Cause of the disappearance of side bias in dogs’ choice tests

Ascertain the cause of the disappearance of side bias in the choice behavior of Indian free-ranging dogs during the reward-absent test phase (Days 6–10) of the two-experimenter calling paradigm, after a side bias had emerged and influenced choices during Days 2–5.

Background

In the study, two unfamiliar human experimenters stood on opposite sides and simultaneously called free-ranging dogs during repeated trials. A left-side bias emerged from Day 2 to Day 5 and significantly influenced choices, but the bias disappeared when rewards were no longer provided from Day 6 to Day 10.

The authors explicitly state that the reason for this disappearance is unknown and highlight the need for further investigation to identify the underlying cause(s).

References

No side bias was observed on Day 1, but it emerged on subsequent days and influenced choices until Day 5, before disappearing again from Day 6 to 10, when rewards were no longer provided. The cause of this disappearance remains unclear and warrants further investigation.

— Treats or Affection? Understanding Reward Preferences in Indian Free-ranging Dogs for Bonding with Humans  (2505.02756 - Nandi et al., 5 May 2025) in Discussion