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A Short Investigation into Icon Preference for Volume Buttons: Part 1

Conducted as part of the MediVoice Project (a Co-operative Project, funded by the European Commission under FP6)

by Antoinette Fennell
November 2006

A sample of n = 60 visually impaired test subjects were asked to choose the icon pair which they thought was most appropriate for labelling the volume up and volume down buttons on a machine. They were asked to base their choice on how clear the icons appear as well as how appropriate the symbols are. 

The test included subjects with a wide variety of eye conditions. These subjects were recruited from the RNIB Scientific Research Unit database. Visual acuity was not tested during the course of this study; information on eye condition was provided by the subjects themselves. The reported eye conditions in this group included retinitis pigmentosa (n = 13), macular degeneration (n = 12), nystagmus (n = 3), vision impairment resulting from injury or illness (n = 5), glaucoma (n = 4), albinism (n = 4), hereditary (n = 2), cataract (n = 3), optic atrophy (n = 2), cone dystrophy (n = 1), neuropathy (n = 1), myopia (n = 1), more than one eye condition (n = 8). One test subject did not know the cause of her visual impairment.

It should be noted that this short study did not explore the effectiveness of the symbols using task analysis, but rather was an investigation into personal preference.

The following icon pair options were shown to the test subjects:

 

Pair 1:

Icon for labelling a Volume up button consisting of a picture of a loudspeaker with an arrow pointing up
Icon for labelling a Volume down button consisting of a picture of a loudspeaker with an arrow pointing down

 

Pair 2:

Icon for labelling a Volume up button consisting of a picture of a loudspeaker with a triangle pointing up
Icon for labelling a Volume down button consisting of a picture of a loudspeaker with a triangle pointing down

 

Pair 3:

Icon for labelling a Volume down button consisting of a picture of a loudspeaker releasing a single sound waveIcon for labelling a Volume up button consisting of a picture of a loudspeaker releasing three sound waves

The three icon pairs were presented to test subjects in the form of a printed questionnaire.

To avoid bias the order in which the icon pairs were presented was randomised. The icon pairs were presented in four randomly chosen orders; n = 16, 14, 17 and 13 test subjects saw the icon pairs in the following orders respectively: 1-2-3, 1-3-2, 3-2-1 and 2-1-3.

The results were analysed (in SPSS 14.0) using Cochrane Test for k-related samples and McNemar Test for 2 related samples.

There was a significant difference between the three icon pairs (Cochrane Test: Q = 54.2, df = 2, p < 0.001). Further investigation revealed that Pair 1 was chosen as the favourite icon pair significantly more than Pair 2 (McNemar Test: Chi-square = 22.9, n = 60, p < 0.001) and Pair 3 (McNemar Test: Chi-square = 36.2, n = 60, p < 0.001). Pair 2 and Pair 3 were not selected a significantly different number of times (McNemar Test: n.s.)

In conclusion, the preferred icon pair option for the volume buttons on a device was Pair 1, representing a loudspeaker with an arrow pointing up for 'Volume up' and a loudspeaker with an arrow pointing down for 'Volume down'.

 

Sincere thanks to the 60 anonymous volunteers who took part in this short study.

 

 



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