On mac using Spyder 3.3.1 run from Anaconda.
Cmd + I
was not working for me at first to show the object inspector on the right pane for help on a particular function. So I typed in Cmd + ,
(which is to access preferences panel in any app on Mac), and went down to "Help" on the left side.
Then, I checked the boxes for "Editor" and "IPython Console" under the description that says
"This pane can automatically show an object's help information after a left parenthesis is written next to it. Below you can decide to which plugin you want to connect it to turn on this feature."
After checking these boxes and pressing OK, Cmd + I
still did not work for getting the object information.
I restarted Spyder, closing it and reopening it from Anaconda navigator.
Now Cmd + I
works and shows the information for whatever function I click on.
Hope this helps someone. I'm still not quite sure what happened here (since those checkboxes were for the left parenthesis function), but I still thought that sharing the steps will be useful to some people.