Running head: CROSS SENSORY MATCHING
Reaction Time of Cross Sensory and Same Sensory Matching
Kristina J. Luscher
St. Bonaventure University
Abstract
Research has suggested that letters
perceived visually are encoded using a sound or name code (Sperling,
1963). Later research questioned whether
a picture or visual code was also used to store this information (Posner,
Boies, Eichelman, and Taylor, 1969).
Using capital and lowercase letters it was found that the reaction time
for letters with a physical match was faster with a delay between letters of up
to 1.5 seconds. An unpublished
experiment by Luscher (2003) found similar results to those of Posner et
al. This study examined whether visually
processed information is stored as a name code or an image code with the use of
words
Reaction Time of Cross Sensory and Same Sensory Matching
Research has looked at the process of identifying whether or not two visually presented stimuli are the same or different. When both stimuli are presented at the same time this is a simple enough task using visual comparison. However, when there is a delay between the presentation of the first stimulus and the second stimulus, the first must be identified and stored in the memory until the second is presented for the comparison to be made.
Sperling (1963) suggested that in letter recall tasks, letters are stored in short-term memory using a sound or a name code. This conclusion is based on the observation that when participant’s made errors in a recall test confusions were made more often between letters that sounded alike than between letters that looked alike.
Posner, Boies, Eichelman, and Taylor (1969) questioned whether visually processed information was encoded only by using a name code, or whether a visual code was also used. This studied used combinations of capital and lower case letters. This study found that reaction time for letters that had a physical match was 90 msec. faster than letters that only had a name match, but that this difference between reaction times disappeared after a delay of 1.5 seconds. This suggests that after a delay of longer than 1.5 seconds only a name code remains in the short-term memory.
An unpublished study by Luscher (2003) examined whether a name code or a visual code is used to process visually perceived information based on the difference between reaction times when stimuli were presented to only one sensory system (visual) or to two different sensory systems (visual and auditory). In this experiment, the stimuli presented were letters. The second stimulus letter was presented either visually on a computer screen or as a sound wave after a one second delay. The results of this study agreed with those of Posner et al. (1969) in that the reaction times for the visually presented stimuli were less than for the stimuli presented as sound waves with a delay of less than 1.5 seconds. However, this study did not look at the effect of decay of the visual code in short term memory after 1.5 seconds or the effect of a longer delay on a name code in short term memory.
Research done by Umansky and Chambers (1980) suggests
that whole words are the unit of identification used in word perception
Method
Participants
Twenty-two undergraduate students from St. Bonaventure University were recruited through the psychology department participant pool. Seventeen females and five males participated. Most participants were psychology majors and received extra credit in psychology courses in exchange for their participation.
Materials
The computer program E prime (2002) was used to create and run this experiment. The program displayed words and sounds in addition to recording the reaction times of the participants. After all of the data was collected, the program was also used to merge and condense the data.
Design and Procedure
The participants were directed to sit in front of a computer. The instruction presented on the screen informed the participants that they would complete four blocks of trials after completing a practice block to test their accuracy. In the practice block, participants viewed a letter, then after a one second delay, they viewed a second letter. If the two letters were the same the participant was asked to press the “1” key on the keyboard. If the two letters were different the participant was asked to press the “2” key on the keyboard. The letters used in the practice block were A, B, F, H and K, which were the letters, used by Luscher (2003). There were ten trials randomly presented in the practice block. The participants had to repeat the practice block until an accuracy of 80% was achieved.
After completing the practice trial, participants completed four blocks. These blocks included a visual block with a delay of one second between stimuli, a visual block with a delay of three seconds between stimuli, an auditory block with a delay of one second between stimuli, and an auditory block with a delay of three seconds between stimuli. The order of presentation of the four blocks was randomized so that participants did not complete the blocks in the same order. Each block contained forty trials, which were randomly presented by the computer. The mean reaction time of all correct responses in a block was calculated in order to get one raw score for each participant in each block.
