Our research studied the physiological response of participants during a creative task to investigate if a person’s psychophysiological state was correlated with divergent thinking performance. We used heart rate variability as our physiological measure. We asked 50 participants to perform a cognitive task that assessed their divergent thinking skills and recorded their heart rate and heart rate variability (HRV) before and during the task. Frequency domain analysis was performed on the HRV. The results showed that there was a significant negative correlation between log-transformed low frequency HRV power and the number of “divergent thinking” words generated. Our results suggest that a person’s psychophysiological state is correlated with their divergent thinking performance, and that attention and motivation may be important factors, however this needs further research. Our findings also suggest that being in a relaxed state before the start of a creative task is not a predictor of creative performance.
Our broader research interests relate to the factors and processes affecting creativity including the psychophysiological state of a person [
One of the commonly agreed definitions of creativity is that “creativity is the ability to produce work that is both novel and appropriate” [
Runco and Chand [
Creativity is widely accepted as a cognitive event and cognition has predominantly been seen as being biologically grounded [
Heart rate variability has been shown to be one of the most promising methods for measuring Autonomic Nervous System (ANS) activity [
Heart rate is regulated by the sympathetic and parasympathetic branches of the ANS. Sympathetic activity causes an increase in heart rate while parasympathetic activity causes a decrease in heart rate. Parasympathetic activity is mainly regulated by the vagus nerve and can result in relatively fast changes to the heart rate. Past research on the frequency analysis of heart rate variability has found that HRV frequencies in the high frequency (HF) range (0.15 - 0.4 Hz) relate to the variation in the heart rate due to the breathing cycle, also known as respiratory sinus arrhythmia (RSA), and HRV frequencies in the low frequency (LF) range (0.04 - 0.15 Hz) relate to the regulation of blood pressure [
High frequency (HF) HRV is usually associated with purely parasympathetic activity. However low frequency (LF) HRV is thought to be influenced by both sympathetic and parasympathetic activity [
Several researchers including Friedman [
Past research studies on mental workload and attention have shown that an increase in mental workload and attention causes a reduction in HRV and an increase in heart rate [
Capa et al. [
Our main aim in this research study was to record and analyse the physiological response of participants during a divergent thinking task to:
1) Investigate if a person’s psychophysiological state is correlated with divergent thinking performance.
2) Explore whether getting people into a relaxed state before the start of the creative task might have an effect on divergent thinking performance.
A total of 50 participants took part in the study, 35 males (70%) and 15 females (30%). Ethnic representation in the sample was 90% White, 6% Asian, 2% Black and 2% Eurasian. Criteria for inclusion in the study were that participants were aged between 18 and 22 years of age, and were students at the Cardiff School of Art and Design. Ethics approval for the study was given by the Cardiff School of Art and Design’s Research Ethics Committee. All participants gave their informed consent prior to their inclusion in the study.
We used the same creative task as the one used by Dijksterhuis and Meurs [
Male and female participants were randomly allocated to one of two conditions. 7 females and 18 males were assigned to the first condition and 8 females and 17 males were assigned to the second condition. This was done to reduce the effect of variation in the distribution of males and females between the two conditions. In the first condition (immediate), participants were given the instructions related to the task and given one minute to come up with as many new pasta names as they could think of, which they had to write down on a sheet of paper. On the printed instructions, five examples were given of existing pasta names and all examples ended with the letter “i”. The idea being that the priming of the participants with pasta names that all end in the letter “i” might influence them to come up with “conventional” answers that also end in the letter “i”. Any new pasta names ending in the letter “i” would be categorised as “convergent thinking” names. More “varied” pasta names not ending in the letter “i” would be categorised as “divergent thinking” names.
In the second condition (relaxed), participants were initially asked to relax and focus on breathing slowly. Their heart rate variability was monitored in real-time using the emWave Pro software [
The reason for separating the participants into two conditions was to gain answers related to objective two- whether getting people into a relaxed state before the start of the creative task might have an effect on divergent thinking performance.
For each of the 50 participants, the number of pasta names categorised as divergent thinking (Td) and convergent thinking (Tc) names were recorded.
All the pulse cycle interval data recorded for each of the 50 participants was exported from the emWave Pro software into the HRV analysis software, KUBIOS version 2.2 [
The KUBIOS software converted the pulse cycle interval data into equidistant samples using an interpolation method and then calculated the power spectrum density (PSD) estimates of HRV using Welch’s Fast Fourier Transform (FFT) method. PSD estimates were recorded for both LF ranges and HF ranges. In our study we set the HF range to 0.15 - 0.4 Hz and the LF range to 0.07 - 0.15 Hz rather than the more common LF range of 0.04 - 0.15 Hz. This was because our creative task only lasted one minute, and frequencies below 0.07 Hz would have had a limited number of samples to form reliable spectral information. We didn’t want to have our creative task longer than one minute as we felt that this might reduce the effect of the relaxed condition compared to the immediate condition and put more emphasize on sustained attention and effort during the task.
