Does Weed Actually Make You Creative?

On screen, in order

1. 1:21

   SCHAFER ET AL. · 2012 · A WORD TASK · PREVIOUS CREATIVE ACHIEVEMENTS · Intoxicated day / sober day · LOWER · HIGHER · No placebo

   

   Users were tested after smoking their own cannabis and on a drug-free day. The key comparison is the bottom and top quartiles of the Creative Achievement Questionnaire. The “earlier work” picture is our illustration.

   • [1] Schafer et al., Consciousness and Cognition 2012, p. 293, §2.1
   • [1] Schafer et al., Consciousness and Cognition 2012, p. 294, §2.3.1, §2.3.2 and §2.4
2. 1:35

   LOWER PREVIOUS ACHIEVEMENT · MORE WORDS · Illustrative task examples · Examples are not participant responses

   

   Verbal fluency: words beginning with a given letter in 60 seconds. The low-achievement group scored higher on the intoxicated day than on the drug-free day. BRIDGE, BUTTON and BICYCLE are our examples.

   • [1] Schafer et al., Consciousness and Cognition 2012, p. 294, §3.1.1
   • [1] Schafer et al., Consciousness and Cognition 2012, p. 295, Fig. 1
3. 1:40

   HIGHER PREVIOUS ACHIEVEMENT · NO SUCH IMPROVEMENT · In this comparison

   

   The high-achievement group’s scores did not differ between the two days.

   • [1] Schafer et al., Consciousness and Cognition 2012, p. 294, §3.1.1
4. 1:44

   A POSITIVE FINDING. WITH AN ADDRESS. · A PARTICULAR GROUP · A WORD TASK · NO PLACEBO · The test counted words. · Not a measure of song quality

   

   The task was scored as the number of correct words. The comparison day was drug-free; no placebo was used.

   • [1] Schafer et al., Consciousness and Cognition 2012, p. 293, §2.1–2.2
   • [1] Schafer et al., Consciousness and Cognition 2012, p. 294, §2.3.1 and §2.4
5. 1:57

   WHAT WAS TESTED · A specific group. A specific word task. · NEVER HELPS · GENERAL UPGRADE · WHAT SURVIVES A TOUGHER TEST? · The finding does not establish either universal claim

   

   A gain on one word task in one subgroup shows neither that cannabis never helps nor that it upgrades creativity in general. The category task showed no such day effect.

   • Checked[1] Schafer et al., Consciousness and Cognition 2012, pp. 294–295, §3.1.1–3.1.3
6. 2:12

   CREATIVE USES FOR A BRICK · Illustrative answer · Study 1

   

   Participants listed as many creative uses for a brick as they could in four minutes. The bookend answer is our illustration, not a participant’s idea.

   • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 Method, Participants and Procedure
7. 2:18

   STUDY 1 · 191 · Creative uses for a brick

   

   Analysis sample: 107 in the cannabis condition, 84 in the control condition.

   • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 Method, Participants and Procedure
8. 2:22

   STUDY 2 · 140 · Revenue ideas for a band

   

   Analysis sample of full-time employees: 62 in the cannabis condition, 78 in the control condition. “OUR EXAMPLE: SELL TICKETS” is our illustration, not a participant’s idea.

   • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 2 Method, Participants and Procedure
9. 2:27

   CONDITION · Raters did not know the condition

   

   Trained research assistants and crowdsourced raters were blind to the experimental condition in both experiments. The reviewer and the label are our illustration.

   • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 Method, Measures: Creativity
   • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 2 Method, Measures: Creativity
10. 2:36

    STUDY 1 · NO SIGNIFICANT BENEFIT DETECTED · STUDY 2 · NO SIGNIFICANT BENEFIT DETECTED · Externally rated creativity

    

    Two sets of ratings in Study 1 and four in Study 2; none differed significantly between the cannabis and control conditions.

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 Results and Discussion, Table 2
    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 2 Results and Discussion, Table 4
11. 2:40

    VARIED PRODUCTS · EVERYDAY SETTINGS · NO PLACEBO · IMPERFECT COMPLIANCE · Cannabis condition / abstaining control · Methods and limitations

    

    Participants used their own cannabis in their daily lives; none was provided and the comparison was abstinence, not a placebo. In Study 1, among the 117 who completed the saliva test, 72% of the cannabis group tested positive and 64% of the control group tested negative; in Study 2, the check on the cannabis group (an image of their product or receipt) showed 79.0% compliance. The authors say they did not achieve perfect random assignment.

