The roles of social information, asocial information, and initial bias in nest-building decisions.

Animals can use asocial (e.g., environmental cues) or social (e.g., conspecific behavior) information when making decisions. We investigated decisions made by zebra finches when asocial and social sources conveyed agreeing or conflicting information, and assessed the influence of initial bias on decision making. Finches completed an initial preference test ranking preference for three colors of nest-building material. Birds in the agree group (n = 14) then observed demonstrators build nests using nonpreferred color material (social information) that matched the environment color (asocial information). Birds in the conflict group (n = 15) observed demonstrators build nests with nonpreferred color material that did not match the cage environment (another nonpreferred color). A final preference test assessed any changes in color preference. The agree group reduced average preference for their initially preferred color, but did not significantly increase average preference for the asocial/social colors. The conflict group also reduced average preference for the initially preferred color and also increased preference for the socially demonstrated color. Observers with stronger initial bias were less likely to choose the socially demonstrated color than observers with weaker initial bias. This shows that social information informs nest-building decisions, even when in conflict with asocial information. However, bias influences social information use and adds nuance to how different individuals use information when making decisions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Zebra finches have style: Nest morphology is repeatable and associated with experience.

We investigated whether birds build nests in repeatable styles and, if so, whether styles were associated with past nest-building experience. Laboratory, captive bred zebra finches in an Experimental group were given nest-building experience, whereas, birds in a Control group were not. Each pair (n = 20) then built four nests that underwent image analyses for nest size, geometric shape and entrance orientation. Birds built nests in repeatable styles, with lower morphometric variation among nests built by the same pair and higher morphometric variation among nests built by different pairs. Morphology was not associated with construction time, body weight, nor age of birds. We found lower morphometric variation among nests built by the Experimental group, which also used less material to build nests compared to the Control group. Prior experience may therefore have been advantageous, as learning to reduce material usage while achieving a similar product (nest) may have lowered building costs.

Effect of feed-time duration on discrimination of vocalizations in a go/no-go operant paradigm.

Refining and modifying experimental procedures play a vital role in improving methodology while also reducing animal distress. In this study, we asked if an increase in feed time duration affects discrimination in an operant go/no-go task. Specifically, we used zebra finches' sexually dimorphic distance calls as acoustic stimuli to test whether there were any significant differences in performance on an operant discrimination task requiring zebra finches to classify calls according to the sex of the producer when a key experimental parameter, feed time duration, was increased from 1 s to 2 s. We found no differences in learning speed (trials to criterion) between birds that were given 1 s or 2 s of food access following a correct go response. Our results indicate doubling food access duration did not impact the speed of acquisition of distance call discrimination in zebra finches. These findings suggest that we can provide twice as much time for zebra finches to access food, potentially improving animal welfare, with no impact on experimental outcomes.

Among-individual differences in auditory and physical cognitive abilities in zebra finches.

Among-individual variation in performance on cognitive tasks is ubiquitous across species that have been examined, and understanding the evolution of cognitive abilities requires investigating among-individual variation because natural selection acts on individual differences. However, relatively little is known about the extent to which individual differences in cognition are determined by domain-specific compared with domain-general cognitive abilities. We examined individual differences in learning speed of zebra finches across seven different tasks to determine the extent of domain-specific versus domain-general learning abilities, as well as the relationship between learning speed and learning generalization. Thirty-two zebra finches completed a foraging board experiment that included visual and structural discriminations, and then these same birds went through an acoustic operant discrimination experiment that required discriminating between different natural categories of acoustic stimuli. We found evidence of domain-general learning abilities as birds' relative performance on the seven learning tasks was weakly repeatable and a principal components analysis found a first principal component that explained 36% of the variance in performance across tasks with all tasks loading unidirectionally on this component. However, the few significant correlations between tasks and high repeatability within each experiment suggest the potential for domain-specific abilities. Learning speed did not influence an individual's ability to generalize learning. These results suggest that zebra finch performance across visual, structural, and auditory learning relies upon some common mechanism; some might call this evidence of "general intelligence"(g), but it is also possible that this finding is due to other noncognitive mechanisms such as motivation.

