The processing-speed theory of adult age differences in cognition

“…we cannot exclude an alternative interpretation, namely that elderly adults may need more training to achieve a performance level which is comparable to the young (Charness & Campbell, 1988; Dunlosky & Salthouse, 1996; Harrington & Haaland, 1992; Salthouse, 1994, 1996; Touron & Hertzog, 2004).”

“…findings suggests that age-related cognitive decline and working memory performance might be influenced by several factors, for instance decline in sensory functioning, poorer interference control and reduced processing speed (Salthouse 1996; Baltes and Lindenberger 1997; Hasher and Zacks 1988).”

“Decreased performance during normal aging may be the result of general slowing (Salthouse, 1996).”

“Note that the slowed performance found in elderly persons might be explained by the general cognitive slowing theory (Salthouse, 1996).”

“…with a decline in a number of cognitive functions, including episodic and working memory, attention and executive control [e.g., Park et al., 2002; Salthouse, 1996, 2009], as well as motor functions [e.g., Cerella, 1985; Spirduso, 1982; Ward, 2006; Ward and Frackowiak, 2003; Welford et al., 1969].”

“DSST performance in particular has been found to mediate age differences in a wide variety of cognitive performance measures (Salthouse, 1991, 1996) and this has been explained in terms of its shared variance with measures of ¯uid intelligence (Parkin & Java, in press).”

“Other studies showed that episodic memory antecedents, such as processing speed and working memory, predicted training benefits, especially in transfer tasks (Park et al., 2002; Salthouse, 1996).”

“Normal aging is associated with declines in many cognitive functions including episodic memory, working memory, processing speed, and executive functions (Baltes and Lindenberger, 1997; Nilsson, 2003; Park, et al., 2001; Salthouse, 1996), but there is preservation in select cognitive domains such as verbal abilities a…”

“…reductions of prefrontal cortex and the hippocampus (Raz et al., 2005), and associated functional changes involve reductions in processing speed (Salthouse, 1996), impairments of executive function (West, 1996) and episodic memory (Small, 2001), and changes in the availability of certain…”

“Three contemporary views stemming from a resource theories framework of cognitive ageing were explored to explain the relationship between age and mental imagery components: the processing resource hypothesis ( Salthouse, 1996 ), the executive function hypothesis ( Dempster, 1992 ) and the common cause hypothesis ( Li…”

“Reductions in WM capacity with age have been ascribed to various general cognitive factors, including speed of processing (Salthouse, 1996 ), inhibitory control (Hasher & Zacks, 1988 ), and dual-task coordination (Verhaeghen, Kliegl, & Mayr, 1997 ).”

“Secondly, as we age the speed with which information is processed decreases (Howard et al., 1986; Salthouse, 1996).”

“Processing speed is an index of the speed of cognitive processing and is considered a general mechanism underpinning performance on a wide range of cognitive tasks, as constrained speed of processing results in poor performance on time limited cognitive tasks (Salthouse, 1996).”

“At a domain-general cognitive level, earlier reearch has reported decreased processing speed in older adults ( Bennett nd Madden, 2014; Salami et al., 2012; Salthouse, 2011; 1996 ).”

“In this regard, during the last two decades a number of explanatory approaches have been proposed ( Craik & Byrd, 1982 ; Hasher & Zacks, 1988 ; Salthouse, 1996 ).”

“Salthouse (1985) has also emphasized that the decline in Gf is partly a function of the well-known age-related decrease in virtually all tasks that require speed of performance, but the most parsimonious synthesis of the wealth of accumulated data suggests that processing speed plays a moderate to substantial role in…”

“The most likely mechanism underlying older athletes’ loss of the PV advantage is the limited time mechanism referred to by Salthouse (1996).”

“N IH -PA Author M anuscript N IH -PA Author M anuscript N IH -PA Author M anuscript declines in the speed at which one can process information (Ball et al., 2002, Salthouse, 1996, Finkel et al., 2005, Levitt et al., 2006).”

“Factor 1 seems to capture the system’s basic resources, its processing capacity (e.g., Kausler, 1994; Salthouse, 1996).”

