Source Paper
Evan L. MacLean, Brian Hare, Charles L. Nunn, Elsa Addessi, Federica Amici et al.
Proceedings of the National Academy of Sciences • 2014
Significance Although scientists have identified surprising cognitive flexibility in animals and potentially unique features of human psychology, we know less about the selective forces that favor cognitive evolution, or the proximate biological mechanisms underlying this process. We tested 36 species in two problem-solving tasks measuring self-control and evaluated the leading hypotheses regarding how and why cognition evolves. Across species, differences in absolute (not relative) brain volume best predicted performance on these tasks. Within primates, dietary breadth also predicted cognitive performance, whereas social group size did not. These results suggest that increases in absolute brain size provided the biological foundation for evolutionary increases in self-control, and implicate species differences in feeding ecology as a potential selective pressure favoring these skills.
Objective: Quantitatively compare cognitive performance of multiple species on two problem-solving tasks measuring self-control and inhibitory control to test evolutionary hypotheses about cognitive evolution
This is a Self-Control Problem-Solving Task protocol using 36 species (multi-species comparative study) as the model organism. The procedure involves 5 procedural steps. Extracted from a 2014 paper published in Proceedings of the National Academy of Sciences.
Model and subjects
36 species (multi-species comparative study) • Not specified • unknown • Not specified • Not specified • 567
Study window
Estimated timing pending
Core workflow
Study Design and Species Selection • Task Administration • Data Collection
Primary readouts
Key equipment and reagents
Verified items
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Experimentally evaluated major evolutionary explanations by quantitatively comparing cognitive performance across multiple species on two problem-solving tasks measuring self-control
Note: This was a large-scale comparative study integrating experimental and phylogenetic approaches
“experimentally evaluated these major evolutionary explanations by quantitatively comparing the cognitive performance of 567 individuals representing 36 species on two problem-solving tasks measuring self-control”
Subjects were tested on two problem-solving tasks designed to measure self-control and inhibitory control abilities
Note: Specific task details not provided in the methods section excerpt
“tested 36 species in two problem-solving tasks measuring self-control”
Quantitative performance data was collected from all 567 individuals across the 36 species on the two problem-solving tasks
Note: Performance metrics were recorded for subsequent analysis
“quantitatively comparing the cognitive performance of 567 individuals representing 36 species on two problem-solving tasks”
Phylogenetic analysis was conducted to evaluate relationships between brain volume measures and cognitive performance across species
Note: Analysis examined both absolute brain volume and brain volume controlling for body mass
“Phylogenetic analysis revealed that absolute brain volume best predicted performance across species and accounted for considerably more variance than brain volume controlling for body mass”
Within primates, dietary breadth and social group size were evaluated as predictors of species differences in self-control performance
Note: Dietary breadth was found to be a strong predictor while social group size was not
“Within primates, dietary breadth but not social group size was a strong predictor of species differences in self-control”
This section explains what the experiment is doing, which readouts matter, what the data artifacts usually look like, and how the analysis should flow from raw capture to reported result.
Quantitatively compare cognitive performance of multiple species on two problem-solving tasks measuring self-control and inhibitory control to test evolutionary hypotheses about cognitive evolution
Objective
Quantitatively compare cognitive performance of multiple species on two problem-solving tasks measuring self-control and inhibitory control to test evolutionary hypotheses about cognitive evolution
Subjects
From paper36 species (multi-species comparative study) • Not specified • unknown • Not specified • Not specified
Sample count
From paper567
Cohort notes
From paper567 individuals representing 36 species tested across two problem-solving tasks
Study Design and Species Selection (Not specified)
Task Administration (Not specified)
Data Collection (Not specified)
Phylogenetic Analysis (Not specified)
Performance on two problem-solving tasks measuring self-control
From paperPhylogenetic analysis was used to evaluate evolutionary relationships between variables.
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Performance on tasks measuring inhibitory control
From paperPhylogenetic analysis was used to evaluate evolutionary relationships between variables.
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Absolute brain volume correlation with cognitive performance
From paperPhylogenetic analysis was used to evaluate evolutionary relationships between variables.
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Brain volume controlling for body mass correlation with performance
From paperPhylogenetic analysis was used to evaluate evolutionary relationships between variables.
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Performance on two problem-solving tasks measuring self-control
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Performance on tasks measuring inhibitory control
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Absolute brain volume correlation with cognitive performance
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Brain volume controlling for body mass correlation with performance
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Acquisition
Collect raw experimental outputs with enough metadata to preserve sample identity, condition, and timing.
Preprocessing / cleaning
Phylogenetic analysis was used to evaluate evolutionary relationships between variables.
Scoring or quantification
Quantify the primary readouts for this experiment: Performance on two problem-solving tasks measuring self-control; Performance on tasks measuring inhibitory control; Absolute brain volume correlation with cognitive performance; Brain volume controlling for body mass correlation with performance.
Statistical comparison
Statistical method not yet structured for this page.
Reporting output
Report representative outputs alongside summary comparisons for Performance on two problem-solving tasks measuring self-control, Performance on tasks measuring inhibitory control, Absolute brain volume correlation with cognitive performance, Brain volume controlling for body mass correlation with performance.
Source links and direct wording from the methods section for validation and deeper review.
Citation
Evan L. MacLean et al. (2014). The evolution of self-control. Proceedings of the National Academy of Sciences
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