The evolution of the social brain: anthropoid primates contrast with other vertebrates
Open accessAbstract
The social brain hypothesis argues that large brains have arisen over evolutionary time as a response to the social and ecological conflicts inherent in group living. We test predictions arising from the hypothesis using comparative data from birds and four mammalian orders (Carnivora, Artiodactyla, Chiroptera and Primates) and show that, across all non-primate taxa, relative brain size is principally related to pairbonding, but with enduring stable relationships in primates. We argue that this reflects the cognitive demands of the behavioural coordination and synchrony that is necessary to maintain stable pairbonded relationships. However, primates differ from the other taxa in that they also exhibit a strong effect of group size on brain size. We use data from two behavioural indices of social intensity (enduring bonds between group members and time devoted to social activities) to show that primate relationships differ significantly from those of other taxa. We suggest that, among vertebrates in general, pairbonding represents a qualitative shift from loose aggregations of individuals to complex negotiated relationships, and that these bonded relationships have been generalized to all social partners in only a few taxa (such as anthropoid primates).
AI snapshot
Written from the paper’s full text.
TL;DR
The paper tests the social brain hypothesis across birds and four mammalian orders, finding that relative brain size in non-primate taxa is principally associated with pairbonding rather than group size. Primates differ: they show a strong group-size effect on brain size, and anthropoid primates uniquely generalize bonded relationships to all social partners.
Key findings
- Primates showed a positive correlation between group size and relative brain size (λ=0.80, F1,40=8.14, p<0.01), whereas this relationship was not significant in artiodactyls (λ=0.63, F1,67=0.30, p=0.58) or carnivores (λ=0.11, F1,84=0.07, p=0.80).
- Social system was significantly associated with relative brain size in all three focal taxa: primates (F3,38=12.47, p<0.001), carnivores (F3,82=3.10, p=0.03), and artiodactyls (F3,65=2.86, p=0.04). Pairbonded species had larger relative brains than non-pairbonded species in carnivores (t=−2.86, p=0.0025), ungulates (t=−2.53, p=0.0007), and birds (t=−5.67, p<0.001), but not in bats (t=−1.34, p=0.095) or primates (t=−0.13, p=0.445).
- Bonded relationships were unusually common in anthropoid primates: the four taxa differed significantly (Χ²6=19.74, p=0.003), anthropoids differed from the other three combined (Χ²2=8.49, p=0.01), while strepsirhine primates did not differ from ungulates and carnivores combined (Χ²2=1.89, p=0.39).
- Anthropoid primates devoted significantly more time to social activity than ungulates (F1,39=9.59, p=0.004); when adjusted for group size, pairbonded species devoted significantly more time to social activities than harem-based or multimale species in both ungulates and primates.
Methods
- Comparative dataset: 86 carnivore, 69 artiodactyl, and 45 primate species with anatomical brain volume data, plus 135 bird species and 54 bat species from other analyses. Species were assigned to social categories (solitary, pairbonded, harem/single sex, multimale) and ecological factors (diet, habitat, strata, activity).
- Phylogenetic generalized least squares (PGLS) in R using APE estimated residual brain size controlling for body size and phylogeny; minimum adequate models (MAMs) used forward and backward stepwise selection.
- Social intensity was assessed by classifying 205 genera as female–female bonded, pairbonded, or non-bonded from species descriptions, with 93% inter-observer agreement (κ=0.87, τ=14.59, p<0.001); activity budget data for primates and artiodactyls came from the literature.
Limitations
- The paper states possible confounds from ecological and life-history variables, but MAMs confirmed social system independently predicted brain size in all taxa. It also considers alternatives: a bat brain–testis trade-off, which the authors argue is better explained by both covarying with mating system, and biparental care, which they argue does not explain the pairbonding effect across taxa.
- The paper notes phylogeny uncertainty but reports that analyses with and without phylogenetic correction for the mating-system analysis gave the same results.
- Evident from the text: the study is comparative and correlational, so it cannot establish causation; social-time data are available only for a subset of species and use a broad definition of social activity; the bat pairbonding result is not statistically significant (p=0.095); and primates are described as a clear outlier relative to other taxa.
Model-written summary. Check it against the paper before relying on it.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
0 of 44 cited sources checked · 0 supported · 0 flagged
- Findingown data§ 3. Results
The pattern of pairbonded species having the largest brain sizes is closely paralleled in both birds and bats.
“and this pattern is closely paralleled in both birds and bats.”
Quote in the paperNot a substantial claim - Findingown data§ 3. Results
Bonded relationships are unusually common in anthropoid primates.
“are unusually common in anthropoid primates (figure 4).”
Quote in the paperSubstantial claim - Findingown data§ 3. Results
Pairbonded species have significantly larger relative brains than non-pairbonded species in all taxa except bats and primates.
“pairbonded species have significantly larger relative brains than non-pairbonded species in all taxa except bats and primates”
Quote in the paperSubstantial claim - Findingown data§ 4. Discussion
Irrespective of any ecological and life-history covariates, social system independently influences brain size in all taxa.
“However, the MAMs analysis confirms that, irrespective of any ecological and life-history covariates, social system independently influences brain size in all taxa.”
Quote in the paperSubstantial claim - Findingown data§ 3. Results
Anthropoids differ from all three other taxa combined in sociality.
“anthropoids differ from all the three combined (Χ22=8.49, p=0.01).”
Quote in the paperSubstantial claim
- Findingown data§ 3. Results
Social system is consistently included in all the best models as an independent predictor of brain volume.
“social system is consistently included in all the best models as an independent predictor of brain volume (table 2).”
Quote in the paperSubstantial claim - Findingown data§ Abstract
Primate relationships differ significantly from those of other taxa, based on two behavioural indices of social intensity (enduring bonds between group members and time devoted to social activities).
“We use data from two behavioural indices of social intensity (enduring bonds between group members and time devoted to social activities) to show that primate relationships differ significantly from those of other taxa.”
Quote in the paperSubstantial claim - Findingown data§ 3. Results
Harem and multimale primates devote more time per individual group member than ungulates.
“harem and multimale primates devote more time per individual group member than ungulates (F1,25=6.05, p=0.02)”
- Also stated in: § 3. Results · plain
“non-pairbonded primates devote more time to other individuals than non-pairbonded ungulates”
Quote in the paperSubstantial claim - Also stated in: § 3. Results · plain
- Findingown data§ 3. Results
Strepsirhine primates do not differ from ungulates and carnivores combined in sociality.
“strepsirhine primates do not differ from ungulates and carnivores combined (Χ22=1.89, p=0.39)”
Quote in the paperSubstantial claim - Findingown data§ 3. Results
Bird species with long-term pairbonds have significantly larger relative brain sizes than those with annual pairbonds.
