Assessing the External Validity of Successive Negative Contrast - Implications for Animal Welfare

Area of Science:

• Animal Behavior
• Animal Welfare Science
• Comparative Psychology

Background:

• The successive negative contrast (SNC) effect is a phenomenon where animals decrease consumption of a less-preferred reward after experiencing a more preferred one.
• SNC has been proposed as a potential indicator of animal welfare.
• For SNC to be a valid welfare indicator, its external validity must be established outside of controlled laboratory settings.

Purpose of the Study:

• To investigate the external validity of the SNC effect in owned (pet) rats from diverse, non-laboratory environments.
• To determine if the SNC effect observed in laboratory rats is reproducible in pet rats.

Main Methods:

• A consummatory SNC paradigm was employed using solid food rewards.
• Fourteen pet rats were divided into "shifted" and "unshifted" groups.
• The "shifted" group experienced a switch from a high-value to a low-value reward, while the "unshifted" group received only the low-value reward throughout.

Main Results:

• "Shifted" rats consumed more food during pre-shift and re-shift phases compared to "unshifted" rats.
• During the post-shift phase, "shifted" rats ate significantly less of the low-value food than "unshifted" rats, confirming the SNC effect.
• The study demonstrated the SNC effect in pet rats under non-laboratory conditions.

Conclusions:

• The SNC effect exhibits external validity, being reproducible outside of standardized laboratory settings.
• The findings indicate the translatability of the SNC paradigm across different environmental contexts.
• This enhances the potential of the SNC effect as a reliable indicator of animal welfare in diverse settings.