Which has the higher specific heat capacity: an object that cools quickly or an object of the same mass that cools more slowly?
2 answers
If it has a higher specific heat, more heat (Q) must be radiated or conducted away to change its temperature. That will take longer if everything else is the same.
For example water has a pretty high heat capacity. Therefore a tank or pool is a good way to store solar heat during the day for warming the house at night.