He then goes on to look at some possible reasons that people may not vote for the lib dems, and refutes them, for example 'is it that you don;t think the lib dems have enough experience running things?' which he the refuted; 'i don't think so, not while we a running far more local authorities than the tories.'
At the end of the broadcast he asks the audience to write down what they would say to convince people that they can do what they would really like to do (ie vote for the lib dems). This uses the technique of self-generated persuasion Self generated persuasion was shown to be a successful form of persuasion by Lewin (1947) who found that housewives who were asked to generate their own arguments about why serving sweetbreads was a good thing were eleven times more likely to serve them than women who were given a lecture on the subject.
Cacioppo, J. T., Petty, R. E., & Sidera, J. (1982). The effects of a salient self-schema on the evaluation of proattitudinal editorials: Top-down versus bottom-up message processing. Journal of Experimental Social Psychology , 18, 324-388.
Lewin, K. (1947). Group decision and social change. In T. M. Newcomb & E. L. Hartley (EDS>), Readings in social psychology (pp.223-235). New York: Holt.