In episode 325 of Semantic Mastery's weekly Hump Day Hangouts, one participant asked if Google lowers your rankings in SERPs if you check your position in incognito window.
The exact question was:
Hi guys: 1) Does google lower your rankings in the SERPs if you check your position for a keyword in your own device or in incognito window? Or does google hides your page in the SERPs when you make a search from your own decvice? 1.1) Same question as 1 but with multiple search requests on the same device.