How does cognition evolve? Phylogenetic comparative psychology

May combine two claims.

In our example dataset, the maximum likelihood estimate of λ for the cognitive data was near to 0, indicating that more closely related species do not have more similar trait values.

“In our example dataset, the maximum likelihood estimate of λ for the cognitive data was near to 0, indicating that more closely related species do not have more similar trait values.”

May combine two claims.

Likelihood ratio tests reveal that the maximum likelihood estimate for λ does not provide a better fit to the cognitive data than a model in which λ is fixed to 0 (likelihood ratio = ~0, P = 1.0) or 1 (likelihood ratio = 2.85, P = 0.09).

“These tests reveal that the maximum likelihood estimate for λ does not provide a better fit to the cognitive data than a model in which λ is fixed to 0 (likelihood ratio = ~0, P = 1.0) or 1 (likelihood ratio = 2.85, P = 0.09).”

Probably not a substantial claim: may not pass S3 (load-bearing).

The initial suggested comparisons from phylogenetic targeting include the pairing of Daubentonia madagascariensis with Ateles geoffroyi.

“the initial suggested comparisons include the odd pairing of the nocturnal, solitary aye–aye (Daubentonia madagascariensis), with the diurnal, fission–fusion spider monkey (Ateles geoffroyi).”

May combine two claims.

Without recourse to questions of phylogenetic history and function, we cannot understand how or when species evolved to differ cognitively, and we cannot test why certain lineages-including humans-have evolved the cognitive abilities they possess.

“Without recourse to questions of phylogenetic history and function, we cannot understand how or when species evolved to differ cognitively. Moreover, we cannot test why certain lineages—including humans—have evolved the cognitive abilities they possess.”

Probably not a substantial claim: may not pass S4 (based).

Phylogenetic methods can estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species.

“(3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species”

May combine two claims.

Such studies have rarely been conducted with large taxonomic samples; more typically, pairs of closely related species are compared, often with different tests used for different pairs of species, so each study provides a single comparison (N = 1) and it is difficult to generalize results across species.

“However, such studies have rarely been conducted with large taxonomic samples; more typically, pairs of closely related species are compared, often with different tests used for different pairs of species. Each study therefore provides a single comparison (N = 1), and it is difficult to generalize results across species.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The procedure used with lemurs differed from that used with monkeys and apes, so data from the two tasks are combined here strictly for illustrative purposes.

“The procedure used with lemurs differed from that used with monkeys and apes so data from the two tasks are combined here strictly for illustrative purposes.”

May combine two claims.

Many behavioral phenotypes also exhibit phylogenetic signal, and the same principle is likely true for cognition.

“Many behavioral phenotypes also exhibit phylogenetic signal (Freckleton et al. 2002; Blomberg et al. 2003; Thierry et al. 2008), and the same principle is likely true for cognition.”

• cites Freckleton et al. 2002Not checked yet

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• cites Blomberg et al. 2003Not checked yet

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• cites Thierry et al. 2008Not checked yet

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Probably not a substantial claim: may not pass S4 (based).

Phylogenetic methods can guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (phylogenetic targeting).

“Phylogenetic methods can also be used to guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (i.e., phylogenetic targeting).”

May combine two claims.

Many comparative phylogenetic statistical methods require that branch lengths reflect the amount of time since lineages diverged, and that is true in the phylogeny for species in our dataset.

“Many comparative phylogenetic statistical methods require that branch lengths reflect the amount of time since lineages diverged and that is true in the phylogeny for species in our dataset (Fig. 2; consensus tree downloaded from http://www.10ktrees.fas.harvard.edu).”

May combine two claims.

A phylogenetic comparative approach allows for analysis of inter-specific variation in cognitive traits and can be used to make inferences about the likely traits of extinct species and to pinpoint when and where important cognitive changes occurred.

“A phylogenetic comparative approach allows for analysis of this inter-specific variation and can be used to make inferences about the likely traits of extinct species. It can also be used to pinpoint when (in time) and where (in phylogeny) important cognitive changes have occurred.”

May combine two claims.

Inhibitory control-the ability to resist a prepotent behavioral response-is central to solving many problems and has been linked to social competence, criminal behavior, health, and economic status in humans.

“Inhibitory control—the ability to resist a prepotent behavioral response—is central to solving many problems (Diamond 1990; Hauser 1999) and has been linked to social competence, criminal behavior, health, and economic status in humans (Mischel et al. 1989; Moffitt et al. 2011).”

• cites Diamond 1990Not checked yet

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• cites Hauser 1999Not checked yet

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• cites Mischel et al. 1989 sourceNot checked yet

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May combine two claims.

Empirical evidence suggests that there is no one-to-one relationship between cognitive flexibility and brain size, and cognitive skills across different domains are not necessarily highly correlated with each other either within or across species.

