This week’s resources indicate temperament is composed of four interrelated dimensions: activity, emotionality, sociability, and aggressive/impulsivity (Friedman & Schustack, 2012). Accordingly, various theorists posit models relating to nervous-system temperament and the possibilities of obtaining empirical biological evidence for same. For instance, Eysenck posited the levels of brain arousal as cued by the central nervous system determine whether a person is introverted or extroverted. Hence, lower levels of arousal results in sensation seeking behaviors as exhibited by extroverts.
The problems associated with these types of theories are that there are, as of yet, no definitive biological measurements nor agreement amongst researchers for arousal, high versus low (Derryberry & Rothbart, 1988; Friendman & Schustack, 2012 ). Second, assuming there were a definitive measurement tool, which testing procedure would be best to obtain the information? Further, although there are a variety of medical advances and testing procedures, how would the researcher discriminate one type of arousal from another? Would the neurotransmitters behave differently in different social situations? Researchers frequently disagree as to which dimension of temperament is most important to measure. Eysenck focuses on introversion/extroversion and neuroticism, whereas Gray emphasizes emotional aspects related to “arousal, attentional, and behavioral components” (Derryberry & Rothbart, 1988, p. 959). One of the other issues related to testing nervous-system-based theories is that the human body is inherently self-regulating, which therefore, is continuously adapting and adjusting to both internal and external stimuli (Derryberry & Rothbart, 1988; Friendman & Schustack, 2012). This reality can make it especially difficult to ascertain accurate measurements of transient phenomena.
Derryberry, D., & Rothbart, M. K. (1988). Arousal, affect, and attention as components of temperament. Journal Of Personality And Social Psychology, 55(6), 958-966. doi:10.1037/0022-35220.127.116.118
Friedman, H. S., & Schustack, M. W. (2012). Personality: Classic theories and modern research (5th ed.). Boston, MA: Allyn & Bacon.