Temperament: half a century in the Journal

Socio-emotional development in infancy is primarily shaped by early emotional responses and social connections, with temperament playing a central role. Temperament refers to the consistent patterns in an individual's emotional and behavioral responses, observable even in infancy. By examining temperament, researchers can better understand an infant's unique ways of interacting with the world, influencing subsequent personality and socio-emotional growth.
Primary Temperament Types
Stella Chess...

Behaviors are actions that an organism engages in—they can be related to finding food, reproducing, defending against threats, and many other possible actions. Behaviors include activities related to the environment around the animal—such as migration—as well as social interactions within a species or population. Many behaviors involve motor output—that is, muscle movements—while others involve less visible actions, such as learning.

Many human characteristics, like height, are shaped by both nature—in other words, by our genes—and by nurture, or our environment. For example, chronic stress during childhood inhibits the production of growth hormones and consequently reduces bone growth and height. Scientists estimate that 70-90% of variation in height is due to genetic differences among individuals, and 10-30% of variation in height is due to differences in the environments that individuals experience, such as differences...

Personality encompasses a set of enduring traits and behavioral patterns that define how individuals think, feel, and interact, ultimately shaping their unique identities. The concept of personality has deep historical roots, deriving from the Latin term "persona," which means "mask." This term initially referred to the roles played by actors in ancient theater, signifying the different facets individuals display in various contexts.
Early Theories of Personality
The study of personality dates...

Long-term depression, or LTD, is one of the ways by which synaptic plasticity—changes in the strength of chemical synapses—can occur in the brain. LTD is the process of synaptic weakening that occurs over time between pre and postsynaptic neuronal connections. The synaptic weakening of LTD works in opposition to synaptic strengthening by long-term potentiation (LTP) and together are the main mechanisms that underlie learning and memory.

Hans and Sybil Eysenck developed a widely recognized theory of personality, which emphasizes the role of temperament and genetically based differences in shaping individual traits. Their theory posits that biological factors primarily determine personality and can be understood through two main dimensions: extroversion/introversion and neuroticism/stability.
In the extroversion/introversion dimension, highly extroverted people are sociable, outgoing, and easily connect with others. In contrast,...