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- All Subjects: Behavioral psychology
- All Subjects: Sexual risk behavior
- Creators: Robles, Elías
- Creators: Agrawal, Ankit
Description
Understanding human-human interactions during the performance of joint motor tasks is critical for developing rehabilitation robots that could aid therapists in providing effective treatments for motor problems. However, there is a lack of understanding of strategies (cooperative or competitive) adopted by humans when interacting with other individuals. Previous studies have investigated the cues (auditory, visual and haptic) that support these interactions but understanding how these unconscious interactions happen even without those cues is yet to be explained. To address this issue, in this study, a paradigm that tests the parallel efforts of pairs of individuals (dyads) to complete a jointly performed virtual reaching task, without any auditory or visual information exchange was employed. Motion was tracked with a NDI OptoTrak 3D motion tracking system that captured each subject’s movement kinematics, through which we could measure the level of synchronization between two subjects in space and time. For the spatial analyses, the movement amplitudes and direction errors at peak velocities and at endpoints were analyzed. Significant differences in the movement amplitudes were found for subjects in 4 out of 6 dyads which were expected due to the lack of feedback between the subjects. Interestingly, subjects in this study also planned their movements in different directions in order to counteract the visuomotor rotation offered in the test blocks, which suggests the difference in strategies for the subjects in each dyad. Also, the level of de-adaptation in the control blocks in which no visuomotor rotation was offered to the subjects was measured. To further validate the results obtained through spatial analyses, a temporal analyses was done in which the movement times for the two subjects were compared. With the help of these results, numerous interaction scenarios that are possible in the human joint actions in without feedback were analyzed.
ContributorsAgrawal, Ankit (Author) / Buneo, Christopher (Thesis advisor) / Santello, Marco (Committee member) / Tillery, Stephen Helms (Committee member) / Arizona State University (Publisher)
Created2016
Description
The value of safe sex may be discounted based on contextual factors associated with an opportunity for sex. College students (n = 75) in a within-subjects study selected hypothetical sexual partners from a set of pictures and classified them based on attractiveness and estimated chance of having an STI. In the sexual delay discounting (SDD) task, participants rated their likelihood (0 – 100%) of waiting for some period of time (e.g., 3 hours) to have protected sex with their selected partners, when they could have immediate sex without protection. In the sexual probability discounting (SPD) task, participants rated their likelihood of having protected sex if the opportunity was uncertain (e.g., 50%), when they could have unprotected sex for sure (100%). All participants included in the final analyses were aware of and had a positive attitude towards protection against STIs as they indicated preference for immediate (or certain) protected sex. Results show that participants’ willingness to have safe sex systematically decreased as the delay to and odds against having safe sex increased. However, these discounting patterns were observed only in some partner conditions but not others, showing that preference for delayed (or uncertain) safe sex was altered by perceived attractiveness and STI risk of sexual partners. Moreover, the hyperbolic discounting model provided good to acceptable fit to the delay and probability discounting data in most-wanted and least-STI conditions. Gender differences in devaluation of safe sex were also found.
ContributorsWongsomboon, Sineenuch (Author) / Robles, Elías (Thesis advisor) / Roberts, Nicole A. (Committee member) / Burleson, Mary H (Committee member) / Arizona State University (Publisher)
Created2016
Description
The attractiveness of a reward depends in part on the delay to its receipt, with more distant rewards generally being valued less than more proximate ones. The rate at which people discount the value of delayed rewards has been associated with a variety of clinically and socially relevant human behaviors. Thus, the accurate measurement of delay discounting rates is crucial to the study of mechanisms underlying behaviors such as risky sex, addiction, and gambling. In delay discounting tasks, participants make choices between two alternatives: one small amount of money delivered immediately versus a large amount of money delivered after a delay. After many choices, the experimental task will converge on an indifference point: the value of the delayed reward that approximates the value of the immediate one. It has been shown that these indifference points are systematically biased by the direction in which one of the alternatives adjusts. This bias is termed a sequencing effect.
The present research proposed a reference-dependent model of choice drawn from Prospect Theory to account for the presence of sequencing effects in a delay discounting task. Sensitivity to reference frames and sequencing effects were measured in two computer tasks. Bayesian and frequentist analyses indicated that the reference-dependent model of choice cannot account for sequencing effects. Thus, an alternative, perceptual account of sequencing effects that draws on a Bayesian framework of magnitude estimation is proposed and furnished with some preliminary evidence. Implications for future research in the measurement of delay discounting and sensitivity to reference frames are discussed.
The present research proposed a reference-dependent model of choice drawn from Prospect Theory to account for the presence of sequencing effects in a delay discounting task. Sensitivity to reference frames and sequencing effects were measured in two computer tasks. Bayesian and frequentist analyses indicated that the reference-dependent model of choice cannot account for sequencing effects. Thus, an alternative, perceptual account of sequencing effects that draws on a Bayesian framework of magnitude estimation is proposed and furnished with some preliminary evidence. Implications for future research in the measurement of delay discounting and sensitivity to reference frames are discussed.
ContributorsBecker, Ryan J (Author) / Robles, Elías (Thesis advisor) / Sanabria, Federico (Committee member) / Hall, Deborah L. (Committee member) / Arizona State University (Publisher)
Created2018