Separating Features within a Complex Sound
This is a research project that I completed in my psychophysical research methods and Signal Detection Theory class in Winter 2016. I worked with a group to examine how long-term musical training and different kinds of short-term training affected people's ability to separate features within a complex sound, or more specifically, their ability to discriminate the number of notes within a chord.
Featured Skills: Research, Writing, Presentation
Featured Skills: Research, Writing, Presentation
Research
Research Proposal
The first step in any research process is to pose a question that needs to be answered. We used previous research to inspire and motivate our question. Past studies in music perception have suggested that musical background is a positive influence on the ability to perceive patterns within music. In the educational domain, studies of instructional methodology have suggested that presenting both positive and negative examples of the topic being learned can facilitate learning. Based off of this research, my group and I wanted to investigate how long-term training (musical background) and different kinds of short-term training (positive example training vs negative example training) influence how well people are able to discern a chord with three notes in it from a chord with either two or four notes in it.
We created a research proposal that outlined this question, our hypotheses about the answer, and our methods that we planned to use to assess the question.
The first step in any research process is to pose a question that needs to be answered. We used previous research to inspire and motivate our question. Past studies in music perception have suggested that musical background is a positive influence on the ability to perceive patterns within music. In the educational domain, studies of instructional methodology have suggested that presenting both positive and negative examples of the topic being learned can facilitate learning. Based off of this research, my group and I wanted to investigate how long-term training (musical background) and different kinds of short-term training (positive example training vs negative example training) influence how well people are able to discern a chord with three notes in it from a chord with either two or four notes in it.
We created a research proposal that outlined this question, our hypotheses about the answer, and our methods that we planned to use to assess the question.
Study Design
After our research had been approved, we began planning more specifics of our project and thinking through every small detail. We determined exactly what chord stimuli we wanted to use and what program we were going to use to make the experiment module. Perhaps the most important decision that we made during this time was to present one chord in each trial rather than use a forced-choice experiment design as we had originally intended. A forced-choice experiment would have presented two chords at a time and asked "Which one of these chords contains three notes?" We instead decided to present only one chord at a time and ask a yes/no question of "Does this chord contain three notes?" We made this decision after simulating the experiment on ourselves and realizing that a forced-choice experiment was much too easy and would likely result in a ceiling effect, where everybody performs almost perfect so differences between groups cannot be detected. This was a very important decision, and had we not piloted the experiment on ourselves and simply moved forward with the forced-choice design, it likely would have caused us to have very poor results.
After our research had been approved, we began planning more specifics of our project and thinking through every small detail. We determined exactly what chord stimuli we wanted to use and what program we were going to use to make the experiment module. Perhaps the most important decision that we made during this time was to present one chord in each trial rather than use a forced-choice experiment design as we had originally intended. A forced-choice experiment would have presented two chords at a time and asked "Which one of these chords contains three notes?" We instead decided to present only one chord at a time and ask a yes/no question of "Does this chord contain three notes?" We made this decision after simulating the experiment on ourselves and realizing that a forced-choice experiment was much too easy and would likely result in a ceiling effect, where everybody performs almost perfect so differences between groups cannot be detected. This was a very important decision, and had we not piloted the experiment on ourselves and simply moved forward with the forced-choice design, it likely would have caused us to have very poor results.
Creation of Research Materials
I took charge of creating the chords for our experiment. Using my electric keyboard to record and Audacity to cut the clips, I created 72 unique chord recordings (we later decided to only use 48 of them). I thought about ways in which the chords could possibly bias our results and made sure to control for those things. Specifically, I made sure that each chord was presented at the same volume, for the same amount of time, and in the same octave range.
I took charge of creating the chords for our experiment. Using my electric keyboard to record and Audacity to cut the clips, I created 72 unique chord recordings (we later decided to only use 48 of them). I thought about ways in which the chords could possibly bias our results and made sure to control for those things. Specifically, I made sure that each chord was presented at the same volume, for the same amount of time, and in the same octave range.
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We also all worked together to create our actual experiment module in PsychoPy. The experiment presented the chord recordings and recorded participants' responses on the keyboard by logging them in Excel files. It randomized the order of the stimuli to protect against order bias and fatigue effects. Because our experiment design and stimuli were slightly more complex than the drag-and-drop PsychoPy interface allowed us to create, the creation of our experiment involved some programming. We faced a couple of challenges along the way but were able to solve them pretty quickly. During this stage, we also determined exactly what language we would use in the instructions. We wanted to ensure that the instructions would be clear to avoid any confounding effects of confusion.
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Screen shown to participants during chord presentation
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Run Subjects
We ran all of our subjects in one experimental session in a computer lab. We moderated the session and ensured that everything ran smoothly.
We ran all of our subjects in one experimental session in a computer lab. We moderated the session and ensured that everything ran smoothly.
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Analyze Data
I took the lead on the data analysis for the project. We used Signal Detection Theory to analyze our results, a statistical framework that allows for the quantification of the ability to discriminate between signal (in our case, three-note chords) and noise (in our case, two-note and four-note chords). We did a very in-depth data analysis, looking at many different factors and how they were affected by the manipulation of different variables within our study. We used both Excel and SPSS to analyze the data and represent it in graphs. Many hours went into compiling and organizing the data, performing analysis, interpreting what we found, and repeating the process again as we found new directions to explore each time. I found the analysis process to actually be similar to an iterative design process, in that each time you go through the process, you have new ideas and find new avenues to explore while refining your original work. In total, the data analysis took about a week of hard work to complete. |
Excel spreadsheet holding the data
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Writing
Research Paper
The last thing we had to do was turn our quantitative results into words to pose a question and effectively communicate the answer. I split from my team at this time to write my own independent research paper on our study. Following standard APA guidelines, I wrote, edited, and revised my paper multiple times until I felt satisfied that my writing was clear and concise, while still telling a compelling story. My paper received a perfect score in the class.
The last thing we had to do was turn our quantitative results into words to pose a question and effectively communicate the answer. I split from my team at this time to write my own independent research paper on our study. Following standard APA guidelines, I wrote, edited, and revised my paper multiple times until I felt satisfied that my writing was clear and concise, while still telling a compelling story. My paper received a perfect score in the class.
PresentationFinal Presentation
Using a PowerPoint presentation, my teammates and I presented our completed research project to the class. We outlined our entire process from start to finish, including the previous research that inspired our research, our hypotheses, how our study was designed and implemented, and finally our results and what they meant for psychology and future research. |
Results represented in a line graph
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