Younger apes and human children plan their moves in a maze task

Area of Science:

• Cognitive Evolution
• Developmental Psychology
• Comparative Cognition

Background:

• Planning is a key executive function for complex problem-solving.
• Understanding its origins requires examining both developmental (ontogenetic) and evolutionary (phylogenetic) trajectories.
• Executive functions are critical for goal-directed behavior across species.

Purpose of the Study:

• To investigate the ontogenetic and phylogenetic origins of planning abilities.
• To compare planning skills in great apes and human preschoolers.
• To identify age-related changes and species-specific limitations in planning.

Main Methods:

• A vertical maze task was administered to four great ape species (N=12) and human preschoolers (4- and 5-year-olds, N=24).
• Subjects had to retrieve a reward by navigating a maze with flexible trap configurations, requiring planning up to two steps ahead.
• Performance was assessed based on the ability to plan actions in response to varying task demands.

Main Results:

• Planning ability in nonhuman apes showed a negative correlation with age.
• Five-year-old children and younger apes could plan two steps ahead, while four-year-olds planned only one step ahead.
• Both apes and children demonstrated similar task performance but differed in underlying limitations: apes struggled with motor control, while children had difficulty with attentional shifting.

Conclusions:

• Planning skills develop differently across species and with age.
• Nonhuman apes' planning is constrained by motor control, whereas human children's planning is limited by attentional flexibility.
• This study provides insights into the evolutionary and developmental pathways of executive functions, particularly planning.