Introduction to Psychology
Summary of Psychological Science by Gazzaniga
Ch.1, Ch.2-Ch.8
,Chapter 1: The Science of Psychology
1.1 What is psychological science?
Psychology is the study of mental activity and behavior. A psychologist attempts to
understand mental processes and predict behavior. Psychological science
investigates mental processes, brain function, and behavior. The mind refers to
mental activity, which results from biological processes in the brain. Behavior
encompasses the entirety of observable human actions, which can vary in
complexity and exclusivity (only for humans or also in animals).
Critical thinking involves systematically questioning whether something is accurate
and evaluating information using well-founded evidence. Intuition often leads to
incorrect conclusions. Human thoughts are often biased, which arise when people
are motivated to use their intelligence. Psychological reasoning refers to the use of
psychological research to assess how people normally think, so we can understand
when and why they draw faulty conclusions.
Often, we see what we want to see and ignore the rest of the information. Just as
stereotypes about people shape our expectations about them, we interpret their
behavior in a way that confirms these stereotypes.
Types of biases:
- Confirmation bias
- Only accepting information that confirms expectations and ignoring
information that falsifies expectations. A contributing factor to
confirmation bias is selective sampling of information.
- Incorrectly assessing the value of a source
- Appeal to authority: being inclined to believe someone with authority.
- Misunderstanding or not using statistics
- Seeing causality that is not there (trying to find something)
- We are inclined to see two events happening simultaneously as having a
relationship.
- Use of relative comparisons
- How something is stated determines how someone reacts. Positive
information leads to more positive reactions.
- Accepting after-the-fact explanations
- Hindsight bias, coming up with an explanation for something that has already
happened, is a common pitfall in scientific research. However, three key strategies
can be employed to overcome this bias: adopting a hypothesis-testing approach,
using proper experimental controls, and conducting a pre-registration of study
protocols.
A hypothesis-testing approach requires researchers to formulate specific, testable
predictions before conducting an experiment. This helps minimize the chances of
molding explanations to fit the observed data, thereby reducing hindsight bias.
Proper experimental controls ensure that the experiment measures the effect of the
independent variable on the dependent variable accurately. By controlling for
,confounding factors, researchers can draw more reliable conclusions from their
experiments.
Pre-registration of study protocols involves documenting the research plan,
including hypotheses, methodology, and data analysis procedures, in a publicly
accessible database before starting the study. This practice promotes transparency
and discourages selective reporting, as researchers are held accountable for the
predefined methods and outcomes. By following these strategies, researchers can
effectively mitigate hindsight bias and ensure the credibility of their scientific findings.
Chapter 3: Biology and Behavior
3.1 How does the nervous system operate?
The nervous system consists of nerve cells (neurons). Neurons receive, integrate,
and transmit information throughout the nervous system. These networks of neurons
that receive and send signals are the functional basis of psychological activity.
Neural networks develop through maturation, experience, and repeated firing. The
nervous system is composed of the central nervous system and the peripheral
nervous system.
Central Nervous System (CNS): neurons in the brain + spinal cord
Peripheral Nervous System (PNS): neurons in the rest of the body
The PNS consists of:
● Somatic nervous system
● Autonomic nervous system
● Sympathetic nervous system
● Parasympathetic nervous system
Anatomically, these nervous systems are separate but work closely together. The
PNS sends information to the CNS, which organizes and evaluates the information
and instructs the PNS to execute specific behaviors. Neurons are specialized in
transmitting information. They are powered by electrical impulses and communicate
with other neurons through chemical signals. During the reception phase, neurons
pick up chemical signals from other neurons, during the integration phase,
chemical signals are evaluated, and during the transmission phase, neurons send
their signals to other neurons.
Types of neurons:
● Sensory neurons: detect external information and transmit it to the brain, often
via the spinal cord.
● Somatosensory neurons: obtain information through the skin and muscles.
● Motor neurons: command muscles and produce movement.
● Interneurons: communicate between neuronal networks.
A neuron consists of:
● Dendrites: short branches that detect chemical signals from surrounding
neurons.
● Cell body (soma): information from other neurons reaches the cell body,
where it is collected and integrated.
, ● Axon: electrical impulses from the cell body are passed along the axon. At the
end of the axon are 'terminal buttons.'
● Synapse: chemical communication between neurons occurs at the synapse.
The synapse is a gap between neurons where chemical signals can be
transferred from one side to the other.
A neuron is protected by a membrane, a fatty barrier. The membrane is semi-
permeable, allowing some substances to enter or exit the membrane. Ion channels
are located on the membrane, allowing ions to enter or exit when the neuron emits
signals. Ions are molecules that are negatively or positively charged. The membrane
regulates the concentration of electrically charged molecules that form the basis of
the neuron's electrical activity.
A nerve is a bundle of axons that transmit information between the brain and the
body. When a neuron is inactive, there is an electrical discrepancy inside and
outside the membrane. This discrepancy is the resting potential. There are more
negative ions inside the membrane. When the neuron has more negative ions inside
the membrane than outside, the neuron is polarized. The polarization creates the
electrical energy needed to fire the neuron.
Two ions essential for the resting potential are sodium and potassium. Ions enter
and exit the membrane through ion channels. Sodium channels only allow sodium
ions to pass, and potassium channels only allow potassium ions. The passage of
ions is controlled by a gate mechanism and the permeability of the membrane. Due
to the selective permeability of the membrane, there are more potassium ions than
sodium ions inside the membrane. The sodium-potassium pump also contributes
to the polarization of the membrane. The pump increases potassium and decreases
sodium inside the neuron.
Neuronal activity depends on the neuron's ability to respond to incoming stimuli.
The neuron reacts by changing the electrical charge and thereby transmitting signals
