Abstract
Past studies have established links between sleep and emotions, but there are limited measurement tools for sleep/sleep specific measures of emotion. The aim of this study was to develop a specific Preliminary Scale Development for sleep/emotion measure. It was hypothesized that there would be a distinct cluster of emotions different from the clusters of emotions that constitute the PA and NA subscales of PANAS-C.
The participants were undergraduate psychology students at Monash University, 245 students (M=22.6 years, SD=5.15 years, 82% females, 18% males) recruited with convenience sampling. Subscale items were based on procedures used in PANAS and PANAS-C. The developed Preliminary Scale Development for sleep/emotion measure provided two clusters of Positive Reaction (PR) and Negative Reaction (NR) not found in PANAS-C. They showed high internal consistency reliability with the Cronbach’s Alpha of.88 for factor 1 and.82 for factor 2. Therefore, it was concluded that the Preliminary Scale Development measure was suitable for sleep/emotion measure.
Introduction
A human being is, however, imperfect and, thus, behaviors portrayed may not reflect expected moral standards. Multiple possible studies have been presented to account for the discrepancy between actual behaviors and behavioral decisions considered as intentional from both moral and non-moral perspectives (Tangney, Stuewig, & Mashek, 2007). Facial expressions readily communicate the affective state and intent of a person. Such affective stimuli need mutual signaling between peripheral-autonomic body systems and central viscerosensory brain regions, resulting in accurate emotional reactions (Goldstein-Piekarski, Greer, Saletin, & Walker, 2015).
Sleep deprivation has been linked to impaired moods (Talbot, McGlinchey, Kaplan, Dahl, & Harvey, 2010). In fact, current literature suggests that sleep deprivation is linked to progressive mood worsening and engagement in negative, unethical behaviors at work the next day (Christian & Ellis, 2011). Studies have also reported enhanced amygdala activity as a reaction to an emotional stimulus linked to sleep-deprived individuals (Goldstein-Piekarski et al., 2015). The enhanced amygdala reactivity is related to low diminished activity in the medial-prefrontal cortex – this section is known for top-down control and function to control emotional reactions based on a given context (Talbot, McGlinchey, Kaplan, Dahl, & Harvey, 2010).
Recent studies have focused on two dominant and comparatively structures of effect, which include positive affect and negative affect. As such, there are multiple mood scales to assess these factors. It is however observed that most available scales do not account for all factors and depict low reliability or poor validity (Watson, Clark, & Tellegen, 1988).
The first major theoretical aspect focuses on various emotions, such as anxiety, anger, fear, pride, and guilt while the second approach looks at emotions in terms of higher-order dimensions by focusing on overlapping attributes. From these observations, Watson et al. (1988) developed a scale referred to as the Positive and Negative Affect Schedule (PANAS). This self-reported descriptive tool has two 10-items subscales developed to assess both negative and positive affect. Positive affect items measure alert, active, attentive, excited, inspired, determined, interested, proud, and strong whereas negative affect assesses afraid, distressed, ashamed, hostile, guilty, hostile, irritated, jittery, nervous, scared, and upset (Gaudreau, Sanchez, & Blondin, 2006, p. 240).
High scores on PA are associated with an ideal state of concentration, energy, and pleasurable involvement. Conversely, low scores show fatigue and sadness. NA depicts a common element of subjective anguish, including multiple states, such as anxiety and anger. High scores reflect distress and nasty involvement while low scores are associated with serenity and calmness (Gaudreau et al., 2006).
Given the limitations observed in PANAS, including unusual and inconsistent results (Watson, Clark, & Tellegen, 1988), other researchers started to question the factorial structure empirically (Gaudreau et al., 2006). Earlier critics had argued that PANAS was not suitable for children, and this led to the development of specific PANAS-C for children (Laurent et al., 1999).
PANAS was generally applied to evaluate affective states in the present time, today, and past. It could assess mood after months, and traits based on the provided time. Laurent et al. (1999) observed favorable convergent and discriminant validity from Positive Affect (PA) and Negative Affect (NA) scales with data obtained from self-reports of children with depression and anxiety. It was concluded that the PANAS-C works well just like PANAS. PANAS-C was therefore effective for differentiating anxiety from depression in children. Hence, it was effective for addressing the notable limitations of existing tools for assessing childhood depression and anxiety (Hughes & Kendall, 2009).
