The impact of restricting sleep duration on physical activity: Secondary analysis of a randomized crossover study.

OBJECTIVES: This study investigated the causal impact of sleep durations on participants' physical activity (PA) in real-world conditions. METHOD: We performed a secondary analysis of PA data from 146 young adults using a randomized crossover design: both restricted (5-6 hr/night) and well-rested (8-9 hr/night) sleep weeks were assessed, with a washout week in between. Sleep and activity were tracked via research-grade actigraphy. Data analysis of PA involved repeated-measures analysis of variance (ANOVA) and regression techniques. RESULTS: Analysis plans and hypothesis were preregistered before data analysis. The exogenously assigned sleep restriction (SR) treatment reduced nightly sleep an average of 92.65 min (± 40.44 min) compared to one's well-rested sleep treatment. The impact of SR on PA was substantial, leading to a 7% reduction in average hourly PA: 18,081.2 (well-rested) versus 16,818.2 (restricted sleep). Significant findings were revealed in daily, F(1, 6) = 84.37, p < .001, ηp² = 0.934, and hourly comparisons, F(1, 166) = 30.47, p < .001, ηp² = 0.155. Further, sensitivity analysis using a variety of regression specifications also found that exogenously assigned SR decreased average wake-hour activity counts by approximately 4.4%-4.7% (p < .01 in all cases) when controlling for other factors. Exploratory analysis showed the PA effects of SR manifested via reductions in PA intensity with concurrent increases in the proportion of time considered as sedentary. CONCLUSIONS: SR significantly lowered PA by around 7%, characterized by reduced intensity and elevated sedentary behavior in a naturalistic setting. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Is having your cell phone the key to happiness, or does it really matter? Evidence from a randomized double-blind study.

BACKGROUND: Affect can influence people's perceptions, decisions, and the way they make sense of an experience. Some studies show that having one's cell phone removed will lead to negative emotional reactions, while others have found no significant impact on how we feel. In this paper we investigate the impact of cell phone possession and removal on participant's affective state. METHODS: We use a randomized double-blind procedure to examine whether cell phone removal enhances negativity, promotes positivity, or is emotionally inconsequential. We measure affect using a PANAS self-report scale as well as a less transparent temporal-estimation procedure. RESULTS: Our findings suggest that cell phone possession or removal has no influence on a person's affective state. CONCLUSIONS: Measured through both the PANAS self-report scale and temporal estimation task, affect remained consistent regardless of cell phone possession. These results suggest that cell phones may not carry the emotional weight often attributed to them. This finding challenges a common theme revolving around the negative emotional impact of cell phones and technology. Consequently, these findings may have important implications for the generally perceived notion that cell phones are having a negative effect on people's emotions.

Thinking about complex decisions: How sleep and time-of-day influence complex choices.

In this study, we systematically manipulate a person's state of sleep; Sleep-deprived and Well-rested along with Matching or Mismatching the decision time-of-day to their circadian preferred time-of-day. We assessed how these conditions influenced performance on an incentivized complex decision task. In the overall analysis of these variables no differences emerged. However, a comparison of the more cognitively depleting Sleep-deprivation/Circadian-mismatch condition to the cognitively enhancing Well-rested/Circadian-match condition showed improved performance in the Well-rested/Circadian matched group for one complex decision task but not for the other. These findings build upon the existing literature on sleep and circadian rhythm effects while uniquely observing the combined effects of these variables on complex decision making.

The viability of an ecologically valid chronic sleep restriction and circadian timing protocol: An examination of sample attrition, compliance, and effectiveness at impacting sleepiness and mood.

Chronic sleep restriction (SR) increases sleepiness, negatively impacts mood, and impairs a variety of cognitive performance measures. The vast majority of work establishing these effects are tightly controlled in-lab experimental studies. Examining commonly-experienced levels of SR in naturalistic settings is more difficult and generally involves observational methods, rather than active manipulations of sleep. The same is true for analyzing behavioral and cognitive outcomes at circadian unfavorable times. The current study tested the ability of an at-home protocol to manipulate sleep schedules (i.e., impose SR), as well as create a mismatch between a subject's circadian preference and time of testing. Viability of the protocol was assessed via completion, compliance with the SR, and success at manipulating sleepiness and mood. An online survey was completed by 3630 individuals to assess initial eligibility, 256 agreed via email response to participate in the 3-week study, 221 showed for the initial in-person session, and 184 completed the protocol (175 with complete data). The protocol consisted of 1 week at-home SR (5-6 hours in bed/night), 1 week wash-out, and 1 week well-rested (WR: 8-9 hours in bed/night). Sleep was monitored with actigraphy, diary, and call-ins. Risk management strategies were implemented for subject safety. At the end of each experimental week, subjects reported sleepiness and mood ratings. Protocol completion was 83%, with lower depression scores, higher anxiety scores, and morning session assignment predicting completion. Compliance with the sleep schedule was also very good. Subjects spent approximately 2 hours less time in bed/night and obtained an average of 1.5 hours less nightly sleep during SR, relative to WR, with 82% of subjects obtaining at least 60 minutes less average nightly sleep. Sleepiness and mood were impacted as expected by SR. These findings show the viability of studying experimental chronic sleep restriction outside the laboratory, assuming appropriate safety precautions are taken, thus allowing investigators to significantly increase ecological validity over strictly controlled in-lab studies.

