Supplementary Information
Koivisto, M.*, Virkkala, M., Puustinen, M., & Aarnio, J.: Open and empathic personalities see two things at the same time: the relationship of big-five personality traits and cognitive empathy with mixed percepts during binocular rivalry. Current Psychology.
* Corresponding author: Department of Psychology, University of Turku, e-mail:
mika.koivisto@utu.fi
Mixed percepts occur most likely in the beginning of the stimulation (Stanley et al. 2011) or during the changes of dominance (Blake 2001). It is possible that the individual differences in the reported number of mixed percepts reflect differences in response criterion such that some of the observers have a lower response criterion to press the “mixed button” in response to even brief mixed
experiences in the beginning of the trials or during switches of dominance, whereas others, although may experience brief mixed percept similarly, might not report them. To study this issue, we first computed correlations between the number of mixed percepts and their duration. The number of initial mixed percepts in the beginning of the trials showed a positive correlation with the duration of initial mixed percepts (rs = .329, p = .001): the participants who reported frequently initial mixed percepts also reported their duration as longer than average. The number of late mixed percepts correlated negatively with their duration (rs = -.279, p = .008): the more frequently late mixed percepts were reported, the shorter they were. Thus, the number of mixed percepts was associated with their duration, but in reversed manner for the initial and later percepts.
Next, we ran control regression analyses in which the log-transformed mixed perception durations were included as control variables to account for the influence of possible response biases. These regression analyses included always Cognitive Empathy as a predictor and either Openness or
Agreeableness as the other predictor, and Duration of the initial or later mixed percept as a control variable, respectively, depending on whether initial or late percepts were analysed. For all models including durations as a predictor: F > 8, R2 > .22, p < .001. For comparison, in the analyses below, we report in parentheses the β and p-values for the corresponding model which did not include Duration as a variable).
Openness predicted the number of initial mixed percepts, β = .066, SE = .03137, t = 2.109, p = .038 (model without duration: β = .03, p = .284), but not the number of later mixed percepts, β = .053, SE = .060, t = 0.877, p = .383 (model without Duration: β =.06, p = .353). Cognitive Empathy did not predict the initial mixed percepts, β = .026, SE = .031, t = 0.833, p = .407 (model without Duration: β = .036, p = .304), but it did predict the later mixed percepts , β = .223, SE = .060, t = 3.710, p < 0.001 (model without Duration: β =.193, p = .005). Agreeableness did not predict later mixed effects, β = -.012, SE = 0.056, t = -0.215, p = 0.830 (model without Duration: β = -.051, p = . 393), but Cognitive Empathy did, β =.25584, SE = .055, t = 4.619, p < .001 (model without
Duration: β = .210, p < .001) .
In sum, the main results of the regression analyses were supported: openness explained the probability of experiencing mixed percepts in the beginning of the 10 sec trials when cognitive empathy and initial mixed perception duration was controlled for, whereas cognitive empathy explained later mixed percepts when Openness and late mixed percept duration was controlled for.
These analyses do not support the account that high number of reported mixed percepts simply reflects a lower response criterion for reporting mixed percepts which occur briefly between the shifts of dominance or in the beginning of trials.
