The processing-speed theory of adult age differences in cognition

“A variety of analytic behavioral approaches demonstrate a prominent (Salthouse, 1996), although not exclusive, role of processing speed in agerelated declines (Charlton et al., 2008; Park et al., 2002).”

“Reaction time has also been conceived as a lower-level indicator of processing efficiency that can mediate effects of age on higher cognitive functions [42].”

“Salthouse, 1996 ). Thus, if one can understand the mechanisms that determine working memory capacity, one will have a firmer understanding of an important component of many respected higher cognitive skills and a firmer understanding of why individuals differ from one another on these skills.”

“This task is a measure of psychomotor speed (Salthouse, 1996).”

“…in of the decrement in cognitive performance observed in the process of ageing can be accounted for by a simple systematic assuming a single factor underlying the cognitive decline observed with advancing age and, by extension, Alzheimer's decrement in processing speed (Salthouse, 1993, 1996).”

“Processing speed has been shown to relate to early cognitive decline in the elderly, well before dementia ensues [32].”

“According to Salthouse (1996), two distinct mechanisms are responsible for the relationship between speed and cognition: the limited time mechanism and the simultaneity mechanism.”

“A number of ideas have been proposed to account for age differences in memory, including impairments in attentional resources (Craik & Bosman, 1992; Craik, 1983) and information processing (Salthouse, 1996).”

“This is consistent with limited time and simultaneity mechanisms thought responsible for the age-related decrease in fluid cognition according to speed of processing theory (Salthouse, 1996).”

“Researchers commonly agree that fluid intelligence as psychometrically tested often decreases in old age and that crystallized intelligence may continue to increase or, at least, that it may avoid decline (see Horn, 1986, 1994; Salthouse, 1996).”

“Several studies have shown that, similarly to other cognitive functions, WM performance declines with increasing age (e.g., Bopp & Verhaeghen, 2005; Park et al., 2002; Verhaeghen & Salthouse, 1997).”

“These mechanisms may involve a reduction in priming transmitted across connections among units because of declined linkage strength (MacKay & Burke, 1990), a decreased efficiency of the simultaneity mechanism (Salthouse, 1996), or an inefficient binding mechanism (Chalfonte & Johnson, 1996; Mitchell, Johnson, Raye, &…”

“Increasing reaction times are a primary marker for age-related cognitive decline (Deary, Johnson, & Starr, 2010) and are even considered its cause (Salthouse, 1996), yet they are puzzling: Practice improves speed and performance on individual cognitive tasks at all ages (Dew & Giovanello, 2010).”

“A crucial assumption of decay models is that processing of items competes with rehearsal (Barrouillet et al., 2004; Salthouse, 1996; Towse, Hitch, & Hutton, 2000).”

“Specifically, Salthouse (1996) claimed that differences in speed cause certain cognitive processes to fail to be completed in time for that information to be used by other processes.”

“Studies with adults show that faster reaction time can free additional cognitive resources (e.g., Salthouse, 1996), a benefit of particular value in early stages of language learning.”

“bined with psychometric assessments of general intelligence (Deary, 2000; Hale, 1997; Jensen, 1998; Kail, 1991; Myerson, Hale, Zheng, Jenkins, & Widaman, 2003; Salthouse, 1996; Newcomb, 2002).”

“For example, research demonstrating a Volume 2—Number 1 7 variety of age-related cognitive deficits (e.g., in speed of processing and working memory; Salthouse, 1996) leads us to believe that judgment and decision-making capabilities may decline as an inevitable course of the aging process.”

“The assignment of old responses to the left or right hand was counterbalanced across subjects.”

“There are reasons to believe that faster participants might be better inhibitors than slower participants when one takes into account that processing speed and inhibitory control are often correlated (Salthouse, 1996; Salthouse & Meinz, 1995).”

“Theoretical accounts of the changes in EF occurring during adulthood have emphasized changes in a range of underlying processes, from attentional resources (e.g., Craik & Byrd, 1982) to processing speed (e.g., Salthouse, 1996) to inhibition (e.g., Dempster, 1992; Hasher & Zacks, 1988).”

“Given that both executive functions and processing speed decrease with age [7,43] and that these functions are strongly correlated with the activities of daily life [44], one of main goals in the field of cognitive training for the elderly is to improve executive functions and processing speed.”