Both the PSD estimates for the LF and HF ranges were natural-log transformed to obtain Gaussian distributions [
The LF and HF measures were also analysed using an ANOVA based on the median split of the number of “divergent thinking” words generated for all 50 participants. This resulted in LF and HF measures for two groups; group one for the 25 participants producing the lowest number of “divergent thinking” words (Low Td) and group two for the 25 participants producing the highest number of “divergent thinking” words (High Td). This was undertaken to investigate further how the divergent thinking performance might relate to the physiological measures recorded.
The alpha level was set at 0.05 for the classification of significant difference and at 0.10 for marginal significance. Based on Cohen [
Measure | During Relaxation | During Task | ||||||
---|---|---|---|---|---|---|---|---|
Mean | SD | Mean | SD | F | p | Effect Size | ||
HR | 76.24 | 11.07 | 83.68 | 11.57 | 26.91 | <0.01 | 0.66 | |
ln LF | 7.20 | 1.32 | 6.58 | 0.99 | 3.31 | 0.08 | 0.53 | |
ln HF | 7.62 | 0.98 | 6.83 | 1.02 | 16.21 | <0.01 | 0.79 | |
HR is Heart Rate, ln LF is log transformed absolute low frequency power, ln HF is log transformed absolute high frequency power. Note: Effect size is measured using Cohen’s d.
shown in
There was a significant difference between the heart rate of the participants during the last minute of relaxation and during the task [F (1, 48) = 26.91, p < 0.01] with a medium effect size, with the mean heart rate increasing during the task; there was a marginally significant difference between the log transformed absolute LF power (ln LF) for the two conditions [F (1, 48) = 3.31, p = 0.08] with a medium effect size, with the mean ln LF reducing during the task; and there was a significant difference between the log transformed absolute HF power (ln HF) for the two conditions [F (1, 48) = 16.21, p < 0.01] with a medium effect, with the mean ln HF reducing during the task.
When analysing the changes in ln LF and ln HF it is important to ask whether respiration can account for some of these effects [
There was no significant difference between the number of “divergent thinking” words (Td), “convergent thinking” words (Tc) or total number of words (Tw) generated for the two conditions. In addition, no other significant effects of condition were present for the other measures. Again, respiration was estimated from the peak of the spectral information of the inter-beat intervals, with the average respiration rate being 0.23 Hz for the immediate condition and 0.19 Hz for the relaxed condition. This is a marginally significant difference [F (1, 48) = 3.52, p = 0.07] with a medium effect size.
When comparing the heart rate of participants during the one-minute task (HR) against the number of “divergent thinking” words (Td) they generated, for all 50 participants, there was no significant correlation. Pearson’s correlation, r = 0.02, p (2-tailed) = 0.91, N = 50, representing a small effect size.
When comparing the log transformed absolute LF power (ln LF) of participants during the one-minute task against the number of “divergent thinking” words (Td) they generated, for all 50 participants, there was a significant negative correlation. Pearson’s correlation, r = −0.47, p (2-tailed) < 0.01, N = 50, representing a large effect size. When comparing the log transformed absolute HF power (ln HF) of participants during the one- minute task against the number of “divergent thinking” words (Td) they generated, for all 50 participants, there was a marginal, negative correlation. Pearson’s correlation, r = −0.26, p (2-tailed) = 0.06, N = 50, representing a medium effect size. There was no significant correlation between the total number of words generated (Tw) and
Measure | Immediate Condition | Relaxed Condition | ||||||
---|---|---|---|---|---|---|---|---|
Mean | SD | Mean | SD | F | p | Effect Size | ||
Td | 1.84 | 2.03 | 1.92 | 1.44 | 0.03 | 0.87 | 0.05 | |
Tc | 3.64 | 2.08 | 3.52 | 2.63 | 0.03 | 0.86 | 0.05 | |
Tw | 5.48 | 2.02 | 5.44 | 2.38 | <0.01 | 0.95 | 0.02 | |
HR | 78.84 | 11.61 | 83.68 | 11.57 | 2.18 | 0.15 | 0.43 | |
ln LF | 6.53 | 1.09 | 6.58 | 0.99 | 0.04 | 0.85 | 0.06 | |
ln HF | 6.74 | 1.07 | 6.83 | 1.02 | 0.10 | 0.75 | 0.09 | |
Td is number of “divergent thinking” words generated, Tc is number of “convergent thinking” words generated, Tw is total number of words generated, HR is Heart Rate, ln LF is log transformed absolute low frequency power, and ln HF is log transformed absolute high frequency power. Note: Effect size is measured using Cohen’s d.
ln LF (r = −0.12, p (2-tailed) = 0.39, N = 50) and between Tw and ln HF (r = 0.18, p (2-tailed) = 0.21, N = 50). There was a significant, positive correlation between ln LF and ln HF. Pearson’s correlation, r = 0.57, p (2-tailed) < 0.01, N = 50, representing a large effect size.