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 Method, Participants and Procedure
    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 Results and Discussion (manipulation checks)
    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 2 Results and Discussion (compliance check)
    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, General Discussion (limitations)
12. 2:47

    NO DETECTED BENEFIT ≠ PROOF OF ZERO EFFECT

    

    Non-significant differences in two experiments do not establish an effect of exactly zero.

    • Checked[2] Heng, Barnes & Yam, J. Applied Psychology 2023, Tables 2 and 4
13. 2:50

    I FELT INSPIRED. · THE STORY · Assess the work without the creator’s story

    

    The raters scored the ideas without knowing the participants’ condition. The reviewer, her notes and the “I felt inspired” label are our illustration.

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 Method, Measures: Creativity
    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 2 Method, Measures: Creativity
14. 3:05

    A RELIABLE IMPROVEMENT IN THE WORK? · DOESN’T HOLD · Not proof of no effect in every person. · Verdict applies to this claim and these tests

    

    Our verdict on the narrow claim, from the external ratings in both experiments. The authors’ combined analysis of all six sets of ratings found d = −.04, 95% CI [−.17, .09].

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Tables 2 and 4
    • [3] Heng et al., Supplement D (OSF), Main Effect of Cannabis Use on Creativity (second results paragraph)
15. 3:13

    STUDY 1 · SELF-RATINGS · HIGHER · Cannabis versus control

    

    Mean self-rating 3.52 in the cannabis condition and 3.23 in the control condition on a 1–5 scale; F = 4.98, p < .05.

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 Results and Discussion, Table 2
16. 3:17

    STUDY 2 · SELF-RATINGS · NO SIGNIFICANT OVERALL DIFFERENCE · Revised rating questions · The self-rating measures are not identical

    

    Global self-rating 3.75 in the cannabis condition and 3.80 in the control condition on a 1–5 scale; F = 0.15. Study 2 added two usefulness items to the Study 1 scale. Idea-level self-ratings did not differ significantly either.

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 2 Results and Discussion, Table 4
    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 2 Method, Measures: Creativity Self-Evaluation
17. 3:20

    STATISTICAL MODEL · CHEERFUL MOOD - - - MORE FAVOURABLE JUDGMENTS · Modelled indirect association · Mediation model

    

    “Cheerful mood” is the authors’ measure of state joviality. The indirect effect via joviality on self-ratings was significant in Study 1 (.06, 95% CI [.01, .13]) and Study 2 (global: .17, 95% CI [.02, .34]); in Study 2 it also reached ratings of other people’s ideas.

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 Results and Discussion
    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 2 Results and Discussion
18. 3:25

    SUPPLEMENT D · SELF-EVALUATIONS · (close-up of the supplement) Main Effect of Cannabis Use on Creativity Self-Evaluations: “…significant in Study 1 but not Study 2. … d = .18, 95% CI = [-.04, .39], Z = 1.58, p = .114, for a fixed effect model, and … d = .16, 95% CI = [-2.43, 2.74], Z = .77, p = .584, for a random effects model.”

    

    The authors’ own paragraph, shown as a close-up of the supplement. Not our calculation.

    • [3] Heng et al., Supplement D (OSF), Main Effect of Cannabis Use on Creativity Self-Evaluations (first results paragraph)
19. 3:30

    SELF-RATINGS · BOTH STUDIES · d = 0.18 · 95% CI: −0.04 to 0.39 · Fixed effect model · p = .114 · NO DIFFERENCE · The interval includes no difference.

    

    The authors’ internal meta-analysis of the two experiments, drawn as a chart; not our calculation. Their random-effects model gave d = .16, 95% CI [−2.43, 2.74], p = .584.

    • [3] Heng et al., Supplement D (OSF), Main Effect of Cannabis Use on Creativity Self-Evaluations (first results paragraph)
20. 3:32

    The mood-related finding remains.

    

    The supplement concludes that the effect on self-ratings is primarily indirect, via joviality.

