Continuous or discrete magnitudes? A comparative study between cats, dogs and humans

Area of Science:

• Cognitive Science
• Comparative Psychology
• Animal Behavior

Background:

• Quantity discrimination is a fundamental cognitive ability.
• Species differ in whether they rely on numerical or continuous magnitude cues for decisions.
• Understanding these differences sheds light on the evolution of cognition.

Purpose of the Study:

• To investigate whether numerosity or total surface area influences choice in cats, dogs, and humans.
• To compare decision-making processes across these species using a spontaneous choice paradigm.
• To explore the role of shape preference in quantity discrimination.

Main Methods:

• A two-way spontaneous choice paradigm was employed.
• Food stimuli were used for cats and dogs; image stimuli for humans.
• Ratios of stimuli (0.5 and 0.67) and shape variations were systematically manipulated.

Main Results:

• Cats preferred larger food quantities at a 0.5 ratio but not 0.67.
• Dogs did not differentiate food quantities regardless of ratio.
• Humans discriminated quantities almost perfectly; dogs and humans showed shape preferences (e.g., circles).
• Human reaction times varied with stimulus properties, unlike cats and dogs.

Conclusions:

• Quantity estimation is not universally processed; it is influenced by a species' ecological context.
• Decision-making strategies for quantity vary significantly across cats, dogs, and humans.
• Future research should explore quantity estimation in diverse contexts and motivational states.