# Presentation: 433630

## Effect of Symbology Location and Format on Attentional Deployment on a Cockpit Display of Traffic Information

- Walter W. Johnson, NASA Ames Research Center
- Min-Ju Liao, National Research Council
- Stephen Tse, San Jose State University

## Introduction

- Free Flight seeks to give real-time flight path control to the flight deck.  This requires the flight crew to have ongoing traffic situation awareness, including
- Traffic location
- Potential collisions**  **
- This requires advanced Cockpit Displays of Traffic Information (CDTIs) that support
- Intermittent monitoring
- At-a-glance extraction of critical information
** **

## Introduction (cont.)

- CDTI design will therefore need to
- Accommodate inherent biases in how attention is deployed across a CDTI
- Direct attention to important elements or areas of a CDTI

## Background

- Egeth & Yantis (1997) posited 3 issues in the selection/control in visual attention:
- top down or bottom up nature of attentional control
- spatially or object oriented basis of attentional control
- the time course of attention
- Previous research relevant to these issues, and to CDTI design
- Kee, Jung, and Chung (1992) examined search time in a 54 wide x 43 high region.  They found _isoresponse_ time contours that were related primarily to range from a visual fixation point at display center.

## Background (cont)

-   Previous Research (cont)
- Wolfe, O’Neil, and Bennett (1998) examined search times in a 16 x 16region with a center fixation, and found faster responses to upper visual field targets.
- Delzell, Johnson, and Liao (1998) used a task requiring recall of CDTI contents, and found _isoprobability_ recall contours that were related primarily to range from an Ownship symbol at the bottom of the display.
- Fisher and Tan (1989), Philipsen (1993), and others, have investigated brightness highlighting using structured alphanumeric stimulus arrays, and found that relative brightness effects are probably top down.

## Research Goals

- The first goal of the present research was to use visual search tasks to determine the spatio-temporal distribution of attention on a baseline CDTI.  This task differs from the previously cited work of Kee et. al. in the following ways:
- CDTI symbology (Ownship, range rings, and compass arc)
- Absence of any instructed fixation point
- A smaller display (search region (13.1 high x 16.6 wide)
- Two types of search tasks defined the target in terms of:
- An associated numeric altitude tag
- A colliding course with Ownship
- .

## Research Goals (cont)

- A second goal of the present research was to test for bottom-up effects of brightness highlighting on attentional deployment.  This extends previous highlighting research to the case of randomly scattered stimuli.

## Method

- CDTI Display:
- Ownship flying at FL350,
- Traffic aircraft, plus associated altitude tags, flying between FL310 and FL390
- Tasks
- _Collision Detection Task_: Participant must find the one aircraft, out of nine shown, on a colliding trajectory.
- _Altitude Detection Task_: Participant must find the one aircraft, out of nine shown, with an altitude tag indicating an odd numbered flight level (all other aircraft at even numbered flight levels).
- _Collision Evaluation Task_: Participant must evaluate whether a single aircraft on the CDTI is on a colliding trajectory.

## Method (cont)

- Manipulations
- Target Location: Target appearing in one of nine equally sized regions on the CDTI.
- Symbol Brightness: In both detection tasks, three symbol brightness conditions were used.
- 1) all aircraft were bright
- 2) all aircraft were dim
- 3) heterogeneous condition: half aircraft bright, and half aircraft dim.
- Measures: Response accuracy and response time.
- Participants: Eight University Students.

## Sample Trial – Heterogeneous Presentation

**Sample Trial – Heterogeneous Presentation**

## Data Analysis

- Two within subject ANOVAs analyzed data...
- 1) in which the highlighting was homogeneous (i.e., all bright or all dim)
- 2) in which the highlighting was heterogeneous (i.e., half bright, half dim)
- Independent Variables Tested:
- 1) Task (collision vs. altitude detection)
- 2) Target Location
- 3) Target Brightness

## Results

- No direct relationship between errors and RT:
- Average error rates for Collision Evaluation, Collision Detection, and Altitude Detection were 3.4%, 2.94%, and 1.96%, respectively.
- In the nine target collision search task
- RT was never  influenced by target brightness (p > .05).
- There was a lateral x vertical display location interaction (p < .01) with best performance near Ownship and display center

## Results (cont)

- RT was never influenced by target brightness (p > .05).
- There was a lateral x vertical display location interaction (p < .01) with best performance toward the left and center of the display
- In the one target collision evaluation task
- RT was related to lateral display position (p < .01)

## Detection Time Results

- Collision Detection Time

- Altitude Detection Time

- Lateral x Vertical Display Location Interaction (p < .01) for both Collision and Altitude Detection Time

## Collision Evaluation Time

- Significant Effect of Lateral Display Location  (p < .01)

- Faster Evaluation Times for aircraft nearer vertical midline of display
- Small overall effect

**Evaluation Time**
**(seconds)**

- Display Surface Contour Plot

## Highlighting Results

- No Significant Effects of Highlighting on Detection Time (p > 0.05)
- Equal detection times when presented homogeneously
- Equal detection times when presented heterogeneously

## Discussion

- Participants had attentional biases to different locations, and these biases were different depending on the task.
- The bias revealed in the Collision Detection Task is somewhat similar to that found by Delzell, Johnson, & Liao (1998), but shows a greater focus on the center of the display.
- The left-right bias in the Altitude Detection Task suggests that a natural left to right reading tendency may be influencing performance.
- Brightness highlighting had little effect which suggests a top-down (goal-directed) process.

## Future Research

- To determine the bottom-up effects of highlighting:
- Testing different types of highlighting modes.
- Evaluating how the number or proportion of highlighted items affects attention.