Unsurprisingly, there was a significant difference between the numbers of “divergent thinking” words (Td) generated between the two groups [F (1, 48) = 78.15, p < 0.01], with a large effect size. There was no significant difference between the total numbers of words (Tw) generated between the two groups, however there was a significant difference between the numbers of “convergent thinking” words (Tc) generated [F (1, 48) = 15.20, p < 0.01], with a large effect size. For ln LF there was a significant difference between the two groups [F (1, 48) = 13.31, p < 0.01] with a large effect size, with the average ln LF being significantly lower in the group with the highest number of “divergent thinking” words (High Td), (
The results suggest that the 25 participants in the “relaxed” condition were more relaxed during the relaxation period compared to the time they were undertaking the task with, on average, a lower heart rate and higher HF power (ln HF), suggesting higher parasympathetic activity. Estimates of the respiration rate also suggest that there were slower respiration rates, on average, during the relaxation period compared to the time during the task and this might partially account for the higher LF power (ln LF) during the relaxation period. The increase in heart rate during the task is in line with the findings from other studies associated with mental workload and suggests an increase in sympathetic activity and increased arousal [
The physiological measures recorded during the task, including heart rate (HR), LF power (ln LF) and HF power (ln HF) suggest that, during the task itself, there was no significant difference between the two conditions (relaxed and immediate). Therefore, a participant being relaxed before the start of the task was not a predictor of their physiological state during the task. In addition, there was no significant difference between the numbers of
Measure | Low Td | High Td | ||||||
---|---|---|---|---|---|---|---|---|
Mean | SD | Mean | SD | F | p | Effect Size | ||
Td | 0.52 | 0.65 | 3.24 | 1.39 | 78.15 | <0.01 | 2.55 | |
Tc | 4.72 | 2.22 | 2.44 | 1.89 | 15.20 | <0.01 | 1.11 | |
Tw | 5.24 | 2.13 | 5.68 | 2.27 | 0.50 | 0.48 | 0.20 | |
ln LF | 7.03 | 1.00 | 6.08 | 0.84 | 13.31 | <0.01 | 1.05 | |
ln HF | 7.02 | 1.08 | 6.55 | 0.95 | 2.65 | 0.11 | 0.47 | |
Td is number of “divergent thinking” words generated, Tc is number of “convergent thinking” words generated, Tw is total number of words generated, ln LF is log transformed absolute low frequency power, and ln HF is log transformed absolute high frequency power. Note: Effect size is measured using Cohen’s d.
“divergent thinking” words (Td) generated for the two conditions, which maybe not that surprising considering the similarity of physiological measures between the two conditions during the task. Therefore, getting people into a relaxed state before the start of a creative task does not have an effect on their divergent thinking performance. Our previous research on the effect of play on creative problem solving [
There was no significant correlation between the heart rate during the task (HR) and the number of “divergent thinking” words (Td), suggesting that this is not a determining factor for divergent thinking performance. However further research is required to study within-person effects from baseline to task to gain a deeper understanding of the importance of the change in heart rate.
The significant negative correlation between LF power (ln LF) and the number of “divergent thinking” words (Td) suggests that divergent thinking performance might be related to the level of mental workload and attention applied to the task, as similar reductions in LF power have been shown in other mental workload tasks [
Our results suggest that a person’s psychophysiological state is correlated with their divergent thinking performance. However, the interpretation of the findings needs further research, for example, the importance of motivation, valence, mental effort and attention in creativity and how these different factors may interact.
One of the limitations of the study was that each task only lasted one minute, and therefore only one minute of HRV data was analysed to cover the task duration. The recommendation by the Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology [
A relatively small sample size of 50 participants in the study means that any conclusions drawn from the results should be tentative. Further studies are required by other researchers to see if the results found in this study are replicated.
We plan to conduct further studies on the relation between attention, play and a person’s psychophysiological state to help answer some of the questions raised from this research study and our previous research studies on play [
Gareth H.Loudon,Gina M.Deininger, (2016) The Physiological Response during Divergent Thinking. Journal of Behavioral and Brain Science,06,28-37. doi: 10.4236/jbbs.2016.61004