“, a global slowing of neural responses across modalities (e.g., Myerson et al., 1990; Salthouse, 1996).”

“Another possibility is that speed of processing, which may account for much of the age‐related variance in working memory (eg, Salthouse, 1996 ), is the mechanism that accounts for this factor structure.”

“Older adults suffer not only from a general slowing of information processing (Cerella, 1990; Salthouse, 1992, 1994, 1996) but also from deterioration in specific higher cognitive functions (Kramer et al., 1994; West, 1996).”

“…on the processing aspect and have thus been couched in terms of differences in cognitive resources (Craik & Byrd, 1982), cognitive slowing (Salthouse, 1996), and in problems with executive functioning such as failures to inhibit irrelevant material (Hasher & Zacks, 1988; Rouleau &…”

“A measure of processing speed was included for investigative purposes, as speed of processing has been offered as an explanation for age-related performance deficits in complex cognitive tasks (Salthouse, 1996).”

“Another explanation attributes memory loss to the inevitable decay of synaptic connections with age (Salthouse 1996).”

“It is possible that the small age difference found in Experiment 1 can be explained by a general slowing of cognitive and motor functions (Salthouse, 1996).”

“…work has failed to demonstrate a detrimental effect of aging on speech intelligibility in steady or fluctuating noise maskers for NH listeners (Schoof and Rosen 2014), aging is shown to be accompanied with decline in auditory temporal processing (Fitzgibbons and Gordon-Salant 1996; Saija et…”

“…motor dysfunction is common in certain patient populations (e.g., patients with dystonia, Huntington’s disease, and PD), it is crucial to distinguish between the assessment of speed of mental information processing and motor speed (Salthouse, 1994, 1996) when determining actual mental slowness.”

“Based on theoretical considerations, age (Salat et al., 2004; Salthouse, 1996), sex (for review, see Cosgrove, Mazure, & Staley, 2007; Herlitz, Nilsson, & Backman, 1997), and education (Apostolova et al., 2006; Stern, 2002) were selected a priori as covariates for inclusion in the GLMs. APOE4…”

“A major difference between reduced vs. impaired functions is often seen in the amount to which they require active, quick and flexible cognitive processing that involves manipulation of information (see e.g., Salthouse, 1996; Salthouse et al., 2003).”

“Two aging hypotheses are classically studied to explore potential mediators of agerelated cognitive functioning decline, namely executive dysfunctioning and cognitive slowing (Luszcz & Lane, 2008; Salthouse, 1996).”

“Others have argued that the relationship may reflect speed of pro‐ cessing within individuals rather than WM proper (Conway, Cowan, Bunting, Therriault & Minkoff, 2002; Fry & Hale, 2000; Salthouse, 1996; Salthouse & Pink, 2008).”

“Processing speed was evaluated through Trail Making Test‐A (TMT‐A)(45) and the Salthouse Letter Comparison Test.(46) The Stroop Test(47) (color‐word and interference) and Trail Making Test‐B (TMT‐B)(45) were used to assess executive functioning.”

“The Box Completion Task requires that participants use a pencil to fill in the fourth side of an open-ended square as rapidly as possible.”

“Healthy aging is marked by broad declines in episodic memory (Arking, 1998; Balota, Dolan, & Duchek, 2000; Salthouse, 1996).”

“As pointed out by Salthouse, slowed processing may result in “impairments of higher order processes such as abstraction, elaboration, or integration, because not all of the relevant information will be available in a usable form when it is needed” (Salthouse, 1996, p. 406).”

“Moreover, Gv has shown incremental validity in predicting educational and vocational attainment (Shea, Lubinski, & Benbow, 2001), and Gs has been shown to play an important role in the development of cognitive abilities (Salthouse, 1996).”

“…processing experienced by older adults in general, and memory in particular, are reductions in attentional or working memory capacity (Baddeley, 1986; Craik, 1986), slowed speed of processing (Salthouse, 1996) and lack of inhibitory control (Hasher & Zacks, 1988; Hasher, Zacks, & May, 1999).”