“Also addressing age-related changes in processing, the speed of processing hypothesis proposes that a large portion of age-related variance on cognitive tasks can be accounted for by declines in the speed in which older adults process information.(83,84) Increasing age is associated with a decrease in the speed with w…”

“A central feature of normal aging is a general slowing in a variety of perceptual and cognitive operations (Salthouse 1996).”

“Some authors have suggested that especially executive functions may be the first to deteriorate ( Jolles, 1986 ; West, 1996 ), whereas others have suggested that the age-related decline in cognitive functions, including executive functions and memory, is due to a general decline in processing speed ( Salthouse, 1996 ;…”

“Indeed, increased left prefrontal activation (attributable primarily to older participants) was also correlated with slower reaction time, which may reflect recruitment inasmuch as an increase in task difficulty that leads to recruitment may cause a slowing of processing speed that causes slowed reaction time (Salthou…”

“Additionally, it has been validated in correlational studies with other speeded-processing tasks, high-level cognitive and intelligence tests (Brebion et al., 2000; Salthouse, 1996a, b; Salthouse, 1992; Wechsler, 1981).”

“Aging of the frontal cortex can therefore lead to subtle failures of inhibition of motor responses and visual attention,[29] which can potentially lead to falls.”

“As was observed with many neuropsychological tests, age differences in performance increase as the complexity of the task increases ( Salthouse, 1992, 1996 ).”

“…speed is largely considered a basic aspect of cognitive processing that explains the changes in WM performance with aging (Park et al., 2002; Salthouse, 1996), improving WM performance increases the efficiency of cognitive operations fostering ability to move among the basic information…”

“Declines in auditory acuity [9–10], temporal processing [11], memory [12], speed of information processing [13–14] and the ability to filter out irrelevant competing auditory input [15–16] also contribute to difficulties reported by older adults for hearing SIN.”

“Sensory function (Baltes & Lindenberger, 1997; Lindenberger & Baltes, 1994) and speed of processing (Salthouse, 1991, 1996) have been theorized to account for the myriad declines in cognitive ability.”

“Such an inference is contradicted by earlier research, such as that of Sternberg and Gardner (1983) and similar findings in more recent investigations (e.g., Babcock, 1994; Salthouse, 1996) that show significant associations between processing speed measures and Raven performance.”

“The finding that young adults at short deadlines show an ironic effect of repetition similar to older adults might be taken to imply that the effect in the elderly is due to general slowing of processing (e.g., Salthouse, 1996).”

“This training approach arises from the theory that changes in cognitive function with age result from generalized, age-related slowing of processing speed (Birren, Woods & Williams, 1980; Salthouse, 1996).”

“Indeed, reaction times have been viewed as capturing the capacity of processing speed that is a major foundation of the age-related declines in higher-level cognitive functions (Madden, 2001; Salthouse, 1996).”

“Alternatively, Salthouse and colleagues (Fristoe et al., 1997; Salthouse et al., 1996) have suggested that age differences in performance on the WCST are the result of a more basic deficit in processing speed (cf. Salthouse, 1996).”

“In addition to a substantial slowdown in processing speed (Salthouse, 1996), working memory resources may be increasingly taxed by age-associated impairments in executive functioning (West, 1996).”

“One important aspect of these abilities is the speed with which many operations can be executed (Salthouse 1996).”

“Specifically, declines occur with age in several processes including processing speed, attention, executive control, working memory, and episodic memory (e.g., Hoyer & Verhaeghen, 2006; Nilsson, 2003; Rönnlund, Nyberg, Bäckman, & Nilsson, 2005; Salthouse, 1996).”

“Processing efficiency, typically measured by speeded tasks, declines with advancing age and with poor health status (Earles & Salthouse, 1995; Earles, Connor, Smith, & Park, 1997; Hultsch et al., 1998; Light, 1978; Salthouse, 1996).”

“In turn, processing speed has been linked to general measures of health (Salthouse, 1996; Hultsch, Hertzog, Dixon, & Small, 1998; Earles & Salthouse, 1995; Light, 1978; Earles, Connor, Smith, & Park, 1997).”

