Memory span experiment

Abstract

Memory span experiment is a test that was conducted among one hundred and thirty-one Murdoch on-campus psychology undergraduate students to evaluate the number of various variables that a person can memorize without referencing. The participants were provided with three sets of variables; Numbers, Letters and Words each at a time. The sets ranged from three to ten characters and participants were required to correctly memorize a set of these variables before they proceeded to the next set that had one more character than the previous one added to it. It was established that the many of the participants could only remember between four to seven variables in a particular set. These findings made it be concluded that human mind can memorize a few variables, particularly words and letters.

Human memory span

Introduction

Memory span refers to the duration that mind of a person can hold a memory of a given number of variables. This report records the findings on the question under investigation, “Memory Span.” Numerous cognitive theories are of the opinion that there exists a system of working memory that can only allow for a limited amount of data to be stored temporarily, (Wheatley, J. P., 2005, p46). The short-term memory system comprises of functional cognitive components that allow for understanding the immediate environment of an individual, personal representation and reaction to stimuli in the niche and it also retains information from the present and immediate past events, (Vandenessche, E., 2015, p89). The primary purpose of this report is to make an exploration of the capacity of mind and the extent of which it can remember data before discarding it. Researchers and scholars have explored this field to try and understand the level of which various things can be forgotten over a short time. Among many questions that they sought to answer include:

1.    Can an individual memorize everything he/she sees?

2.    What is the approximate number of variables that can be memorized? 

3.    Is there any relationship or differences between the number of figures, letters, sounds, words and images that an individual can remember?

4.    What are the factors that determine the ability of individuals to remember variables?

The research, Superficial Memory did by “CogLab” was conducted on two hundred respondents who were well prepared for the test. They were asked to listen to different keys played on a piano and were also allowed to look at the sequence of numbers that were written on a big screen for ten seconds. The subjects, after five seconds were asked to recall the variables. The same procedure, but now with a different set of variables, was repeated and the respondents were asked to memorize the variables after twenty seconds. The respondents could apparently remember from three to five variables in a given set, after five seconds of the experiment. However, when they were asked to memorize variables after twenty seconds, it was established that they could not remember with the precision as compared to when they remembered the characters after five minutes. The study concluded that human beings could only remember a few number of variable or characters after a short duration of time. Before conducting the experiment, several factors were made constant such as; mental rest, the size of fonts of the variables, time of exposure and the volume of sound variables. The findings made by CogLab relates with my predictions in the sense that both experiments were aimed at evaluating the extent that human mind can hold data. The Memory Span Lab that I participated only varies with CogLab in the sense that CogLab included other variables like sound and images during experimentation.

Memory span of a human

Hypothesis 

To examine the span of the memory of the participants, the respondents were asked to memorize characters in variable sets and the sequence that they occurred. Based on the theory that memory span is limited and it decreases with time, it was hypothesized that human memory could hold approximately four to seven variables at ago without rehearsing them or reviewing the original codification. It can also be hypothesized that buffer memory on the variables that can be memorable reduces as time lapses. When a set of digits, words, figures, and sounds were presented to a respondent during the experiment, it was found that they can only memorize between four to seven characters in their original sequence. In this report, digits, letters, and words are the independent variables. The dependent variable in this report is the length of variables that a respondent last correctly memorized. 

Methodology

Participants

The experiment was conducted on one hundred and thirty-one Murdoch on campus full-time psychology undergraduate students. Six researchers contacted students via their g-mail and asked them to volunteer as psychology students to take part in the experiment. However, there were no privileges to some students or incentives for the participants for taking part in the experiment. Eighty-seven female and forty-four male students of varied ages attended the experiment. They were of ages 18 to 29 years and represented all the levels in the psychology course. There were thirty freshmen, twenty-two juniors, sixty-one sophomores and fifteen seniors. All the students who took part were reported to have a normal vision that enabled them to see variables on the screen clearly. 

Equipment

In this experiment, the researchers used computers and LCD monitors. The features of the computers were supportive to the experiment as they were of HP Models and had Pentium4 processors. A large monitor of an EPD88 model was used. The experiment of Free Recall Memory was run in the computer using a program called Cognition Laboratory Experiments, (Riddell, 2013, p84). The particulars of the experiment and the host program were both written in Java. Researchers used foolscaps and pencils to record the result of experiments and responses from the respondents on the questions/tasks presented to them.  

