{"id":1172,"date":"2023-03-31T17:37:24","date_gmt":"2023-03-31T17:37:24","guid":{"rendered":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/chapter\/biological-approaches\/"},"modified":"2026-01-12T19:54:07","modified_gmt":"2026-01-12T19:54:07","slug":"biological-approaches","status":"publish","type":"chapter","link":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/chapter\/biological-approaches\/","title":{"raw":"Explaining Personality: Learn It 4\u2014Biological Approaches","rendered":"Explaining Personality: Learn It 4\u2014Biological Approaches"},"content":{"raw":"

Biological Approaches to Personality<\/h2>\r\n

Biological approaches explain personality by looking at the body\u2014especially the brain<\/b><\/span>, nervous system<\/b><\/span>, and genetics<\/b><\/span>. From this perspective, personality is partly shaped by biological systems that influence how strongly we react to stress, how sensitive we are to rewards, and how we regulate emotion and attention.<\/p>\r\n

A key takeaway is not that<\/span> \u201cgenes determine who you are.\u201d Instead, biology helps explain tendencies<\/span>\u2014and those tendencies develop through experience over time.<\/p>\r\n

Evolutionary Psychology and Personality<\/h3>\r\n

From an evolutionary psychology perspective, personality researchers ask two related questions:<\/p>\r\n

    \r\n\t
  • Which traits are common across humans?<\/span> (because they may have helped people survive and cooperate)<\/li>\r\n\t
  • Why do individuals differ?<\/span> (because different traits can be useful in different environments)<\/li>\r\n<\/ul>\r\n

    For example, in some situations, being bold and risk-taking could help someone gain resources or status, while in other situations, being cautious could improve safety and long-term survival. Some evolutionary theories explore how people allocate time and energy (such as investing in growth, mating, parenting, or long-term planning) and how people communicate qualities to others through reputation, generosity, or displays of competence (Buss, 2009).<\/p>\r\n

    Behavioral Genetics and Heritability<\/h3>\r\n

    Earlier in the course, we learned about nature and nurture and the idea that some personality traits may be more heritable than others.<\/p>\r\n

    Heritability<\/b><\/span> refers to the proportion of variation in a trait within a population<\/b><\/span> that is associated with genetic differences.<\/p>\r\n

    Behavioral genetics researchers ask how much of the variation<\/i> in personality (across a population) is associated with genetic differences. Twin and family studies consistently find that many personality traits are moderately heritable<\/b><\/span>\u2014often in the range of \u201csome genetic influence, some environmental influence,\u201d rather than all-or-nothing.\u00a0 <\/span><\/p>\r\n

    Two common misunderstandings:<\/p>\r\n

      \r\n\t
    • Heritability is not destiny.<\/b><\/span> A heritability estimate does not<\/i> mean a trait is fixed or can\u2019t change.<\/li>\r\n\t
    • Heritability is about groups, not individuals.<\/b><\/span> It describes variation in a particular population living in particular environments.<\/li>\r\n<\/ul>\r\n
      \r\n

      Heritability and Twin Studies<\/h3>\r\n

      One major body of evidence comes from twin research, including the Minnesota Study of Twins Reared Apart (conducted from 1979 to 1999). Researchers compared identical and fraternal twins raised together and apart and found that identical twins tend to show greater similarity on many personality measures than fraternal twins\u2014even when raised in different homes (Bouchard, 1994; Bouchard et al., 1990; Segal, 2012). Those traits with high heritability ratios include leadership, obedience to authority, a sense of well-being, alienation, resistance to stress, and fearfulness.<\/p>\r\n

      At the same time, these studies also show that environment matters<\/b><\/span>: life experiences, relationships, culture, and opportunities shape how personality develops.<\/p>\r\n

      It\u2019s also important to note that personality traits are not<\/b><\/span> determined by a single gene. Instead, they are influenced by many genes working together<\/b><\/span>, along with environmental factors that influence how those genes are expressed.<\/p>\r\n<\/section>\r\n

      [ohm2_question height=\"300\"]4389[\/ohm2_question]<\/section>\r\n
      \r\n

      Temperament<\/h2>\r\n

      Most contemporary psychologists believe temperament has a biological basis due to its appearance very early in our lives (Rothbart, 2011). Thomas and Chess (1977) found that babies could be categorized into one of three temperaments:<\/p>\r\n

        \r\n\t
      • easy<\/li>\r\n\t
      • difficult<\/li>\r\n\t
      • slow to warm up<\/li>\r\n<\/ul>\r\n

