General intelligence is a source of individual differences between species: Solving an anomaly.

Area of Science:

• Comparative psychology
• Cognitive evolution
• Behavioral neuroscience

Background:

• General intelligence factors (g) are established at individual and aggregate levels across species.
• Ambiguous evidence exists for 'g' when comparing individuals across species using mixed-methods analysis.
• This discrepancy presents a paradox in understanding intelligence evolution.

Purpose of the Study:

• To empirically resolve the paradox of the general intelligence factor (g) in cross-species comparisons.
• To clarify the existence and nature of 'g' in mixed-methods analyses.
• To advance the understanding of cognitive similarities and differences across species.

Main Methods:

• Utilizing a mixed-methods approach to analyze cognitive ability data.
• Comparing performance on a standardized cognitive ability battery across diverse species.
• Employing advanced statistical techniques to identify general intelligence factors.

Main Results:

• Empirical data supports the existence of a general intelligence factor (g) across species.
• The study successfully reconciles findings from individual-level and aggregate-level analyses.
• Evidence for 'g' is robust even within a mixed-methods framework.

Conclusions:

• The general intelligence factor (g) is a valid construct in cross-species comparative studies.
• Mixed-methods analyses can reliably detect 'g' when appropriate methodologies are applied.
• This research provides a unified framework for understanding intelligence across the animal kingdom.