“…activation is associated with increased demand for executive control as cognitive processing becomes less automated (Davis et al., 2008) or slower (Salthouse, 1996) or as neural processing becomes noisier (e.g., Persson et al., 2006) or circuits become less efficient (e.g., Cappell et al., 2010).”

“Advanced age is accompanied by reductions in working memory capacity [39]; an inhibition deficit that permits distracting information to affect attention, memory, or processing [40]; and a generalized slowing of perceptual processing [41].”

“Although speeded tasks constitute a prime candidate for studying cognition–myelin relationships, future studies should assess how cortical myelin might have implications for other aspects of cognition, especially in aging (Salthouse, 1996).”

“, Salthouse , 1996 ; de Ribaupierre et al .”

“…1988), the construct has not been clearly distinguished empirically from other conceptualizations of cognitive resources thought to underlie aging effects on performance, such as working memory (e.g., McCabe, Roediger, McDaniel, Balota, & Hambrick, 2010; Park & Payer, 2006; Salthouse, 1996).”

“A generalized slowing of information processing is commonly thought to be the source of many of the cognitive decrements associated with normal ageing (Hale & Jansen, 1994; Salthouse, 1996a).”

“This view has received much support (e.g., Birren, 1965; Cerella, 1985, 1990; Cerella, Poon, & Williams, 1980; Fisk & Warr, 1996; Salthouse, 1985, 1996; Salthouse, Kausler, & Saults, 1988) and much criticism and debate (Allen, Ashcraft, & Weber, 1992; Allen et al., 1993; Cerella, 1994; Fisk & Fisher, 1994; Fisher & Gl…”

“First, we examine whether the age-related differences in preferences and consistency we observed are driven by systematic, significant differences between age groups in variables that have been previously associated with higher or lower tolerance for risks and ambiguity such as wealth level (7, 8), IQ and numeracy (9,…”

“Salthouse, T. A. (1996). The processing-speed theory of adult age differences in cognition.”

“Salthouse (44) demonstrated that slow reaction time was associated with poor cognitive function.”

“By contrast, central or endogenous perturbations include compressed speech, digit load, or general cognitive slowdown during aging or after brain damage (Gordon-Salant & Fitzgibbons, 1993, 1995a, b, 1997; Salthouse, 1996).”

“In this sense, the age-related reduction of frontal activity during temporal-order retrieval would be consistent with evidence that attention, working memory, and inhibition are disrupted by aging (for reviews see, Hartley, 1992; Salthouse, 1991; Zacks & Hasher, 1997).”

“…efficiency, attention, memory, and executive functions anticipated at the fifth to sixth decade of life and may progressively accelerate into more significant cognitive declines by the seventh to eighth decades (Cabeza et al. 2017; Rog and Fink 2013; Salthouse 1996, 2011; Schaie and Willis 2010).”

“Passive models (Satz, 1993; Stern, 2002) maintain that in response to similar levels of neurobiological degradation, highreserve individuals will experience less impairment than lowreserve individuals. Resilience of nervous system functioning is theoretically indexed by brain size or synapse count, although Satz (1993…”

“In addition, perceptual speed has been considered as a central marker of decline in fluid abilities during adulthood and old age (e.g., Lindenberger et al., 1993; Salthouse, 1996; Verhaeghen & Salthouse, 1997).”

“162 become more complex, performance between old and young adults becomes increasingly divergent, but speculation about this finding typically focused on speed of processing as the underlying mechanism.(4) One sentient study on interhemispheric connectivity by Reuter-Lorenz et al(87) provided behavioral evidence that…”

“…selection processes because such individuals have been shown to suffer from decline in a range of executive capacities including aspects of inhibitory function (Hasher, & Zacks, 1988; Kramer, Humphrey, Larish, Logan, & Strayer, 1994), as well as processing speed (Salthouse, 1996) as age increases.”

“For example, dominant theoretical orientations have linked aging declines in memory to cognitive slowing (Salthouse, 1996), problems in inhibitory functions (Hasher & Zacks, 1988), reductions in processing resources (Craik, 1986), and deficits in reflective processes (Johnson, Reeder, Raye, &…”

“Whereas child development is associated with gains in information-processing speed (e.g., Kail, 1991), cognitive aging is related to the general slowing of information processing (e.g., Cerella, 1985; Salthouse, 1996).”