An Enriched Environment Primates in the wild, like this marmoset, live in complex, challenging, and ever-changing environments. At psychologist Elizabeth Gould’s Princeton lab, marmosets are housed in large enclosures with natural vegetation and novel objects that are changed frequently. In one experiment, synaptic and dendritic connections increased dramatically in marmosets who lived in the enriched environment for just four weeks after being raised in standard laboratory cages (Kozorovitskiy & Gould, 2004).

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