#2 Brain, Mind and Behavior

Overview of Experimental Design

• Controlled Conditions: An experiment can be set up in controlled conditions to measure the effect of an independent variable on a dependent variable.

  • Example: Measuring heart rate under stress.

Variables in Experimentation

• Independent Variable: The factor that is manipulated or changed in the experiment.

  • In the example, it is the stress level.

• Dependent Variable: The outcome or measurement that is affected by the independent variable.

  • Here, it is the heart rate.

• Confounding Variables: Other variables that can affect the dependent variable and may interfere with the results.

  • Example: Prior physical activity such as running up stairs could influence heart rate measurements.

Establishing Baseline Control

• Establish a baseline by allowing the subject to relax before implementing stress to get accurate measurements.

• To control confounding variables, ensure uniformity in other conditions:

  • Same rest periods,

  • Same time of day for testing.

Experimental Designs

• Between-Subjects Design: Different groups are subjected to different conditions.

  • Comparison is made across groups.

• Within-Subjects Design: The same group of subjects is tested under different conditions.

  • Example: measuring the same subject's heart rate before and after inducing stress.

Problem of Individual Variability

• High individuality among subjects can complicate between-subjects design.

• To minimize this, within-subjects design is preferred when measuring physiological variables as you can average results across multiple measures of the same individual.

Experimental Set-Up and Order

• Researchers may use counterbalancing to manage the order of conditions across trials:

  • Example: One day may focus on stress, another on non-stress conditions with the same baseline.

Causality in Experiments

• An experiment can assert causality if an independent variable reliably causes a change in the dependent variable, assuming all confounding variables are controlled.

Case Study: Shoe Size Hypothesis

• Hypothesis Example: Men wear larger shoes than women.

  • Independent Variable: Gender.

  • Dependent Variable: Shoe size (affected by foot size).

  • Identifying confounding variables such as overall body size which relates to foot size.

Quasi-Experimental Design

• Definition: An experimental design that lacks control over variables.

  • Involves convenience sampling, meaning subjects are not randomized and may not represent a larger population.

• Example: College students used in research may not accurately represent the general population, limiting findings.

Research Methodologies: Pure vs. Applied

• Pure Research: Conducted out of curiosity to understand phenomena (e.g., how the eye works).

• Applied Research: Focused on addressing real-world problems from research findings (e.g., how to treat visual disorders).

Confounding Variables & Generalizability

• When evaluating conclusions from research, consider the context and sample population:

  • Conclusions drawn from psychology students may not generalize to the broader population due to shared experiences.

Key Experimental Terms to Remember

• Independent Variable: What is manipulated.

• Dependent Variable: What is measured.

• Confounding Variable: What complicates interpretation of results.

Subfields of Study in Behavioral Neuroscience

• Neuroanatomy: Study of the structure of the nervous system.

• Neurochemistry: Study of chemicals in the nervous system.

• Neuroendocrinology: Study of interaction between the nervous system and endocrine system.

Physiological Psychology

• Focuses on how the brain contributes to behavior; challenging to conduct on humans due to ethical and technical constraints.

Psychopharmacology

• Involves the study of how drugs impact the brain and behavior.

Neuropsychology

• Testing methods to understand how brain damage affects behavior (e.g., studies on Phineas Gage).

Eastern Psychology - Case Studies

• Case studies provide in-depth information on specific individuals but have limited generalizability to broader populations.

Psychological Research: Pure vs. Applied

• Pure Research: Gains knowledge for its own sake.

• Applied Research: Focused on practical issues and transferring findings to real-world applications.

Evolutionary Psychology & Genetics

• Nature vs. Nurture: Current understanding recognizes both genetic and environmental factors shape behavior and abilities.

Concepts in Evolutionary Psychology

• Evolution attempts to explain the development of behaviors and cognition.

• Darwin's Theory: Proposed mechanisms of natural selection based on adaptation to environments and selective breeding.

• Example: Variability allows traits that favor survival to be passed on.

Importance of Case Studies in Psychology

• Learning about individual cases can illuminate wider experiences, especially in neuropsychological contexts.

Conclusion and Future Directions

• Address the blend of genetics, environment, and experiences in shaping behavior, continuing to explore through interdisciplinary approaches in psychology.

• Ongoing studies examine how epigenetics influence behavior and cognitive function.

Final Notes on Research Ethics

• When conducting research, especially involving humans, consider ethical implications and the importance of participant consent and well-being.