Visual Search Task
How do people search for targets in their environments?
Searching our environment for a target (i.e. looking for your keys on a messy table or your name in a list of names, etc.) is critical for human adaptation and has evolutionary advantages. Visual search tasks have been adapted thousands of times to measure the cognitive processes of perception and attention, using target and distractor cues. Multiple brain areas interact to deploy attention in visual search including the right posterior parietal cortex (PPC) and the motion area V5, just to name a few. One of the important ideas related to searching for features with specific items--such as searching for a green round bottle among a large collection of bottles--is that this task cannot be done in parallel; hence, the more items there are to search through, the longer it takes.
Resources - Lewis, A.J. et al. (2019). I spy with my little eye: What visual research can tell us about how we see the world. Frontiers for Young Minds. Jan 7. https://doi.org/10.3389/frym.2019.00004
- Treisman, A. (1986). Features and objects in visual processing. Scientific American, 255(5), 114B–125. https://doi.org/10.1038/scientificamerican1186-114B
- Treisman, A. and Gelade, G. (1980). A feature integration theory of attention. Cognitive Psychology, 12, 97-136. https://doi.org/10.1016/0010-0285(80)90005-5
- Treisman, A. (1977). Focussed attention in the perception and retrieval of multidimensional stimuli. Perception and Psychophysics, 9, 40-50. http
Parameters
The following features can be tweaked (default values in parentheses):- Task instructions
- Number of repetitions (1)
- Number of practice repetitions (3)
- Inter-trial interval (500 ms)
- Duration of feedback (2000 ms)
- Whether trials should be randomized (yes)
Note: each repetition consists of 8 trials that are balanced across conditions (5 letters/10 letters/15 letters/20 letters)
What data is collected? How is it scored?
The following variables are recorded:
- proportion_correct_fiveLetters
- proportion_correct_tenLetters
- proportion_correct_fifteenLetters
- proportion_correct_twentyLetters
- reaction_time_fiveLetters
- reaction_time_tenLetters
- reaction_time_fifteenLetters
- reaction_time_twentyLetters
The main variables are reaction time (ms) and the percentage of correct responses, calculated for all conditions (5 letters/10 letters/15 letters/20 letters)
Note: each repetition consists of 8 trials that are balanced across conditions (5 letters/10 letters/15 letters/20 letters)
What participants see before taking the task
In this task, you are asked to indicate as quickly as possible whether or not something is shown on the screen.
What participants see after taking the task
Why this task? Research has found that searching for items with specific visual properties cannot be done in parallel: the more items there are to search through, the longer it takes to find what you're looking for (like Wally in a Where's Wally? scene). By varying the complexity of the visual scene, as well as the items, researchers can learn about how our brain organizes the information we see.
Aggregate Variables
These data are automatically written to a csv file upon completion of the task
- Proportion correct and average response time by condition (5 letters/10 letters/15 letters/20 letters)
Duration
5 mins
Resources
- Lewis, A.J. et al. (2019). I spy with my little eye: What visual research can tell us about how we see the world. Frontiers for Young Minds. Jan 7. https://doi.org/10.3389/frym.2019.00004
- Treisman, A. (1986). Features and objects in visual processing. Scientific American, 255(5), 114B–125. https://doi.org/10.1038/scientificamerican1186-114B
- Treisman, A. and Gelade, G. (1980). A feature integration theory of attention. Cognitive Psychology, 12, 97-136. https://doi.org/10.1016/0010-0285(80)90005-5
- Treisman, A. (1977). Focussed attention in the perception and retrieval of multidimensional stimuli. Perception and Psychophysics, 9, 40-50.