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 and Study 2 Results and Discussion
    • [3] Heng et al., Supplement D (OSF), Main Effect of Cannabis Use on Creativity Self-Evaluations (first results paragraph)
21. 3:38

    STATISTICAL MODEL · PROPOSED ≠ PROVEN · A statistical model does not establish a biological mechanism

    

    The indirect effect comes from the authors’ statistical model. Mood was measured, not assigned, so the model does not show a mechanism in the brain.

    • Checked[2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 and Study 2 Results and Discussion
22. 3:45

    CAN IT CHANGE HOW IDEAS ARE JUDGED? · PARTLY · A universal self-rating boost is not established. · A DEBUNK NEEDS EVIDENCE, TOO. · Verdict applies to this claim and these tests

    

    Our verdict. The indirect effect via mood was significant in both experiments; the overall self-rating difference was significant only in Study 1 and not in the combined analysis.

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Tables 2 and 4; Study 1 and Study 2 Results and Discussion
    • [3] Heng et al., Supplement D (OSF), Main Effect of Cannabis Use on Creativity Self-Evaluations (first results paragraph)
23. 3:58

    A MORE CONTROLLED COMPARISON · PLACEBO · 18 participants · LOWER AMOUNT · 18 participants · HIGHER AMOUNT · 18 participants · RANDOM ASSIGNMENT · 54 regular users

    

    Randomized, double-blind, placebo-controlled; the placebo was cannabis plant material with very little THC. Of 59 people who took part, 54 were analysed for the alternative-uses task.

    • [4] Kowal et al., Psychopharmacology 2015, Materials and methods: Participants; Table 1
    • [4] Kowal et al., Psychopharmacology 2015, Materials and methods: Design and procedure
24. 4:11

    HIGHER AMOUNT vs PLACEBO · IDEA FLUENCY · WORSE · VARIETY · WORSE · ORIGINALITY · WORSE · Divergent-thinking measures

    

    Fluency is the number of uses, flexibility (shown as variety) the number of different categories, originality how rare the uses were. Higher amount compared with placebo: p = 0.01, 0.011 and 0.045. The fourth score, elaboration, showed no significant effect.

    • [4] Kowal et al., Psychopharmacology 2015, Results: Creativity tasks, Divergent thinking; Table 2
25. 4:19

    Lower amount: no benefit over placebo.

    

    The lower-amount group showed no significant increase over placebo on any of the four scores.

    • [4] Kowal et al., Psychopharmacology 2015, Results: Creativity tasks, Divergent thinking; Table 2
26. 4:22

    54 · 18 PER CONDITION · Regular users · Mostly men · THIS SAMPLE · Sample limitations

    

    Analysed sample: 48 men and 6 women. Regular use meant at least four times a week for at least two years. The groups differed in their share of women, which the authors list as a limitation. The connecting-word task had 53 participants.

    • [4] Kowal et al., Psychopharmacology 2015, Materials and methods: Participants; Table 1
    • [4] Kowal et al., Psychopharmacology 2015, Limitations
27. 4:30

    MORE ≠ BETTER · No benefit at the lower amount. Worse performance at the higher amount. · Compared with placebo

    
    • [4] Kowal et al., Psychopharmacology 2015, Results: Creativity tasks, Divergent thinking; Table 2
28. 4:40

    WHICH COMPARISON? · BETTER THAN THE HIGHER-AMOUNT GROUP · DOES NOT MEAN BETTER THAN PLACEBO

    

    In this study the lower-amount group scored significantly higher than the higher-amount group, but not higher than placebo.

    • [4] Kowal et al., Psychopharmacology 2015, Results: Creativity tasks, Divergent thinking; Table 2
29. 4:55

    USERS · NON-USERS · WHO THEY ARE ≠ WHAT HAPPENS WHEN HIGH · Illustrative people · Not participant portraits or counts

    

    The 2017 study tested users while sober. It compared users with non-users; it did not measure what happens during intoxication. The people are illustrations.

    • Checked[5] LaFrance & Cuttler, Consciousness and Cognition 2017, Abstract
30. 5:01

    LAFRANCE & CUTTLER · 2017 · BOTH GROUPS SOBER · Users compared with non-users · SELF-RATED CREATIVITY · CONNECTING ANSWERS · Observational comparison

    

    412 sober users and 309 non-users. The abstract describes the task as “a measure of convergent thinking”.

