1. Evaluating Psychological Research in
Developmental Psychology: Piaget's Theory of
Cognitive Development
Piaget's constructivist theory revolutionized our understanding of how children
learn, proposing that they actively build knowledge by adapting new information
to fit their existing mental frameworks, or schemas. This adaptation occurs
through two key processes: assimilation, where new experiences are incorporated
into existing schemas, and accommodation, where schemas are modified to
accommodate new information.
Piaget's research relied heavily on the clinical interview, an open-ended
conversational approach designed to probe children's comprehension of various
tasks. While insightful, this method has been critiqued for potential researcher
bias, as the interviewer's interpretations could influence the findings. Furthermore,
methodological limitations include the possibility that young children may struggle
to understand complex questions, exhibit short attention spans, lack the verbal
skills to express their thoughts accurately, or feel pressured to provide answers
they believe the experimenter wants to hear.
A significant challenge to Piaget's work comes from the distinction between
competence (what a child is truly capable of) and performance (what they
demonstrate in a specific task). Piaget's tasks may have underestimated children's
cognitive abilities by relying heavily on verbal explanations and complex
manipulations.
Subsequent research has challenged some of Piaget's specific age-related
milestones:
Object Permanence: Baillargeon and Devos (1991) demonstrated through a
violation-of-expectation paradigm using a carrot model that infants as
young as 4 months show evidence of object permanence, significantly earlier
than Piaget's proposed 9 months. This suggests that infants possess an earlier
understanding that objects continue to exist even when out of sight.
Egocentrism: Piaget's classic three mountains task suggested that
preoperational children struggle to take another person's perspective.
However, Hughes (1975) used a simpler "policeman doll" task and found
, that even 4-year-olds could understand another person's viewpoint when the
task was more relatable and less abstract.
Conservation: Piaget's conservation tasks (e.g., liquid, number, mass)
indicated that children under 7 typically fail to understand that quantity
remains the same despite changes in appearance. However, Samuel and
Bryant (1984) found that reducing the need for verbal justification in
conservation tasks led to younger children (under 7) demonstrating an
understanding of conservation.
Finally, Piaget's theory has been criticized for its limited emphasis on the social
and cultural context of cognitive development. Piaget viewed children as largely
independent learners, neglecting the crucial role of social interaction, guidance
from more knowledgeable others, and cultural tools in shaping cognitive growth.
Vygotsky's sociocultural theory offers a contrasting perspective, highlighting the
importance of these social and cultural influences.
2. The Influence of Social and Environmental
Variables on Cognitive Development
Cognitive development is not solely determined by innate processes; social and
environmental factors play a crucial role in shaping a child's intellectual trajectory.
Social Variables:
Dieting and Nutrition: The increasing rates of childhood obesity are
intertwined with concerns about cognitive development. Northstone (2010),
in a longitudinal study monitoring 4000 children in the UK from birth to 8.5
years, found a significant negative correlation between the regular
consumption of processed foods, fats, and sugars before age 4 and
intellectual performance at age 8.5. Specifically, children's IQ scores
decreased by an average of 1.67 points for each increase on a dietary pattern
scale reflecting higher processed fat intake.
o Hibbeln (2007) compared mothers with high versus low levels of
omega-3 fatty acid intake during pregnancy. The study revealed that
children of mothers with low seafood consumption (a primary source
of omega-3) exhibited poorer motor skills, social development, and
communication skills compared to children whose mothers had higher
omega-3 intake. This highlights the critical role of prenatal nutrition
in neurodevelopment.