Influence of Task-Specific Processing Speed on Age Differences in Memory

Abstract

Two studies were conducted to investigate the aspect(s) of processing involved in the hypothesized speed mediation of adult age differences in memory. Both studies involved a serial memory task in which information was to be recalled either in the original order of presentation, or in a reordered sequence. Results from both studies indicated that task-specific processing durations were slower among older adults than among young adults, but that the attenuation of the age-related variance in memory was nearly as great after statistical control of a task-independent speed measure as after control of task-specific speed measures. These findings are consistent with the hypothesis that a substantial proportion of the adult age-related differences in memory is associated with a decrease with increased age in the speed of executing many cognitive processes, and not simply the speed of one or two specific processes.

The processing-speed theory of adult age differences in cognition.

“…The third point to be noted about Figure 8 is that the functions for older adults (open circles) are consis- ' The functions in this figure have asymptotes below 100%, indicating that perfect performance was not achieved even at the longest available duration. A similar finding has been reported by Salthouse and Coon (1993), and this may be characteristic of relatively difficult tasks in which only limited amounts of practice are provided (cf. Kliegl et al, 1994). tently to the right and below those for younger adults (filled circles).…”

“…Vertical contrasts in this type of representation reflect the level of accuracy at a given time, and horizontal contrasts reflect the amount of time needed to achieve a given level of accuracy. If the complete function is available, then parameters of the mathematical function can be examined and compared across experimental conditions or age groups (e.g., Kliegl et al, 1994;Mayr & KJiegl, 1993;Salthouse & Coon, 1993). Figure 8, based on results of an unpublished study by Kersten and Salthouse (1993), illustrates a typical pattern from manipulations of stimulus presentation time in adults of different ages.…”

The Nature of Processing Speed Deficits in Traumatic Brain Injury: is Less Brain More?

“…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. For example, deficits in WM and processing speed have been documented in TBI (McDowell et al 1997;Stuss et al 1985) multiple sclerosis (Demaree et al 1999;Mostofsky et al 2003;Rao et al 1989a, b), schizophrenia (Cohen et al 1997;Saykin et al 1991Saykin et al , 1994, dementia (Bradley et al 1989;Collette et al 1999; Morris and Baddeley 1988) and normal aging (Salthouse 1992(Salthouse , 1996Salthouse and Coon 1993).…”

Processing Speed in the Aging Process: Screening Criteria for the Spanish Quick Test of Cognitive Speed

“…Previous studies have associated diminished speed of processing with normal age-related general cognitive declines ( Salthouse & Coon, 1993 ) as well as in other cognitive domains such as working memory, long-term episodic memory, verbal ability, and visuospatial skills ( Salthouse, 1996a( Salthouse, , 1996bSliwinski & Buschke, 1997 ;Madden, 2001 ;Edwards, Wadley, Myers, Roenker, Cissell, & Ball, 2002 ). Several studies have concluded that a reduction of cognitive processing speed could be related directly to the cognitive changes underlying the aging process ( Salthouse, 1980( Salthouse, , 1985( Salthouse, , 1992( Salthouse, , 1994( Salthouse, , 2000.…”