Lecture 3: Executive Functions and Speed Flashcards
(37 cards)
¨What are executive functions (EF)?
- general agreement
- Multiple processes for control and regulation
- No single definition EF or standard tests for EF
- General agreement: EF refers to the control of thought and regulation of behaviour
- “EF are multifaceted control processes that regulate thought and behaviour” (Reuter-Lorenz et al., 2016, p. 246)
- Multiple processes for control and regulation
- Resistance to interference, inhibitory control or inhibition
- Cognitive flexibility, task switching or task shifting
- Monitoring, updating or memory updating
- variety of tests attempt to assess EF processes
What are executive functions (EF)?
- Important for everyday activities:
- Important for everyday activities:
- e.g. instrumental activities of daily living (IADL)
- EF would be particularly susceptible to effect ageing
Age effect inhibition
- Stroop:
- Uttl & Graf (1997).
Stroop:
- Increase incongruent color-word RTs with ageing: less efficient inhibition
- Relatively little effect age on word and color conditions

Age effect inhibition
- Haylings sentence completion (McAlister &Schmitter-Edgecombe, 2016)
- The captain decided to stay with the sinking ……?
- Young adults (M 21) > young old (M 68) = old (M 79)
Executive functions and speed
- Age effect task switching
- TMT - Trials B (McAlister &Schmitter-Edgecombe, 2016)
- Young adults = Young old = Old old
Number – letter task
- Young adults > young old = Old old
- meaning young aadults are better than young olds, young olds perform similar to old olds

Executive functions and speed
- CANTAB spatial working memory task (Robbins et al. 1998)
- Open box by touching screen
- Collect blue tokens hidden in boxes
- Token never hidden in same box twice (keep spatial positions in WM)

- Age effect working memory (Robbins et al. 1998)
- More errors (open box where token had already been found) with increasing age.

Age effect working memory
- Reading span (McAlister &Schmitter-Edgecombe, 2016)
- Remember last word of 6 sentences read aloud
Reading span
- Young adult > young old > old old (the younger the better)
- Meta-analysis executive function and ageing studies (Verhaeghen, 2011)
- Poorer performance older adults on wide range EF tasks
- Larger difference young-old on EF conditions than on control conditions
Longitudinal studies:
- Follow-up EF Baltimore Longitudinal Study of Aging (Goh, An & Resnick, 2012)
- 148 participants, 56-86 years at first assessment, follow-up for up to 14 years
- Inhibition: perseverations on fluency task.
- Switching: TMT
- Decline EF with age, but inter-individual variation
Executive functions (EF)
- Important for everyday activities:
- Important for everyday activities:
- e.g. instrumental activities of daily living (IADL)
- Trails B predicted informant-rated IADL
- Neuropsychological EF tasks explained 19-23% measures daily functioning (McAlister &Schmitter-Edgecombe, 2016)
- EF would be particularly susceptible to effect ageing
- EF impairment may underlie impairments other cognitive tasks
Executive functions and speed
- Stern & White (2003)
- concept

EF theories of ageing
- Role of EF in cognitive ageing:
- Handbook of Psychology of Aging, Ch. 13
Role of EF in cognitive ageing:
- Inhibitory deficits theory
- Goal maintenance deficit
- Production deficit hypothesis
- Frontal lobe hypothesis of cognitive ageing
EF theories of ageing
- Inhibitory deficits theory
Inhibitory deficits theory:
- core deficit ageing: difficulties to inhibit irrelevant information or to control interference
- Inhibition deficit affects other functions, in particular working memory
- irrelevant material enters WM
EF theories of ageing
- Goal maintenance deficit
Goal maintenance deficit
- Ability to maintain task-relevant goals deteriorates with ageing
- Affects top-down processing and regulation of behaviour
- Proactive control: prepare attention and action systems
- Effect memory, including prospective memory
EF theories of ageing
- Production deficit hypothesis
Production deficit hypothesis
- Self-initiated, effortful processing declines with ageing
- Deficit linked to impairments in frontal lobe functions
- affects learning and memory
EF theories of ageing
- Frontal lobe hypothesis of cognitive ageing
Frontal lobe hypothesis of cognitive ageing
- Reductions in frontal lobe function can explain many age-related changes in cognition
- EF deficits, which rely on intact frontal lobes, are first signs of cognitive ageing
- EF affected disproportionally severely by ageing
EF theories of ageing
Executive functions first cognitive abilities to decline.
- Longitudinal evidence:
- ¨Baltimore Longitudinal Study of Aging (Goh, An & Resnick, 2012)
- Functions that deteriorated early included:
- Switching (TMT), inhibition (perseverations on fluency), WM, long-term memory (delayed free recall)
Age effects EF more severe than other functions
- Cross-sectional evidence
Meta-analysis executive function and ageing studies (Verhaeghen, 2011)
- EF impaired in older adults, but not disproportionally impaired
- age effect in EF condition did not go beyond age effect in the control condition
- Suggests no specific EF deficit
Age effects EF more severe than other functions
- Conclusion based on Brinley plots:
Executive functions and speed
- Stroop task: Brinley plot
- RTs old adults in color-word condition not disproportionately higher than RTs in color condition (both conditions fall on single regression line)

Executive functions and speed
- Trail making Task: Brinley Plot
- TMT : RTs old adults in Trials B not disproportionately higher than RTs in Trial A (points from both conditions fall on a single regression line)
- Performance older adults poorer than performance young adults with constant factor.

EF theories of ageing:
- EF first cognitive abilities to decline
- impairments EF more severe than other functions
- summary of findings:
- EF impaired in older adults
- Impairments EF do not emerge earlier than in all other cognitive functions (i.e. memory)
- Impairments are not disproportional: effects of age on EF not more severe than effect on other functions
EF theories of ageing
- executive functions impairments underlie deficits in other cognitive functions in older adults
- What is the evidence?
- Verhaeghen (2011): best fitting model to explore effect EF on other cognitive functions (based on 119 studies). All paths are significant.
- Performance EF tasks not associated with other cognitive functions (over and above the effects of speed of responding)
- Unlikely that EF impairments underlie age-related deficits in other cognitive functions
- WM may be exception
EF theories of ageing
- EF relies on intact frontal lobes
- Frontal lobes first brain areas to deteriorate with ageing

- Positive correlations: larger PFC associated with better EF performance. (Yuan & Raz (2014))
- Pfefferbaum et al. (2013): changes in brain volume with ageing
- Healthy adults, 20 - 85 years, followed up 1 – 8 years
- More rapid decline volume in lateral and medial frontal cortex, than in other parts of cortex
- In line with frontal hypothesis



