Implementation intention versus monetary incentive comparing the effects of interventions to promote the purchase of organically produced food

The present field experiment investigates the effects of three interventions on the enactment of the goal intention to test organically produced food offered by a local bio-shop. Study participants were 320 German University students who normally did not purchase organically produced food. The three interventions consist in a monetary incentive, the stimulation to form a specific plan when to act (so-called implementation intention), and a combination of both interventions. The interventions are assumed to promote the enactment of the test-intention by suppressing the distracting influence of past food purchase habits. As expected, in the control group food purchase habit exerts a strong negative influence on the probability of the shop-test purchase of organic produce. Compared with the control group, all three experimental groups showed a significantly greater probability of enacting their purchase intention. In the experimental groups food purchase habit does not influence the actual test purchase. But contrary to expectations the effectiveness of the three interventions does not differ significantly. (C) 2002 Elsevier Science B.V. All rights reserved.