Disjunctive Reaction Time As It Relates To Complexity Level Essay, Research Paper

Abstract

The reaction time for subject with increase complexity is the focus of this study. The ten respondents were randomly selected on the campus of University Wisconsin at Milwaukee. Ten subjects reaction time was evaluated with a computer simulation program using one, two, or four choice trails, which lasted forty to sixty minutes. The data were analyzed using t test and ANOVA. The t test showed no significance as far as practice effects were concerned, but inferences can be made. Also the ANOVA showed a significant difference with reaction time as it relates to complexity. I found that as the level of complexity increase so does the reaction time.

Disjunctive Reaction Time Measure as it relates to Complexity of Task

This study was conducted to prove that reaction time increases as the level of complexity increases. Disjunctive reaction time was measured to eliminate subject reacting too early to the stimulus. Also make the tack more complicated and for subject to uses discrimination before responding to stimulus. Postman and Egan (1949) defines disjunctive reaction time as ”two or more different stimuli are presented in random order…the subject is instructed to react to one but not to the other stimuli”(p 240). Rikli and Busch (1986) defined reaction time “as the latency from the onset of the visual stimulus to the depression of the microswitch”(p 646). Although a joystick was used to respond to the visual stimulus the same principle applies. For the purposes of this study both definition of reaction time were incorporated to facilitate proper measurement.

Baron and Journey (1989) tried to prove that with increase age so did the reaction time. Also within the study they also found that as the level of complexity increased so did the reaction time for the young group 18 to 26 and the old group 62 to 75. For their study the stimulus was a pair of asterisks presented in a square, where one the four symmetrical positions on the screen of the monitor, center on the right left side or the top or bottom. The respondent used a lever to indicate what direction the asterisk appeared on the screen. Also in Baron and Journey (1989) study three level of complexity were presented, there were one, two and four choice intervals. As a result of there study the found that reaction time increase with increased alternatives. This also seems to be the case with Rikil and Bush (1986), although they compared age with reaction time; they also found that with increase complexity reaction time increased.

Method

Participants

Ten subjects, men and women, were randomly selected at various locations on the campus of University of Wisconsin at Milwaukee. Subjects were between the age of 18 to 35.

Procedure

The procedure used for this used for this experiment is modeled after the one used by Baron and Journey (1989). Using a microcomputer the reaction time is measured with an associated response lever, a joystick. The joystick can be moved left, rift, back and forward. The stimuli are presented on the computer monitor, and the response involves appropriate operation of the lever. When the appropriate response is given, by using different directions as responses this ensures that reaction time can be measured as a function of complexity.

Before each subject participated in the study in formed consent was given. Prior to subject being seated, the experimenter test equipment to make sure it is functioning properly. The subject is seated in front of the monitor, where instruction for the experiment appears on the screen. The experimenter is seated next to the subject where they are able to access the keyboard to press enter after every trail. The experiment starts with 12 practice trails, with 144 total test trails. When the 12 practice trails are finished the experimenter informs the subject that the test trails are about to begin, and if the subject has any questions ask them now, because during the test trails the experimenter is not allowed to answer any questions.

The subject starts the beginning of test trails, when the subject presses a key at the base of the joystick. When key is pressed a stimulus appears on the screen. It is a circle where one, two, or four arrowheads are positioned inside. The pace where the arrowhead appears gives the subject an indication where the arrowhead may appear again. With one choice trails, the single arrowhead provides information about the direction, where the arrowhead will appear again. With the two choice trails, the information either left or right, or back or forward. Finally, with four choice trails, all four alternatives are possible. At this juncture the subject should not respond to the just observed display.

When the arrowheads disappear from the screen, the circle remaining, the subject must wait for a variable fore period of one to three seconds. A single arrowhead is displayed at this point the subject should react as quickly as possible to the stimulus in the appropriate direction. The response ends the trail. At this time the results are displayed on the screen. The experimenter who is not depressing the ENTER key on the keyboard should record the result on a data sheet. The data sheet should include trail number, trail type, required response, subject response, and latency rounded to the nearest millisecond, and a column for failed responses. Failed responses included those responses in the foreperiod and those responses to the wrong direction. After all 144 trail are complete, thank the subject for their time and offer answer any question the may have.

Results

The means of the first 36 trails and the last 36 trails were analyzed. Within the first and last36 trails an equal number of one choice, two choice and four choice stimuli were supplied. An examination of reaction time as it compares to complexity of task revealed a simple main effect, suggesting that as the level of complexity increase so do reaction time. An analysis using ANOVA supported this observation, F (2,18) = 5.98, p * .014 as seen in Figure 1. An analysis using t test revealed (M = 461.50) for the first 36 and the (M=408.89) for last 36 trails, t (9) = 0.718 p = .497 for 1 choice, was not significantly different. The (M=569.59) for the first 36 trails and the (M = 554.84) for last 36 trails, t (9) .560 p = 594 for 2 choice, was not significantly different. The (M=597.366) for first 36 trail and the (M =554.84) the last 36 trails, t (9) 1.092 p =. 304 there were no significant findings, suggesting no practice effects seen in table 1.

Discussion

Although t test did not provide any significant results, the inference can be made that practice effects may have occurred because the means of the first 36 trails were shorter than those of the last 36 trials. Also the inference of fatigue or boredom may be a reasons that the t test were not significant. Postaman and Eagan (1949) propose that the subjects has an “concentrated attention on the stimulus,”(p. 255) if the subject becomes bored or fatigue with repeatedly doing the same task practice effect result may not occur. Another reason that practice effects result did not occur may have been the sample size and number of trials. With Rikli and Busch (1989) the sample size was 60 adult females, compared to 10 randomly chosen adults for this study. The number of trails for the Rikli and Busch (1989) study was 10, where that last 8 trails were used to determine the mean scores for the analysis, this procedure has a reliability of .87. This study also used the last trials to determine variance however, fatigue or boredom may have set in by the last 36 trails of 144 trails.

However, there were increases in reaction time when the complexity level increase, similar to the results in Baron and Journey (1989). Rikli and Bucsh (1986) comapred the means of the simple reaction time versus choice reaction time, the choice reaction time was twice that of the simple reaction time suggesting with increase complexity the reaction time increases. The means of the one choice, two choice and four choice, for last 36 trails showed that with increased complexity reaction time increased, as seen in figure 1.

Bibliography

Reference

Baron, A. & Journey, J.W. (1989). Age differences in manual versus vocal reaction time: Further evidence. Journal of Gerontology: Psychological Sciences, 44, P157- P159.

Postman, L. & Egan, J.P. (1949). Experimental psychology: An introduction (Chapter 12). New York: Harper.

Rikli, R., & Busch, S (1986). Motor performances of women as a function of age and physical activity. Journal of Gerontology, 41 645-649

Reference

Baron, A. & Journey, J.W. (1989). Age differences in manual versus vocal reaction time: Further evidence. Journal of Gerontology: Psychological Sciences, 44, P157- P159.

Postman, L. & Egan, J.P. (1949). Experimental psychology: An introduction (Chapter 12). New York: Harper.

Rikli, R., & Busch, S (1986). Motor performances of women as a function of age and physical activity. Journal of Gerontology, 41 645-649