“bird species with long-term pairbonds have significantly larger relative brain sizes than those with annual pairbonds (figure 3).”
Quote in the paperSubstantial claim - Findingown data§ 3. Results
For artiodactyls and carnivores, the relationship between relative brain size and group size was not significant.
“the relationship between relative brain size and group size was not significant (artiodactyls: λ=0.63, F1,67=0.30, p=0.58; carnivores: λ=0.11, F1,84=0.07, p=0.80).”
Quote in the paperSubstantial claim - Findingreasoning§ Abstract
In primates, relative brain size is related to enduring stable relationships.
“but with enduring stable relationships in primates”
Quote in the paperSubstantial claim - Findingown data§ 3. Results
Anthropoid primates devote significantly more time to social activity than ungulates.
“Overall, anthropoid primates devote significantly more time to social activity than ungulates (ANOVA arcsin proportion of social time: F1,39=9.59, p=0.004, figure 5a).”
- Also stated in: § 3. Results · hedged
“and, in general, primates devote more time to social activity than ungulates do (F1,39=9.59, p=0.004).”
Quote in the paperSubstantial claim - Also stated in: § 3. Results · hedged
- Findingown data§ 4. Discussion
Species that live in stable mixed groups (e.g. canids) have relatively larger brains than social carnivores that forage solitarily (e.g. badgers).
“This suggestion is given some support by the relatively large brains of species that live in stable mixed groups (e.g. canids) as compared to those social carnivores that forage solitarily (e.g. badgers: see the electronic supplementary material for species data).”
Quote in the paperNot a substantial claim - Findingown data§ 3. Results
Artiodactyls and carnivores differ significantly in sociality.
“artiodactyls and carnivores differ significantly (Χ22=10.99, p=0.01)”
Quote in the paperNot a substantial claim - Findingown data§ 3. Results
Artiodactyl and carnivore species with pairbonded mating systems consistently had the largest brain sizes.
“artiodactyl and carnivore species with pairbonded mating systems consistently had the largest brain sizes”
Quote in the paperSubstantial claim - Findingown data§ 3. Results
In primates, brain size increases progressively from solitary to multimale groups.
“brain size increases progressively from solitary to multimale groups.”
Quote in the paperSubstantial claim - Findingown data§ 3. Results
There is a positive correlation between group size and relative brain size in primates.
“there is a positive correlation between group size and relative brain size (λ=0.80, F1,40=8.14, p<0.01)”
Quote in the paperSubstantial claim - Findingown data§ Abstract
Primates differ from other taxa in that they also exhibit a strong effect of group size on brain size.
“However, primates differ from the other taxa in that they also exhibit a strong effect of group size on brain size.”
- Also stated in: § 3. Results · plain
“there is a positive correlation between group size and relative brain size”
Quote in the paperSubstantial claim - Also stated in: § 3. Results · plain
- Findingown data§ 3. Results
In all four non-primate taxa, pairbonded species have much larger brains than would be predicted for group size.
“Thus, in all four non-primate taxa, pairbonded species have much larger brains than would be predicted for group size.”
Quote in the paperSubstantial claim - Findingown data§ 3. Results
Social system was significantly associated with relative brain size for all three focal taxa (primates, carnivores and artiodactyls).
“social system was significantly associated with relative brain size for all three taxa (table 1).”
Quote in the paperSubstantial claim - Findingown data§ Abstract
Across all non-primate taxa, relative brain size is principally related to pairbonding.
“across all non-primate taxa, relative brain size is principally related to pairbonding”
- Also stated in: § 3. Results · plain
“in all four non-primate taxa, pairbonded species have much larger brains than would be predicted for group size.”
Quote in the paperSubstantial claim - Also stated in: § 3. Results · plain
- Findingown data§ 3. Results
When social time is corrected for the number of other individuals in the group (N−1), pairbonded species devote significantly more time to social activities than harem-based or multimale grouping species.
“When social time is corrected for the number of other individuals in the group (N−1), pairbonded species devote significantly more time to social activities than do harem based or multimale grouping species (figure 5b; ungulates: LSD pairbonded (P) versus harem (H), p<0.001, and P versus multimale (M), p<0.001; primates: LSD P versus H, p=0.01 and P versus M, p=0.005).”
Quote in the paperSubstantial claim- Rests on an assumption: Primates are typically found in larger social groups than ungulates.
- Findingown data§ 3. Results
Primates appear to be a clear outlier in the trend of pairbonded species having larger relative brains.
“although primates appear to be a clear outlier (figure 2).”
Quote in the paperSubstantial claim - Findingown data§ 3. Results
There is no difference in social time between pairbonded primates and pairbonded ungulates.
“There is no difference in social time between pairbonded primates and pairbonded ungulates (ANOVA with arcsin proportion of time: F1,12=0.10, p=0.76)”
- Also stated in: § 3. Results · plain
“pairbonded primates and pairbonded ungulates do not differ significantly from each other”
Quote in the paperSubstantial claim - Also stated in: § 3. Results · plain
- Findingown data§ 4. Discussion
Across a wide range of non-primate taxa, pairbonded species of vertebrates have significantly larger brains for body size than species with all other mating systems.
“We have shown that, across a wide range of non-primate taxa, pairbonded species of vertebrates have significantly larger brains for body size than species with all other mating systems”
- Also stated in: § 4. Discussion · boosted
“despite the fact that they also show a strong effect of pairbonding on brain size”
Quote in the paperSubstantial claim - Also stated in: § 4. Discussion · boosted
- Findingown data§ 3. Results
The four taxa (anthropoid primates, strepsirhine primates, artiodactyls and carnivores) differ significantly in sociality.
“The four taxa differ significantly (Χ62=19.74, p=0.003).”
Quote in the paperSubstantial claim - Findingown data§ 4. Discussion
In primates, the relationship between brain and group sizes is much stronger than the relationship between brain size and any other factor (including social system or pairbonding).
“In primates, the relationship between brain and group sizes is much stronger than the relationship between brain size and any other factor (including social system or pairbonding).”
Quote in the paperSubstantial claim - Interpretationreasoning§ 4. Discussion
The relatively small brains of carnivores, ungulates, bats and birds in multimale groups can be explained by a lack of cognitive demand placed on individuals in relatively unstable groupings, even when these are large.
“Conversely, the relatively small brains of carnivores, ungulates, bats and birds in multimale groups can be explained by a lack of cognitive demand placed on individuals in relatively unstable groupings, even when these are large.”
