Rosenzweig, Bennet & Diamond (1972)

aim

The aim of the study was to investigate whether environmental factors (such as a rich or impoverished environment) would affect the development of neurons in the cerebral cortex.

participants

randomly allocated 3 male rats from a common litter

method

true experiment, independent samples

conditions

random allocation to 1 of 3 conditions

• control condition [CC]

  • 3 rats in the same cage

• impoverished condition [IC]

  • each rat in individual cages

• enriched condition [EC]

  • placed 10-12 rats in a cage containing different stimulus objects to explore and play with

all conditions had free and adequate access to food and water.

Execution

• rats spent 30 to 60 days in their conditions before they were killed in order to study the changes in the brain’s anatomy

results (3)

• the anatomy of the brain was significantly different in the EC and IC

• increased thickness and higher weight of the cortex in the EC compared to the IC rats

• rats in the EC condition had developed significantly greater activity in the neurons of the cerebral cortex associated with the transmission of acetylcholine

follow up results

• revealed that just 30 mins in the EC can produce the same changes in the brain in rats

ethics

• animals were not protected from undue stress and harm

• they were isolated and the researchers knowingly put the rats in an impoverished environments

• additionally they were killed at the end of the study

• a cost-benefit analysis should demonstrate that the goals of the study are worth the harm done to the animals