Visual working memory¶
Implemented through extensions systems in the VisualWorkingMemory module.
The task consists in remembering the colors of a set of squares displayed on a computer screen, termed memory array, and then comparing them with the colors of a second set of squares located in the same positions, termed test array 1. A trial of the task begins with an arrow indicating either the left or the right side of the screen for 0.2 s. Then, a memory array appears on the screen for 0.1 s. For every trial, memory arrays are displayed on both hemifields, but the subject must remember only those appearing on the side indicated by the arrow cue. Next, after a retention interval lasting 0.9 s, a test array appears for a period of 2 s. During this period the subject reports if the colors of all the items in the memory and test arrays match. The task has three levels according to the number of elements in the memory array: low memory load (one square), medium memory load (two squares), and high memory load (four squares). The subject must perform a total of 300 trials, with 100 trials for each memory load level (50 trials per hemifield). Trials from different levels are presented at random. The color of one of the squares in the test array differs from its counterpart in the memory array in 50% of the trials.
Stimuli presentation¶
All stimuli are presented on a computer screen situated 120 cm away from the subject. The stimulus arrays appear within two \(7.2^{\circ}\) × \(13.15^{\circ}\) rectangular regions that are centered \(5.4^{\circ}\) to the left and right of a central fixation cross on a gray background (the symbol \(\circ\) stands for degrees of visual angle 2). Each colored square (\(1.17^{\circ}\) × \(1.17^{\circ}\)) is randomly selected from a set of seven colors (red, blue, violet, green, yellow, black and white). A given color can appear no more than twice within an array. Stimulus positions were randomized on each trial, with the constraint that the distance between squares within a hemifield was at least \(3.5^{\circ}\) (center to center) 3.
Configuration options¶
Squares¶
Intervals¶
Trial¶
Presentation¶
References¶
- 1
Edward K Vogel and Maro G Machizawa. Neural activity predicts individual differences in visual working memory capacity. Nature, 428(6984):748–751, 2004.
- 2
LR Newsome. Visual angle and apparent size of objects in peripheral vision. Perception & Psychophysics, 12(3):300–304, 1972.
- 3
Mario Villena-González, Iván Rubio-Venegas, and Vladimir López. Data from brain activity during visual working memory replicates the correlation between contralateral delay activity and memory capacity. Data in brief, 28:105042, 2020.