“If older adults’ cognitive processes are slowed in general (Salthouse, 1996), they need the bottleneck longer for completion of Task 1, and this inevitably leads to a longer delay of Task 2 at short SOAs.”

“A number of cognitive aging researchers (Cerella, 1990; Salthouse, 1996; Verhaeghen, Kliegl, & Mayr, 1997) have generally observed that the magnitude of age differences increases as the processing demands—or complexity—of the task increases (for a meta-analysis, see Cerella, 1985).”

“On the contrary, if interactions that were significant before the logarithmic transformation are not significant any more after it, it is possible to assign the effects to general factors such as age-related slowing (Salthouse and Babcock, 1991; Salthouse, 1996).”

“…past decades have found that there are general, domain-independent changes in processing speed across the lifespan that are probably biologically caused (cf. Kail, 1991; Salthouse, 1996); such differences would be uninteresting from the present perspective as they call for no special explanation.”

“…constraint, which would be expected based on well-documented demonstrations of age-related processing limitations, whether due to cognitive slowing (Salthouse, 1991; 1996), inhibitory deficits (Hasher & Zacks, 1988; Zacks & Hasher, 1997), and/or working memory constraints (Salthouse, 1991; Titone,…”

“Similar to what has been demonstrated in normal ageing (22), performance in simple speeded tasks has often been found to account for a large proportion of depression-related variance in executive function as well as in overall cognition (14, 15, 20, 23).”

“At the same time, it is clear that these basic parameters of information processing efficiency account for a large portion of the age- and disease-related variance in higher-level cognitive ability (cf. Salthouse, 1996; Hultsch et al., 2000).”

“These results are consistent with, and extend, previous findings of slower encoding of information (Zanto et al., 2010; Salthouse, 1996, 2016) and increased difficulty with top-down suppression of distractors (Clapp and Gazzaley, 2012) with age in older adults.”

“A single global measure intended to gauge multiple aspects of cognition should be distinguished from a general underlying factor, such as processing speed, that may prove successful in characterizing patterns of relationships between chronological age and a range of cognitive domains.(7) Numerous cross-sectional studi…”

“Because of the association between global deterioration of WM microstructure and processing speed (Salthouse, 1996; Eckert et al., 2010), a whole brain analysis approach is suitable for this cognitive function.”

“Individuals are known to varymeasurably in the efficiency of these cognitive processes (Miyake et al., 2000; Salthouse, 1996).”

“that comes with age, which would lead to difficulties in information storage (Salthouse, 1996).”

“These observations are coherent with the macro-analysis of aging proposed by Salthouse, who affirms that a single basic construct (such as processing speed) can be assumed to account for most, although not necessarily all, age-related cognitive decline ( Salthouse, 1993 , 1996 , 2000 ; Salthouse & Coon, 1993 ).”

“This indicates that the cost of switching is disproportionate with respect to other RT costs observed in aging and cannot be simply attributed to generalized slowing (Salthouse, 1996).”

“These mechanisms may operate across the life span; for instance, cognitive ageing involves slowing of processing speed (Salthouse, 1996), which is associated with decreases in myelination at the upper end of the age continuum (Bartzokis, 2004).”

“Therefore, it is possible that, because of reduced speed of processing, the products of early processing are lost by the time the later processes are complete in older participants (Salthouse, 1996).”

“Age-related selection or decision problems have been reported in the literature using event-related potentials as a measure of processing (Bashore, van der Molen, Ridderinkhof, & Wylie, 1997), as well as elsewhere in the aging literature (Kausler, 1991; Salthouse, 1996).”

“Speculatively, impaired strategy selection with age may be accounted for by decreased processing speed, which is consistent with processing speed theories (Cerella, 1985, 1990; Myerson, Hale, Wagstaff, Poon, & Smith, 1990; Salthouse, 1996a, 1996b).”

“cognition (Baltes & Lindenberger, 1997; Nilsson, 2003; Salthouse, 1996) such as executive functioning (Coppin et al.”