Lecture notes on cognitive/physical development (week 4)

Broad issues in cognitive development:

Horizontal vs Vertical:

Horizontal -- general abilities such as memory, attention, learning that cross all domains. Presumes more holistic development of cognitive ability

Vertical -- specific forms of perception, memory, and learning for different domains, such as language, music, logic-math, spatial, interpersonal. Attends more to individual differences within and across people.

Howard Gardner's theory of Multiple Intelligences focuses on vertical differentiation, and highlights prodigies and autististic people as examples of uneven development

Stage vs Continuous

Stage-- Piaget is the best exemplar. Proposes qualitative shifts in how children reason about the world in different periods. Piaget tends toward a more horizontal conception, but this can also be applied to a vertical conception.

Continuous-- Focuses on gradual changes, such as improving ability to use working memory, increased automaticity, and underlying changes in the nervous system.

Integrative: Qualitative shifts in behavior (change of strategy) may occur as a consequence of more gradual underlying changes (pp. 516-518)

Crystallized and Fluid Intelligence(pp. 520-521):

Crystallized: Store of knowledge: facts, concepts, strategies--both knowing "that" something is true and knowing "how" to do things (learned strategies).

Fluid-- Horizontal intellectual capacities that have no specific content but are used in processing information, especially new information. Speed of processing, ability to grasp or form new concepts, learn new information.

Note: Crystallized knowledge typically increases (accumulates) throughout the lifespan, showing declines only in very old age. Fluid intelligence capacity--particularly the speed of learning new information, peaks in the 20s and declines in middle & later adulthood.

Three methods:


Measurement at a single time, across cohorts


Measurement at multiple times across the lifespan


Combination of first two: Multiple cohorts followed over time

Piaget (* indicates empirical evidence that is not in line with Piaget's stages):

0-2 Sensorimotor

Object permanence develops*


Explore with mouth & hands

* OP early as 2 months

* pretend play, 18 months

2-7 Pre-operational

Language: symbolic thought

Centration, literal thinking

Cannot do perspective taking*

* PT early as 2.5 years

* False belief task 4 years

7-12 Concrete operaional



Reversible mental operations

Apply logic to concrete situations

* 12.5 months: Infants understand that objects take up space relative to size

12 + Formal operational

Abstract reasoning that is not tied to concrete objects

* Even in adulthood, can see "failures" of conservation and other reasoning

Adult Physical & Cognitive Development : Use it or lose it.

For physical abilities, people start to lose those gradually even if the DO use them (witness early retirement ages for athletes).

For cognitive abilities, however (except for the speed of processing issue), the picture is more mixed.

Data on "average" declines of cognitive abilities over time are often misleading (Figure 13.17). As Figure 13.17 illustrates, it may be more appropriate to make a CATEGORICAL, qualitative distinction between adults who retain their cognitive abilities with no measurable decline, even in very late adulthood (the majority of people, over 60%) and those who show declines. Note that the Figure does NOT measure for the same people across 21 years, but for people at different ages compared to where they were seven years ago. It's possible that a 21 year study would show measurable declines in some of these people classified as "no decline" over a shorter period.

We also discussed why 60-year-olds in the late 1980s would be DIFFERENT from people who are 81 in late 1980s--due to more schooling, changing cultural patterns, and changing stereotypes about what is possible for older people.