It has been however noted that there is no known sleep/sleep deprivation a specific measure of emotion (Daniela et al., 2010). This study, therefore, focused on developing a Preliminary Scale Development for this measure. The aims of the study included
- determining the types of emotions that are typically experienced when one fails to get the required sleep;
- whether these emotions cluster together in any meaningful way;
- conceptualizing what a sleep specific measure of emotions might look like;
- evaluating whether the discrete emotions measured by an existing measure of emotion/affect (e.g. PANAS-C) correspond with the findings associated with (1) and (2).
Hypothesis
It was hypothesized that there would be a distinct cluster of emotions and they differ from the clusters of emotions that constitute the PA and NA subscales of PANAS-C.
Method
Participants
The participants in this study were undergraduate psychology students at Monash University, 245 students (M=22.6 years, SD =5.15 years, 82% females, 18% males) in Clayton campus. They were recruited with convenience sampling.
Materials
An online questionnaire was used in this research. There were two parts to the online questionnaire. Each part consisted of 100 items. The 100 items in the questionnaire were from PANAS by Watson, Clark & Tellegen (1988), PANAS-C by Lambert, Osborne, and Gathright (1999) and PANAS-X (Watson & Clark, 1994). The test was divided into two parts. The first part of the questionnaire was rating 100 emotions on the degree to which they were associated with ‘not getting the sleep you need’. It was based on the 5 points Likert scale to rate the questions from 1 to 5. The scale included “very slightly/not at all”, “little”, “moderately”, “quite a bit”, and “extremely”. The second part of the test rated the same 100 emotions on how useful they were in understanding emotions associated with ‘not getting the sleep you need’. It used the 3-point classification scale to rate the question, from 1 to 3, which included “essential”, “useful” and “unnecessary”.
An outline developed by Cohen, Swerdlik, and Sturman was used to guide the scale development (Cohen, Swerdlik, & Sturman, 2013).
Procedure
Participants first logged in Monash University‘s Moodle and clicked the questionnaire link. The submission was anonymous, but participants needed to fill in the demographics. There was no timing during the participant’s rating of the questionnaire. For the first part, participants used the scale that was provided in the questionnaire to rate their beliefs about the emotion they experienced during ‘not getting enough sleep’. For the second part, participants rated how useful the emotions were when ‘not getting enough sleep’.
Results
The data were analyzed using the SPSS program to test the content validity in which 50% or more of the participants rated those 100 emotions items. “Unnecessary” items were removed. A principal axis factor analysis was conducted on the remaining 66 items with orthogonal rotation (varimax). The Kaiser- Meyer-Olkin measure was used to verify sampling adequacy for analysis, KMO=.93, indicating that the sample size was adequate for factor analysis. Bartlett’s test of sphericity, 2 (2080) = 11968.2, p <.001 indicated that the correlation between items was sufficiently large for principal-axis factoring.
An initial analysis was run to obtain eigenvalues for each component in the data. Four factors with eigenvalues over 2 combinations explained 48.17% of the variance. However, the screen ploy showed inflection that would justify retaining only factors 1 and 2 (Figure 1). Table 1 shows the factor loadings after rotation. The items loaded on factor 1 represent (positive reaction) and the items loaded on factor 2 represent (negative reaction).
Table 1 Rotated Factor Matrix from factor 1 to 4.
Cronbach’s Alpha represents the overall reliability of the test in each factor. In factor 1, the Cronbach’s Alpha was.97 and.96 in factor 2, which means both factors had high internal consistency reliability. Any item-total correlation was less than.3 should be removed from the test. Factor 1 was named as Positive Reaction (PR), which captured positive mood states like energetic, cheerful, and content. Factor 2 was named as Negative Reaction (NR), and it reflected negative mood states like Upset, Hostile and Alone. Both factors show changes in sleep deprivation.
Preliminary Scale Development
After the items were removed from factor 1: Positive Reaction (PR) and factor 2: Negative Reaction (NR), a qualitative method was used for further reduction in the test items by using the Cambridge dictionary in both factors. All items that had synonym meaning were grouped together to make sure the Cronbach’s Alpha was still high enough. The items were removed according to Cronbach’s Alpha. Some words remained due to their uniqueness and relation with emotion and sleep. After using the qualitative method, the final subscales of PR and NR were showed in table 2.
