Optimism: The Biology of Hope

activity animals appears become behavior biological body brain cause changes child circumstances commitment communities complex concerned connection consequences considerable countries course cultural depression described discussion drugs economic effect evidence evolution example existence experience extremely fact feel females force function future genetic given hope human ideas important increase individual interesting involved kind least less lives major males matter means moral mother nature noted one's optimism optimistic organism parents particular pattern perhaps period placebos political population possible practice present presumably problem produce psychological question reason reflect relationship relatively religious reproductive response result seek seems sense sexual skill social society species structure substances suggests suicide symbols things tion turn understanding University various women York young