“Empirical evidence suggests that there is no one-to-one relationship between cognitive flexibility and brain size, while cognitive skills across different domains are not necessarily highly correlated with each other either within or across species”

• cites Hare et al. 2002Not checked yet

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• cites Emery and Clayton 2004Not checked yet

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• cites Herrmann et al. 2007Not checked yet

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May combine two claims.

The last two of Tinbergen's four questions-phylogeny and function-are intractable without a phylogenetic comparative perspective and have historically been the most challenging for comparative psychologists to pursue.

“However, the last two questions of phylogeny and function, which address how, when, and why a cognitive trait evolved, are intractable without a phylogenetic comparative perspective and have historically been the most challenging for comparative psychologists to pursue.”

• cites Tinbergen 1963Not checked yet

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• cites Shettleworth 2010Not checked yet

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Probably not a substantial claim: may not pass S4 (based).

Phylogenetic methods can measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species.

“(2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species”

May combine two claims.

A lower amount of phylogenetic signal may reflect high levels of individual differences within a species, substantial error in measurement of the trait, or suggest that independent variables (e.g., social/ecological) have influenced the evolution of the trait relatively independently from phylogeny.

“For example, a lower amount of phylogenetic signal may reflect high levels of individual differences within a species, substantial error in measurement of the trait, or suggest that independent variables (e.g., social/ecological) have influenced the evolution of the trait relatively independently from phylogeny (Blomberg et al. 2003; Ives et al. 2007).”

• cites Blomberg et al. 2003Not checked yet

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• cites Ives et al. 2007Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

In the latter case, λ estimates whether the deviations from the predicted values in a phylogenetic regression are correlated with species' expected covariance due to shared evolutionary history.

“In the latter case, λ estimates whether the deviations from the predicted values in a phylogenetic regression are correlated with species’ expected covariance due to shared evolutionary history.”

May combine two claims.

In an analysis of 119 traits, Blomberg et al. (2003) showed that anatomical traits (e.g., body mass) tended to exhibit more phylogenetic signal than behavioral traits (e.g., daily path length), corroborating the long-held notion that behavior is more evolutionarily labile than morphology.

“For example, in an analysis of 119 traits, Blomberg et al. (2003) showed that anatomical traits (e.g., body mass) tended to exhibit more phylogenetic signal than behavioral traits (e.g., daily path length), corroborating the long-held notion that behavior is more evolutionarily labile than morphology (i.e., “behavioral drive”, Mayr 1963).”

• cites Blomberg et al. 2003Not checked yet

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• cites Mayr 1963Not checked yet

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May combine two claims.

In analyses of comparative data, weak phylogenetic signal may indicate that strict phylogenetic statistical approaches are not needed or may not be particularly informative (e.g., when reconstructing ancestral states on the tree).

“In analyses of comparative data, weak phylogenetic signal may indicate that strict phylogenetic statistical approaches are not needed (Abouheif 1999) or may not be particularly informative (e.g., when reconstructing ancestral states on the tree).”

• cites Abouheif 1999Not checked yet

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May combine two claims.

New phylogenetic methods allow researchers to reconstruct values at ancestral nodes in a phylogeny and to place statistical measures of confidence on these reconstructions.

“new phylogenetic methods allow researchers to reconstruct values at the ancestral nodes in a phylogeny and to place statistical measures of confidence on these reconstructions (Schluter et al. 1997; Garland et al. 1999; Pagel et al. 2004).”

• cites Schluter et al. 1997Not checked yet

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• cites Garland et al. 1999Not checked yet

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• cites Pagel et al. 2004Not checked yet

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• AssumptionRests on an assumption: Cognitive performance does not fossilize, so one cannot directly measure the cognitive traits of extinct species.

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Phylogenetic signal may be low for traits that are highly conserved among all taxa in a phylogeny (e.g., vertebrate body plans).

“Similarly, phylogenetic signal may be low for traits that are highly conserved among all taxa in a phylogeny (e.g., vertebrate body plans).”

Probably not a substantial claim: may not pass S3 (load-bearing).

A common way to investigate adaptive hypotheses involves testing whether two or more traits covary across species.

“A common way to investigate adaptive hypotheses involves testing whether two or more traits covary across species.”

May combine two claims.

Analyses incorporating phylogenetic information increase statistical power to detect real relationships and reduce the probability of erroneously inferring significance when no association exists.

“analyses incorporating phylogenetic information increase statistical power to detect real relationships, while reducing the probability of erroneously inferring significance when no association exists (Garland et al. 1992; Rohlf 2006).”

• Also stated in: § Correlated evolution · plain

  “phylogenetic approaches provide superior statistical performance in terms of reducing both false positives (type I error rates) and false negatives (i.e., increasing statistical power).”

• cites Garland et al. 1992Not checked yet

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• cites Rohlf 2006Not checked yet

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May combine two claims.

