<PAGE>   1
                                                                   EXHIBIT 10.25

                              CERIDIAN CORPORATION
                            EXECUTIVE INVESTMENT PLAN

                         FIRST DECLARATION OF AMENDMENT

Pursuant to the retained power of amendment contained in Section 6.2 of the
Ceridian Corporation Executive Investment Plan, the undersigned hereby amends
the Plan in the manner described below.

1.       Section 7.28 of the Plan is amended to read as follows:

         7.28     QUALIFIED EMPLOYEE.

                  (a)      "Qualified Employee" means an individual who performs
                           services for a Participating Employer as an employee
                           of the Participating Employer (as classified by the
                           Participating Employer at the time the services are
                           performed without regard to any subsequent
                           reclassification) and who is (i) an officer of the
                           Participating Employer elected by the Participating
                           Employer's Board, (ii) a Vice President of the
                           Participating Employer or (iii) a Director of the
                           Participating Employer with a salary grade level of
                           D1 or D2; provided, that, for Plan Years beginning
                           after December 31, 2000, any individual who is a
                           Media Information Business Employee, within the
                           meaning of Subsection (b), is not a Qualified
                           Employee.

                  (b)      A Media Information Business Employee is an employee
                           of an Affiliate who has employment duties principally
                           related to the Media Information Business, including
                           any such employee who, at the time in question, is on
                           medical, non-medical, short-term disability or
                           long-term disability leave of absence or absent from
                           active employment due to occupational illness or
                           injury covered by workers' compensation who,
                           immediately prior to becoming an inactive employee,
                           had such employment duties. For this purpose, Media
                           Information Business means:

                           (i)      the provision of media and marketing
                                    research services to broadcasters,
                                    advertising agencies, advertisers, on-line
                                    webcasters and cable television in the
                                    United States, the United Kingdom, Japan and
                                    Mexico;

                           (ii)     through a joint venture the provision of
                                    media audience and consumer retail behavior
                                    research services to cable systems,
                                    television broadcasters, magazines and
                                    newspapers;

                           (iii)    the provision of application software used
                                    to access and analyze media audience
                                    information and through a joint venture
                                    software applications to access and analyze
                                    consumer retail behavior and media usage;

                           (iv)     the business of

                                    (1)     CSW Research Limited,


<PAGE>   2


                                    (2)     Ceridian Infotech (India) Private
                                            Limited,

                                    (3)     Euro Fieldwork Limited and

                                    (4)     Arbitron Holdings Inc.;

                           (v)      any other business conducted by the Company
                                    or another Affiliate primarily through the
                                    use of assets treated by the Company or the
                                    Affiliate as part of the Media Information
                                    Business.

2.       A new Section 9.7 is added to the Plan which reads as follows:

         9.7      ARBITRON EXECUTIVE INVESTMENT PLAN.

                  (a)      Transfer of Accounts. Effective as of January 1,
                           2001, the Company adopted the Arbitron Executive
                           Investment Plan and, except as otherwise provided in
                           Subsection (b), caused the Account balances of the
                           Transferred Participants, as defined in Subsection
                           (c), as of the close of business on December 31,
                           2000, to be transferred to the Arbitron Executive
                           Investment Plan. Effective as of the close of
                           business on December 31, 2000, except as otherwise
                           provided in Subsection (b), each Transferred
                           Participant will cease to be a Participant and
                           neither any Transferred Participant nor anyone
                           claiming by, through or on behalf of a Transferred
                           Participant will have any right to a benefit arising
                           under or in connection with the Plan unless he or she
                           again becomes an Active Participant after December
                           31, 2000.

                  (b)      Exception to Transfer. The portion of a Transferred
                           Participant's Account scheduled to be distributed to
                           the Transferred Participant on January 1, 2001 will
                           not be transferred to the Arbitron Executive
                           Investment Plan pursuant to Subsection (a) and will
                           be distributed to the Transferred Participant
                           pursuant to applicable provisions of the Plan.

                  (c)      Transferred Participant. Each of the following
                           individuals is a Transferred Participant: Dolores
                           Cody Harper; Claire Lee Kummer; Marshall L. Snyder;
                           and William J. Walsh.

The foregoing amendments are effective as of the close of business on December
31, 2000.

The undersigned has caused this instrument to be executed by its duly authorized
officers this 31st day of December, 2000.

                                           CERIDIAN CORPORATION


Attest: /s/ Gary M. Nelson                 By /s/ Shirley J. Hughes
        -----------------------------         -----------------------------


                                       2