Animal Models in Psychological Research

Definition

• Animal Model: Using non-human animals to study psychological or psychopathological processes similar to human conditions.

Why Animals are Used

• Genetic and Physiological Similarity: Animals, such as mice, share genetic and physiological traits with humans (e.g., mice have 99% of DNA responsible for brain construction).
• Breeding and Aging: Animals breed and age faster, allowing for observation of multiple generations and effects of aging in a short period (e.g., mice life span is 2 years, sexual maturity at 3 weeks).
• Ethical Considerations: Animals can undergo procedures not ethically permissible for humans (e.g., brain lesions, post-mortem).

Brain and Behaviour Studies

Key Studies

1. Rosenzweig’s Study on Neuroplasticity

   • Studied impact of enriched vs. impoverished environments on rats' brains.
   • Found anatomical brain differences showing how environment affects brain and behavior.

2. Merzenich’s Study on Neuroplasticity

   • Demonstrated reorganization in monkey somatosensory cortex due to training.
   • Showed adaptation of neural networks to physical handicaps.

Evaluation

• Rosenzweig
  • Good reliability and application to therapeutic settings.
  • Ethical concerns due to animal treatment and generalizability issues.
• Merzenich
  • Demonstrated neuroplasticity effectively.
  • Limitations in generalizing findings to humans.

Hormones and Pheromones Studies

Key Studies

1. Romero et al (Oxytocin in Dogs)

   • Examined oxytocin's effect on dog affection and bonding.
   • Showed physiological similarities in social bonding between dogs and humans.

2. Berthold et al (Testosterone in Roosters)

   • Demonstrated role of testosterone in male behavior through castration experiments.
   • Findings applicable to understanding puberty in humans.

Evaluation

• Romero
  • Linked oxytocin to social bonding in dogs.
  • Limited generalizability due to species differences.
• Berthold
  • Low repeatability and applicability due to historical and species-specific factors.

Genetics and Behaviour

Key Studies

1. Weaver et al (2004)

   • Explored epigenetics and maternal response to stress.
   • Highlighted gene-environment interactions.

2. Lassi and Tucci (2017)

   • Studied maternal influence on offspring stress and behavior.
   • Supported findings on attachment and nurturing.

Evaluation

• Weaver
  • Demonstrated standard procedures but limited generalizability due to lab conditions.
• Lassi and Tucci
  • High concurrent validity with past research but interpretational challenges.

General Evaluation of Animal Studies

• Arguments Against Use

  • Generalizability issues due to species differences.
  • Ethical concerns over potential suffering and communication barriers in animals.

• Justification and Ethical Considerations

  • Must be justified by potential human benefits.
  • Considerations include moral value, number of beneficiaries, and harm to animals.
  • Laws and protections are in place to ensure humane testing conditions.