Recent methodological advances provide a way to assess phylogenetic signal with quantitative metrics, and even to scale the branches of a phylogenetic tree to reflect the strength of phylogenetic signal.

“Recent methodological advances provide a way to assess phylogenetic signal with quantitative metrics, and even to scale the branches of a phylogenetic tree to reflect the strength of phylogenetic signal (Freckleton et al. 2002; Blomberg et al. 2003).”

• cites Freckleton et al. 2002Not checked yet

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• cites Blomberg et al. 2003Not checked yet

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May combine two claims.

Because species values in comparative studies may be similar due to descent from a common ancestor, the assumption of independence is commonly violated, and this nonindependence results in phylogenetic signal.

“However, because species values in comparative studies may be similar due to descent from a common ancestor, this assumption is commonly violated, and it is this nonindependence that results in phylogenetic signal.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The parameter λ can estimate phylogenetic signal in the raw data (e.g., species values for a trait) or alternatively in the residual variance from a phylogenetic regression.

“The parameter λ can estimate phylogenetic signal in the raw data (e.g., species values for a trait) or alternatively in the residual variance from a phylogenetic regression (Revell 2010).”

• cites Revell 2010Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

Estimates of λ that are significantly greater than zero provide evidence for phylogenetic signal in the data.

“Estimates of λ that are significantly greater than zero provide evidence for phylogenetic signal in the data.”

Probably not a substantial claim: may not pass S2 (checkable).

This finding highlights the importance of generating large comparative cognitive databases in order to test whether particular cognitive traits exhibit phylogenetic signal.

“This finding highlights the importance of generating large comparative cognitive databases in order to test whether particular cognitive traits exhibit phylogenetic signal (i.e., with a larger sample, we would have more confidence in the lack of phylogenetic signal in our example analysis).”

May combine two claims.

The example dataset is a small sample by comparative biology standards, so we cannot rule out the possibility that low statistical power is responsible for the lack of phylogenetic signal observed.

“However, the example dataset, which is relatively large by comparative psychology standards, is a small sample by comparative biology standards. Consequently, we cannot rule out the possibility that low statistical power is responsible for the lack of phylogenetic signal observed.”

Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

Determining the strength of phylogenetic signal in a given dataset facilitates the use of appropriate statistics and guides decisions regarding how to interpret statistical results.

“Therefore, determining the strength of phylogenetic signal in a given dataset facilitates the use of appropriate statistics and guides decisions regarding how to interpret statistical results.”

May combine two claims.

With a phylogeny, it becomes possible to examine correlated evolutionary change directly along the branches of the tree, for example with the method of independent contrasts, or to statistically control for nonindependence in the underlying data, for example by using phylogenetic generalized least squares (PGLS).

“With a phylogeny, it becomes possible to examine correlated evolutionary change directly along the branches of the tree, for example with the method of independent contrasts (Felsenstein 1985; Garland et al. 1992; Nunn and Barton 2001). Alternatively, one can use the phylogeny to statistically control for nonindependence in the underlying data, for example by using phylogenetic generalized least”

• cites Felsenstein 1985 sourceNot checked yet

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• cites Garland et al. 1992Not checked yet

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• cites Nunn and Barton 2001Not checked yet

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Probably not a substantial claim: may not pass S4 (based).

An assumption of standard correlation and regression analyses is that data points (e.g., each species) are statistically independent of one another.

“An assumption of standard correlation and regression analyses is that data points (e.g., each species) are statistically independent of one another.”

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

If intraspecific variation is large relative to interspecific variation, species differences should be interpreted with great caution.

“If intraspecific variation is large relative to interspecific variation, species differences should be interpreted with great caution.”

Probably not a substantial claim: may not pass S4 (based).

The majority of comparative psychologists study only one or a few species.

“The majority of comparative psychologists study only one or a few species (e.g., due to the cost of establishing and maintaining a conventional laboratory population).”

May combine two claims.

The process of one group adopting and modifying another's methods promotes iterative refinement but prevents broad coordinated comparison because testing methods differ among research groups.

“While this process promotes the iterative refinement of experimental procedures, with each study building on the former’s methods, it prevents broad coordinated comparison because testing methods end up differing among research groups.”

• AssumptionRests on an assumption: At present, there have been few attempts at this level of collaboration.

May combine two claims.

Species will differ in contextual variables such as food motivation, perceptual mechanisms, attention, experimental experience, and housing conditions, all of which may affect behavioral results.

“species will differ in their food motivation, perceptual mechanisms, attention, experimental experience, and housing conditions, all of which may affect behavioral results (Macphail 1987).”

• cites Macphail 1987Not checked yet

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Amici et al. (2008) compared seven primate species on five different tasks that assess inhibitory control, ranking species within each task and averaging ranks across tasks to approximate relative capacities for inhibitory control.

