Modality Source Monitoring Experiment

Thank you for participating in the experiment. The purpose of the study is to understand how divided attention affects participants' ability to remember the modality (visual or auditory, in this case) in which stimuli were originally presented.

In this experiment, subjects saw 40 pictures representing simple words, and heard 40 different words spoken. Subjects were randomly assigned to one of three groups. Group 1, the simultaneous group, saw pictures and heard words simultaneously. Group 2, the non-divided attention group, saw pictures and heard words presented separately. Group 3, the divided attention control group, saw pictures and heard words separately while performing a distracting task which resulted in divided attention. Later, all subjects were shown a list of 80 written words. They had seen twenty of these words previously as pictures, heard twenty previously as spoken words, but had not experienced forty of these words in the experiment at all. For each of the test words, subjects were asked whether the words had been presented before, and in what modality. In this research, we are trying to answer three questions in particular:

  1. Modality source monitoring errors, where subjects confuse things they experienced with one sense with things they experienced with another, have been shown to occur with visual and tactile stimuli. This experiment seeks to determine whether this phenomenon is generalizable to other pairs of modalities — in this case, visual and auditory.

  2. Is divided attention (i.e., doing two things at one) necessary to cause modality source monitoring errors? Do these errors occur with a similar frequency when subjects study items while fully attending to the stimuli?

  3. Does divided attention affect visual source memory or auditory source memory more? That is, for the simultaneous group and control groups (Groups 1 and 3), will memory for modality be worse for items they saw or items they heard, relative to the non-divided attention group (Group 2)?

Again, I appreciate your taking the time to participate in this experiment. I hope the description above explains the purpose of today's experiment clearly. I am interested in hearing any reactions you may have to the experiment in terms of its design or implementation, or your participation in it. Please feel free to email me ( with your comments. When more data is collected, I will make available an analysis of the results of the experiment, as well as the raw data for downloading. Please check back to the experiment home page after January 15, 2003. If you keep track of your subject number and/or the date and time you participated in the experiment, you will be able to see your data and how it compares with that of other subjects.

Jan Richard
Bryn Mawr College

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