The processing-speed theory of adult age differences in cognition

“Salthouse (1991, 1996) has marshaled consider-ableevidenceforthisargumentinanimpressive subjects and many different and creative methodological methodological approaches. www.annualreviews.org • Aging and the Adaptive Brain 175 A second important approach to understanding cognitive aging comes from…”

“Speed View The speed view proposes that older adults’ cognitive deficits are primarily a consequence of a general age-related reduction in processing speed (for a review, see Salthouse, 1996).”

“Lindenberger and Baltes (1994) and Baltes and Lindenberger (1997) have also argued, like Salthouse (1996), for a single mechanism model of age-related cognitive decline.”

“Likewise, age-related changes in speed of information processing will constrain performance in timelimited decisions (Birren, 1970; Salthouse, 1996).”

“Consistent with general age-related slowing (Salthouse 1996), older adults were slower than younger adults in both the VP task ( t 22 = 2.64, P < 0.05) and the ER task ( t 22 = 2.43, P < 0.05); however, the no response rate was less than 1% in both groups, indicating that participants had ample…”

“Because mean RT in adults correlates so consistently with measures of memory, reasoning, language, and fluid intelligence, Salthouse (1996) has argued that gradual increases in processing speed account fundamentally for developmental change with age in cognitive and language functioning.”

“Ageing is associated with declines in general processing speed and inhibitory ability (Earles et al., 1997; Salthouse, 1996).”

“A reduction in grey matter is a feature of ageing, which is inherently associated with cognitive decline and in particular in the speed of information processing and executive functions (Salthouse, 1996; Salthouse et al., 1998).”

“There is evidence to suggest that processing speed may be an important factor underlying developmental differences in cognitive ability in childhood (Fry & Hale, 1996) and in aging (Salthouse, 1996).”

“Similar findings with independent data were also reported by Salthouse (1996b).”

“This is a variant of a hypothesis popular in explaining the effects of aging on cognition called "age-related slowing" (Kail & Salthouse, 1994; Salthouse, 1996); it is also similar to views advocated by some theorists of intelligence (Jensen, 1982, 1998).”

“A number of speculations have been offered about the mechanisms that might be responsible for the speed and working memory relation (e.g., Salthouse, 1992b, 1996b), but regardless of their ultimate accuracy, the results of our analyses clearly indicate that a large proportion of the age-related…”

“For instance, Sauzéon et al. (2011; see also Salthouse, 1991, 1996) found that participants with smaller vocabularies produced fewer words than did participants with larger vocabularies.”

“Primary points of contention concern the specific definition of working memory (Ackerman, Beier, & Boyle, 2005) and the extent to which speed of processing rather than working memory best explains individual differences in intelligence (Conway, Cowan, Bunting, Therriault, & Minkoff, 2002; Fry & Hale, 2000; Salthouse,…”

“Aging itself is associated with a reduction in the immediate span of attention [54], slowed processing speed [55,56], and a reduction in the amount of information that can be learned and retrieved over time [17,57–59].”

“For instance, age-based changes in working memory are often explained by alluding to changes in processing efficiency or processing speed (Case, 1985; Salthouse, 1996).”

“Various theories of how processing speed affects higher level cognition, including agerelated differences in cognitive performance, have been proposed (Faust et al., 1999; Fry & Hale, 1996, 2000; Salthouse, 1996).”

“Reductions in specific cognitive abilities like mental speed (Salthouse, 1996), executive function (Connelly et al., 1991; Schretlen et al., 2000; Rabbitt et al., 2001) and episodic memory (Salthouse, 2003; Buckner, 2004; Nyberg et al., 2012) are commonly experienced in aging, while verbal…”

“For example, age-related deficits in white matter integrity (for a review, see Raz, 2000) may reduce conduction speed and slow down responses in most cognitive tasks (Salthouse, 1996).”