In the visual blocks, the participants were presented one of four words on the computer screen. After either a one-second or a three-second delay the participants were presented with a second word and were asked to identify whether the two words were the same or different as in the practice block by pressing “1” or “2” on the keyboard. The auditory blocks were the same as the visual blocks except that the second word was presented as a wave file through the speakers. All of the wave files were recorded using the same female voice and were the same length (.499 sec).
The words used in this experiment were: clock, dress, peach, and snail. The words were randomly selected from a first-grade-level spelling book (Benthul, 1977). All four words were five letters in length so that they would take up the same amount of space on the screen. In addition, it was ensured that all of the words began with a different letter, and that none of the words rhymed.
Results
A repeated measures ANOVA for a 2x2 factorial design was used to analyze the data. The mean reaction time for the visual block with a one-second delay (M = 478.32 ms, SD = 72.16) was the fastest as was predicted. The mean reaction time for the auditory block with a one-second delay (M = 528.98 ms, SD = 78.55) was slightly faster than the mean reaction time for the visual block with a three-second delay (M = 531.30 ms, SD = 95.48). The mean reaction time for the auditory block with a three-second delay (M = 585.39 ms, SD = 96.57) was the slowest (see Figure 1). These means show an increase in reaction time as the delay between stimuli increases for both senses. In other words, reaction time was longer when there was a three-second delay between stimuli than when there was a one-second delay between stimuli. This indicates a main effect of delay between stimuli (F (1,22) = 19.92, p < .01). In addition, a longer reaction time is shown for the auditory sense than for the visual sense in both levels of delay between stimuli. This indicates a main effect of the type of stimulus presented (F (1,22) = 13.29. p < .01). The main effects of each variable were significant. There was not a significant interaction between these two independent variables (F (1,22) = 0.01, p > .05).
Discussion
Based on the results of this study the reaction time in a word matching task, when the two stimuli are presented to either the same sensory system or different sensory systems, does not depend upon the length of delay between the two stimuli. These results agree with the findings of Posner et al. in that there was a decay of the visual image in the short-term memory after 1.5 sec, evident by the slower reaction times in the three-second delay blocks. However, it appears that there may also be a decay of the name code in the short-term memory, since reaction times were also slower in the auditory three-second delay block, than in the auditory one-second delay block. The results of Posner et al. also suggested that the difference between the reaction times of identical letters and letters with a name match disappeared after 1.5 sec. This result did not occur when the words with a name match were presented to a different sensory system. The reaction times of the visual blocks were faster than the reaction times of the auditory blocks, regardless of the length of delay between the stimuli.
One reason that the reaction times for the cross-sensory groups were greater may be that the participants had to hear the entire word before they could perceive which word they were hearing. The speed of presentation of the words presented in the auditory blocks was set and consistent for all participants. However, in the visual blocks, participants read the words to themselves, and may have been able to read at a faster speed than the words in the auditory block were spoken. There may also be a difference in the processing speed of the two sensory systems causing much faster reaction times in the visual blocks.
References
Benthul, H. F., Anderson, E. A., & Utech, A. M. (1977). Spell Correctly Teachers Edition 1.
Luscher, K. (2003). Cross Sensory Matching. Unpublished manuscript, St. Bonaventure
University, NY
Posner, M. I., Boies, S. J., Eichelman, H. W., & Taylor, R. L. (1969). Retention of Visual and
Name Codes of Single Letters. Journal of Experimental Psychology, 79(1, Pt. 2), 1-16.
Schneider, W., Eschman, A. & Zuccolotto, A. (2002). Eprime Version 1.0 [Computer Software]
Psychology Software Tools Inc.
Sperling, G. (1963). A Model for Visual Memory Tasks. Human Factors, 5, 19-31.
Umansky, J. A., & Chambers, S. M. (1980). Letters and Words in Word Identification. Memory
and Cognition, 8 (5), 433-446.
Figure 1. Mean Reaction Times of Matching Task (ms)