The effect of construal level on unethical behavior.

Construal level theory predicts that people will judge immoral events more harshly when these are presented in a way that elicits a higher construal level, relative to a lower construal level. Previous research supported this prediction using an Israeli sample but not a U.S. SAMPLE: This article compared Israeli and U.S. samples with respect to the interactive effect of utility and construal level on unethical behavioral intentions. We found that construal level did not affect unethical behavioral intentions in either the U.S. samples for low-utility level or the Israeli samples for low- and high-utility levels. In contrast, construal level affected unethical behavioral intentions in the U.S. sample for high-utility level: unethical behavioral intentions were higher in the low-construal level compared to the high-construal level. We discuss these findings and suggest additional factors that challenge arguments concerning the direct effect of construal level on unethical behavior.

The physical sacrifice of thinking: Investigating the relationship between thinking and physical activity in everyday life.

Physical activity level is an important contributor to overall human health and obesity. Research has shown that humans possess a number of traits that influence their physical activity level including social cognition. We examined whether the trait of "need for cognition" was associated with daily physical activity levels. We recruited individuals who were high or low in need for cognition and measured their physical activity level in 30-second epochs over a 1-week period. The overall findings showed that low-need-for-cognition individuals were more physically active, but this difference was most pronounced during the 5-day work week and lessened during the weekend.

Making estimates and sensitivity to anchors: exploring the role of hemispheric processing.

In this paper we set out to explore how the processing differences associated with the respective hemispheres would influence susceptibility to anchoring effects. To do so we provided participants with both a positive and negatively valenced anchoring task. Based on prior research, we predicted stronger anchoring effects under conditions of right hemisphere activation and relatively attenuated anchoring effects under left hemisphere activation. Further, based on the valence hypothesis, we predicted stronger anchoring effects under conditions of hemispheric-valence consistency. Our results support the former hypothesis but do not support the latter.

An investigation of measurement validity for a hemispheric activation scale.

In this paper we report the outcomes of two attempts to correlate the Zenhausern Preference Questionnaire (PT) with the Polarity Questionnaire (PQ). Across two laboratories we consistently found no correlation between these two scales. Our findings are consistent with a previous attempt to validate the PQ (Genovese, 2005). We conclude that researchers attempting to use the PQ should take note of this validity question.

Affective imposition influences risky choice: handedness points to the hemispheres.

The study of risk preference has become a widely investigated area of research. The current study is designed to investigate the relationship between handedness, hemispheric predominance and valence imposition in a risky-choice decision task. Research into the valence hypothesis (e.g., Ahern & Schwartz, 1985; Davidson, 1984) has shown that the left hemisphere is more active in processing positively valenced stimuli, whereas the right hemisphere is more active in processing negatively valenced stimuli. A total of 520 individuals (343 female, 117 male) participated in a self-imposed framing task and took a degree of handedness questionnaire. The results of the framing task and handedness questionnaire showed that participants' degree of handedness significantly influenced the positive/negative valence they imposed onto the framing task as well as their level of risk preference.

On the other hand am I rational? Hemispheric activation and the framing effect.

In recent decades the investigation of framing effects has become the foremost studied phenomenon of rational/irrational decision making. Two experiments were conducted to determine whether the functional specializations of the left and the right hemispheres would produce different responses to a traditional framing task. In Experiment 1, a behavioral task of finger tapping was used to induce asymmetrical activation of the respective hemispheres. In Experiment 2, a monaural listening procedure was used. In both experiments, the predicted results were found. Framing effects were found when the right hemisphere was selectively activated whereas they were not observed when the left hemisphere was selectively activated. The results are interpreted in light of a dual-processing approach of decision-making.

Attributional biases in the service of stereotype maintenance: a schema-maintenance through compensation analysis.

Six experiments were conducted to test assumptions of a schema-maintenance through compensation analysis. The results of these experiments indicated that perceivers can compensate for the inconsistent action of one individual (the target) by altering their attribution concerning the action of a fellow group member. When the target performed an inconsistent behavior, perceivers compensated by making especially extreme stereotypically consistent attributions concerning a fellow group member's subsequent action. In addition, in Experiment 5, perceivers compensated via a fellow group member for a target's inconsistent action while maintaining their general view of group members. Experiments also provided tests of the capability and motivation assumptions of the schema-maintenance through compensation analyses.