The chapter discusses the negativity effect, a phenomenon where negative stimuli have a greater impact than equally intense positive stimuli. This effect is observed in various contexts, such as decision-making under risk, information integration, and reactions to situational changes. The authors review evidence supporting the negativity effect, including studies on animal conditioning and human evaluations of social situations. They emphasize the importance of controlling for the intensity of stimuli to ensure that the effect is not due to differences in intensity alone. The chapter also explores the broader context of positive-negative asymmetry, which includes both the positivity bias and the negativity effect. The positivity bias refers to the tendency to form positive hypotheses about reality, while the negativity effect is a manifestation of this bias. The authors propose a behavioral-adaptive theory that explains these phenomena as adaptive mechanisms for survival and self-actualization. They argue that the positivity bias is driven by a tendency to approach positive outcomes, while the negativity effect helps avoid negative outcomes. The chapter further examines the dimensional restrictions of positive-negative asymmetry, suggesting that it primarily involves an approach-avoidance related evaluative dimension called "other-profitability." This dimension is more consistently associated with the positivity bias than the self-profitability dimension. The authors provide evidence supporting this claim through studies on compound terms and impression formation. Additionally, the chapter discusses the informational negativity effect, where negative stimuli are perceived as more informative and lead to more complex cognitive representations. This effect is distinct from the affective negativity effect and is explained by the objective anchoring of negative information. The authors suggest that the informational negativity effect may be driven by the need to accommodate and process complex cognitive representations. Finally, the chapter addresses the discrepancy between affective and informational negativity effects, particularly for weakly negative stimuli, and the marked character of negative categories. It proposes a behavioral-adaptive explanation involving affective and cognitive coping modes, where weak negative stimuli elicit stronger informational negativity effects due to the minimal interference of affective defense responses and the ease of controlling their sources.The chapter discusses the negativity effect, a phenomenon where negative stimuli have a greater impact than equally intense positive stimuli. This effect is observed in various contexts, such as decision-making under risk, information integration, and reactions to situational changes. The authors review evidence supporting the negativity effect, including studies on animal conditioning and human evaluations of social situations. They emphasize the importance of controlling for the intensity of stimuli to ensure that the effect is not due to differences in intensity alone. The chapter also explores the broader context of positive-negative asymmetry, which includes both the positivity bias and the negativity effect. The positivity bias refers to the tendency to form positive hypotheses about reality, while the negativity effect is a manifestation of this bias. The authors propose a behavioral-adaptive theory that explains these phenomena as adaptive mechanisms for survival and self-actualization. They argue that the positivity bias is driven by a tendency to approach positive outcomes, while the negativity effect helps avoid negative outcomes. The chapter further examines the dimensional restrictions of positive-negative asymmetry, suggesting that it primarily involves an approach-avoidance related evaluative dimension called "other-profitability." This dimension is more consistently associated with the positivity bias than the self-profitability dimension. The authors provide evidence supporting this claim through studies on compound terms and impression formation. Additionally, the chapter discusses the informational negativity effect, where negative stimuli are perceived as more informative and lead to more complex cognitive representations. This effect is distinct from the affective negativity effect and is explained by the objective anchoring of negative information. The authors suggest that the informational negativity effect may be driven by the need to accommodate and process complex cognitive representations. Finally, the chapter addresses the discrepancy between affective and informational negativity effects, particularly for weakly negative stimuli, and the marked character of negative categories. It proposes a behavioral-adaptive explanation involving affective and cognitive coping modes, where weak negative stimuli elicit stronger informational negativity effects due to the minimal interference of affective defense responses and the ease of controlling their sources.