    • [5] LaFrance & Cuttler, Consciousness and Cognition 2017, Abstract
31. 5:12

    GROUP DIFFERENCES · Self-ratings / connecting answers · OPENNESS · Differences no longer significant after statistical adjustment. · Openness-adjusted analysis

    

    Controlling for the users’ higher openness to experience removed both differences.

    • [5] LaFrance & Cuttler, Consciousness and Cognition 2017, Abstract
32. 5:25

    OBSERVATIONAL ≠ CAUSAL

    

    An observational comparison of users and non-users; nothing was assigned, so it cannot show which way cause and effect run.

    • Checked[5] LaFrance & Cuttler, Consciousness and Cognition 2017, Abstract
33. 5:45

    A BRIEF BRICK TASK · One constrained response · A FINISHED ALBUM · Selection · revision · collaboration · A short task samples part of creativity

    

    The reviewed tasks were short, single-session tasks: listing uses for a brick or other everyday objects, revenue ideas for a band, or words in 60 seconds. None assessed finished creative works.

    • Checked[2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 and Study 2 Method, Participants and Procedure
    • [4] Kowal et al., Psychopharmacology 2015, Materials and methods: Alternate Uses Task
    • [1] Schafer et al., Consciousness and Cognition 2012, p. 294, §2.3.1
34. 6:16

    GROUP RESULT · A group result does not predict every individual. · Illustrative people · No individual outcomes shown

    

    The studies compare group averages; they do not show which individuals would do better or worse.

    • Checked[2] Heng, Barnes & Yam, J. Applied Psychology 2023
    • [4] Kowal et al., Psychopharmacology 2015
35. 6:22

    LIMITS GO BOTH WAYS · Not proof of a benefit for everyone. · Not proof of no benefit for anyone. · Broad claims need broad evidence.

    

    None of the reviewed studies shows a benefit for everyone, and none shows that no one could benefit.

    • Checked[1] Schafer et al., Consciousness and Cognition 2012
    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023
    • [4] Kowal et al., Psychopharmacology 2015
    • [5] LaFrance & Cuttler, Consciousness and Cognition 2017
36. 6:49

    RELIABLY BETTER WORK? · DOESN’T HOLD · Across the tasks reviewed here. · Verdict applies to this claim and these tests

    

    Our verdict across the reviewed tasks: no significant improvement in externally rated creativity (Heng et al.); worse divergent thinking at the higher amount and no benefit at the lower amount (Kowal et al.). The one positive result was a word-task gain in one subgroup, which was not a quality rating (Schafer et al.).

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Tables 2 and 4
    • [3] Heng et al., Supplement D (OSF), Main Effect of Cannabis Use on Creativity (second results paragraph)
    • [4] Kowal et al., Psychopharmacology 2015, Results: Creativity tasks, Divergent thinking; Table 2
    • [1] Schafer et al., Consciousness and Cognition 2012, p. 294, §3.1.1
37. 6:55

    A DIFFERENT JUDGMENT OF IDEAS? · PARTLY · Mood-related findings; inconsistent overall self-ratings. · Verdict applies to this claim and these tests

    

    Our verdict. Indirect effects via mood in both experiments; overall self-ratings higher only in Study 1 and not significant when both experiments were combined.

    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Tables 2 and 4; Study 1 and Study 2 Results and Discussion
    • [3] Heng et al., Supplement D (OSF), Main Effect of Cannabis Use on Creativity Self-Evaluations (first results paragraph)
38. 7:06

    NO ONE COULD EVER BENEFIT? · NOT SHOWN · The reviewed studies do not establish this universal claim. · Verdict applies to this claim and these tests

    

    Checked all five documents: none tests or establishes that no one could ever benefit. Schafer et al. report a gain on one word task in one subgroup.

    • Checked[1] Schafer et al., Consciousness and Cognition 2012
    • [2] Heng, Barnes & Yam, J. Applied Psychology 2023
    • [3] Heng et al., Supplement D (OSF)
    • [4] Kowal et al., Psychopharmacology 2015
    • [5] LaFrance & Cuttler, Consciousness and Cognition 2017
39. 7:22

    A MEANINGFUL EXPERIENCE · How it felt · DEMONSTRATED IMPROVEMENT · What the comparison shows · MAY · OVERLAP IS POSSIBLE. EQUIVALENCE IS NOT ESTABLISHED. · Conceptual illustration · Connection does not show causation

    

    In Heng et al., self-ratings rose in one experiment while externally rated creativity did not. Kowal et al. note that the experience of intoxication may not reflect actual performance. The diagram is a conceptual illustration.

