Habituation and Novelty

Beginning in infancy and throughout the life span, humans are motivated by newness, change, and excitement. Habituation, the tendency to lose interest in a repeated event and gain interest in a new one, is one of the most fundamental human reflexes. If the thermostat were to suddenly turn the air conditioning on, you would hear the loud humming sound begin, but within minutes you couldn’t even hear it if you tried. Habituation, a fundamental property of the nervous system, provides mechanis...

 How Brains Respond to Positive/Negative Feedback in Child...

In children up to eight or nine years old, the dopamine-modulating reward center in the nucleus accumbens reacts strongly to positive feedback (activating the prefrontal cortex) and minimally to negative feedback. In older children, increased activation still occurs in the PFC when dopamine is released in response to positive feedback (particularly in response to correct answers/ predictions). However, the greatest age-related change is the higher reactivity of the NAc to negative feedback an...

 Chemical Cognitive Enhancers

Pharmaceutical amphetamines (such as Adderall and Ritalin) These drugs have been used withouit a prescription, for their tirednessreducing and concentration-enhancing effects, by about 5% of students in U.S. colleges, according to a recent study, with some colleges reporting rates as high as 25%. Modafinil Modafinil is a nonamphetamine stimulant, marketed to help people with narcolepsy stay awake. It has been reported as popular with otherwise healthy individuals who are using it to mai...

 Temperament is Influenced by Chemicals

Some 40 percent to 60 percent of the observed variance in personality is due to traits of temperament. They are heritable, relatively stable across the life course, and linked to specific gene pathways and/or hormone or neurotransmitter systems. Moreover, our temperament traits congregate in constellations, each aggregation associated with one of four broad, interrelated yet distinct brain systems: those associated with dopamine, serotonin, testosterone, and estrogen/oxytocin. Each constellat...