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A Short Investigation into Icon Preference for Volume Buttons: Part 2

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

by Antoinette Fennell
January 2007

A previous study into colour contrast preference identified a black icon on a white button with a black surround as favoured over three other black and white combination options. As a result it was necessary to carry out a second short investigation into volume icon preference, presenting the icons using the new colour contrast option.

A sample of n = 93 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 device. They were asked to base their choice on how clear the icons appear as well as how appropriate the symbols are. In the printed questionnaire, the icons were approximately 15mm x 17mm (measurement represents the white square in which the black icon was framed).

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 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 = 22), Macular Degeneration (n = 13), Nystagmus (n = 11), detached or damaged retina (n = 6), vision impairment resulting from injury or illness (n = 5), Glaucoma (n = 4), hereditary (n = 3), Cataract (n = 3), Optic Atrophy (n = 3), brain tumour (n = 3), myopia (n = 3), blocked optic nerves (n = 1), more than one eye condition (n = 14). Two test subjects did not provide this information. 

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

Pair 1

picture depicting the first volume icon pair option with loudspeakers and arrows

Pair 2

picture depicting the first volume icon pair option with loudspeakers and triangles

Pair 3

picture depicting the first volume icon pair option with loudspeakers and waves

Pair 4

picture depicting the first volume icon pair option with loudspeakers and a plus and minus sign

The four 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 = 27, 22, 24 and 20 test subjects saw the icon pairs in one of the four orders.

The results were analysed (in SPSS 14.0) using Chi-squared analysis and McNemar Test for 2 related samples.

Table 1 shows the percentage scores for each icon pair.


Table 1. A breakdown of the percentages that each icon pair was chosen as the preferred option for labelling 'Volume up' and 'Volume down' buttons.

Pair 1
Pair 2
Pair 3
Pair 4

% of people who chose this icon pair as their preferred option



There was a significant difference between the three icon pairs (Chi-square = 13.8, df = 3, p < 0.01).

The most popular icon pair was Pair 1. Further investigation revealed that Pair 1 was chosen a significantly higher number of times than Pair 2 (McNemar Test: Chi-square = 6.1, n = 93, p < 0.05) and Pair 3 (McNemar Test: Chi-square = 9.9, n = 93, p < 0.01). The relationship between Pair 1 and Pair 4 was not significant. However, in the author's opinion, the difference (see Table 1) is sufficient to justify choosing Pair 1 over Pair 4.

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'.


The author wishes to express her sincerest gratitude to the 93 anonymous volunteers who took part in this short study.



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