Quote in the paperSubstantial claim - Premisecitation§ 4. Discussion
Individuals in lifelong monogamous mating relationships forego opportunities to mate or search for other partners.
“Individuals in lifelong monogamous mating relationships forego opportunities to mate or search for other partners (Komers & Brotherton 1997)”
Quote in the paperSubstantial claim0 of 1 sources checked- cites Komers & Brotherton 1997
Not checked in the free run.
- Interpretationreasoning§ 1. Introduction
Many non-social life history and ecological variables are constraints on the evolution of large brain size rather than selection pressures.
“It is important to appreciate that many of these are constraints on the evolution of large brain size rather than selection pressures”
Quote in the paperSubstantial claim - Interpretationcitation§ 1. Introduction
The relationship between brain size and sociality may be more complex than previously supposed.
“implying that the relationship between brain size and sociality may be more complex than previously supposed.”
Quote in the paperSubstantial claim - Interpretationown data§ 3. Results
Strepsirhine primates resemble carnivores more than they do anthropoid primates.
“strepsirhine primates (who have smaller brains for body size than anthropoids) seem to resemble carnivores more than they do anthropoid primates.”
Quote in the paperNot a substantial claim - Premisecitation§ 1. Introduction
Strong support for a correlation between social group size and brain size has been found in primates.
“Although strong support for this prediction has been found in primates (Dunbar 1992, 1998; Barton 1996)”
Quote in the paperSubstantial claim0 of 2 sources checked- cites Dunbar 1992, 1998
Not checked in the free run.
- cites Barton 1996
Not checked in the free run.
- Interpretationreasoning§ 4. Discussion
Pairbonded species of vertebrates are cognitively more demanding than species with other mating systems.
“which implies that they are cognitively more demanding”
Quote in the paperSubstantial claim - Interpretationreasoning§ Abstract
Among vertebrates in general, pairbonding represents a qualitative shift from loose aggregations of individuals to complex negotiated relationships.
“We suggest that, among vertebrates in general, pairbonding represents a qualitative shift from loose aggregations of individuals to complex negotiated relationships”
Quote in the paperSubstantial claim - Interpretationown data§ Abstract
Bonded relationships have been generalized to all social partners in only a few taxa, such as anthropoid primates.
“and that these bonded relationships have been generalized to all social partners in only a few taxa (such as anthropoid primates).”
Quote in the paperSubstantial claim - Interpretationreasoning§ 1. Introduction
The nature and stability of relationships may be more important than the sheer number of aggregating individuals.
“Thus, the nature and stability of relationships may be more important than the shear number of aggregating individuals.”
Quote in the paperSubstantial claim - Premisecitation§ 1. Introduction
For both birds and primates, life history and diet act as constraints on brain evolution, independently of effects due to sociality.
“We have elsewhere shown, using path analysis, that for both birds (Shultz & Dunbar submitted) and primates (Dunbar & Shultz 2007), life history and diet act as constraints on brain evolution, and do so quite independently of effects due to sociality.”
Quote in the paperNot a substantial claim0 of 2 sources checked- cites Shultz & Dunbar submitted
Not checked in the free run.
- cites Dunbar & Shultz 2007
Not checked in the free run.
- Interpretationreasoning§ 4. Discussion
Individuals in transitory groups may not need to invest in cognitive resources for cataloguing previous experiences, judging relative resource holding potential, manipulating the behaviour of other individuals or recognizing relatedness.
“Unlike those in bonded groups, individuals in transitory groups may not need to invest in cognitive resources for cataloguing previous experiences (or identifying cheats), judging relative resource holding potential, manipulating the behaviour of other individuals or recognizing relatedness.”
Quote in the paperSubstantial claim - Interpretationreasoning§ Abstract
The relation between relative brain size and pairbonding reflects the cognitive demands of the behavioural coordination and synchrony necessary to maintain stable pairbonded relationships.
“We argue that this reflects the cognitive demands of the behavioural coordination and synchrony that is necessary to maintain stable pairbonded relationships.”
Quote in the paperSubstantial claim - Premisecitation§ 1. Introduction
Group size does not consistently correlate with brain size in some taxonomic groups.
“group size does not consistently correlate with brain size in some taxonomic groups (Beauchamp & Fernandez-Juricic 2004; Shultz & Dunbar 2006)”
Quote in the paperSubstantial claim0 of 2 sources checked- cites Beauchamp & Fernandez-Juricic 2004
Not checked in the free run.
- cites Shultz & Dunbar 2006
Not checked in the free run.
- Premisecitation§ 1. Introduction
Relative brain size in mammals, including primates, correlates with a number of non-social life history and ecological variables.
“Relative brain size in mammals (including primates) has also been shown to correlate with a number of non-social life history and ecological variables (Clutton-Brock & Harvey 1980; Armstrong 1985; Harvey & Krebs 1990).”
Quote in the paperSubstantial claim0 of 3 sources checked- cites Clutton-Brock & Harvey 1980
Not checked in the free run.
- cites Armstrong 1985
Not checked in the free run.
- cites Harvey & Krebs 1990
Not checked in the free run.
- Premisecitation§ 4. Discussion
The relationship between testis size and brain size is an artefact of both covarying with mating system.
“the relationship between testis size and brain size is an artefact of both covarying with mating system, as has been demonstrated in other vertebrate taxa (Harcourt et al. 1981; Møller & Briskie 1995)”
Quote in the paperSubstantial claim0 of 2 sources checked- cites Harcourt et al. 1981
Not checked in the free run.
- cites Møller & Briskie 1995
Not checked in the free run.
- Interpretationreasoning§ 4. Discussion
More minor disagreements in phylogeny are unlikely to significantly alter the conclusions.
“We can be confident that more minor disagreements are unlikely to significantly alter the conclusions.”
Quote in the paperNot a substantial claim - Premisecitation§ 4. Discussion
Biparental care is relatively rare in primates.
“is relatively rare in primates (Dunbar 1988)”
Quote in the paperSubstantial claim0 of 1 sources checked- cites Dunbar 1988
Not checked in the free run.
- Interpretationreasoning§ 4. Discussion
The same factors explain why primate sociality seems to be so different in quality from that found in other social vertebrates.
“It would also explain why primate sociality seems to be so different in quality from that found in other social vertebrates (see also Harcourt 1992).”
Quote in the paperSubstantial claim0 of 1 sources checked- cites Harcourt 1992
Not checked in the free run.
- Rests on an assumption: Female-bonded social systems are relatively common in primates but occur only in isolated and exceptional cases among non-primates.
- Premisecitation§ 4. Discussion
Pairbonded social systems are more common among primates than among other mammalian taxa.