Stimuli

This experiment constituted two independent variables that the team used to determine the accuracy of the span of the memory of letters, words, and numbers. The type of stimulus that resulted after the experiment and the span of memory were the independent variables in this research. The variables had two levels that created four conditions that participants were made to experience. Some series of figures, letters or words were included in the stimuli. A series of three digits at a minimum and ten at maximum were used, and they all used numbers from zero to nine. For the independent variables to be manipulated, there are four conditions that correspond to the three levels of independent variables. Every condition had a level of the length (time) of stimulus and the type of exhibited stimulus. Three repetitions were done on every level such that, there were two conditions that contained numbers, other two that contained digits and the other two that contained words. In all the levels of conditions, the researchers observed constant stimulus at the duration of one second to allow for fixation, duration of five seconds for each item that was presented, thirty seconds for recognizing the participant, and 0.5-word distance about positions of X and Y. This constant level of stimulus was maintained at 24 size font. The table below shows the levels of stimuli. 

Condition	Type	Length
One	Word type	(3-4 Characters) short
Two	Word type	(7-8 Characters) Long
Three	Digit type	(2 Digits) Short
Four	Digit type	(4 Digits) Long

Procedure

The researchers came up with many words to enable them to run the experiment without having to repeat some words. These words were then reduced to a hundred short words that had three to four letters and another hundred that consisted of words with letters between seven and eight that the participants were familiar. The members were briefed of the informed consent, and each was given to choose between exclusively using a computer in the experiment or use a large LCD screen. The ones who opted for the large screen were given pencil and foolscap(s) to record each of the ten cases tested in the experiment. The lab was spacious so as to avoid participants copying information from one another. They were required to write the digits, letters, and words as they are displayed on the screens. The order and precision of the characters were strictly taken into consideration in determining the final lab results. Five short character and five long character tests were displayed on the screens for between five to ten seconds, and the participants made entries on what they recalled. Upon completion, the participants were required to provide researchers with their demographic information such as; age, sex and year of study. They were also briefed and thanked for the participation.

Human brain memory capacity

Results 

After the experiment, data was compiled and analyzed by ANOVA where the accuracy of the participants was computed. The results showed that the participants recognized data with short stimuli more accurately as compared to the ones that contained long stimuli, 11.4.<0.01. Words were also identified more quickly than letters, 671.01<0.01. This meant that word stimulus and number stimulus were different. The accuracy of the participants significantly increased when words were presented to them than when numbers were provided. However, the increase in accuracy was opposite in the comparison of the two stimuli on the longevity of characters. When the numbers have increased the accuracy reduced significantly as opposed to when letters were raised. The increase in letters showed an increase in the accuracy of the participants.

Discussion

From the results of this experiment, it can be noted that effects of an independent variable were also found manifested on the dependent variable. This result found was as expected since in the past researches people were found to remember words more easily than numbers. This is because words are stored in the memory of an individual and it is only revisited, unlike the figures that must either be crammed or memorized to shorter extents. As words become longer, their structures become distinct from other words. Long words are then easily recognized and memorized due to this unique factor than when they are short. Words, unlike numbers, are characterized with the aspect of automaticity. The stimuli were carefully chosen so as to give a balanced assessment of the effects of the longevity of variable under consideration. These results can, however, be interpreted to lack accuracy because demographic issues do affect mind tests. The participants were of ages between 18 and 29, and this bracket did not show any differences in their memory spans. If people of diverse ages and different literacy levels were included in the experiment, the result would have changed a little bit. Long and technical words are difficult to remember if a participant is at his or her advanced age. This applies to numbers whereby it becomes difficult to memorize seven numbers. The experiment did not factor in the fact that linguistics students have recorded higher accuracy in word remembrance as compared to students studying numeric courses like Biochemistry, Statistics and Engineering and vice versa when it comes to number memorization. Had the two factors were considered the result of the lab will have had more significance in applying the knowledge in real life situations. 

Future researches should consider having respondents from diverse backgrounds, different literacy level and areas of specialization to get better results. The mental status of interviewees should also be assessed because it is the main factor for concentration during the experiment. Respondents who have petite level end up scoring very poorly in the assessment, (Minirth, F. B., 2010, p75). The result of this study is useful in life situations as people are often found to remember significant data that is presented using words that when figures are used. Memory span of persons is limited and reduces as time after the conception of a variable or data lapses.

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