evidence that age-related changes in many cognitive functions such as reasoning and memory correlate with changes in relatively simple measures of information processing speed (e.g., Salthouse, 1996).”

“This finding simply illustrates the comparability of the present data with a vast number of aging studies that illustrate the importance of speed measures in predicting individual differences in cognition in age heterogeneous samples (see Salthouse, 1996 for a review).”

“Both processing speed (Salthouse, 1996) and executive functions (Craik and Salthouse, 2007) decline with age and such declines appear to contribute to listening difficulties in older adults (Humes and Dubno, 2010).”

“As we get older, we decline in a broad range of behavioral measures, from simple processing speed (Salthouse, 1996) to overall performance on batteries of intelligence tests (Kaufman, Reynolds, & McLean, 1989).”

“For example, Salthouse (1996a) has demonstrated that the majority of the variance in episodic memory impairment in aging can be attributed to PS deficits.”

“…that cognitive test results are affected by demographic variables, such as age, gender and level of education, as well as by learning, i.e., the effect of a second presentation of the same test (Leibovici et al., 1996; Salthouse, 1996; Jorm et al., 2004; Mungas et al., 2009; Scharfen et al., 2018).”

“…depend on the rapid and flexible coordination of attention and memory, decline during healthy aging, relative to knowledge-based and expertise-based (crystallized) abilities, which often exhibit age constancy (Craik and Bialystok, 2006; Kramer et al., 1994; Park et al., 2002; Salthouse, 1996).”

“N IH -PA Author M anuscript N IH -PA Author M anuscript N IH -PA Author M anuscript Salthouse (1996) delineated the hypothesis that a basic parameter such as processing speed is directly related to biological factors and is essential for higher order cognitive processing.”

“Finally, the summary cognitive measure used in our study, while convenient and useful as an indicator of general cognitive function, is insufficient to test some of the existing theories of cognitive aging regarding the relative contributions of processing speed (Salthouse, 1996), executive functions (Rabbitt and Lowe…”

“One influential theory posits that age differences in working memory performance might be tied to a slowing down of basic processes (Salthouse, 1996), and that basic speed mediates some of the age-related variance in span tasks (Verhaeghen & Salthouse, 1997).”

“These constitute three ‘‘reference abilities’’ designated by Salthouse as capturing the major aspects of age-related cognitive changes [16,17].”

“Salthouse 1996).”

“Mimicry in young adulthood therefore occurs extremely quickly, and to the extent that response speed is an important component of the usual mimicry response, this therefore raises the possibility that the latency of older adults’ mimicry may be increased due to declines in processing speed (Salthouse, 1996).”

“…theories exist to explain this pattern of preserved and declining functions (e.g., Craik, 1983; Hasher & Zacks, 1988; Lindenberger & Mayr, 2014; Salthouse, 1996), with the advent of modern neuroimaging techniques, the question of how age affects cognition can now be addressed at a more…”

“Despite these positive results, aging is usually associated with the slowing down of processing speed [9, 10], a significant decline in working memory [7] and long-term memory [11], and difficulty inhibiting irrelevant stimuli [12].”

“The latter finding might suggest that older adults’ perceptual processes are simply slower than those of younger adults (compare Salthouse, 1996).”

“Naming latencies are rarely discussed despite the fact that aging is associated with increased latencies on a wide variety of language and cognitive tasks (e.g., Eckert, 2011; Salthouse, 1996).”

“Older subjects had prolonged RTs to targets in agreement with the notion that behavioral slowing due to reduction in sensory-perceptual and response execution processes is a cardinal characteristic of normal aging (Cerella, 1985; Salthouse, 1996; Madden and Whiting, 2004).”

“Several higher order factors have been proposed to explain the apparently uniform age-related decline in cognitive processing efficiency across a wide range of tasks—for example, reduced inhibitory control over the contents of working memory (Hasher & Zacks, 1988), reduced working memory capacity (Salthouse, 1990), or…”

“Research into aging effects indicates a general processing speed decline that occurs with increased age in adulthood that is manifest in many tasks (Salthouse, 1996) and is thought to be involved in most fluid cognitive abilities.”

“, 1996) or changes in speed and/or sensory or cognitive capacities (e.g., Hultsch, Hertzog, Dixon, & Small, 1998; Lindenberger & Baltes, 1997; Salthouse, 1996).”

“Second, the processingspeed theory (Salthouse, 1996) suggests that when processing time is long, there may be less time for information to be encoded and elaborated.”

“Processing speed, considered a key construct in cognitive operations (Salthouse, 1996), can be reliably evaluated using the Digit Symbol Test (DST), a subtest of the Wechsler Adult Intelligence Scale (WAIS III; Wechsler, 1997).”

