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The effect of gaze-contingent stimulus elimination on preference judgments.

Morii M, Sakagami T - Front Psychol (2015)

Bottom Line: There was no significant difference in the preference of the two alternatives.In Experiment 2, we did not predefine any target stimulus.Results showed that controlling participants' choices using gaze-contingent SE was impossible, but the different results between these two experiments suggest that participants decided which stimulus to choose during their first period of gazing at each alternative.

View Article: PubMed Central - PubMed

Affiliation: Global Centre for Advanced Research on Logic and Sensibility, Keio University Tokyo, Japan.

ABSTRACT
This study examined how stimulus elimination (SE) in a preference judgment task affects observers' choices. Previous research suggests that biasing gaze toward one alternative can increase preference for it; this preference reciprocally promotes gaze bias. Shimojo et al. (2003) called this phenomenon the Gaze Cascade Effect. They showed that the likelihood that an observer's gaze was directed toward their chosen alternative increased steadily until the moment of choosing. Therefore, we tested whether observers would prefer an alternative at which they had been gazing last if both alternatives were removed prior to the start of this rising gaze likelihood. To test this, we used a preference judgment task and controlled stimulus presentation based on gaze using an eye-tracking system. A pair of non-sensical figures was presented on the computer screen and both stimuli were eliminated while participants were still making their preference decision. The timing of the elimination differed between two experiments. In Experiment 1, after gazing at both stimuli one or more times, stimuli were removed when the participant's gaze fell on one alternative, pre-selected as the target stimulus. There was no significant difference in the preference of the two alternatives. In Experiment 2, we did not predefine any target stimulus. After the participant gazed at both stimuli one or more times, both stimuli were eliminated when the participant next fixated on either. The likelihood of choosing the stimulus that was gazed at last (at the moment of elimination) was greater than chance. Results showed that controlling participants' choices using gaze-contingent SE was impossible, but the different results between these two experiments suggest that participants decided which stimulus to choose during their first period of gazing at each alternative. Thus, we could predict participants' choices by analyzing eye movement patterns at the moment of SE.

No MeSH data available.


Mean gaze likelihoods in each experiment. Blue and green lines represent the mean likelihood in Experiments 1 and 2, respectively.
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Figure 6: Mean gaze likelihoods in each experiment. Blue and green lines represent the mean likelihood in Experiments 1 and 2, respectively.

Mentions: An unpaired t-test was performed after arcsine-transformation in order to compare the results of both experiments. The concordance rate in Experiment 2 was higher than the target choice rate in Experiment 1 [t(14) = 3.08, p < 0.01, Cohen’s d = 1.54]. Meanwhile the choice consistency rate in Experiment 2 was not significantly different from that in Experiment 1 [t(14) = 0.26, n.s., Cohen’s d = 0.13]. The mean gaze likelihoods in both experiments are shown in Figure 6. The gaze likelihoods fluctuated up and down above chance before SE in both experiments, and the likelihood was higher in Experiment 1 than it was in Experiment 2 at the moment of SE. The gaze likelihood before the response gradually increased about 400 ms before responding in both experiments. The likelihood in Experiment 2 was generally higher than it was in Experiment 1.


The effect of gaze-contingent stimulus elimination on preference judgments.

Morii M, Sakagami T - Front Psychol (2015)

Mean gaze likelihoods in each experiment. Blue and green lines represent the mean likelihood in Experiments 1 and 2, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4563161&req=5

Figure 6: Mean gaze likelihoods in each experiment. Blue and green lines represent the mean likelihood in Experiments 1 and 2, respectively.
Mentions: An unpaired t-test was performed after arcsine-transformation in order to compare the results of both experiments. The concordance rate in Experiment 2 was higher than the target choice rate in Experiment 1 [t(14) = 3.08, p < 0.01, Cohen’s d = 1.54]. Meanwhile the choice consistency rate in Experiment 2 was not significantly different from that in Experiment 1 [t(14) = 0.26, n.s., Cohen’s d = 0.13]. The mean gaze likelihoods in both experiments are shown in Figure 6. The gaze likelihoods fluctuated up and down above chance before SE in both experiments, and the likelihood was higher in Experiment 1 than it was in Experiment 2 at the moment of SE. The gaze likelihood before the response gradually increased about 400 ms before responding in both experiments. The likelihood in Experiment 2 was generally higher than it was in Experiment 1.

Bottom Line: There was no significant difference in the preference of the two alternatives.In Experiment 2, we did not predefine any target stimulus.Results showed that controlling participants' choices using gaze-contingent SE was impossible, but the different results between these two experiments suggest that participants decided which stimulus to choose during their first period of gazing at each alternative.

View Article: PubMed Central - PubMed

Affiliation: Global Centre for Advanced Research on Logic and Sensibility, Keio University Tokyo, Japan.

ABSTRACT
This study examined how stimulus elimination (SE) in a preference judgment task affects observers' choices. Previous research suggests that biasing gaze toward one alternative can increase preference for it; this preference reciprocally promotes gaze bias. Shimojo et al. (2003) called this phenomenon the Gaze Cascade Effect. They showed that the likelihood that an observer's gaze was directed toward their chosen alternative increased steadily until the moment of choosing. Therefore, we tested whether observers would prefer an alternative at which they had been gazing last if both alternatives were removed prior to the start of this rising gaze likelihood. To test this, we used a preference judgment task and controlled stimulus presentation based on gaze using an eye-tracking system. A pair of non-sensical figures was presented on the computer screen and both stimuli were eliminated while participants were still making their preference decision. The timing of the elimination differed between two experiments. In Experiment 1, after gazing at both stimuli one or more times, stimuli were removed when the participant's gaze fell on one alternative, pre-selected as the target stimulus. There was no significant difference in the preference of the two alternatives. In Experiment 2, we did not predefine any target stimulus. After the participant gazed at both stimuli one or more times, both stimuli were eliminated when the participant next fixated on either. The likelihood of choosing the stimulus that was gazed at last (at the moment of elimination) was greater than chance. Results showed that controlling participants' choices using gaze-contingent SE was impossible, but the different results between these two experiments suggest that participants decided which stimulus to choose during their first period of gazing at each alternative. Thus, we could predict participants' choices by analyzing eye movement patterns at the moment of SE.

No MeSH data available.