The Blue Peter thermometer is clever in particular because it uses several persuasive worms on one fundraising fishing-line.

• People tend to do what they see other people doing.

• You’re more likely to stick with a task if you believe you have already made progress towards it. Remember how the thermometer never started empty? There was always some donation to start with, to get us going.

• The more similar a person seems to you, the more likely you are to respond to their request for help, or do what they are doing. This explains why the successful Blue Peter appeals screened documentary footage of other children collecting carloads of milk-bottle tops.

This can also be seen in petition signing…..

• Petition signatures increase when we display the numbers of signers to visitors.

• We get further increases when we show others’ comments and names on the petition.

• Given a campaign action with several steps, if we show a progress bar somewhat completed, people are more likely to finish it.

There are of course ethical boundaries for the use of these powerful techniques. From a purely personal perspective, my conscience would throb if I lied or messed with the truth when using them.

This leads me on to one of the most obvious research findings: people are more likely to respond to a request if they trust the person who’s askinp. Trust is perhaps the most powerful persuasion tactic of all.

from Rachel Collinson  – director of knowledge sharing and innovation atEngaging Networks.