“It has been repeatedly demonstrated that information processing slows with age (e.g., Boyle, Wilson, Schneider, Bienias, & Bennett, 2008; Salthouse, 1996); performance on experimental tasks such as listening to sentences and making plausibility judgments is likely to be affected by the speed with which the information…”

“Yet, evidence for reduced speed of information processing with aging – linked to age-related white matter atrophy (Kennedy and Raz, 2009) – is pervasive in the cognitive literature (Reuter-Lorenz and Park, 2010), and numerous studies have shown the role of processing speed in the agerelated decline observed in differe…”

“Assuming that both processes are more physiologically based and relatively independent of environmental factors, this correlation seems readily interpretable from a processing resources point of view ( Salthouse 1996 ).”

“Literature states that speed of processing declines considerably with age (Fry & Hale, 1996; Salthouse, 1996).”

“It has been well established that increasing age in adulthood is associated with decreased motor and slower information processing speed [17].”

“Salthouse (1996, 2005) has suggested that reasoning and perceptual speed could be regarded as the underlying factors saturating all the executive functions.”

“Perhaps the ambulatory reaction time task used in this study is not adequately sensitive to actual group differences in processing speed; processing speed is a relatively basic, lowerorder cognitive domain that underlies and mediates higher-order cognitive functions, such as executive functioning and memory (41,42).”

“To illustrate, the processing speed theory (Salthouse, 1996) would predict that potential developmental paths representing decrements in perceptual speed accompanied by stability or increase in other cognitive abilities should be less frequently observed than expected by chance.”

“For example, cognitive and motor slowing leads to age-related differences in reaction times, gait speed, and bfluidQ intelligence [20–22].”

“…volumetric reductions of the frontal lobe and the hippocampus are associated with decline in cognitive processes, including fluid reasoning, mental processing speed, episodic memory, and spatial ability (Park et al., 2001; Salthouse, 1996; Verhaeghen and Salthouse, 1997; Whalley et al., 2004).”

“Thus, longer response times for older adults could be expected primarily because of reduction in processing speed, which has been shown to be a strong mediator of age differences in cognition (see Salthouse, 1996 , for a review; Bugg, DeLosh, Davalos, & Davis, 2007 ).”

“However, the possible existence of a relationship between a deficit in updating and a slowing in information processing is not supported by the current results.(34) Although patients are generally slower, the results observed on the Stroop colournaming test and in the information-processing speed task suggest that inf…”

“Early accounts of cognitive aging pointed to deficits in elementary processing resources, such as speed (Birren, 1965; Salthouse, 1996), but recently, attention has turned to processes of executive control as a basic mechanism to explain age differences in relatively complex aspects of cognition.”

“The assessment of information processing speed requires finely graded norms that take into account of the decline in processing speed with advancing age (16, 20).”

“One hypothesis in cognitive ageing is that speed of information processing has a special place in understanding what happens in the older person’s brain [21], [22].”

“However, age-related decline in cognitive processes such as decreased processing speed (Salthouse 1996) and working memory (Bo et al. 2009) may negatively impact motor abilities and skills in older adults.”

“This was because impairments to speed of processing are thought fundamental in accounting for agerelated effects on cognitive task performance (33).”

“A decline in processing speed represents a fundament l aspect of cognitive aging (Salthouse, 1996).”

“This was chosen because Spanish is the most prevalent L1 of the majority of non-native speakers of English currently residing in the U.S. Shin and Bruno, 2003 .”

“From previous research on various tasks, it is clear that developmental changes in the speed of processing co-occur with developmental changes in immediate memory ability and in many other cognitive skills (Cowan et al., 1998; Fry & Hale, 1996; Kail & Park, 1994; Kail & Salthouse, 1994; Salthouse, 1996).”

“4.1 Within-language lexical activation and competition As expected (e.g., Salthouse, 1996), lexical activation and target identification were subject to age-related slowing.”

“…in the release of neuromodulator transmitters such as dopamine, norepinephrine, and acetylcholine (all of which are crucial in the support of synaptic plasticity), which then lead to further declines in cognitive processing speed (Mahncke, Bronstone, & Merzenich, 2006; Salthouse, 1994, 1996).”

“executive functions (West, 1996) or is mostly mediated by a general decline in processing speed (Salthouse, 1996; Verhaeghen & Salthouse, 1997).”

“Older adults’ propensity to individualize a learning context that places low demands on their cognitive processes not only results in a less than favorable learning context but also suggests an explicit awareness of their age-related changes to information processing abilities and working memory capacity (Bäckman, Lin…”

“Several studies have shown that these cognitive impairments are observable in tasks measuring functions such as processing speed (Salthouse, 1996), episodic memory (Nyberg, Bäckman, Erngrund, Olofsson, & Nilsson, 1996), and working memory (WM) (Kramer, Hahn, & Gopher, 1999; Park et al.”

“Consistent with other reports and theories on cognitive aging, our sample was characterized by better performance in younger age groups [14, 27, 37].”

“We also included measures of processing speed and attention, which can influence test performance [44].”

“The memory and processing speed measures have been shown to have moderate to high relations with age (Knopman & Ryberg, 1989; Salthouse, 1996a; Wechsler, 1987).”

“Towse et al. (1998) argued that processing speed is an important variable for working-memory span development in children.”