    • Checked[2] Heng, Barnes & Yam, J. Applied Psychology 2023, Tables 2 and 4
    • [4] Kowal et al., Psychopharmacology 2015, Conclusion

Also said in the narration

1. 1:30

   Its key comparison used groups with higher and lower previous creative achievements.

   

   90 participants from the top and bottom quartiles of the Creative Achievement Questionnaire.

   • [1] Schafer et al., Consciousness and Cognition 2012, p. 294, §2.3.2 and §2.4
2. 1:35

   In the lower-achievement group, people produced more words beginning with a given letter while intoxicated.

   
   • [1] Schafer et al., Consciousness and Cognition 2012, p. 294, §2.3.1 and §3.1.1
   • [1] Schafer et al., Consciousness and Cognition 2012, p. 295, Fig. 1
3. 1:41

   The higher-achievement group did not show that improvement.

   
   • [1] Schafer et al., Consciousness and Cognition 2012, p. 294, §3.1.1
4. 2:27

   Participants were assigned to complete the study after their usual cannabis use or after abstaining.

   

   Random assignment to a cannabis-use condition or an abstinence condition; participants used their own products.

   • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 1 Method, Participants and Procedure
   • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Study 2 Method, Participants and Procedure
5. 3:13

   The same paper found higher self-ratings in the first experiment, but not the second.

   
   • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Tables 2 and 4
6. 3:59

   A Dutch experiment randomly assigned regular cannabis users to a placebo, a lower amount of cannabis, or a higher amount.

   

   Approved by the Leiden University Medical Center ethics committee; participants were native Dutch speakers, recruited in part through Dutch coffee shops.

   • [4] Kowal et al., Psychopharmacology 2015, Materials and methods: Participants
   • [4] Kowal et al., Psychopharmacology 2015, Materials and methods: Design and procedure
7. 4:27

   It does not tell us what every occasional user would experience.

   

   All participants were regular users. The authors write that effects in occasional or drug-naïve users can only be speculated about.

   • Checked[4] Kowal et al., Psychopharmacology 2015, Conclusion
8. 5:05

   Users rated themselves as more creative and performed better on a task that required finding a connecting answer.

   

   The abstract describes the task as “a measure of convergent thinking”; the full text was not checked.

   • [5] LaFrance & Cuttler, Consciousness and Cognition 2017, Abstract
9. 7:12

   The positive word-task finding belongs in the picture. So do the null results, the poorer performance in the higher-amount group, and the limits of all those tasks.

   
   • [1] Schafer et al., Consciousness and Cognition 2012, p. 294, §3.1.1
   • [2] Heng, Barnes & Yam, J. Applied Psychology 2023, Tables 2 and 4
   • [4] Kowal et al., Psychopharmacology 2015, Results: Creativity tasks, Divergent thinking; Table 2

Documents

• Page numbers are the documents’ own printed page numbers where the checked copy carries them (Schafer et al.).
• Heng, Barnes & Yam and Kowal et al. are cited by section, table and figure. The copy of Heng et al. checked is the advance online version, paginated 1–12, whose page numbers differ from the printed issue (pp. 635–646). The Kowal et al. text checked is the PubMed Central version, which has no page numbers. Supplement D has no page numbers either.
• In the video, most study cards carry a DOCUMENTED label on screen. Here DOCUMENTED means a finding the study reports for its own setup, not proof that a hypothesis is true.
• The verdicts are our reading of these studies. Each applies only to the claim and the tests named on its card.
• The d, confidence interval and p values on screen come from the authors’ own combined analysis in Supplement D. The episode makes no calculations of its own.
• Illustrations and marked examples are ours and are not evidence: the lamp, the spaghetti umbrella, the brick-as-bookend answer, BRIDGE / BUTTON / BICYCLE, “OUR EXAMPLE: SELL TICKETS”, the reviewer, the people, the camera analogy, the album and the proposed better study.
• Only the published abstract of LaFrance & Cuttler (2017) was checked.

