Temperament and the Challenge of Impulse Control

Key Insight

Individuals like Erica often exhibit a 'fight-or-flight' response to stress, indicating an inherent temperament that predisposes them to react intensely. Psychologist Jerome Kagan's 1979 study with five hundred infants identified 20 percent as 'high reactive' (crying vigorously to unfamiliar stimuli) and 40 percent as 'low reactive.' A decade later, a fifth of the 'high reactives' still responded sharply to stress, while a third of the 'low reactives' remained calm, suggesting that while temperaments evolve, their range has limits and a basic 'home state' tends to persist.

Erica's struggle with self-control was vividly displayed during a tennis match where, despite her general determination, a bad performance triggered intense anger. She became frustrated, shouting and throwing her racket, ultimately disrupting the match and physically intimidating others. During this meltdown, she felt a surge of power and a desire to humiliate, later describing it as if 'some strange angry person who had hijacked my body.' Her mother observed that Erica's moods oscillated more wildly than most, identifying her as an 'orchid child'—capable of spectacular success in the right environment but prone to catastrophe in the wrong one.

The long-term effects of chronic stress, often linked to such reactive temperaments, include cell loss in the hippocampus leading to memory impairment, weakened immune systems, reduced bone minerals, and increased body fat accumulation. A study on engineers revealed elevated stress hormones (cortisol and epinephrine) persisted for up to eighteen months after a highly stressful project, even with extended vacations. Erica's intense outburst and subsequent shame highlight the profound internal conflict, reinforcing research by Angela Duckworth and Martin Seligman that self-control is twice as important as IQ for high-school performance and crucial for a fulfilling life.