Do sex differences in construction behavior relate to differences in physical cognitive abilities?

Nest-building behaviour in birds may be particularly relevant to investigating the evolution of physical cognition, as nest building engages cognitive mechanisms for the use and manipulation of materials. We hypothesized that nest-building ecology may be related to physical cognitive abilities. To test our hypothesis, we used zebra finches, which have sex-differentiated roles in nest building. We tested 16 male and 16 female zebra finches on three discrimination tasks in the following order: length discrimination, flexibility discrimination, and color discrimination, using different types of string. We predicted that male zebra finches, which select and deposit the majority of nesting material and are the primary nest builders in this species, would learn to discriminate string length and flexibility-structural traits relevant to nest building-in fewer trials compared to females, but that the sexes would learn color discrimination (not structurally relevant to nest building) in a similar number of trials. Contrary to these predictions, male and female zebra finches did not differ in their speed to learn any of the three tasks. There was, however, consistent among-individual variation in performance: learning speed was positively correlated across the tasks. Our findings suggest that male and female zebra finches either (1) do not differ in their physical cognitive abilities, or (2) any cognitive sex differences in zebra finches are more specific to tasks more closely associated with nest building. Our experiment is the first to examine the potential evolutionary relationship between nest building and physical cognitive abilities.

The impact of environmental and social factors on learning abilities: a meta-analysis.

Since the 1950s, researchers have examined how differences in the social and asocial environment affect learning in rats, mice, and, more recently, a variety of other species. Despite this large body of research, little has been done to synthesize these findings and to examine if social and asocial environmental factors have consistent effects on cognitive abilities, and if so, what aspects of these factors have greater or lesser impact. Here, we conducted a systematic review and meta-analysis examining how different external environmental features, including the social environment, impact learning (both speed of acquisition and performance). Using 531 mean-differences from 176 published articles across 27 species (with studies on rats and mice being most prominent) we conducted phylogenetically corrected mixed-effects models that reveal: (i) an average absolute effect size |d| = 0.55 and directional effect size d = 0.34; (ii) interventions manipulating the asocial environment result in larger effects than social interventions alone; and (iii) the length of the intervention is a significant predictor of effect size, with longer interventions resulting in larger effects. Additionally, much of the variation in effect size remained unexplained, possibly suggesting that species differ widely in how they are affected by environmental interventions due to varying ecological and evolutionary histories. Overall our results suggest that social and asocial environmental factors do significantly affect learning, but these effects are highly variable and perhaps not always as predicted. Most notably, the type (social or asocial) and length of interventions are important in determining the strength of the effect.

Medial amygdala ERα expression influences monogamous behaviour of male prairie voles in the field.

Formation of long-term pair-bonds is a complex process, involving multiple neural circuits and is context- and experience-dependent. While laboratory studies using prairie voles have identified the involvement of several neural mechanisms, efforts to translate these findings into predictable field outcomes have been inconsistent at best. Here we test the hypothesis that inhibition of oestrogen receptor alpha (ERα) in the medial amygdala of male prairie voles would significantly increase the expression of social monogamy in the field. Prairie vole populations of equal sex ratio were established in outdoor enclosures with males bred for high levels of ERα expression and low levels of prosocial behaviour associated with social monogamy. Medial amygdala ERα expression was knocked down in half the males per population. Knockdown males displayed a greater degree of social monogamy in five of the eight behavioural indices assessed. This study demonstrates the robust nature of ERα in playing a critical role in the expression of male social monogamy in a field setting.

Learning about construction behaviour from observing an artefact: can experience with conspecifics aid in artefact recognition?

