Blur detection is unaffected by cognitive load

Figures & data

Figure 1. (a) Sample images that have been blurred at 0°, 3°, 6°, and 9° retinal eccentricity from an unblurred base image (centre). The dotted ring represents the edge of the window (absent in the 0° retinal eccentricity where the entire image is blurred), but was not seen by the participants. Note that the strength of the blur increases with increasing window edge retinal eccentricity (as represented by distance from the yellow dot to the dotted ring, neither seen by participants). This was done to equate blur detectability at each retinal eccentricity. (b) Several enlarged samples of the example image are shown to more easily perceive the blur strengths for each retinal eccentricity. To make the blur levels more perceptible for readers, we increased the example blur strength for each eccentricity by setting the low-pass filter cpd cut-off to 76% of the mean threshold cpd cut-off value found in Experiment 1. The blur is most easily perceived by comparing the unblurred and blurred fine detailed areas such as the window blinds (upper left) and the text on the upside-down bucket (lower right).

Figure 2. Experiment 1, N-back sensitivity (d’) as a function of N. Results shown for individual participants (1–3) and their overall mean. Error bars = 95% CI of the mean.

Figure 3. Experiment 1, scene recognition memory accuracy (% correct) as a function of cognitive load (N-back level, or control condition). Results shown for individual participants (1–3) and their overall mean. Error bars = 95% CI of the mean.

Figure 4. Experiment 1, fixation location dispersion (measured by the bivariate contour ellipse in pixels) as a function of cognitive load (N-back level, or control condition). Results shown for individual participants (1–3) and their overall mean. Error bars = 95% CI of the mean.

Figure 5. Experiment 1, blur detection low-pass filtering cut-off thresholds (in cpd) as a function of retinal eccentricity (in degrees visual angle) and cognitive load (in terms of N-back level, or control condition). Results shown for individual participants (1–3) and their overall mean. Error bars = 95% CI of the mean.

Figure 6. Experiment 1, blur detection low-pass filtering cut-off thresholds (in cpd) as a function of cognitive load (in terms of N-back level, or control condition) and retinal eccentricity (in degrees visual angle). Results shown for individual participants (1–3) and their overall mean. Error bars = 95% CI of the mean.

Figure 7. Trial schematic of Experiment 2, showing one pair of target/catch images for the 9° eccentricity. The participant was required to fixate the centre of the screen to initiate the trial, followed by a central fixation screen in which the participant had to maintain gaze at the centre of the screen in order for the following presentation to be considered valid.

Figure 8. Experiment 2, N-back sensitivity (d’) as a function of N. Results shown for individual participants (1–3) and their overall mean. Error bars = 95% CI of the mean.

Figure 9. Experiment 2, blur detection low-pass filtering cut-off thresholds (in cpd) as a function of retinal eccentricity (in degrees visual angle) and cognitive load (in terms of N-back level, or control condition). Results shown for individual participants (1–3) and their overall mean. Error bars = 95% CI of the mean.

Figure 10. Experiment 2, blur detection low-pass filtering cut-off thresholds (in cpd) as a function of cognitive load (in terms of N-back level, or control condition) and retinal eccentricity (in degrees visual angle). Results shown for individual participants (1–3) and their overall mean (see inset). Error bars = 95% CI of the mean.