“…pictures slightly more slowly than young adults (for a review see Griffin & Spieler, 2006), older adults have higher baseline activation levels because age related slowing presumably reflects generalized slowing that originates from outside the language production system (e.g., Salthouse, 1996).”

“Cognitive aging researchers have argued that reduced working memory capacity does not capture the declines associated with normal aging (Stoltzfus, Hasher, & Zacks, 1996) and that other factors, such as increased interference in memory (Hasher & Zacks, 1988) or slowed perceptual and cognitive processes (Salthouse, 199…”

“The most dominant member of this family is probably the processing-speed hypothesis [3,4].”

“Older adults without clinical signs of dementia nonetheless show differences in cognitive performance when contrasted with younger adults including slowed processing and disruption of executive functions associated with cognitive control (Craik and Byrd, 1982; Moscovitch and Winocur, 1992; Nyberg et al., 1996; Salthou…”

“(Salthouse, 1996; Verhaeghen & Salthouse, 1997).”

“, Chiappe, Hasher, & Siegel, 2000), as well as to speed of processing (Salthouse, 1996) and knowledge (see, e.”

“The visual recall task was based on a procedure developed by Salthouse, Kausler and Saults (1988). The task required the recall of seven spatial locations marked simultaneously with Xs within a 5x5 matrix.”

“…intelligence, memory, analogical reasoning, and language performance (Kail, 1992; Kwong See & Ryan, 1995; Salthouse, 1991) that many researchers believe developmental increases in processing speed can account fundamentally for age-related growth in cognitive functioning (e.g., Salthouse, 1996).”

“This observation supported our hypothesis that information processing speed is a mediating factor in the cognitive functioning of the elderly, depressed patients and is consistent with current models of cognitive aging.(50) To examine these relationships further, we regressed the language, visuospatial, memory, and ex…”

“This could be the simultaneity mechanism of cognitive slowing (Salthouse, 1996), or mechanisms related to age differences in volume and activation of the prefrontal cortex (Park, Polk,”

“This viewpoint suggests a simple and parsimonious explanation for age-related cognitive decline, namely, that it is due to a general slowing of the system’s processing speed (Salthouse, 1996).”

“Participants completed the Rey Auditory-Verbal Learning Test (RAVLT) (Schmidt, 1996) using a 30 min delayed interval (score indicates number of items recalled), two measures of speed of processing (for both, score indicates the number of items completed in 45 s)—pattern matching and number matching (Salthouse, 1996),…”

“It could be argued that the age-related cognitive differences in performance on the DL tasks are due to a general reduction in information-processing speed rather than localized changes in the DL region per se (Salthouse, 1996).”

“Much converging evidence now exists to suggest that reductions in processing speed are related to decreases in the overall efficiency of cognitive processing for younger and older adult”

“Normal aging (Salthouse, 1993, 1996; Fozard et al., 1994) and many neurological disorders (van Zomeren and Brouwer, 1994; Whyte et al., 1995; Collins and Long, 1996; Bleiberg et al., 1998; Leth-Steensen et al., 2000) produce a general slowing on numerous reaction time (RT) tasks, and overall RT…”

“The interdependence of these and other cognitive functions (e.g., long-term memory) presents a major challenge to understanding the etiology of cognitive deficits associated with age (i.e., .60 years) (Salthouse, 1996).”

“Rather, in accord with Salthouse (1996, 1998), we claim that the reverse may be true, namely, that lower intelligence scores are consequences of limits on attentional accessibility to many rates.”

“The recent study by Sliwinski and Buschke (1999) examined a particular kind of dynamic hypothesis from the point of view of a processing speed hypothesis (Salthouse, 1996), using multilevel models of time with initial age and processing speed as predictor variables.”

“Older adults typically perform more poorly than young adults in terms of both response latency and accuracy on tasks as diverse as perceptual speed, working memory, tracking, decision making, explicit memory and multiple task processing[21,113,149] .”

