Lecture 5

• Prefrontal cortex


  executive functions (EF)

  • EF: umbrella term for cognitive skills guiding goal-directed behavior

  • Cognitive flexibility/Shifting (ability to shift between tasks)

  • Inhibition (ability to stop or suppress actions)

  • Updating (ability to keep information ‘online’)
• Switching task


  Participants are less accurate and slower when they need to switch task sets
• 3- & 4-year-olds shift...

  between two simple, contextualized response sets
• Between 5 and 6 years shifting...


  further improvement in more complex shifting task

  → generalizing rules to new, unseen objects
• Shift cost


  = difference between shift and non-shift trials) greater for 7- and 11-

  year-olds than for 15-year-olds, 15-year-olds comparable to young adults

  • Speed-accuracy tradeoff: slowing down to enhance accuracy: more noticeable across childhood → emerging presence of metacognition

  • In older age, marked age-related decline: higher shift costs
• Motor inhibition


  e.g., dancing, but when music stops, do not move anymore
• Oculomotor inhibition


  Flanker tasks: “respond to direction of arrow in center”
• Simple response inhibition tasks:


  “press key if background is green, but do not press it if background is red”
• Cognitive inhibition


  Stroop task „Name the color of the word“
• Inhibition early childhood


  rapid improvements → first signs
• Inhibition preschool years


  significant reduction of inhibition errors
• Inhibition middle childhood


  continued improvements on (a) motor inhibition, (b) oculomotor inhibition and (c) simple response inhibition tasks
• Inhibition adolescence and adulthood


  little further improvement, continued improvement on oculomotor and response inhibition tasks until age 15, and until age 21 on a (d) cognitive inhibition task
• Inhibition in aging


  decline in response inhibition, no age-related decline in oculomotor inhibition and cognitive inhibition
• Short-term memory span


  = Passive short-term storage: Retaining information for up to 30

  seconds without rehearsal of information → longer retention

  with rehearsal
• Short-term memory span early childhood

  very limited capacity → increases during childhood

  • From about two digits in 2- to 3-year-old children to five digits in

  7-year-olds

  • Between 7 and 12 years of age, memory span increased only by

  1.5 digits
• Short-term memory span older age


  older adults retain about 90% of the elements that younger adults can retain – only small age-related decline
• Working memory (WM)


  = active short-term storage: systems that keep things in mind while performing complex tasks like reasoning, comprehension and learning
• WM slow development


  by 8 years of age, children can only hold half the items that adults can remember in memory
• Children who have better working memory are more advanced in


  • Language comprehension

  • Math skills

  • Problem solving
• WM adolescence


  further brain maturation

  → Greater functional use of working memory

  • Information processed more quickly

  • Simultaneous process of more chunks of information

  → 13-year-olds with greater working memory ability show better

  performance on a variety of academic subjects

  → Lower working memory associated with impulsivity and adolescent

  alcohol use
• WM capacity diminishes with age, but disagreement on..

  peak: after 20s (see figure) or around 45 years
• In aging, WM capacity predicts performance on a range of cognitive tasks:


  • Long-term memory

  • Problem-solving

  • Tests of intelligence
• Long-term memory


  Procedural, semantic, episodic
• Procedural memory


  Automatic, unconscious memory (often motor memory). Being able to prepare coffee
• Semantic memory


  Knowledge of facts, concepts, word meanings. Knowing what coffee is
• Episodic memory


  Remembering specific episodes that one has experienced. Remembering having had coffee with a friend last week
• Long-term memory – Procedural memory


  • Implicit memory develops earlier in infancy than explicit memory:

  Infants as young as 2½ months of age can retain information from the experience of being conditioned

  • Implicit memory capacity changes little across the lifespan

  • Young children often do no worse than older children

  • Older adults often do no worse than younger adults

  → Young and old alike learn and retain a tremendous amount of

  information from their everyday experiences without any effort

  • With advancing age, affected by biological decline (decreasing balance, tremor, fatigue,…)
• Long-term memory – Semantic memory


  • Growth during childhood as a function of a child’s

  exposure to information→ environmental context, acculturation, social status, schooling

  • Preserved with age – even expansion in some

  areas (vocabulary, historical facts)

  • Knowledge and skills learned long ago persist for long

  periods of time → permastore

  • BUT older adults have difficulties with tip-of-the-tongue,

  word finding, retrieval of proper names

  →Older adults show difficulties when semantic information

  needs to be accessed rapidly + according to arbitrary rules,

  such as word fluency
• Episodic Memory


  Memory of events and experiences in a person's life
• Development of episodic memory in childhood


  1. Hippocampus maturation (second half of 1st year)

  2. Substantial improvements across second year of life

  3. 6-month-olds can remember information for 24 hours

  4. By 20 months, infants can remember information from 12 months earlier

  5. Most conscious memories of young infants are fragile and short-lived
• Episodic memory in 3-5 year olds


  • Increasingly remember events as occurring at a specific time and location
  • Include more elements that are rich in detail in their narratives
• Episodic memory in preschool years


  • Young children increasingly remember more autobiographical characteristics
  • In some areas reasonably good memories
• Episodic memory in middle and late childhood


  • Improvements especially in strategies use
• Memory – Strategies


  • Use of mental activities to improve processing of information

  • Not much used by preschool children but older children (and adults)

  • Encoding strategy usage increases gradually:

  1. Rehearsal (repetition): beneficial for short-term memory

  2. Organization: beneficial for long-term memory, including

  Imagery for verbal information

  3. Elaboration on the information to be remembered, and

  making it personally relevant: beneficial for long-term

  memory
• Memory – Episodic Memory in adolescence


  • Episodic memory performance of young teens (11–12 years)

  similar to children, both groups markedly worse than young adults

  → New strategies during adolescence:

  • Memory strategy of elaboration is mastered

  • Develop and refine advanced learning and memory strategies

  highly relevant to school learning

  • More deliberate use of strategies than younger children

  • More selective use of strategies, only on relevant material
• Memory – Episodic Memory in adulthood


  • Relatively stable in middle adulthood

  • Declines steadily through the older adult years

  • Magnitude of the decline depends on the

  nature of the task and the method of testing

  • Retrieval condition

  • Type of memories (items vs associations)
• Age differences in EM: Retrieval condition


  ▪ Performance level: Recognition > Cued Recall > Free Recall

  ▪ Age differences mostly in recall, not in recognition tasks
• Associative deficit hypothesis


  • Age-related differences recognizing paired (bound) information (e.g., Face-name, Object-Location)

  • Simply recognizing old faces and names (= unpaired items) is

  unaffected by age
• Memory – mechanisms underlying change

  4 Hypotheses why learning and memory improve and decline

  1. Changes in basic capacities (“hardware”)

  Working memory space for manipulating and processing information

  2. Changes in memory strategies (“software”)

  Effective methods for storing information and retrieving

  3. Knowledge of memory

  Results in selecting appropriate strategies to learn

  4. Knowledge of the world

  To-be-learned material more familiar → easier to learn and remember