This seems likely to be them in the 1841 Census, with probably a daughter and son - along with many other residents, of whom I have cut out the majority-
1841 census transcription details for:Maryhead, Maryhead, Kirkintilloch Print Close National Archive Reference: RG number: Piece: 498 Book/Folio: 11 Page: 10 Reg. District: Sub District: Parish: Kirkintilloch Enum. District: Ecclesiastical District: City/Municipal Borough: Address: Maryhead, Maryhead, Kirkintilloch County: Dunbartonshire Name Relation Sex Age Birth Year OccupationWhere Born ARTHUR, RobtM 1 1840Dunbartonshire ... COCHRANE, RobertM 55 1786 Ag Labourer Scotland COCHRANE, CatherineF 50 1791Scotland COCHRANE, RobertM 20 1821 Cotton H L W Scotland COCHRANE, ElisabethF 18 1823 Cotton H L W Scotland ... PATRICK, JohnM 25 1816 Cotton H L W Dunbartonshire
I have not found her in the 1871 Census, given her Age etc, not surprising.
It seems that Robert died between the 1851 Census and the 1861 Census.
Unfortunately, it looks as though he may have died before 1st January 1855, when Statutory Registration was introduced.
It may be his Death was recorded in the previous Old Parish Registers, OPRs, - BUT these are very patchy.
However, given that he is recorded as a Pauper in 1851, there may be mention of his Death in the Parish Relief Records.
His Birth may be recorded in the OPRs for Wigtonshire.
I have not found Catherine's Death Record on Scotland's People in the likely period of 1861 to 1871; but that may be due to mis-transcriptions etc - as generally the early Statutory Registrations ar almost complete in their coverage.
Again Parish Relief Records may be of use.
Assuming that the two younger persons in the 1841 Census are their children, then it may be advantageous to follow them up, particularly if you can find Marriage Records for them, which could be in either the OPRs or the SRs.
You may find the LDS Family Search site of use in doing preliminary investigations - BUT always try to confirm on Scotland's People, where Scanned IMAGEs of the original documents are available to VIEW and Download.