Social buffering in horses

I think the way to look at these results is that horses do find comfort from a companion, whether a known one or a stranger, but in the case of being startled reactions are faster than the buffering effect of companionship. Seems to agree with my experiences but there are exceptions. I have known horses that without their companions where far more reactive than with. This summary would suggest it would not matter who the companions were.
DrO

Social buffering in horses is influenced by context but not by the familiarity and habituation of a companion
Sci Rep. 2021 Apr 23;11(1):8862. doi: 10.1038/s41598-021-88319-z.
Authors
Claire Ricci-Bonot 1 , Teresa Romero 2 , Christine Nicol 2 3 , Daniel Mills 2
Affiliations

1 Animal Behaviour, Cognition and Welfare Group, School of Life Sciences, University of Lincoln, Lincolnshire, LN6 7TS, UK. cRicciBonot@lincoln.ac.uk.
2 Animal Behaviour, Cognition and Welfare Group, School of Life Sciences, University of Lincoln, Lincolnshire, LN6 7TS, UK.
3 The Royal Veterinary College, Hawkshead Lane North Mymms Hatfield, Hertfordshire, AL9 7TA, UK.

PMID: 33893366
DOI: 10.1038/s41598-021-88319-z

Abstract

Social buffering occurs when the presence of one animal attenuates another’s stress response during a stressful event and/or helps the subject to recover more quickly after a stressful event. Inconsistent previous results might reflect previously unrecognised contextual influences, such as the nature of the stimulus presented or social factors. We addressed these issues in a two-part study of horses paired with familiar (16 subjects) or unfamiliar (16 subjects) companions. Each subject performed 4 tests in a counterbalanced order: novel object test (static ball)-alone or with companion; and umbrella opening test-alone or with companion. Social buffering was significantly influenced by the nature of the stimulus presented, but not by companion’s habituation status or familiarity. Importantly, the stimulus used produced differential effects on behavioural and physiological measures of buffering. A companion significantly reduced behavioural response (reactivity) in the novel object test but not in the umbrella test. However, heart rate recovered more quickly for subjects with a companion in the umbrella test but not in the novel object test. We propose that circumstances which permit greater contextual processing may facilitate demonstration of behavioural effects of social buffering, whereas buffering in response to startling events may be manifest only during post-event physiological recovery.