Temperament: Nature or Nurture? PDF

§ What is temperament? § Are temperament and personality the same thing? ----- § When does one’s temperament become visible? § Can temperament change over time? § Where does temperament come from, nature or nurture? § Individual differences in quality and intensity of our internal and external respo...

§ What is temperament? § Are temperament and personality the same thing? ----- § When does one’s temperament become visible? § Can temperament change over time? § Where does temperament come from, nature or nurture? § Individual differences in quality and intensity of our internal and external responses to our environment that… § Emerge early in life § Show some stability over time § Are pervasive across § “Personality is a wide range of situations the typical behavioral patterns (including emotions and thoughts) that characterize a person’s adaptation to the events of life.” Walter Mischel (1976) § Definition: the tendency to respond in characteristic & predictable ways to environmental events (Chess et al., 1987) § Longitudinal Study (N = 141): clinical interviews with mothers of 2- to 3-month-old infants; continued interviewing children infancy - young adulthood 9 Dimensions Activity level Quality of mood Biological rhythmicity Persistence/attention span Approach/withdrawal Distractibility Adaptability Sensory threshold Intensity of reaction Flexible Fearful Feisty (40%) (15%) (10%) (“easy”) (cautious/slow-to-warm) (“difficult”) Regular rhythms Adapts slowly Active Positive mood Withdraws Intense Adaptability Distractible Low intensity Sensitive Low sensitivity Irregular Moody 7 Definition: Behavioral Inhibition = a temperament that reflects one’s tendency to withdraw from unfamiliar people, situation, or things Inhibited Uninhibited 4 mos Upset at novel stimuli No negative reaction to novelty 1-2 yrs Shy, fearful of unfamiliar situations, people, toys Little fear of new situations, people 4.5 yrs Little talking or smiling w/ strangers Spontaneous talking, smiling ♦ Extremes showed the most stability over time § Phenotypes in infancy >> Different phenotypes in adulthood § Inhibited temperament in infancy >> anxiety in childhood/adolescence/adulthood What is the source of this trait? § Human amygdala § Basic neuroanatomical architecture is present at birth (Humphrey, 1968; Ulfig, et al., 2003) § Amygdala volumetric growth is complete by age 4 in girls (Giedd et al., 1996) § Animal studies suggest that the most rapid rate of development is within the early postnatal period Payne et al., 2010 § Phenotypes Adulthood in infancy >> Different phenotypes in § Inhibited temperament in infancy >> anxiety in childhood/adolescents/adulthood § Amygdala identified as long-term mediator of this continuity (Schwartz et al., 2003) Autonomic responses to fear Emotional responses One definition: the tendency to respond in characteristic & predictable ways to environmental events (Chess et al., 1987) Another definition: reflects one’s tendency to approach/withdraw from unfamiliar people, situations, or things (Kagan, 1987) Another definition: the tendency to express particular emotions with a certain intensity that is unique to each individual (Fox, 1998) “One of the most significant things ever said about emotion may be that everyone knows what it is until they are asked to define it.” Joseph LeDoux (1996) § Emotion = reflects a kind of motion outward § An inferred complex sequence of reactions to a stimulus including cognitive evaluations, subjective changes, autonomic and neural arousal, impulses to action, and behavior designed to have an effect (functional) upon the stimulus that initiated the complex sequence (Plutchik, 1982) § Inferred § Reactive § Functional § Emotions are essential for survival § Emotions help us navigate world § Rapid system § usually works faster than cognitive processes Emotion processing includes both reactivity AND regulation Another definition: the tendency to express particular emotions with a certain intensity that is unique to each individual (Fox, 1998) Focused on both positive and negative emotionality More emphasis on development (e.g., neuro-cortical maturation) Spectra of reactivity and regulation: Reactivity refers to individual differences in the emotional arousability of the child: how easily the child is moved to action Regulation refers to individual differences in managing these reactive emotional tendencies 2 dimensions (reactivity and regulation) 4 temperament types: 25 Regulation Low Reactivity, High Regulation High Reactivity, High Regulation These are more fearful and controlled children. They are not easily impressed by positive or negative events and maintain high level of regulation. Many consider this to be the optimal temperamental profile. Such children are easily impressed by events in their environment but can self-regulate and use their excitement toward goaldirected behavior. Low Reactivity, Low Regulation High Reactivity, Low Regulation Such children appear to be withdrawn, not excited by their surroundings, and not directed into any intentional program of action. These children run the risk of developing attention or hyperactivity problems. Stimulation can easily excite them and throw them off-balance, but they lack self-regulation to use their excitement toward adaptive goals (playing, learning, mastery of skills). Reactivity § Part of developmental change involves: § learning about safety and danger in the environment (reactivity) § learning how to manage our emotions to achieve our goals (regulation) § Amygdala (early developing) à Reactivity § Which neural region is implicated in regulation? *Baseline ability relates to temperament The Amygdala Huttenlocher et al., 1997 Gogtay et al., 2004 § In the first months of life, caregivers help infants regulate their emotional arousal by controlling their exposure to stimulating events § By 6 months, infants can reduce their distress by averting their gaze and sometimes by selfsoothing § Between ages 1 and 2, infants increasingly turn their attention to non-distressing objects or people to distract themselves from sources of distress With age comes an increasing ability to regulate one’s own emotions § prefrontal cortex can facilitate or attenuate the amygdala during affect regulation in adults (e.g. Ochsner et. al., 2002; 2004; Kalisch et. al., 2006; Eippert et. al., 2006) Look at this image and make yourself feel WORSE about what you are seeing. Look at this image and make yourself feel BETTER about what you are seeing. fMRI task Ochsner et al., 2004 Lateral and Orbital PFC Ochsner et al., 2004 Amygdala reactivity was modulated by regulation strategy Ochsner et al., 2004 Temperament has traditionally been viewed as a “genetic” (nature) phenomenon… Schneider, 1992 (one of many examples) Monkeys exposed to noise stressors once a day while pregnant Offspring: highly stress reactive; little exploration; clingy Based on what we’ve discussed today in class, is temperament an exclusively “genetic” phenomenon? A. Yes B. No Temperament has traditionally been viewed as a “genetic” phenomenon, but…. Temperament (like anything else we study in this class) is an emergent property of the brain Therefore, it is susceptible to the same influences as anything else discussed in class. Since environment can affect brain, most likely, can affect temperament as well