“One primary difference between primates and other mammalian taxa is that pairbonded social systems are more common among primates (Kleiman 1977)”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites Kleiman 1977
Not checked in the free run.
- Premisecitation§ 4. Discussion
In birds, brain size correlates with pairbonding independently of biparental care.
“while in birds brain size correlates with pairbonding independently of biparental care (Shultz & Dunbar submitted)”
Quote in the paperSubstantial claim0 of 1 sources checked- cites Shultz & Dunbar submitted
Not checked in the free run.
- Premisecitation§ 4. Discussion
There is little if any paternal care in monogamous ungulates.
“there is little if any paternal care in monogamous ungulates (Brotherton & Rhodes 1996)”
Quote in the paperSubstantial claim0 of 1 sources checked- cites Brotherton & Rhodes 1996
Not checked in the free run.
- Study design and conductown data§ 4. Discussion
Running the analyses both with and without phylogenetic correction for the mating system analysis for the three focal mammalian orders yields the same results.
“Nonetheless, as a check on this, we ran the analyses both with and without phylogenetic correction for the mating system analysis for the three focal mammalian orders and the results remain the same.”
Quote in the paperNot a substantial claim - Premisecitation§ 4. Discussion
Biparental care does not correlate with brain size in carnivores.
“biparental care does not correlate with brain size in carnivores (Gittleman 1986)”
Quote in the paperSubstantial claim0 of 1 sources checked- cites Gittleman 1986
Not checked in the free run.
- Premisecitation§ 4. Discussion
Bonded social groups are especially characteristic of primates.
“more generally, that bonded social groups are especially characteristic of primates (many anthropoid primate species, in particular, have large social groups with a stable structure of related individuals, often based on matrilineal or patrilineal kinship, as well as coalition and grooming relationships between genetically unrelated individuals: Smuts et al. 1987; Dunbar 1988)”
Quote in the paperSubstantial claim0 of 2 sources checked- cites Smuts et al. 1987
Not checked in the free run.
- cites Dunbar 1988
Not checked in the free run.
- Interpretationown data§ 4. Discussion
These results undermine conventional notions of what constitutes social complexity.
“These results undermine conventional notions of what constitutes social complexity.”
Quote in the paperNot a substantial claim - Premisecitation§ 4. Discussion
Large testis size is a response to sperm competition.
“a more likely scenario is that large testis size is a response to sperm competition”
Quote in the paperSubstantial claim0 of 2 sources checked- cites Harcourt et al. 1981
Not checked in the free run.
- cites Møller & Briskie 1995
Not checked in the free run.
- Classified as probably not a substantial claim. 15
- May combine two claims. 13
- The quote only partly states this claim. 1
Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based). May combine two claims. The quote only partly states this claim.
Findingown data§ 3. ResultsAll five taxa exhibit a consistent trend in the same direction, with pairbonded species having larger relative brains.
“All the five taxa exhibit a consistent trend in the same direction”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S4 (based).
Findingnone given§ 3. ResultsBonded relationships (female-female bonds or pairbonds) are rare in mammals as a whole.
“bonded relationships (defined as having either female–female bonds or pairbonds; see §2), which are rare in mammals as a whole”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown data§ 4. DiscussionPrimates exhibit a strong signature for a quantitative group size effect on brain size, but all other taxa (including birds and a wide range of non-primate mammals) do not.
“Our analyses reveal a marked contrast between primates and all the other taxa (including both birds and a wide range of non-primate mammals) in that primates exhibit a strong signature for a quantitative group size effect on brain size, but all the other taxa do not.”
Quote in the paperSubstantial claimClassified as probably not a substantial claim.
Premisecitation§ AbstractThe social brain hypothesis proposes that large brains have arisen over evolutionary time as a response to the social and ecological conflicts inherent in group living.
“The social brain hypothesis argues that large brains have arisen over evolutionary time as a response to the social and ecological conflicts inherent in group living.”
Quote in the paperSubstantial claim0 of 3 sources checked- cites Jolly 1966
Not checked in the free run.
- cites Byrne & Whiten 1988
Not checked in the free run.
- cites Dunbar 1992, 1998
Not checked in the free run.
Probably not a substantial claim: may not pass S3 (load-bearing).
Premisecitation§ 2. Material and methodsThe four-way categorization of social systems is standard in the primate literature.
“This four-way categorization of social systems is standard in the primate literature (Smuts et al. 1987)”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites Smuts et al. 1987
Not checked in the free run.
May combine two claims.
Premisecitation§ 1. IntroductionIn primates, alternative indices of social complexity such as deception rates, mating strategies, grooming clique size and coalition rates all correlate with relative brain size.
“alternative indices of social complexity such as deception rates (Byrne & Whiten 1988), mating strategies (Pawlowski et al. 1998), grooming clique size (Kudo & Dunbar 2001) and coalition rates (Dunbar & Shultz 2007) all correlate with relative brain size.”
Quote in the paperSubstantial claim0 of 3 sources checked- cites Byrne & Whiten 1988
Not checked in the free run.
- cites Pawlowski et al. 1998
Not checked in the free run.
- cites Kudo & Dunbar 2001
Not checked in the free run.
Probably not a substantial claim: may not pass S3 (load-bearing).
Study design and conductown data§ 2. Material and methodsInter-observer agreement for 205 genera was 93% (κ=0.87, τ=14.59, p<0.001).
“our overall agreement for 205 genera was 93% (κ=0.87, τ=14.59, p<0.001).”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites Cohen 1960
Not checked in the free run.
Classified as probably not a substantial claim.
Study design and conductown data§ 2. Material and methodsMinimum adequate models were constructed to check whether ecological factors were confounds with social measures.
“As a second step to check whether ecological factors were confounds with our social measures, we constructed minimum adequate models (MAMs; table 2) using forward and backward stepwise selection”
Quote in the paperSubstantial claimClassified as probably not a substantial claim.
Premisecitation§ 2. Material and methodsVarious ecological factors are associated with brain size.
“As various ecological factors have been shown to be associated with brain size (Harvey et al. 1980; Reader & Laland 2002)”
Quote in the paperSubstantial claim0 of 2 sources checked- cites Harvey et al. 1980
Not checked in the free run.
- cites Reader & Laland 2002
Not checked in the free run.
Classified as probably not a substantial claim.
Premisecitation§ 1. IntroductionThe cognitive demands imposed by social complexity was proposed as an explanation for why primates have unusually large brains for their body size.
“Several decades ago, the cognitive demands imposed by social complexity was proposed as an explanation for why primates have unusually large brains for their body size (Jolly 1966; Byrne & Whiten 1988).”