Table 2 subscales of PR and NR.
After items were removed, 11 items remained in the PR and NR subscales. The new internal consistency reliability of the Cronbach’s Alpha in each subscale was.88 in positive reaction and.82 in a negative reaction.
Discussion
The study aims included determining emotions generally associated with the failure to get adequate sleep, determine whether emotions cluster together, conceptualize asleep specific measure of emotions, and to evaluate whether the discrete emotions measured by existing PANAS-C correspond with the findings noted in the first two objectives in a sample of undergraduate psychology student at Monash University.
It was hypothesized that there would be a distinct cluster of emotions, and they differed from the clusters of emotions that constituted the PA and NA subscales of PANAS-C. The study hypothesis was accepted because new different clusters of emotions were developed for Positive Reaction (PR) and Negative Reaction (NR). PR cluster of emotions included energetic; sympathy; determined, calm; confident; strong; alert; aroused; concentrating; enthusiastic; and inspired. Conversely, the NR cluster of emotions included nervousness; pain; sadness; wrath; dissatisfied; drowsy; sluggish; jittery; shaky; resignation; and resentment.
The finding, therefore, supported the study hypothesis. It is imperative to note that PR only had three items (energetic, calm, and strong) and NR had a similar number of items (nervous, sadness, and jittery) as those found on the 27-item PANAS-C Scales (Laurent et al., 1999). The correlations between items were sufficiently large for principal-axis factoring while the Cronbach’s Alpha represented the overall reliability of the test in each factor. The final Cronbach’s Alpha of.82 for factor 1 and.88 for factor 2 was determined, which implied that both factors had high internal consistency reliability. Any item-total correlation with less than.3 was removed from the test to develop the Preliminary Scale Development.
Two dominant and comparatively related items were developed for the Preliminary Scale Development to measure sleep/sleep deprivation specific measures of emotion. Watson et al. (1988) had earlier used a similar approach to develop a tool using a cluster of emotions to assess PA and NA among adults and adolescents. The later scale developed, PANAS-C focused on children to assist in differentiating depression from anxiety (Laurent et al., 1999). These scales did not, however, measure sleep/sleep deprivation affect.
Talbot et al. (2010) had earlier observed that some items on the scale used to measure mood overlap with those found in sleep assessment, such as fatigue. The Preliminary Scale Development for PR and NR only had a few overlapping items to suggest that the PANAS-C was not suitable as sleep/sleep deprivation a specific measure of emotion. The finding is consistent with Talbot et al. (2010) result, which showed that PANAS could not measure the type of negative affect reflected in sleep-deprived individuals.
The study reinforced the finding that sleep and motions are linked (Kahn, Sheppes, & Sadeh, 2013), and it provided the Preliminary Scale Development for assessment. The Preliminary Scale Development now joins other tools, such as PANAS and the Profile of Mood State (POMS) to help in assessing a various range of mood states for individuals with sleep deprivation conditions (Klumpers et al., 2015), but the Preliminary Scale Development will be used for sleep specific measures.
One major limitation of the Preliminary Scale Development is that it was only based on samples obtained from university students. As such, it may not be effective as sleep/sleep deprivation a specific measure of emotion in children and senior adults.
In conclusion, the results obtained show consistency with other tools used to assess a wide range of mood states, such as PANAS, PANAS-C, and POMS, but the Preliminary Scale Development is specifically developed as a sleep deprivation specific measure of emotion. The Preliminary Scale Development acts as an alternative tool for assessing sleep/emotion association by presenting clusters of PR and NR subscales not previously found in other measurement instruments for the two broad dimensions of mood consisting of Positive Affect and Negative Affect.
Of course, future studies are necessary for the Preliminary Scale Development to provide empirical data and demonstrate the reliability, validity, and utility of this assessment tool based on its Positive Reaction and Negative Reaction. Such studies should also consider other measures of affect beyond PANAS and PANAS-C used in different contexts. Nevertheless, the Preliminary Scale Development is a tool that will be used in research and practical assessment of sleep-deprived individuals to determine their wide range of emotions.
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