Rosenzweig & Bennett
Year
1972
Applications
The study shows that the brain grows more neurons if stimulated. This can be applied to child development in schools and at home, as more stimulation at a younger age can develop better or more progressive learning habits in the future.
Learning Outcomes
-Animal research may inform our understanding of human behaviour (SAQ). -Lab Experiments (LAQ). -Environment on brain plasticity (LAQ).
Definitions
-Enriched Environment: an environment offering many opportunities for activity and containing much sensory and intellectual stimulation. -Impoverished Environment: an environment lacking the possibility for physical and social activity. -Brain Plasticity: refers to the brain's ability to change throughout life.
Conclusions
-Follow-up of this research indicated that just 2 hours a day in an enriched environment produced the same plastic changes in the brain as in rats that had been constantly in the enriched environment. This shows that the brain can change and adapt to new situations. -Since brain plasticity is assumed to follow the same pattern in animals and humans, the implications of the study are that the human brain will also be affected by environmental factors such as intellectual and social stimulation. -The research challenged the belief that brain weight cannot change.
Procedure
-Rats were placed in either an enriched environment or an impoverished condition. -In the enriched environment, 10-12 rats in a cage were provided with different stimulus objects to explore and play with. This group also received maze training. -In the impoverished condition, each rat was placed in an individual cage, ensuring isolation, and no stimulation was applied. -The rats typically spent 30-60 days in their respective environments before they were killed so the researchers could study changes in brain anatomy.
Findings
-The anatomy of the brain was different for rats in the enriched environment and the impoverished condition. -The brains of the enriched environment rats had increased thickness in the cortex. -The enriched environment rats had developed more acetylcholine receptors in the cerebral cortex, which are important in learning and memory. -The frontal lobe, which is associated with thinking, planning, and decision making, was heavier in the rats that had been in the enriched environment. -Overall, the combination of having company and many interesting toys created the best conditions for developing cerebral thickness.
Evaluations (Limitations)
-This study is difficult to generalize to humans. This is because the brain and environmental contributions differ between humans and animals, such as rats in this case. -This study possesses problems with animal ethics; the rats that were placed in impoverished conditions remained isolated, with no social interaction or environmental stimulus. Furthermore, the rats were killed at the end of the study. -This study has low ecological validity, as it does not show how various levels of stimulation might affect the brain development of animals in their natural environments.
Evaluations (Strengths)
-This study is reliable, as the results can be replicated by redoing the experiment. This study was a laboratory experiment, so researchers had strict control over the variables, which made it easier for replication. -The laboratory experiment established a cause-effect relationship, due to the strict control of variables. -This study provided insight upon brain plasticity; this study showed that the brain can change and adapt to new situations. -This study used rats instead of humans, ensuring no possible harm done to humans. -Rats are inexpensive, and have large litters, which allows for members of the same litter to be assigned to different experimental conditions.
Research Method
Laboratory experiment
Aim
To investigate whether environmental factors such as an enriched or an impoverished environment affect development of neurons in the cerebral cortex.
