Eva Jonas, Stefan Schulz-Hardt, and Dieter Frey (2001)

Konfirmatorische Informationssuche bei simultaner vs. sequentieller Informationsvorgabe

Zeitschrift für Experimentelle Psychologie, 48(3):239--247.

After having made a preliminary or final decision, people often prefer information that supports their chosen alternative to information that conflicts with their choice. Jonas, Schulz-Hardt, Frey, and Thelen (in press) found that sequential presentation of information leads to an even stronger preference for supporting information than the traditional form of simultaneous presentation. Their proposed explanation for this effect was that sequential presentation induces a focus on the prior decision, thereby increasing commitment to this decision. The present experiment was designed to rule out an alternative explanation: Being repeatedly confronted with pieces of information to select from could induce the participants to search for more information than they consider to be necessary, and because less effort is required to process supporting information the additional information requests are predominantly for these supporting pieces of information. To test this alternative explanation, in the present experiment - as in the Jonas et al. (in press) experiments - simultaneous vs. sequential information presentation following a preliminary decision was manipulated. In contrast to the former experiments, this time the number of information requests was fixed: Participants in both conditions had to choose 8 out of 16 pieces of information. The results show that once again a stronger preference for supporting information arises when the information is presented sequentially compared to simultaneously. The alternative explanation mentioned above could thus be ruled out.