Table 1.

Reasoning underpinning the conceptual framework for classifying behavioral responses to multiple stressors based on the direction and magnitude of their individual and interactive effects (Figure 1). Six conditions underpin the integration of schemes for classifying interactions between multiple stressors (Piggott et al., 2015b; hereafter P) and multiple stimuli (Munoz & Blumstein, 2012, MB)

	Condition details
1	Double‐negative/ double‐positive interactions (P) are analogous to redundant stimuli (MB). All other interactions are analogous to nonredundant stimuli.
2	Additive interactions (independence—P) are analogous to equivalence and independence for redundant and nonredundant stimuli, respectively (MB).
3	Double‐negative interactions (Figure 1a) that are more negative than additive are analogous to enhancement (MB), and less negative than additive to antagonism (MB). The latter can be further classified as antagonistic or synergistic (i.e., reversal or “mitigating synergism”) (P) based on the strength of the interaction. The same reasoning applies to double‐positive interactions except the direction of individual effects is in the opposite direction (i.e., more positive than additive = enhancement, less positive = antagonism);
4	For opposing interactions (Figure 1b), antagonism (P) is analogous to dominance (MB), and synergism (P) to modulation (MB). Dominance occurs when the confidence intervals for the interaction and individual effect in the same direction overlap, and modulation when the interaction confidence interval is greater.
5	For negative or positive (i.e., non‐neutral) versus neutral interactions (Figure 1c), all antagonistic interactions are classified as dominance (MB), all synergistic interactions in the same direction as the non‐neutral stimuli as modulation, and in the opposite direction as emergence.
6	Emergence (MB) occurs when any interaction between two neutral individual effects is not additive (Figure 1d).