1. [1]

   Elsevier, Consciousness and Cognition (open copy in UCL Discovery)

   Investigating the interaction between schizotypy, divergent thinking and cannabis use (Gráinne Schafer et al. · vol. 21, no. 1, pp. 292–298 · doi:10.1016/j.concog.2011.11.009) ↗

   Published March 2012 · Retrieved 25 September 2026

   Issue date. Available online on 9 January 2012.

   • Publisher’s version (DOI) ↗

   160 cannabis users were tested on a day when they had smoked their own cannabis and on a drug-free day; there was no placebo. The key comparison is between the top and bottom quartiles (90 people) of a questionnaire on previous creative achievements. The abstract and the methods (§2.4) give the two subgroup sizes, 43 and 47, the other way round; the video does not use them.

   Used at 1:21 · 1:30 · 1:35 · 1:40 · 1:41 · 1:44 · 1:57 · 5:45 · 6:22 · 6:49 · 7:06 · 7:12

2. [2]

   American Psychological Association, Journal of Applied Psychology

   Cannabis Use Does Not Increase Actual Creativity but Biases Evaluations of Creativity (Yu Tse Heng, Christopher M. Barnes and Kai Chi Yam · vol. 108, no. 4, pp. 635–646 · doi:10.1037/apl0000599) ↗

   Published April 2023 · Retrieved 25 September 2026

   Issue date. Published online on 28 July 2022; the copy checked for this episode is that advance online version, paginated 1–12.

   Two randomized field experiments with adult users in a U.S. state where recreational cannabis is legal. Participants used their own cannabis in their own setting or abstained; the researchers provided no cannabis and there was no placebo. The raters who scored the ideas did not know the participants’ condition. Compliance with the assigned condition was imperfect.

   Used at 2:12 · 2:18 · 2:22 · 2:27 · 2:36 · 2:40 · 2:47 · 2:50 · 3:05 · 3:13 · 3:17 · 3:20 · 3:32 · 3:38 · 3:45 · 5:45 · 6:16 · 6:22 · 6:49 · 6:55 · 7:06 · 7:12 · 7:22

3. [3]

   Heng, Barnes & Yam, Open Science Framework (the article’s supplementary materials)

   Supplement D: Internal Meta-Analyses (Supplement to doi:10.1037/apl0000599 · OSF project 3hbd6) ↗

   Published 23 June 2022 · Retrieved 25 September 2026

   Upload date of the file on OSF. The article links the OSF project as its supplementary material.

   • OSF project: Supplements A–D, data and syntax ↗

   The authors’ own combined analysis of their two experiments. The supplement has no page numbers; rows cite its paragraph headings.

   Used at 3:05 · 3:25 · 3:30 · 3:32 · 3:45 · 6:49 · 6:55 · 7:06

4. [4]

   Springer, Psychopharmacology (open access in PubMed Central)

   Cannabis and creativity: highly potent cannabis impairs divergent thinking in regular cannabis users (Mikael A. Kowal et al. · vol. 232, no. 6, pp. 1123–1134 · doi:10.1007/s00213-014-3749-1) ↗

   Published March 2015 · Retrieved 25 September 2026

   Issue date. Published online on 7 October 2014.

   • Publisher’s version (DOI) ↗

   Randomized, double-blind, placebo-controlled experiment with three groups of regular users in the Netherlands. The conflict-of-interest statement says one author received a salary from Bedrocan BV, the company that supplied the study cannabis.

   Licence: Creative Commons Attribution License

   Used at 3:58 · 3:59 · 4:11 · 4:19 · 4:22 · 4:27 · 4:30 · 4:40 · 5:45 · 6:16 · 6:22 · 6:49 · 7:06 · 7:12 · 7:22

5. [5]

   Elsevier, Consciousness and Cognition (abstract in PubMed)

   Inspired by Mary Jane? Mechanisms underlying enhanced creativity in cannabis users (Emily M. LaFrance and Carrie Cuttler · vol. 56, pp. 68–76 · doi:10.1016/j.concog.2017.10.009) ↗

   Published November 2017 · Retrieved 25 September 2026

   Issue date. Published online on 21 October 2017.

   • Publisher’s version (DOI) ↗

   Observational comparison of 412 cannabis users, tested while sober, and 309 non-users. Only the published abstract was checked for this episode; the full text was not.

   Used at 4:55 · 5:01 · 5:05 · 5:12 · 5:25 · 6:22 · 7:06

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