Unit One Summary: Biological Basis of Behavior

Introduction

• This unit focuses on the significance of biological systems in influencing both physical actions and mental processes.

• The importance of active engagement while studying is emphasized to enhance retention and understanding of material.

• It is recommended to utilize a study guide for effective note-taking, allowing for a structured review and a better grasp of complex concepts.

Nature vs. Nurture

• The modern understanding of behavior asserts that both nature (heredity) and nurture (environment) significantly impact mental processes and behaviors.

  • Nature refers to the genetic inheritance of physical traits (such as eye color) and mental traits (such as intelligence) passed down from parents to offspring.

  • Nurture encompasses environmental influences, which include family background, social surroundings, cultural context, and educational opportunities that shape individual behavior and thought processes.

Psychological Perspectives on Nature and Nurture

Evolutionary Approach:

• Informed by Charles Darwin's theory of evolution, this perspective emphasizes how both heredity and environmental factors contribute to an individual's development and behavior.

• Explores the concept of natural selection, where advantageous traits are more likely to survive and reproduce, leading to evolution over generations.

• Misapprehensions of this theory have historically fueled harmful practices such as eugenics, aiming to 'enhance' human populations based on misconstrued notions of fitness and superiority.

Epigenetics:

• Focuses on how environmental factors and individual behaviors can modify gene expression, rather than altering the DNA sequence itself.

• Highlights the concept that identical twins, despite having the same genetic makeup, can exhibit different traits due to varying environmental experiences during their development.

• Research examples include the Minnesota study of twins reared apart, which provided insights into the relative contributions of genetics versus environment, and the COL adoption project, illustrating the effects of adoptive environments on personality and behavior.

Brain Plasticity

• Differentiates from epigenetics by explaining the brain's capacity to reorganize itself by forming new neural connections throughout life.

• Plasticity demonstrates how learning experiences can strengthen or weaken certain neural pathways, contributing to the overall functionality of the brain and the individual's adaptability to new challenges.

Nervous System Overview

Central Nervous System (CNS):

• Comprises the brain and spinal cord, which coordinate all voluntary and involuntary activities in the body. It acts as the main control center for processing information and issuing commands.

Peripheral Nervous System (PNS):

• Consists of nerves that branch out from the brain and spinal cord, connecting the CNS with body organs and muscles, facilitating communication and reflexes.

Types of Nerves

• Afferent Neurons (Sensory Neurons):

  • Function to send sensory signals to the CNS from sensory receptor cells in various parts of the body, including skin, eyes, and ears.

• Efferent Neurons (Motor Neurons):

  • Responsible for transmitting signals from the CNS to the PNS, initiating responses in muscles and glands.

• Mnemonic: A for approach (afferent) as they approach the CNS; E for exit (efferent) as they exit the CNS to initiate action.

Parts of the Peripheral Nervous System

• Somatic Nervous System:

  • Controls voluntary movements, such as walking and talking, and also processes information from the five senses (sight, hearing, taste, touch, and smell).

• Autonomic Nervous System:

  • Regulates involuntary bodily functions such as heartbeat, blood pressure, respiration, and digestion, maintaining homeostasis within the body.

Divisions of Autonomic Nervous System

• Sympathetic Division:

  • Prepares the body for action through the "fight or flight" response, which includes increasing heart rate, dilating pupils, and enhancing respiration to provide more oxygen for energy and alertness during perceived threats.

• Parasympathetic Division:

  • Operates during restful states, aimed at calming the body and conserving energy, commonly referred to as the "rest and digest" system, which involves slowing the heart rate and boosting digestive processes.

Neurons and Neural Communication

Types of Cells:

• Glial Cells:

  • Essential for providing structural support, insulation, and transportation of nutrients to neurons, though they do not transmit information themselves.

• Neurons:

  • The primary functional units of the nervous system, specialized for communication via electrical impulses and chemical neurotransmitters.

Reflex Arc

• A fundamental neural pathway involving sensory neurons, interneurons, and motor neurons that enables rapid, involuntary reactions to stimuli (for example, quickly withdrawing a hand from a hot surface).

• The sequence of the reflex arc pathway follows:

  • Sensory neuron → interneuron (located in the CNS) → motor neuron → muscle response, demonstrating the brain's ability to process information virtually instantaneously without conscious thought.

Neural Transmission

• Introduces the intricate process through which neurons communicate and transmit signals, highlighting the role of neurotransmitters in sending messages across synapses.

• Further study resources are available in the ultimate review packet, which contains additional review questions and detailed explanations for better comprehension of the material covered.