Quote in the paperSubstantial claim0 of 2 sources checked- cites Jolly 1966
Not checked in the free run.
- cites Byrne & Whiten 1988
Not checked in the free run.
Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.
Interpretationreasoning§ 4. DiscussionIn lifelong monogamous mating relationships, it is imperative that the risk of cuckoldry is minimized and that individuals optimize mate choice.
“making it imperative that the risk of cuckoldry is minimized and that individuals optimize mate choice”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).
Premisecitation§ 3. ResultsIt has been widely assumed that managing polygamous mating relationships is cognitively more taxing.
“it has been widely assumed that managing polygamous mating relationships is cognitively more taxing (e.g. Gittleman 1986).”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites Gittleman 1986
Not checked in the free run.
Probably not a substantial claim: may not pass S2 (checkable).
Premisecitation§ 1. IntroductionThe essence of the social brain hypothesis is that the need to solve ecological problems in a social context, rather than in a demographic vacuum, imposes significant cognitive demands.
“The essence of the SBH is that the need to solve (ecological) problems in a social context, rather than in a demographic vacuum, imposes significant cognitive demands.”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites Dunbar 1992, 1998
Not checked in the free run.
May combine two claims.
Premisecitation§ 4. DiscussionMaintaining a lasting pairbond entails inevitable conflict between partners over resources, parental investment decisions and time budgets, which necessitates an ability to resolve conflicts and coordinate scheduling.
“maintaining a lasting bond entails inevitable conflict between partners over resources, parental investment decisions and time budgets, which in turn necessitates an ability to resolve conflicts and coordinate scheduling (Dunbar & Dunbar 1980)”
Quote in the paperSubstantial claim0 of 1 sources checked- cites Dunbar & Dunbar 1980
Not checked in the free run.
Classified as probably not a substantial claim.
Premisecitation§ 2. Material and methodsThe key factor in primate sociality has long been thought to be female-bondedness.
“the key factor in primate sociality has long been thought to be female-bondedness (Wrangham 1980)”
Quote in the paperSubstantial claim0 of 1 sources checked- cites Wrangham 1980
Not checked in the free run.
Classified as probably not a substantial claim.
Study design and conductown data§ 2. Material and methodsEach of us independently classified all primate, carnivore and ungulate genera as a function of the kinds of bonds exhibited by females.
“Each of us independently classified all primate, carnivore and ungulate (artiodactyl) genera as a function of the kinds of bonds exhibited by females”
Quote in the paperSubstantial claimClassified as probably not a substantial claim.
Study design and conductcitation§ 2. Material and methodsPGLS analysis was used to estimate residual brain size controlling for body size and phylogeny.
“we employed phylogenetic generalized least squares (PGLS) analysis (Grafen 1989) to estimate residual brain size controlling for body size and phylogeny (as a fixed factor)”
Quote in the paperSubstantial claim0 of 1 sources checked- cites Grafen 1989
Not checked in the free run.
May combine two claims.
Interpretationreasoning§ 4. DiscussionFor bats, rather than polygamous species trading brain tissue for larger testes, monogamous species require more brain volume.
“A more plausible alternative explanation for their bat results is thus that, rather than polygamous species trading brain tissue for larger testes, monogamous species require more brain volume.”
Quote in the paperNot a substantial claimMay combine two claims.
Premisecitation§ 4. DiscussionWolves (and other group-living canids), callitrichids and many lemurid prosimians have social groups based around breeding pairs.
“Possible examples of this type of sociality are wolves (and other group-living canids), callitrichids and many lemurid prosimians (van Schaik & Kappeler 1993), all of whose social groups are based around breeding pairs.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites van Schaik & Kappeler 1993
Not checked in the free run.
May combine two claims.
Interpretationreasoning§ 4. DiscussionThere is a qualitative difference (at least in terms of cognitive demands) between bonded and non-bonded social systems, suggesting that there may be two separate evolutionary routes between asociality, aggregations and bonded social systems.
“Additionally, there is a qualitative difference (at least in terms of cognitive demands) between bonded and non-bonded social systems, suggesting that there may be two separate evolutionary routes between asociality, aggregations and bonded social systems.”
Quote in the paperSubstantial claimProbably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.
Study design and conductcitation§ 4. DiscussionThe phylogenies used are the most recent and widely accepted; the primate phylogeny (Purvis 1995) is standard and not in serious dispute.
“We have used those that are the most recent and widely accepted; indeed, that for primates (Purvis 1995) is the standard phylogeny used in all comparative analyses, and is not in serious dispute.”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites Purvis 1995
Not checked in the free run.
May combine two claims.
Premisecitation§ 4. DiscussionBoth brain and testis sizes are strongly associated with mating system, while the relationship between relative brain and testis sizes is much weaker.
“Pitnick et al. (2006) themselves show that both brain and testis sizes are strongly associated with mating system, while the relationship between relative brain and testis sizes is much weaker.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites Pitnick et al. (2006)
Not checked in the free run.
May combine two claims.
Study design and conductreasoning§ 4. DiscussionFor orders where there is disagreement, it usually concerns the insertion points of major taxonomic groups rather than the detailed arrangement of species within families, and such disagreements are likely to affect only a handful of high-level nodes and have limited statistical impact on the results.
“For those orders where there is disagreement, this usually concerns the insertion points of major taxonomic groups, rather than the detailed arrangement of species within families; since such disagreements are likely to affect only a handful of high-level nodes in the phylogeny, they will have rather limited statistical impact on the results.”
Quote in the paperSubstantial claimMay combine two claims.
Premisecitation§ 4. DiscussionMany anthropoid primate species have large social groups with a stable structure of related individuals, often based on matrilineal or patrilineal kinship, as well as coalition and grooming relationships between genetically unrelated individuals.
“many anthropoid primate species, in particular, have large social groups with a stable structure of related individuals, often based on matrilineal or patrilineal kinship, as well as coalition and grooming relationships between genetically unrelated individuals: Smuts et al. 1987; Dunbar 1988”
Quote in the paperSubstantial claim0 of 2 sources checked- cites Smuts et al. 1987
Not checked in the free run.
- cites Dunbar 1988
Not checked in the free run.
May combine two claims.
Interpretationreasoning§ 4. DiscussionThe rarity of female-bonded social systems in non-primates and their relative commonness in primates might explain why primates exhibit a much stronger quantitative signature for group size than other taxa.
“Although female-bonded social systems appear to be relatively common in primates, they seem to have happened only in isolated and rather exceptional cases among non-primates (e.g. elephants, equids). This might explain why primates exhibit a much stronger quantitative signature for group size than other taxa.”
