Biological Approach

ANIMAL RESEARCH / ANIMAL MODELS

📌Definition Table

Term	Definition
Animal models	The use of non-human animals to study biological and behavioural processes that are assumed to be similar to those in humans, particularly when human research is unethical or impractical.
Invasive procedures	Research techniques that involve entering the body or directly manipulating organs or tissues, such as lesioning or brain stimulation.
Internal validity	The extent to which a study accurately establishes a cause-and-effect relationship by controlling extraneous variables.
Ecological validity	The degree to which research findings reflect behaviour in real-world, natural settings.
Generalizability	The extent to which findings from animal research can be applied to humans or other populations.
Comparative psychology	A branch of psychology that studies animal behaviour either for its own sake or by comparing it with human behaviour.
Gene knockout	A genetic research technique in which a specific gene is deliberately deactivated to examine its effect on behaviour or physiology.
Cross-species extrapolation	The process of applying findings from animal research to human behaviour, which may be limited due to biological and psychological differences.

📌What Are Animal Models?

Animal models refer to living, non-human organisms, often specially bred or genetically modified, that are used to investigate human behaviour. Because they share biological similarities with humans, they help researchers study processes that would be unethical or impossible to explore using human participants.

They are particularly useful when:

• Researchers need a level of control that is not possible with human subjects
• Invasive procedures are required
• Studying long-term or generational effects is important

📌The Value of Animal Research

1. High Levels of Control: Animal research allows scientists to isolate, manipulate, and measure variables with precision. This level of control boosts internal validity, making it easier to establish tentative cause-and-effect relationships.

2. Access to the Brain and Body: Invasive investigations (e.g., examining brain structure, removing or stimulating neural tissue) are much easier and more acceptable in animals. Human bodies cannot ethically or practically be used for such procedures.

3. Fast Breeding Cycles: Many animals reproduce quickly, allowing researchers to study heredity, generational changes, and environmental influences across several lifespans (something impossible to do with humans).

4. Biological and Evolutionary Similarities: Humans and many animals (especially mammals) share evolutionary pathways. This means certain traits or behaviours may have similar adaptive functions, making them suitable analogues for human processes.

5. Objectivity (but With Limits): Animals are often considered more objective research subjects, but they also think, feel, and respond to subtle environmental cues.

📌Advantages & Disadvantages of Animal Models

Table1: Advantages of Using Animal Models in Research

Advantages	Explanation
Biological similarity to humans	Animals share genetic and structural similarities with humans, especially in brain organisation. This makes them helpful for studying behavioural and physiological processes.
Generation of meaningful findings	Many significant scientific discoveries—like insulin—were first identified through animal experiments.
Full lifespan observation	Animals have shorter lifespans, allowing researchers to track behaviour across entire life cycles and across generations.
High experimental control	Techniques such as gene “knockouts” allow researchers to alter one specific gene and study its effect with fewer confounding variables.
Cost-effective and accessible	Animals are easier to house, manage, and use consistently in controlled experiments.

Table 2: Disdvantages of Using Animal Models in Research

Disadvantages	Explanation
Human–animal differences	No animal is an exact match to humans. Results must still be tested on humans to confirm generalisability.
Psychological differences	Even with biological similarities, humans and animals differ in cognition, emotion, and social behaviour (Premack, 2007).
Limited direct application of biomedical findings	Treatments that work on mice often fail when tested on humans; larger animals must be tested before moving to clinical trials.
Stress due to laboratory conditions	Animals may behave unnaturally because they are kept in artificial, controlled environments—lowering ecological validity.
Unreliable cross-species translation	Example: more than 85 HIV vaccines that succeeded in primates failed in humans (Bailey, 2008); aspirin was harmful to animals but safe for humans.

📌Ethical Considerations in Animal Research

Core Ethical Principles

• Acceptability with justification: Using animals is considered permissible only when there is clear scientific and societal benefit.
• Minimisation of use: Researchers must limit the number of animals used as much as possible without compromising results.
• Minimisation of suffering: Pain, distress, and long-term harm should be avoided or kept to the lowest possible level.

The British Society of Animal Science has introduced the 3Rs that form the global standard for ethical animal research:

• Refinement: Research procedures must be designed to reduce or eliminate pain and discomfort. Experiments should be focused, realistic, and scientifically necessary.
• Replacement: Scientists must explore all alternative methods before using animals. This includes computer simulations, tissue cultures, or human-based techniques.
• Reduction: The number of animals used must be scientifically justified. Only the minimum number required to produce valid, meaningful data can be used.

📌Different Purposes of Animal Research

Animal research is not uniform; it varies by goal:

• Comparative psychology:
  Studies animals for their own sake, either focusing on one species or comparing it to humans.
• Animals as models of humans:
  Assumes findings from animals can be broadly generalised to humans.
• Models for specific human conditions:
  Used to test cause-and-effect hypotheses for disorders like depression.
  Examples of depression models include:
  • Stress-based models (depression linked to chronic stress)
  • Separation models (depression due to loss of attachment)
  • Medical models (chemical imbalances)
    

Types of Experimental Manipulations (Shapiro, 1998)

• Genetic manipulation: selective breeding or altering specific genes
• Neural manipulation: stimulation, lesioning, or removal of brain areas
• Bodily manipulation: altering other body systems through chemicals or physical procedures
• Behavioural/environmental manipulation: changing surroundings, applying stimuli (e.g., shocks), or using learning tasks