Can we understand how developmental stress enhances performance under future threat with the Yerkes-Dodson law?

The paper examines whether stress experienced during adolescence can prepare individuals to function more effectively under future threat, extending theories derived from prenatal stress such as the thrifty phenotype and maternal/fetal mismatch hypotheses. The authors report that adolescent stress improves adult foraging under high-threat conditions without reducing performance under low-threat conditions, and they interpret these findings through the lens of the Yerkes-Dodson law, which describes a context-specific, curvilinear relationship between arousal and performance for tasks of moderate difficulty.

The Yerkes-Dodson law originates from experiments showing linear improvements in simple task acquisition with increased stimulation and a curvilinear (inverted-U) relationship for moderately difficult tasks. Subsequent work across taxa and contexts (e.g., athletic training, workplace performance, and video games) has supported this principle. Moderate arousal can enhance performance through motivation, whereas high arousal can impair performance by reducing information processing capacity (Easterbrook hypothesis). The authors reference foundational and modern studies (e.g., Yerkes & Dodson 1908; Diamond et al.; Telegdy & Cohen; Anderson; Dickman) to situate their interpretation within robust empirical and theoretical traditions.

The discussion centers on results from Chaby et al. (2015), where adult rats previously exposed to chronic stress during adolescence were tested in a moderately challenging, problem-solving foraging task. The task involved varying motor actions and object manipulations and was conducted under two conditions: high-threat (auditory and visual predator cues and bright light) and low-threat (standard laboratory conditions with dim red light). Performance metrics included latency to initiate foraging, number of transitions between foraging patches, and food consumed (number of rewards obtained). Comparisons were made between adolescent-stressed and unstressed control rats, and performance changes from low-threat to high-threat were quantified (e.g., [final-initial/initial] × 100 for rewards obtained).

- Under high-threat conditions, adult rats exposed to adolescent stress increased foraging performance by 43% compared to unstressed rats. - Control (unstressed) animals decreased performance by an average of 28% ± SE 9% (number of rewards obtained) in high-threat compared to prior low-threat testing. - Adolescent-stressed rats showed a small average performance increase of 2% ± SE 16% when moving from low-threat to high-threat conditions. - In low-threat conditions, adolescent-stressed rats took 106% longer to initiate foraging but consumed the same amount of food as unstressed rats. - The authors propose that adolescent stress shifts the inverted-U arousal–performance curve (Yerkes-Dodson), expanding the optimal arousal range and conferring an advantage under elevated threat.

The findings indicate that developmental stress can enhance performance in high-threat environments without broadly impairing function in safe contexts. Interpreted through the Yerkes-Dodson law, adolescent stress may shift the arousal–performance curve so that optimal performance occurs at higher arousal levels, providing an advantage when threat-induced arousal exceeds the optimal range for unstressed animals. This "arousal-shift hypothesis" suggests that differences between stressed and unstressed animals will be minimal in very low-threat or extremely stressful conditions, but pronounced near and above the control optimal arousal level for tasks of moderate difficulty. The results underscore the importance of context (threat vs. safety) and task complexity (simple vs. complex) in assessing long-term effects of developmental stress and align with adaptive frameworks of early-life stress without contradicting prenatal stress hypotheses.

The article proposes the arousal-shift hypothesis to explain how adolescent stress alters the arousal–performance relationship, enhancing performance under future threat. This framework emphasizes context and task dependency and highlights adolescence as a period of plasticity with potential for transformative change. Future research should test the hypothesis across task complexities (simple vs. complex), varying threat intensities, and developmental stages, and examine how aging and environmental changes modulate the long-term effects of early stress.