Observation of or interaction with the enduring products of behaviour, called 'social artefacts' (e.g. an abandoned nest) is a potential source of social information. To learn from an artefact, that artefact needs to be recognized as the product of a behaviour that can provide relevant information (i.e. the artefact should be recognized as a nest). We used zebra finches (Taeniopygia guttata) to experimentally test whether observing a conspecific using a nest facilitates recognition of a future artefact as a source of social information. We manipulated the opportunity to form an association between a conspecific and their nest: half the subjects observed a pair of birds incubating eggs in a nest, the control subjects did not get this opportunity. Then, subjects observed an artefact made of their non-preferred colour and finally were allowed to build a nest. We predicted that the subjects given the opportunity to associate a nest with conspecifics would copy the colour of the artefact (i.e. use social information). We found that subjects who had the opportunity to learn what a nest is used social information obtained from the artefact by increasing their use of the artefact-material colour after artefact observation, while control birds did not. These data suggest that forming an association between conspecifics and their nest facilitates recognition of an artefact as a nest affecting how first-time builders use social information. This finding is important because it demonstrates that social learning is not limited to observing behaviour, but rather inferring behaviour from an artefact.

If it ain't broke don't fix it: Breeding success affects nest-building decisions.

Observational studies in the wild suggest that birds select material to build their nests based on functional aspects of material that promote reproductive success. How birds select material for nest building from the variety of materials available in their environment is unclear. In the current laboratory experiment we manipulated breeding success (i.e. raising fledglings) of zebra finch (Taeniopygia guttata) pairs to test if this affects the subsequent selection of nest material between a familiar versus a novel material, that differ in structural properties. All birds experienced one breeding attempt using coconut fiber as nest material during which their breeding success was manipulated: half of the breeding pairs fledged their nestlings while the remaining pairs had their eggs removed to simulate nest failure. In a second nest-building attempt, all pairs were given access to both familiar nesting material (coconut fiber) and a novel nesting material (white cotton string). Pairs that were successful in their first breeding attempt built their second nest with significantly more familiar material compared to novel material. Pairs that were unsuccessful, however, incorporated similar amounts of familiar and novel material in their second attempt. Our results show that experiencing either a successful or an unsuccessful breeding attempt influences how birds select between familiar and novel material with different structural properties (e.g. flexibility, thickness) to build a second nest. Moreover, our experiment shows that learning from experience plays an important role for decision making in future structure-building endeavors.

Breeding patterns of female prairie voles (Microtus ochrogaster) displaying alternative reproductive tactics.

Individuals of either sex may display alternative behaviors to obtain copulations, but few studies have examined the breeding patterns of females and males in populations where individuals of both sexes exhibit alternative reproductive tactics (ARTs). In prairie voles (Microtus ochrogaster), most adults are territorial, residing at a single nest site either as male-female pairs or as solitary individuals. However, some adults adopt nonterritorial, wandering tactics. During two field seasons monitoring prairie vole populations maintained in seminatural enclosures, we found evidence that females exhibiting different ARTs bred differentially with resident and wandering males. Females residing at a nest with a male bred significantly more often with a paired resident male, primarily their social partner, and significantly less often with male wanderers compared to single resident females or wandering females. These patterns were not due to chance, because paired resident females produced offspring with paired resident males significantly more than expected based on the relative abundance of these males in the population, whereas single resident females produced offspring with male wanderers significantly more than expected based on the proportion of male wanderers in the population. We did not find any evidence that multiple paternity was greater in the litters of single resident females and wanderer females even though these females lacked a male social partner to limit mating access by multiple males. This suggests that mate guarding by a female's male social partner was not the primary determinant of multiple paternity in the litters of females exhibiting different reproductive tactics. However, male ART did affect the likelihood of multiple paternity. Females that produced offspring with single resident or wanderer males had an increased likelihood of multiple paternity relative to females producing offspring with paired resident males. The results of this study show that female and male ARTs can affect breeding patterns.

Questioning the developmental effects of group size on cognitive abilities.

Australian magpies living in larger social groups learned quicker and made fewer errors across four cognitive tasks compared with birds living in smaller social groups, and this pattern may be driven by a developmental effect associated with the cognitive demands of living in larger groups. While Smulders (2018, Learning and Behavior, 1-2, doi:10.3758/s13420-018-0335-0) questioned whether this group size-cognitive performance pattern was driven by motivation rather than cognitive abilities, we question whether there is truly evidence of a developmental effect and whether the relationship between group size and cognitive performance can be explained in other ways. We highlight potential alternative explanations for the relationship between group size and cognitive performance and highlight some of the theoretical issues underlying the developmental effects of group size on cognitive abilities.