“Amici et al. (2008) compared seven primate species on five different tasks that assess inhibitory control. Species were ranked within each task, and these ranks were averaged across tasks to approximate relative capacities for inhibitory control.”

• cites Amici et al. (2008) sourceNot checked yet

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Classified as probably not a substantial claim. May combine two claims.

Phylogenetic targeting allows users to focus on the variable of interest while controlling for other potential confounds or testing constraints, conferring flexibility and statistical power for designing comparative tests.

“Because phylogenetic targeting allows users to focus on the variable of interest, while simultaneously controlling for other potential confounds or testing constraints, it confers flexibility and statistical power for designing comparative tests.”

• AssumptionRests on an assumption: A comparative approach to cognition requires building large datasets across a diverse range of species.
• AssumptionRests on an assumption: It is prohibitive to collect data on all possible species in a large group of organisms such as primates given finite resources and time.

May combine two claims.

Many other studies of animal cognition have produced highly similar results in different populations, and species differences have been replicated across multiple paradigms and populations.

“many other studies of animal cognition have produced highly similar results in different populations (e.g., mirror self-recognition—reviewed in Povinelli et al. 1993; point following in dogs—reviewed in Miklosi and Soproni 2006; perspective taking in chimpanzees—reviewed in Hare 2011); and species differences have been replicated across multiple paradigms and populations (e.g., spatial cognition”

• cites Povinelli et al. 1993Not checked yet

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• cites Miklosi and Soproni 2006Not checked yet

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• cites Hare 2011Not checked yet

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Probably not a substantial claim: may not pass S3 (load-bearing).

Phylogenetic targeting can be implemented via a user-friendly web page.

“methods such as “phylogenetic targeting” (Arnold and Nunn 2010), which can be implemented via a user-friendly web page (http://www.phylotargeting.fas.harvard.edu/).”

• cites Arnold and Nunn 2010Not checked yet

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May combine two claims.

Phylogenetic comparative methods have been applied to the study of brain evolution but have yet to be applied to systematic investigations of cognitive variation between species as measured through behavioral assays, with few exceptions.

“While phylogenetic comparative methods have been applied to the study of brain evolution (e.g., Barton 1998; Dunbar 1998b; Deaner et al. 2000, 2007; Lindenfors et al. 2007; Isler and van Schaik 2009), with few exceptions (e.g., Amici et al. 2008; Shultz and Dunbar 2010), they have yet to be applied to systematic investigations of cognitive variation between species as measured through behavioral”

• cites Barton 1998Not checked yet

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• cites Amici et al. 2008 sourceNot checked yet

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• cites Shultz and Dunbar 2010 sourceNot checked yet

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• AssumptionRests on an assumption: Having made progress toward revealing development and causal mechanisms of problem-solving skills in animals, we are now in a position to quantitatively examine the phylogenetic distribution and function of cognitive traits.

May combine two claims.

Researchers have identified links between feeding ecology and performance on memory tests, social dominance hierarchies and transitive reasoning, domestication's effect on cognition, fission-fusion dynamics and inhibitory control, and social relationships and cooperative problem-solving.

“researchers have now identified links between feeding ecology and performance on memory tests (Balda and Kamil 1989; Shettleworth 1990; Clayton and Krebs 1994; Jacobs and Spencer 1994; Macdonald 1997), social dominance hierarchies and transitive reasoning (Bond et al. 2003, 2010; Paz-y-Miño et al. 2004; Grosenick et al. 2007; MacLean et al. 2008), domestication’s effect on cognition (Hare et al.”

• cites Balda and Kamil 1989Not checked yet

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• cites Bond et al. 2003Not checked yet

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• cites Hare et al. 2002Not checked yet

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Probably not a substantial claim: may not pass S2 (checkable).

To determine whether these associations reflect robust evolutionary relationships, we need to explore these questions from a phylogenetic comparative approach.

“In order to determine whether these associations reflect robust evolutionary relationships, we will need to explore these questions from a phylogenetic comparative approach.”

• AssumptionRests on an assumption: Having made progress toward revealing development and causal mechanisms of problem-solving skills in animals, we are now in a position to quantitatively examine the phylogenetic distribution and function of cognitive traits.

Probably not a substantial claim: may not pass S2 (checkable), S4 (based).

By adding phylogenetic techniques to our tool kit, comparative psychologists can build on past success by incorporating tests of correlated trait evolution, phylogenetic signal, and ancestral state reconstruction into our research.

“By adding phylogenetic techniques to our tool kit, comparative psychologists can build on past success by incorporating tests of correlated trait evolution, phylogenetic signal, and ancestral state reconstruction into our research.”

• AssumptionRests on an assumption: Having made progress toward revealing development and causal mechanisms of problem-solving skills in animals, we are now in a position to quantitatively examine the phylogenetic distribution and function of cognitive traits.