Quote in the paperSubstantial claim- Rests on an assumption: Female-bonded social systems are relatively common in primates but occur only in isolated and exceptional cases among non-primates.
The paper relies on this without support.
In bonded groups, animals need to maintain relationships with their social partners.
“A key problem faced by animals that live in bonded groups is the need to maintain relationships with their social partners.”
The authors state this as an assumption.
Time invested in social activity is a valid measure of investment in social relationships.
“we here use the amount of time invested in social activity as a measure of investment in social relationships.”
The paper relies on this without support.
Male-bonded social systems are rare in any order.
“male-bonded social systems are rare in any order”
The paper relies on this without support.
The four-way categorization of social systems can be applied to any order.
“it can be applied perfectly well to any order.”
The paper relies on this without support.
Social grooming is a widely accepted index of bondedness in primates.
“where social grooming is a widely accepted index”
The paper relies on this without support.
With the exception of primates, there has been little attempt to define behavioural measures of bondedness in animals.
“With the exception of primates (where social grooming is a widely accepted index), there has been little attempt to define behavioural measures of bondedness in animals.”
The paper relies on this without support.
Within a social environment, individual decisions must be responsive to the decisions made by other group members and the constraints these impose.
“Within a social environment, individual decisions must be responsive to the decisions made by other group members and the constraints these impose.”
The paper relies on this without support.
The number of potential dyadic relationships is proportional to group size.
“the number of potential dyadic relationships (interpreted as one index of social complexity) is proportional to group size.”
The paper relies on this without support.
Primates are typically found in larger social groups than ungulates.
“As this may simply reflect the fact that primates are typically found in larger social groups”
The paper relies on this without support.
Female-bonded social systems are relatively common in primates but occur only in isolated and exceptional cases among non-primates.
“Although female-bonded social systems appear to be relatively common in primates, they seem to have happened only in isolated and rather exceptional cases among non-primates (e.g. elephants, equids).”
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?
According to the social brain hypothesis, the high degree of encephalization reached by the neocortex of social mammals, especially Homo sapiens, may be a direct consequence of the cognitive demands required for the stable management of complex relationships within social groups.
“the high degree of encephalization reached by the neocortex of social mammals, especially by Homo sapiens, may be a direct consequence of the cognitive demands required for the stable management of complex relationships that occur within social groups”
From Internet use and access, behavior, cyberbullying, and grooming: Results of an investigative whole city survey of adolescents (2017) · cites this paper as [39]
Dunbar has identified an approximate number of 150 friends or social relationships that the individual human subject is actually able to maintain.
“Dunbar has come to identify an approximate number of 150 friends or social relationships that the individual human subject is actually able to maintain”
From Internet use and access, behavior, cyberbullying, and grooming: Results of an investigative whole city survey of adolescents (2017) · cites this paper as [39]
Cites
A Coefficient of Agreement for Nominal Scales
Cohen, J. (1960) · Educational and Psychological Measurement · doi:10.1177/001316446002000104 · Cited by 42,398 · see citing works
APE: Analyses of Phylogenetics and Evolution in R language
Paradis, E., Claude, J., & Strimmer, K. (2004) · Bioinformatics · doi:10.1093/bioinformatics/btg412 · Cited by 12,037 · see citing works
Gentleman R: R: A language for data analysis and graphics
Ihaka, R., & Gentleman, R. (1996) · Journal of Computational and Graphical Statistics · doi:10.1080/10618600.1996.10474713 · Cited by 11,747 · see citing works
The comparative method in evolutionary biology
(1992) · Choice Reviews Online · doi:10.5860/choice.29-5104 · Cited by 4,926 · see citing works
The Comparative Method in Evolutionary Biology
Harvey, P. H., & Pagel, M. D. (1991) · doi:10.1093/oso/9780198546412.001.0001 · Cited by 4,337 · see citing works
Nowak, R. (2018) · doi:10.1353/book.59141 · Cited by 4,102 · see citing works
Phylogenetic Analysis and Comparative Data: A Test and Review of Evidence
Freckleton, R. P., Harvey, P. H., & Pagel, M. (2002) · The American Naturalist · doi:10.1086/343873 · Cited by 2,604 · see citing works
Neocortex size as a constraint on group size in primates
Dunbar, R. I. M. (1992) · Journal of Human Evolution · doi:10.1016/0047-2484(92)90081-j · Cited by 2,542 · see citing works
Self-citationGrafen, A. (1989) · Philosophical Transactions of the Royal Society of London. B, Biological Sciences · doi:10.1098/rstb.1989.0106 · Cited by 2,142 · see citing works
The Comparative Method: Moving Beyond Qualitative and Quantitative Strategies
Ragin, C. C. (2014) · doi:10.1525/9780520957350 · Cited by 2,130 · see citing works
An Ecological Model of Female-Bonded Primate Groups
Wrangham, R. W. (1980) · Behaviour · doi:10.1163/156853980x00447 · Cited by 1,978 · see citing works
Kleiman, D. G. (1977) · The Quarterly Review of Biology · doi:10.1086/409721 · Cited by 1,436 · see citing works
Lovejoy, C. O. (1981) · Science · doi:10.1126/science.211.4480.341 · Cited by 1,396 · see citing works
Dunbar, R. (1988) · Springer eBooks · doi:10.1007/978-1-4684-6694-2 · Cited by 1,260 · see citing works
Self-citationSocial intelligence, innovation, and enhanced brain size in primates
Reader, S. M., & Laland, K. N. (2002) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.062041299 · Cited by 1,126 · see citing works
Pagel, M. D. (1999) · Systematic Biology · doi:10.1080/106351599260184 · Cited by 1,085 · see citing works
Testis weight, body weight and breeding system in primates
Harcourt, A. H., Harvey, P., Larson, S. G., & Short, R. V. (1981) · Nature · doi:10.1038/293055a0 · Cited by 988 · see citing works
Coalitions and Alliances in Humans and Other Animals.
