Data Café
A discussion of Dijkstra, N., Kok, P., & Fleming, S. M. (2022). Imagery adds stimulus-specific sensory evidence to perceptual detection. Journal of Vision, 22(2), 11. https://doi.org/10.1167/jov.22.2.11
Design and Hypotheses
Figure 1
Methods
Psychometric function
\(\mu\) is the mean of the normal distribution, reflecting the horizontal offset of the psychometric curve/how much signal is needed to achieve 50% presence responses
\(\sigma\) is the standard deviation, reflecting the slope or sensitivity of presence responses to increases in signal
g is the guess rate, reflecting the vertical offset at the zero point, or how likely presence responses are in the complete absence of signal.
Results
Figure 2
- Congruent imagery was associated with a leftward shift of the psychometric function compared to both no imagery and incongruent imagery.
- In contrast, imagery did not have an effect on either the slope or the guess rate of the psychometric function.
- These results suggest that imagery adds sensory evidence to perceptual signals, thereby increasing the visibility of perceived stimuli.
