Life in the fast lane
Meredith Berry et al.
PLoS ONE, November 2015
Abstract:
Impulsivity in delay discounting is associated with maladaptive behaviors such as overeating and drug and alcohol abuse. Researchers have recently noted that delay discounting, even when measured by a brief laboratory task, may be the best predictor of human health related behaviors (e.g., exercise) currently available. Identifying techniques to decrease impulsivity in delay discounting, therefore, could help improve decision-making on a global scale. Visual exposure to natural environments is one recent approach shown to decrease impulsive decision-making in a delay discounting task, although the mechanism driving this result is currently unknown. The present experiment was thus designed to evaluate not only whether visual exposure to natural (mountains, lakes) relative to built (buildings, cities) environments resulted in less impulsivity, but also whether this exposure influenced time perception. Participants were randomly assigned to either a natural environment condition
or a built environment condition. Participants viewed photographs of either natural scenes or built scenes before and during a delay discounting task in which they made choices about receiving immediate or delayed hypothetical monetary outcomes. Participants also completed an interval bisection task in which natural or built stimuli were judged as relatively longer or shorter presentation durations. Following the delay discounting and interval bisection tasks, additional measures of time perception were administered, including how many minutes participants thought had passed during the session and a scale measurement of whether time "flew" or "dragged" during the session. Participants exposed to natural as opposed to built scenes were less impulsive and also reported longer subjective session times, although no differences across groups were revealed with the interval bisection task. These results are the first to suggest that decreased impulsivity from exposure to natural a s opposed to built environments may be related to lengthened time perception.
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Subjective perception of lower social-class enhances response inhibition
Jinkyung Na & Micaela Chan
Personality and Individual Differences, February 2016, Pages 242-246
Abstract:
An emerging literature suggests that lower-class individuals value ‘adjusting’ and ‘fitting-in’ whereas higher-class individuals emphasize ‘personal control’ and ‘influencing.’ Thus, we hypothesized that individuals with low subjective social class (i.e., those who think that their rank in the social hierarchy is low) would show enhanced performances in a response-inhibition task, compared to individuals with high subjective social class (i.e., those who think that their social rank is high). Supporting this prediction, Study 1 found that one's perception of their social class was negatively associated with inhibition (i.e., lower class → better inhibition). However, subjective social class was not associated with working memory capacity. This suggests that the predicted effect of lower class is inhibition specific. Furthermore, Study 2 established the critical role of subjective social class in this process by ma nipulating participants' subjective social class. Study 2 also showed that individual differences in inhibitory tendency mediated the corresponding differences in response inhibition. Taken together, the present results demonstrate that perceived lower-class is associated with enhanced performance in response inhibition.
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Thinking about Death Reduces Delay Discounting
Nicholas Kelley & Brandon Schmeichel
PLoS ONE, December 2015
Abstract:
The current study tested competing predictions regarding the effect of mortality salience on delay discounting. One prediction, based on evolutionary considerations, was that reminders of death increase the value of the present. Another prediction, based in part on construal level theory, was that reminders of death increase the value of the future. One-hundred eighteen participants thought about personal mortality or a control topic and then completed an inter-temporal choice task pitting the chance to gain $50 now against increasingly attractive rewards three months later. Consistent with the hypothesis inspired by construal theory, participants in the mortality salience condition traded $50 now for $66.67 in three months, whereas participants in the dental pain salience condition required $72.84 in three months in lieu of $50 now. Thus, participants in the mortality salience condition discounted future monetary gains less than other participants, suggesting that thoughts o f death may increase the subjective value of the future.
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Waiting with purpose: A reliable but small association between purpose in life and impulsivity
Anthony Burrow & Nathan Spreng
Personality and Individual Differences, February 2016, Pages 187-189
Abstract:
Purpose in life contributes to health and wellbeing. We examine the link between purpose and behavioral impulsivity that may account for these benefits. In a community sample of 503 adults, we found a small yet reliable positive association between purpose and valuing future rewards on a delayed discounting task, a behavioral index of impulsivity. This bootstrapped correlation remained after accounting for Big-5 personality traits, positive affect, and demographic characteristics, suggesting a unique and robust link between purpose and impulsivity (r = .1). We interpret this connection as evidence that purpose enables a broader life view, which serves to inhibit impulsive distractions.
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Pharmacological manipulation of impulsivity: A randomized controlled trial
Myutan Kulendran et al.
Personality and Individual Differences, February 2016, Pages 321-325
Abstract:
Impulsivity is a trait that is closely linked to addiction, which has been studied in personality, psychiatry and more recently in the neurocognitive arena. Recently, even obesity has been compared to food addiction with the connotation that obese individuals are impulsive in their behavior. This research is a conceptual review of the construct of impulsivity identified inhibitory control and temporal discounting as two key behavioral constructs universal to all key fields of impulsivity research. This research aimed to identify the modifiability of impulsivity through neuronal dopamine pathways through the use of two pharmaceutical agents, modafinil and atomoxetine. A randomized controlled trial design was executed to test the aforementioned neurocognitive enhancement agents (n = 20 participants receiving atomoxetine and n = 20 participants receiving modafinil) against a placebo (n = 40) in normal weight adults. The results showed that modafinil but not atomoxetine was effec tive in reducing deficits in inhibitory control. These findings highlight the multiconstruct nature of impulsivity and the need for psychometric tests, which capture these constructs better.
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Inhibiting Uncertainty: Priming Inhibition Promotes Reduction of Uncertainty
Eyal Kalanthroff et al.
Neuropsychologia, forthcoming
Abstract:
Uncertainty affects performance in many cognitive tasks, including the visual-search task, and individual differences in the experience of uncertainty may contribute to several psychological disorders. Despite the importance of uncertainty, to date, no study has explained the basic mechanisms underlying individual differences in the experience of uncertainty. However, it has been suggested that inhibition, a cognitive mechanism aimed at suppressing unwanted thoughts or actions, may affect the development of uncertainty. In the current study, we investigated the relationship between inhibition and behavioral responses to uncertainty in the visual-search task. To accomplish this goal, forty six university students completed a novel combined visual-search and stop-signal task, in which we manipulated the degree to which the inhibitory control system was activated by varying the proportions of stop signals in separate blocks. We utilized target-absent trials in the visual-search task as a behavioral probe of responses to uncertainty. We found that activating higher levels of inhibitory control resulted in faster responses to target-absent visual-search trials, while not affecting target-present trials. These findings suggest that activation of inhibitory control may causally affect behavioral responses to uncertainty. Thus, individual differences in inhibitory control may influence the ability to rely on internal-ambiguous cues which are common in visual-search and other cognitive tasks. Clinical implications for obsessive-compulsive disorder (OCD) and other disorders involving deficient inhibitory control and difficulty with uncertainty are discussed.