Visual and olfactory signals of conspecifics induce emotional contagion in mice

Area of Science:

• Ethology
• Animal Behavior
• Neuroscience

Background:

• Emotional contagion, the capacity to share and be affected by another's emotional state, is observed across various animal species, including rodents.
• Understanding the specific social signals that mediate emotional state-matching in mice is crucial for comprehending social behavior and inter-individual communication.

Purpose of the Study:

• To investigate the social signals responsible for emotional contagion in mice.
• To determine the relative contributions of visual, olfactory, and auditory stimuli in eliciting emotional contagion.

Main Methods:

• An empirical laboratory experiment was conducted using the Japanese wild-derived mouse strain MSM/Ms (MSM) as observers.
• MSM mice were exposed to visual (video footage of a mouse receiving painful stimuli), olfactory (urine from shocked or unshocked mice, or water), and auditory stimuli.
• Fear-induced freezing behavior in MSM observers was measured in response to different stimuli.

Main Results:

• MSM mice exposed to urine from shocked mice exhibited significantly higher fear-induced freezing behavior compared to controls.
• Observing visual stimuli (pixelated video) was associated with reduced freezing responses.
• Auditory cues did not significantly affect the duration of freezing behavior.

Conclusions:

• Olfactory cues, specifically urine from stressed individuals, are potent social signals for emotional contagion in mice.
• Visual and olfactory information, but not auditory cues, are sufficient to mediate emotional contagion.
• These findings provide clear evidence for the role of multiple sensory modalities in mouse emotional contagion.