Introduction to Auditory Graphs

## Introduction to Auditory Graphs

Before the test begins, a short explanation about Auditory graphs is necessary for those who will be listening to the graphs instead of seeing them. It is a random process as to who gets which graph type, so everyone should understand how to listen to these graphs.

The basic auditory graph involves mapping the Y axis data to pitch, and the X axis data to time. So the greater the Y value, the higher the frequency of the sound, and the greater the X value the later the sound will be played. As an example, in the following graph there are two (X,Y) data points: (1,1) and (2,4). The (1,1) point can be heard first, and has a low tone, the (2,4) point is played second and has a higher tone.

```     MIDI     WAV
```

Note: The concept of 0 is difficult to represent in an auditory graph. We have used the following tone to represent 0 in all of the graphs in this test:

```     MIDI     WAV
```
For most of the graphs that you will encounter, the lowest tone played will represent 0.
A series of points would be played as a series of tones. The following graph gives an example of a series of points that increase in both X and Y values:

```     MIDI     WAV
```
In previous studies, it was noticed that it is difficult to tell when a graph is linearly increasing (i.e. Y = X), vs. when there is some curvature to the graph (i.e. ). For this reason, a sound to alert the listener to the slope and curvature of a graph has been added. This sound is heard as a series of "drum" beats.

The slope of a graph is defined as the rise/run or . The greater the slope, the more rapid the beat.

Please listen to the following graphs to determine which one has the greatest slope.

```1:     MIDI     WAV
```

```2:     MIDI     WAV
```

(The second graph has a greater slope)
The pitch of the drum beat indicates the curvature of the graph. The curvature is defined as the change in the slope, or .

When the curvature is positive ( ), as it is for the graph of , the graph is bowl shaped, and is represented with a low pitched drum beat. This graph looks and sounds like the following:

```     MIDI     WAV
```

When the curvature is negative ( ) as in , the graph is hat, or hill shaped. This type of graph has a high pitched drum beat. This graph looks and sounds like the following:

```     MIDI     WAV
```