What determines visual search ability?
Background
Imagine you are playing a first-person shooting game (e.g., though it's overly simplified, imagine the game requires you to shoot the red T indicated in the white circle among skewed Ls), how fast and accurately are you able to find your shooting target? What are the underlying mechanisms that enable you to visually search for it? Can we evaluate your search ability through some other tests?
Research Question
What are the visual abilities involved in your behaviors of looking for something (i.e. visual search), and to what extent is each visual ability contributing to how fast and accurate you find the target?
Our Strategy
Step 1: Disentangle the search process and identify visual abilities that might be involved:
Possibility 1: Visual Working Memory Capacity
Your ability to hold a target image in mind so that you can use it for search.
Possibility 2: Object Recognition Ability
Your ability to identify whether an item is identical to the target you hold in mind.
Step 2: Measure visual search performance, visual working memory capacity, and object recognition ability. Test whether the last two predict visual search performance.
Operationalization
How is each visual ability measured?
Visual Working Memory Capacity: How many visual items can you hold simultaneously in mind?
Object Recognition Ability: Can you identify a complex visual object from others that are very similar?
Visual Search Ability: When you are looking for something, how fast and accurately can you find it?
Study Preparation
Visual search and visual working memory test programmed in MATLAB.
Novel Object Memory Test (NOMT) programmed in JavaScript and provided by the authors who developed the test.
Sample
187 participants took part in the study
Experimentation
Task 1: Visual Search
Search for target (the red T in the white circle) among distractors of medium (medium search) or high (difficult search) similarity to the target.
Key measurements: search accuracy and efficiency.
Task 2: Visual Working Memory Test
Remember all the colors shown in a "memory set" and respond whether the color shown later belongs to the previous "memory set".
Key measurement: the maximum number of colors in the "memory set" that elicits accurate response.
Task 3: Novel Object Memory Test
Learn novel visual objects and identify the correct object from similar ones.
Key measurement: accuracy in test questions.
Analysis: Structural Equation Modeling
Principal Component Analysis
Identified 2 latent factors that capture over 50% of the variabilities among individual performance of the 3 tasks.
Exploratory Factor Analysis
Determined to what extent is each measure contributing to the latent factors.
Named the 2 factors as Cautiousness and Cognitive Ability.
Confirmatory Factor Analysis
Developed the overall model.
Results
People differ in their cognitive ability which explains why some people search faster than others.
Cognitive ability also predicts how well people identify complex objects, and how many objects people can simultaneously hold in mind to perform cognitive tasks (e.g., for identifying whether a new object is already seen).
People's cognitive ability then predicts how cautious they are in visual search, reflected in how fast they proceed with difficult search situations and how accurately they search.
Confirmatory Factor Analysis results shown below.
Implications
In activities involving visual search (e.g., locating a shooting target in video games), a person's visual working memory capacity and ability to recognize complex objects can predict how fast and accurate they search.
Therefore, to evaluate a person's visual search ability (e.g., identify competent video game players), we can also use a visual working memory test and the object recognition test (NOMT) as measurements.