Dunbar, R., Harcourt, A. H., & de Waal, F. Β. Μ. (1993) · Man · doi:10.2307/2803426 · Cited by 968 · see citing works
Self-citationLemur Social Behavior and Primate Intelligence
Jolly, A. (1966) · Science · doi:10.1126/science.153.3735.501 · Cited by 909 · see citing works
A composite estimate of primate phylogeny
Purvis, A. (1995) · Philosophical Transactions of the Royal Society B Biological Sciences · doi:10.1098/rstb.1995.0078 · Cited by 705 · see citing works
Clutton‐Brock, T. H., & Harvey, P. H. (1980) · Journal of Zoology · doi:10.1111/j.1469-7998.1980.tb01430.x · Cited by 550 · see citing works
On the Ultimate Causes of Primate Social Systems
van Schaik, C. P., & van Hooff, J. A. R. A. M. (1983) · Behaviour · doi:10.1163/156853983x00057 · Cited by 540 · see citing works
The Evolution of Monogamy: Hypotheses and Evidence
Wittenberger, J. F., & TILSON, R. L. (1980) · Annual Review of Ecology and Systematics · doi:10.1146/annurev.es.11.110180.001213 · Cited by 501 · see citing works
Understanding primate brain evolution
Dunbar, R. I. M., & Shultz, S. (2007) · Philosophical Transactions of the Royal Society B: Biological Sciences · doi:10.1098/rstb.2006.2001 · Cited by 392 · see citing works
Self-citationNeocortex size and social network size in primates
Kudo, H., & Dunbar, R. (2001) · Animal Behaviour · doi:10.1006/anbe.2001.1808 · Cited by 366 · see citing works
Self-citationDunbar, R. (2003) · Science · doi:10.1126/science.1092116 · Cited by 314 · see citing works
Self-citationFemale space use is the best predictor of monogamy in mammals
Komers, P. E., & Brotherton, P. N. M. (1997) · Proceedings of the Royal Society B Biological Sciences · doi:10.1098/rspb.1997.0174 · Cited by 301 · see citing works
Neocortex size and behavioural ecology in primates
Barton, R. A. (1996) · Proceedings of the Royal Society B Biological Sciences · doi:10.1098/rspb.1996.0028 · Cited by 299 · see citing works
Mother–infant bonding and the evolution of mammalian social relationships
Broad, K. D., Curley, J. P., & Keverne, E. B. (2006) · Philosophical Transactions of the Royal Society B: Biological Sciences · doi:10.1098/rstb.2006.1940 · Cited by 283 · see citing works
The Evolution of Monogamy in Large Primates: a New Hypothesis and Some Crucial Tests
van Schaik, C. P., & Dunbar, R. (1990) · Behaviour · doi:10.1163/156853990x00284 · Cited by 280 · see citing works
Self-citationCarnivore Brain Size, Behavioral Ecology, and Phylogeny
Gittleman, J. L. (1986) · Journal of Mammalogy · doi:10.2307/1380998 · Cited by 278 · see citing works
Harvey, P. H., & Krebs, J. R. (1990) · Science · doi:10.1126/science.2196673 · Cited by 261 · see citing works
Both social and ecological factors predict ungulate brain size
Shultz, S., & Dunbar, R. (2005) · Proceedings of the Royal Society B Biological Sciences · doi:10.1098/rspb.2005.3283 · Cited by 221 · see citing works
Self-citationBrain size and ecology in small mammals and primates.
Harvey, P., Clutton‐Brock, T. H., & Mace, G. M. (1980) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.77.7.4387 · Cited by 219 · see citing works
Extra-pair paternity, sperm competition and the evolution of testis size in birds
Møller, A. P., & Briskie, J. V. (1995) · Behavioral Ecology and Sociobiology · doi:10.1007/bf00167797 · Cited by 218 · see citing works
Mating system and brain size in bats
Pitnick, S., Jones, K. E., & Wilkinson, G. S. (2005) · Proceedings of the Royal Society B Biological Sciences · doi:10.1098/rspb.2005.3367 · Cited by 197 · see citing works
Neocortical development and social structure in primates
Sawaguchi, T., & Kudo, H. (1990) · Primates · doi:10.1007/bf02380949 · Cited by 178 · see citing works
Neocortex Size, Social Skills and Mating Success in Primates
Pawłowski, B., Lowen, & Dunbar (1998) · Behaviour · doi:10.1163/156853998793066285 · Cited by 149 · see citing works
Re‐Evaluating Primate Monogamy
Fuentes, A. (1998) · American Anthropologist · doi:10.1525/aa.1998.100.4.890 · Cited by 130 · see citing works
Life History, Activity Period and Lemur Social Systems
van Schaik, C. P., & Kappeler, P. M. (1993) · Springer eBooks · doi:10.1007/978-1-4899-2412-4_17 · Cited by 127 · see citing works
Dunbar, R., & Dunbar, E. P. (1980) · Animal Behaviour · doi:10.1016/s0003-3472(80)80026-1 · Cited by 104 · see citing works
Self-citationPrimate brain architecture and selection in relation to sex
Lindenfors, P., Nunn, C. L., & Barton, R. A. (2007) · BMC Biology · doi:10.1186/1741-7007-5-20 · Cited by 86 · see citing works
Is there a relationship between forebrain size and group size in birds
Beauchamp, G., & Fernández‐Juricic, E. (2004) · Evolutionary ecology research · Cited by 76 · see citing works
Neocortex evolution in primates: the ‘social brain’ is for females
Lindenfors, P. (2005) · Biology Letters · doi:10.1098/rsbl.2005.0362 · Cited by 75 · see citing works
Relative brain size in monkeys and prosimians
Armstrong, E. (1985) · American Journal of Physical Anthropology · doi:10.1002/ajpa.1330660303 · Cited by 59 · see citing works
Monogamy without biparental care in a dwarf antelope
Brotherton, P. N. M., & Rhodes, A. (1996) · Proceedings of the Royal Society B Biological Sciences · doi:10.1098/rspb.1996.0005 · Cited by 51 · see citing works
A Prisoner’s Dilemma Model of the Evolution of Paternal Care
Key, C. A., & Aiello, L. C. (2000) · Folia Primatologica · doi:10.1159/000021732 · Cited by 36 · see citing works
Dunbar, R. I. M. (1998) · Evolutionary Anthropology: Issues, News, and Reviews · doi:10.1002/(sici)1520-6505(1998)6:5
Self-citation
Flagged first, then by citations
Research works printed but not linked: 2
- Byrne R.W& Whiten A. 1988 Oxford UK:Oxford University Press.
- Smuts B.B Cheney D.L Seyfarth R.M Wrangham R.W& Struhsaker T.T. 1987 Chicago IL:University of Chicago Press.
Cited by
Sorted by citations
The evolution of self-control.