        However, environmental factors (family interactions, for example) and maturation can affect how children\u2019s personalities are expressed (Carter et al., 2008).<\/p>\r\n

        \r\n

        dimensions of temperament<\/h3>\r\n

        Research suggests that there are two dimensions of our temperament that are important parts of our adult personality\u2014reactivity<\/em> and self-regulation<\/em> (Rothbart, Ahadi, & Evans, 2000).<\/p>\r\n

          \r\n\t
        • Reactivity refers to how we respond to new or challenging environmental stimuli;<\/li>\r\n\t
        • self-regulation refers to our ability to control that response (Rothbart & Derryberry, 1981; Rothbart, Sheese, Rueda, & Posner, 2011).<\/li>\r\n<\/ul>\r\n

          For example, one person may immediately respond to new stimuli with a high level of anxiety, while another barely notices it.<\/p>\r\n<\/section>\r\n

          [ohm2_question height=\"350\"]4390[\/ohm2_question]<\/section>\r\n
          \r\n
          Research suggests that many of our personality characteristics have a genetic component. What traits do you think you inherited from your parents? Provide examples. How might modeling (environment) have influenced your characteristics as well?<\/section>\r\n<\/section>\r\n<\/section>","rendered":"

          Biological Approaches to Personality<\/h2>\n

          Biological approaches explain personality by looking at the body\u2014especially the brain<\/b><\/span>, nervous system<\/b><\/span>, and genetics<\/b><\/span>. From this perspective, personality is partly shaped by biological systems that influence how strongly we react to stress, how sensitive we are to rewards, and how we regulate emotion and attention.<\/p>\n

          A key takeaway is not that<\/span> \u201cgenes determine who you are.\u201d Instead, biology helps explain tendencies<\/span>\u2014and those tendencies develop through experience over time.<\/p>\n

          Evolutionary Psychology and Personality<\/h3>\n

          From an evolutionary psychology perspective, personality researchers ask two related questions:<\/p>\n

            \n
          • Which traits are common across humans?<\/span> (because they may have helped people survive and cooperate)<\/li>\n
          • Why do individuals differ?<\/span> (because different traits can be useful in different environments)<\/li>\n<\/ul>\n

            For example, in some situations, being bold and risk-taking could help someone gain resources or status, while in other situations, being cautious could improve safety and long-term survival. Some evolutionary theories explore how people allocate time and energy (such as investing in growth, mating, parenting, or long-term planning) and how people communicate qualities to others through reputation, generosity, or displays of competence (Buss, 2009).<\/p>\n

            Behavioral Genetics and Heritability<\/h3>\n

            Earlier in the course, we learned about nature and nurture and the idea that some personality traits may be more heritable than others.<\/p>\n

            Heritability<\/b><\/span> refers to the proportion of variation in a trait within a population<\/b><\/span> that is associated with genetic differences.<\/p>\n

            Behavioral genetics researchers ask how much of the variation<\/i> in personality (across a population) is associated with genetic differences. Twin and family studies consistently find that many personality traits are moderately heritable<\/b><\/span>\u2014often in the range of \u201csome genetic influence, some environmental influence,\u201d rather than all-or-nothing.\u00a0 <\/span><\/p>\n

            Two common misunderstandings:<\/p>\n

              \n
            • Heritability is not destiny.<\/b><\/span> A heritability estimate does not<\/i> mean a trait is fixed or can\u2019t change.<\/li>\n
            • Heritability is about groups, not individuals.<\/b><\/span> It describes variation in a particular population living in particular environments.<\/li>\n<\/ul>\n
              \n

              Heritability and Twin Studies<\/h3>\n

              One major body of evidence comes from twin research, including the Minnesota Study of Twins Reared Apart (conducted from 1979 to 1999). Researchers compared identical and fraternal twins raised together and apart and found that identical twins tend to show greater similarity on many personality measures than fraternal twins\u2014even when raised in different homes (Bouchard, 1994; Bouchard et al., 1990; Segal, 2012). Those traits with high heritability ratios include leadership, obedience to authority, a sense of well-being, alienation, resistance to stress, and fearfulness.<\/p>\n

              At the same time, these studies also show that environment matters<\/b><\/span>: life experiences, relationships, culture, and opportunities shape how personality develops.<\/p>\n

              It\u2019s also important to note that personality traits are not<\/b><\/span> determined by a single gene. Instead, they are influenced by many genes working together<\/b><\/span>, along with environmental factors that influence how those genes are expressed.<\/p>\n<\/section>\n