Monday, April 16, 2012

Dual-mode presentation and its effect on implicit and explicit memory

Article – Dual-mode presentation and its effect on implicit and explicit memory

Invitation to Psychology explains the measure of memory in two terms: implicit and explicit. Implicit memory is the “unconscious retention in memory, as evidenced by the effect of a previous experience or previously encountered information on current thoughts or actions” and explicit memory as a “conscious, intentional recollection of an event or of an item of information” (273). These measures are explored in the article “Dual-mode presentation and its effect on implicit and explicit memory.” The authors, Prabu David and Elliot Hirshman, conduct experiments in order to categorize the perceptual systems of identification, such as auditory and visual.

Priming is a term used liberally within the article. It is “a method for measuring implicit memory in which a person reads or listens to information and is later tested to see whether the information affects performance on another type of task” (274). One experiment tests different kinds of priming against each other: multimodal priming (auditory-visual) against within-modality priming (visual) and cross-modality priming (visual).

The experiment consisted of a 3x2x2 design, including two within-subject factors and one between-subject factors. The first w-s factor was the modality; study words were presented in the auditory, visual, or auditory-visual conditions. 360 words were divided into thirds (40) and assigned to each group. The second w-s was the encoding instruction, half semantically, half structurally. Within the groups of 40, half were semantic, the other structural. The between-subject was test instructions, half given implicit instructions, half given explicit instructions.

Three trials were performed: auditory, in which the word was presented through headphones; visual, in which the words were presented on a computer screen, and auditory-visual, in which the words were presented on the screen and through the headphones. During each trial, the subject had to encode the words. “Under semantic encoding, when the study word was presented, the subject was cued to 'generate a sentence using the word.' Under structural encoding, the subject was cued to 'generate a word that begins with the same first letter as the word.' The subject moved to the next trial by pressing the space bar” (81).

After the study portion came the identification tests. The implicit instruction asked the subject to identify the word after it was flashed on the screen for a brief amount of time. The explicit instruction asked the subject to identify the word after it flashed. The difference is that under the implicit, the subject was not cued as to whether or not some of the words were ones they had seen from the study period. The explicit cued “old” for ones previously seen and “new” for ones not included earlier. The subject was meant to say the word out loud in order to identify it, and told to say “Don't know” if unable to.

The results of the experiment state that multimodal priming (auditory-visual) is equal to within-modality priming (visual) and that within-modality is greater than cross-modality priming (auditory). These results match up with view “that there are small but consistent effects of levels of processing on implicit memory tasks” (82).

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