Yumiko Fujii, Saho Ayabe-Kanamura and Hiromi Morita, University of Tsukuba, Japan.

INTRODUCTION

Search for the necessary information with mobile information terminals has visual peculiarity caused by:
A. searching for information on a small display

B. seeing by scrolling- Visible clips of the images are overwritten on the display one after another.
- Coordinates of the visual image relative to the ﬁxation point change with scrolling.

- Peripheral visual ﬁeld is completely unavailable.

S PurposeMWhat kind of eﬀects do these factors have on visual search and visual perception?

METHOD

Condition

700px×700px

Participants count the numberof circles among drops.

Image-Scroll

500px×500px
400px

400px

Window-Move
Visualpeculiarity
A Bs"mulus

targetStimulus

280px

280px

Visualpeculiarity
As"mulus

Visualpeculiarity
nons"mulus

Procedure

sizeM500px×500px or 700px×700px
number of itemsM4 9, or 16
number of targetsM0 1 2 3, or 4

distractor

Control

Each participant performed
1 block (30 trials)
per condition.

Standby

Visual search

Respond

RESULTS Participants 25 students with normal or corrected vision.

Error bars show the standard error.

1. Search time

2-2. Number of

2-1. Scanning path of one

y=0.01x – 0.07

y=0.006x + 1.43

participant (700px×700px, 16 items, 3 targets)- 608C

1 9,

C

The main eﬀect of condition is signiﬁcant (p<0.001).

Scanning path

Scanning path

Stationary point

2. Scanning path

Stationary point

Image-Scroll

We investigated the scanning path of 10 participants to trace
how they search.
We discriminated the stationary period from the moving periodon the basis of the x-, y-coordinates of the center of the visible
clip of the search array.
How to discriminate between the stationary period and the moving period?:x-, y-coordinates of
the center of thevisible clip [px]If the diﬀerence between two consecutive samples is larger than 4.68 px,
in other words the movement exceeds 280 px/s in speed, it is considered
to be moving. The remaining periods are considered to be stationary.
W If the total distance of movements of a series of samples in a moving
period does not reach 70 px, the period is reconsidered to be stationary.
X If the summation of the intervals of a series of samples in a stationary
period is less than 200 ms, the period is reconsidered to be moving.

Number of stationary
periods

C***:p<.001, *:p<0.05

*

All

***

at 4 corners ofat locations
the search array other than the 4corners

Window-Move

2-3. Total distance of movements for one moving period*:p<0.05, +:p<0.10

Image-Scroll***:p<0.001

Window-Move- 6500
400



300

*

200
100
004

8

1208C

161 9

y=1.18x N 433.36***

y=0.25x + 2.64

20

Number of items

stimulus size [px]The main eﬀect of condition is signiﬁcant (p<0.001).

2-4. Average speed of amoving period

2-5. Duration of astationary period*:p<0.05, +:p<0.1028

Time [s]0 the stationary period

C9 638C9 6

1 the moving period**Image-Scroll

Window-Move

Time [s]DISCUSSION
The search time is longer for Image-Scroll condition and WindowMove condition than for control condition. The slope of the searchfunction is shallower for Image-Scroll condition than for WindowMove condition.
In the Image-Scroll condition, the viewers move arrays at ahigher speed and stop at a constant distance where they spend
a longer time. As a result the search time is aﬀected by the size ofthe search array but scarcely aﬀected by the number of the items.
In the Window-Move condition, the viewers move the window
more slowly searching for the targets and only stop at the fourcorners.

Duration of a stationary
period [s],Total distance ofmovements for one
moving period [px]1 9

Speed of a moving
period [px/s]

08C

y=0.001x + 1.37

Window-Move***

Total distance ofmovements for one
moving period [px]stimulus size [px]Y-coordinate [px]Image-Scroll

Number of items y=0.14x + 0.76, R2=0.98- 6

stationary periods

X-coordinate [px]X-coordinate [px]Y-coordinate [px]Search time [s]Search time [s]y=0.11x + 3.98, R2=0.98

y=0.05x + 6.08, R2=0.91

Image-Scroll

0.8
0.7

Window-Move



0.6
0.5
0.4
0.3
0.2
0.1
005

1015

Number of items

20

The main eﬀect of condition issigniﬁcant (p<0.001).

CONCLUSION
A. The factor of small display area aﬀects the search time,
because the visual input from periphery is cut oﬀ and we must
scroll or move the window to see it.
B. The factor of moving stimuli and overwriting of the clips in theﬁxed area aﬀect the search function,
because we cannot see the image moving fast and it’s diﬃcult
to integrate clips of the image in to the whole image.