Rat 50 kHz calls reflect graded tickling-induced positive emotion.
Open accessAbstract
Positive animal emotion (affect) is a key component of good animal welfare [1] and plays an important role in stress-coping and resilience [2]. Methods for reliably inducing and measuring positive affect are critical, but both have been limited in availability. In rats, one promising way of inducing positive affective states is by human-simulated rough and tumble play or 'tickling' [3,4]. However, in humans tickling induces both pleasure and displeasure, and neither an established non-verbal indicator of positive affect, the Duchenne smile, nor laughter detects this variation [5,6]. Rats also show individual differences in response to tickling [7], and this variation needs to be readily quantified if we are to ensure that tickling is only implemented where it generates positive affect. Here, we use a validated and objective measure of affective valence, the affective bias test [8], to show that 50 kHz ultrasonic vocalizations provide a quantifiable and graded measure of positive affect that accurately reflects the positive state induced by this human-rat interaction.
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
USVs in response to tickling are correlated with an independent test of affective state (an affective bias test), indicating that rats vary significantly in their affective response to tickling.
“We have shown that USVs in response to tickling are correlated with an independent test of affective state (an affective bias test) indicating that rats vary significantly in their affective response to tickling ( Hinchcliffe et al., 2020).”
From Stage 2 Registered Report: Refinement of tickling protocols to improve positive animal welfare in laboratory rats (2025) · cites this paper as Hinchcliffe et al., 2020
Rat tickling response is associated with responses indicating affective states ranging from neutral to positive.
“Rat tickling response is associated with responses indicating affective states ranging from neutral to positive ( e.g., Hinchcliffe et al., 2020), and hence tickling may not always be welfare enhancing.”
From Stage 2 Registered Report: Refinement of tickling protocols to improve positive animal welfare in laboratory rats (2025) · cites this paper as Hinchcliffe et al., 2020
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Cites
Assessment of positive emotions in animals to improve their welfare
Boissy, A., Manteuffel, G., Jensen, M. B., Moe, R. O., Spruijt, B., Keeling, L. J., Winckler, C., Forkman, B., Dimitrov, I., Langbein, J., et al. (2007) · Physiology & Behavior · doi:10.1016/j.physbeh.2007.02.003 · Cited by 1,486 · see citing works
Burgdorf, J., Kroes, R. A., Moskal, J. R., Pfaus, J. G., Brudzynski, S. M., & Panksepp, J. (2008) · Journal of Comparative Psychology · doi:10.1037/a0012889 · Cited by 469 · see citing works
Reconstructing the evolution of laughter in great apes and humans
Davila Ross, M., J Owren, M., & Zimmermann, E. (2009) · Current Biology · doi:10.1016/j.cub.2009.05.028 · Cited by 286 · see citing works
Rat tickling: A systematic review of applications, outcomes, and moderators.
LaFollette, M. R., O’Haire, M. E., Cloutier, S., Blankenberger, W. B., & Gaskill, B. N. (2017) · PLOS ONE · doi:10.1371/journal.pone.0175320 · Cited by 84 · see citing works
Flagged first, then by citations
Research works printed but not linked: 4
- [2]Kalisch R. Müller M.B. Tüscher O. A conceptual framework for the neurobiological study of resilience Behav. Brain Sci. 38 2015 e92 25158686
- [4]Burgdorf J. Panksepp J. Tickling induces reward in adolescent rats Physiol. Behav. 72 2001 167 173 11239994
- [8]Hinchcliffe J.K. Stuart S.A. Mendl M. Robinson E.S.J. Further validation of the affective bias test for predicting antidepressant and pro-depressant risk: effects of pharmacological and social manipulations in male and female rats Psychopharmacol 234 2017 3105 3116 PMC5597685 28735366
- [9]Rygula R. Pluta H. Popik P. Laughing rats are optimistic PLoS One 7 2012 e51959 23300582 PMC3530570
Cited by
Sorted by citations
Who’s laughing? Play, tickling and ultrasonic vocalizations in rats.
Burke, C. J., Pellis, S. M., & Achterberg, E. J. M. (2022) · Philosophical Transactions of the Royal Society B · doi:10.1098/rstb.2021.0184 · Cited by 23 · see citing works
Sex differences in 50 kHz call subtypes emitted during tickling-induced playful behaviour in rats.
Tivey, E. K. L., Martin, J. E., Brown, S. M., Bombail, V., Lawrence, A. B., & Meddle, S. L. (2022) · Scientific Reports · doi:10.1038/s41598-022-19362-7 · Cited by 13 · see citing works
Bombail, V., Brown, S. M., Beyts, C., Martin, J. E., Li, T., Meddle, S. L., Mendl, M., Robinson, E. S., Hammond, T. J., Nielsen, B. L., et al. (2025) · F1000Research · doi:10.12688/f1000research.166417.2 · Cited by 4 · see citing works
Self-citation
- Authors
- Hinchcliffe, J. K., Mendl, M., & Robinson, E. S. J.
- Affiliations
- University of Bristol (GB)
- Corresponding author
- Mendl, Michael
- Venue
- Current Biology
- Publisher
- Elsevier BV
- Published
- 2020-09
- Volume
- 30
- Issue
- 18
- Pages
- R1034-R1035
- ISSN
- 0960-9822 (ISSN-L)
- PMC
- PMC7533284
- OpenAlex
- W3087483375
- Cited by
- 45
- References
- 4
- Citations by year
- 2026: 7 · 2025: 9 · 2024: 10 · 2023: 8 · 2022: 6 · 2021: 5
- FWCI
- 4.54
- Type
- journal article
- Language
- en
- Open access
- hybrid
- doi.org
- Licence
- Locations
- Current Biology (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- Bristol Research (University of Bristol) (submittedVersion, cc-by-nc-nd)
- Funders
- University of Bristol
- Medical Research Council (MR/L011212/1)
- Topics
- Health Sciences › Veterinary › Small Animals › Animal Behavior and Welfare Studies
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Developmental Biology › Animal Vocal Communication and Behavior
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Human-Animal Interaction Studies
- Keywords
- tickling, positive affect, emotional valence, 50-kHz ultrasonic vocalizations, rats, rough-and-tumble play, animal welfare, individual differences
- MeSH terms
- Affect, Animals, Emotions, Humans, Male, Physical Stimulation, Sensation, Touch, Ultrasonics, Vocalization, Animal, Rats
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
