CalculateBias: Calculate image bias within a window of time

In tjmahr/lookr: Tools to Analyze Looking While Listening or Visual World Eyetracking Experiments

Description

Bias answers the question, "Which image was this subject viewing during a certain window of time?" For this calculation, we count the number of frames spent on each AOI and multiply the frame-counts by the duration of the window. Over a 100ms (6 frame) window, 3 frames on one AOI would receive a weight of 300. Ties are broken by choosing the image with the earliest fixation. In that same 6 frame window, if 3 frames are spent each on 2 AOIs, the weights would be tied, so the AOI that was fixated on first would be chosen.

Usage

CalculateBias(x, window)

Arguments

x	a Trial with a GazeByImageAOI column or a TrialList where each Trial has a GazeByImageAOI column
window	a twq-element vector specifying the window of time within which to calculate the image bias.

Value

the Trial object(s) updated to include two new attributes: Bias, the name of the AOI with the highest bias or NA if there are no looks to the AOIs during the time window; and BiasSummary, a data-frame detailing the bias calculation.

tjmahr/lookr documentation built on May 31, 2019, 3:41 p.m.