“Probably the most influential class of theories regarding cognitive aging are processing speed theories, which suggest that age-related cognitive deficits are related to a global decline in the speed with which information is processed in the nervous system (Cerella, 1985; Myerson, Hale, Wagstaff, Poon, & Smith, 1990;…”

“Normal aging disproportionately affects fluid relative to crystallized abilities (Salthouse, 1996).”

“…of processing speed correlate with performance in a broad range of cognitive domains (Kail and Salthouse, 1994; Li et al., 2004; Salthouse, 2005; Wechsler, 1997a), as well as age-related changes in cognition during the course of child development (Kail, 1991) and healthy aging (Salthouse, 1996).”

“Behavioral investigations of cognitive aging have addressed this issue by using various data analytic approaches, including transformations of reaction time, so that the influence of general age-related slowing may be taken into account (Salthouse, 1996; Faust et al., 1999; Madden, 2001; Salthouse and Madden, 2007).”

“Bosman (135,136) replicated and extended Salthouse’s typing studies.”

“This cognitive primitive has mostly been identified with the concept of mental resources (see, e.g., Salthouse, 1991, 1996).”

“The unique variance shared between processing time and gF likely reflects more basic differences in speed of processing abilities that are independent of the other abilities (e.g., Salthouse, 1996 ).”

“In older age, speed of processing is reduced [49] and behaviorally, reaction times are longer.”

“…& Zacks, 1988; Stoltzfus, Hasher, & Zacks, 1996), and slowing in many perceptual and cognitive operations (Cerella, 1994; Fisher & Glaser, 1996; Salthouse, 1996) All of these factors may contribute to the common complaint among older adults of increasing difficulty with memory for recently…”

“Thus, the structural and functional integrity of this prefrontal network may be a mechanism of age-related slowing of perceptual-motor speed, which in turn contributes to age-related differences in attention, memory, and other cognitive abilities (Madden 2001; Salthouse 1996; Salthouse and Madden 2007).”

“During healthy aging, behavioral measures of fluid cognitive abilities (those relying on elementary perceptual speed and sensory/motor functioning) tend to decline, whereas measures of crystallized cognitive abilities (those relating to knowledge and expertise) exhibit little or no decline until very late in life [89–…”

“Candidate domains include impaired executive function (Salthouse et al., 2003) and slowing of mental speed (Salthouse, 1996).”

“…accompanied by age-related declines in attentional resources (Craik & Byrd, 1982), working memory capacity (Kausler, 1994), and processing speed (Salthouse, 1996), one can see the challenge facing many older adults as they attempt to comprehend and remember fast-paced speech in their everyday…”

“First, older individuals perform cognitive tasks more slowly (Salthouse, 1996), and this could have affected our measurements of functional health literacy.”

“information processing speed measures, and impairments in this domain have been posited as central to the cognitive decline associated with typical ageing.(20) The nature of our sample did not permit an exhaustive examination of TBI-related and age-related cognitive dysfunction; however, our interpretation of results…”

“Two of the leading cognitive aging hypotheses are the ‘‘processing speed hypothesis,’’ in which performance deficits are attributed to a decline in processing speed (2), and the ‘‘inhibitory deficit hypothesis,’’ which proposes that impairment in diverse cognitive abilities are the result of an inability to reduce int…”

“2242 | Brain 2011: 134; 2233–2247 D. J. Sharp et al. traumatic brain injury (Stuss et al., 1989), which can impact widely on cognitive function by limiting the speed with which individual processing operations can be performed (Salthouse, 1996).”

“Age differences and age-related declines in cognition are most evident in domains such as information processing speed (Salthouse, 1996), free and cued recall (Perlmutter, 1979), inhibitory control (von Hippel & Dunlop, 2005), and mental flexibility and problem solving (Phillips & Henry, 2008).”

“Different cognitive processes are differentially affected by aging (Jagust, 2013), with domains such as processing speed and memory more subject to decline, compared to language and general reasoning (Salthouse, 1996).”