MacLean, E. L., Hare, B., Nunn, C. L., Addessi, E., Amici, F., Anderson, R. C., Aureli, F., Baker, J. M., Bania, A. E., Barnard, A. M., et al. (2014) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1323533111 · Cited by 819 · see citing works
The social role of touch in humans and primates: Behavioural function and neurobiological mechanisms
Dunbar, R. I. M. (2010) · Neuroscience & Biobehavioral Reviews · doi:10.1016/j.neubiorev.2008.07.001 · Cited by 798 · see citing works
Self-citationThe social brain hypothesis and its implications for social evolution
Dunbar, R. I. M. (2009) · Annals of Human Biology · doi:10.1080/03014460902960289 · Cited by 795 · see citing works
Self-citationSocial re-orientation and brain development: An expanded and updated view
Nelson, E. E., Jarcho, J. M., & Guyer, A. E. (2016) · Developmental Cognitive Neuroscience · doi:10.1016/j.dcn.2015.12.008 · Cited by 447 · see citing works
The microbiota-gut-brain axis: neurobehavioral correlates, health and sociality
Montiel-Castro, A. J., González-Cervantes, R. M., Bravo-Ruiseco, G., & Pacheco-López, G. (2013) · Frontiers in Integrative Neuroscience · doi:10.3389/fnint.2013.00070 · Cited by 413 · see citing works
Relationships and the social brain: Integrating psychological and evolutionary perspectives
Sutcliffe, A., Dunbar, R., Binder, J., & Arrow, H. (2012) · British Journal of Psychology · doi:10.1111/j.2044-8295.2011.02061.x · Cited by 415 · see citing works
Self-citationCognitive performance is linked to group size and affects fitness in Australian magpies
Ashton, B. J., Ridley, A. R., Edwards, E. K., & Thornton, A. (2018) · Nature · doi:10.1038/nature25503 · Cited by 336 · see citing works
Morality as Cooperation: A Problem-Centred Approach
Curry, O. S. (2016) · Evolutionary Psychology · doi:10.1007/978-3-319-19671-8_2 · Cited by 293 · see citing works
Parasites, democratization, and the liberalization of values across contemporary countries
Thornhill, R., Fincher, C. L., & Aran, D. (2009) · Biological Reviews · doi:10.1111/j.1469-185x.2008.00062.x · Cited by 260 · see citing works
Shultz, S., & Dunbar, R. (2010) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1005246107 · Cited by 238 · see citing works
Self-citationNeumann, I. D. (2009) · Frontiers in Neuroendocrinology · doi:10.1016/j.yfrne.2009.04.012 · Cited by 162 · see citing works
SHULTZ, S., & DUNBAR, R. I. M. (2010) · Biological Journal of the Linnean Society · doi:10.1111/j.1095-8312.2010.01427.x · Cited by 151 · see citing works
Self-citationSocial cognition on the Internet: testing constraints on social network size
Dunbar, R. I. M. (2012) · Philosophical Transactions of the Royal Society B: Biological Sciences · doi:10.1098/rstb.2012.0121 · Cited by 148 · see citing works
Self-citationOxytocin׳s role in anxiety: A critical appraisal
MacDonald, K., & Feifel, D. (2014) · Brain Research · doi:10.1016/j.brainres.2014.01.025 · Cited by 139 · see citing works
Pearce, E., Wlodarski, R., Machin, A., & Dunbar, R. I. M. (2017) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1700712114 · Cited by 131 · see citing works
Self-citationSocial isolation and the brain in the pandemic era
Bzdok, D., & Dunbar, R. I. M. (2022) · Nature Human Behaviour · doi:10.1038/s41562-022-01453-0 · Cited by 100 · see citing works
Self-citationGibbonFACS: A Muscle-Based Facial Movement Coding System for Hylobatids
Waller, B. M., Lembeck, M., Kuchenbuch, P., Burrows, A. M., & Liebal, K. (2012) · International Journal of Primatology · doi:10.1007/s10764-012-9611-6 · Cited by 97 · see citing works
Evolution of brain size in class-based societies of fungus-growing ants (Attini).
Riveros, A. J., Seid, M. A., & Wcislo, W. T. (2012) · Animal Behaviour · doi:10.1016/j.anbehav.2012.01.032 · Cited by 74 · see citing works
Videos of conspecifics elicit interactive looking patterns and facial expressions in monkeys
Mosher, C. P., Zimmerman, P. E., & Gothard, K. M. (2011) · Behavioral Neuroscience · doi:10.1037/a0024264 · Cited by 67 · see citing works
Wartel, A., Lindenfors, P., & Lind, J. (2019) · PLOS ONE · doi:10.1371/journal.pone.0218655 · Cited by 40 · see citing works
Allomaternal care, brains and fertility in mammals: who cares matters
Heldstab, S. A., Isler, K., Burkart, J. M., & van Schaik, C. P. (2019) · Behavioral Ecology and Sociobiology · doi:10.1007/s00265-019-2684-x · Cited by 29 · see citing works
Vismara, M. F. M., Toaff, J., Pulvirenti, G., Settanni, C., Colao, E., Lavano, S. M., Cemicetti, R., Cotugno, D., Perrotti, G., Meschesi, V., et al. (2017) · Interactive Journal of Medical Research · doi:10.2196/ijmr.6231 · Cited by 19 · see citing works
- Authors
- Shultz, S., & Dunbar, R. I. M.
- Affiliations
- University of Liverpool (GB)
- Venue
- Proceedings of the Royal Society B: Biological Sciences
- Publisher
- The Royal Society
- Published
- 2007-07-25
- Volume
- 274
- Issue
- 1624
- Pages
- 2429-2436
- ISSN
- 0080-4649 (ISSN-L)
- 0962-8452
- 1471-2954
- PMC
- PMC2274976
- OpenAlex
- W2122836078
- Semantic Scholar
- b79c02cc08759e468f50acf9c829e1d005db441d
- Cited by
- 344
- References
- 48
- Citations by year
- 2026: 8 · 2025: 11 · 2024: 26 · 2023: 19 · 2022: 19 · 2021: 34 · 2020: 25 · 2019: 18 · 2018: 19 · 2017: 26 · 2016: 21 · 2015: 14 · 2014: 15 · 2013: 12 · 2012: 28
- FWCI
- 16.67
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Proceedings of the Royal Society B Biological Sciences (publishedVersion)
- Europe PMC (PubMed Central) (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Research Explorer (The University of Manchester) (submittedVersion)
- Topics
- Social Sciences › Psychology › Social Psychology › Primate Behavior and Ecology
- Life Sciences › Agricultural and Biological Sciences › Ecology, Evolution, Behavior and Systematics › Animal Behavior and Reproduction
- Social Sciences › Psychology › Experimental and Cognitive Psychology › Evolutionary Psychology and Human Behavior
- Keywords
- social brain hypothesis, brain size, anthropoid primates, group living, group size, social coordination, comparative neuroanatomy, birds, mammals, Carnivora, Artiodactyla, bats
- MeSH terms
- Animals, Birds, Brain, Biological Evolution, Female, Male, Mammals, Organ Size, Pair Bond, Primates, Social Behavior
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.
Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.
Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.
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
