Limited receipt of support services among people with mild-to-moderate dementia: Findings from the IDEAL cohort.

BACKGROUND: Global initiatives that promote public health responses to dementia have resulted in numerous countries developing new national policies. Current policy guidelines in England, for example, recommend that people diagnosed with mild-to-moderate dementia receive information and psychosocial interventions to improve their ability to 'live well'. However, it remains unclear to what extent these recommendations are being achieved. METHODS: Self-reported information from 1537 people living with dementia and informant-reported information from 1277 carers of people living with dementia was used to quantify receipt of community-based dementia support services, including health and social care services provided by statutory or voluntary-sector organisations, in Britain from 2014 to 2016. Demographic factors associated with differences in receipt of support services were also investigated to identify particularly vulnerable groups of people living with dementia. RESULTS: Both self- and informant reports suggested that approximately 50% of people living with dementia received support services for dementia. Receipt of support services was lower among people living with dementia who are older, female, and have fewer educational qualifications. Receipt of support services also differed according to diagnosis and carer status, but was unrelated to marital status. CONCLUSIONS: Limited receipt of dementia support services among people living with dementia in Britain provides a baseline to assess the efficacy of current policy guidelines regarding provision of information and support. Targeted efforts to facilitate receipt of support services among the particularly vulnerable groups identified in the current study could improve the efficacy of dementia support services both in Britain and internationally, and should inform policy development.

Is habitat selection in the wild shaped by individual-level cognitive biases in orientation strategy?

Cognitive biases for encoding spatial information (orientation strategies) in relation to self (egocentric) or landmarks (allocentric) differ between species or populations according to the habitats they occupy. Whether biases in orientation strategy determine early habitat selection or if individuals adapt their biases following experience is unknown. We determined orientation strategies of pheasants, Phasianus colchicus, using a dual-strategy maze with an allocentric probe trial, before releasing them (n = 20) into a novel landscape, where we monitored their movement and habitat selection. In general, pheasants selected for woodland over non-woodland habitat, but allocentric-biased individuals exhibited weaker avoidance of non-woodland habitat, where we expected allocentric navigation to be more effective. Sex did not influence selection but was associated with speed and directional persistence in non-woodland habitat. Our results suggest that an individual's habitat selection is associated with inherent cognitive bias in early life, but it is not yet clear what advantages this may offer.

Response learning confounds assays of inhibitory control on detour tasks.

The ability to inhibit prepotent actions towards rewards that are made inaccessible by transparent barriers has been considered to reflect capacities for inhibitory control (IC). Typically, subjects initially reach directly, and incorrectly, for the reward. With experience, subjects may inhibit this action and instead detour around barriers to access the reward. However, assays of IC are often measured across multiple trials, with the location of the reward remaining constant. Consequently, other cognitive processes, such as response learning (acquisition of a motor routine), may confound accurate assays of IC. We measured baseline IC capacities in pheasant chicks, Phasianus colchicus, using a transparent cylinder task. Birds were then divided into two training treatments, where they learned to access a reward placed behind a transparent barrier, but experienced differential reinforcement of a particular motor response. In the stationary-barrier treatment, the location of the barrier remained constant across trials. We, therefore, reinforced a fixed motor response, such as always go left, which birds could learn to aid their performance. Conversely, we alternated the location of the barrier across trials for birds in the moving-barrier treatment and hence provided less reinforcement of their response learning. All birds then experienced a second presentation of the transparent cylinder task to assess whether differences in the training treatments influenced their subsequent capacities for IC. Birds in the stationary-barrier treatment showed a greater improvement in their subsequent IC performance after training compared to birds in the moving-barrier treatment. We, therefore, suggest that response learning aids IC performance on detour tasks. Consequently, non-target cognitive processes associated with different neural substrates appear to underlie performances on detour tasks, which may confound accurate assays of IC. Our findings question the construct validity of a commonly used paradigm that is widely considered to assess capacities for IC in humans and other animals.

The inhibitory control of pheasants (Phasianus colchicus) weakens when previously learned environmental information becomes unpredictable.

Inhibitory control (IC) is the ability to intentionally restrain initial, ineffective responses to a stimulus and instead exhibit an alternative behaviour that is not pre-potent but which effectively attains a reward. Individuals (both humans and non-human animals) differ in their IC, perhaps as a result of the different environmental conditions they have experienced. We experimentally manipulated environmental predictability, specifically how reliable information linking a cue to a reward was, over a very short time period and tested how this affected an individual's IC. We gave 119 pheasants (Phasianus colchicus) the opportunity to learn to associate a visual cue with a food reward in a binary choice task. We then perturbed this association for half the birds, whereas control birds continued to be rewarded when making the correct choice. We immediately measured all birds' on a detour IC task and again 3 days later. Perturbed birds immediately performed worse than control birds, making more unrewarded pecks at the apparatus than control birds, although this effect was less for individuals that had more accurately learned the initial association. The effect of the perturbation was not seen 3 days later, suggesting that individual IC performance is highly plastic and susceptible to recent changes in environmental predictability. Specifically, individuals may perform poorly in activities requiring IC immediately after information in their environment is perturbed, with the perturbation inducing emotional arousal. Our finding that recent environmental changes can affect IC performance, depending on how well an animal has learned about that environment, means that interpreting individual differences in IC must account for both prior experience and relevant individual learning abilities.

Early-life learning ability predicts adult social structure, with potential implications for fitness outcomes in the wild.

Social environments influence important ecological processes and can determine how selection acts on traits. Cognitive abilities can shape these social environments and in turn, affect individuals' fitness. To understand how cognitive abilities evolve, we need to understand the complex interplay between an individual's cognitive abilities, the social environment that they inhabit and the fitness consequences of these relationships. We measured the associative learning ability of pheasant chicks, Phasianus colchicus, then released them into the wild where we quantified their social position by observing their associations at feeding stations and monitored the number of days survived. We observed disassortative mixing by learning performance at the population level, and poor learners had more associates than good learners. Learning was beneficial for survival when focal individuals had fewer than four associates, but survival probability across learning abilities equalized for individuals with more than four associates. While the mechanisms underlying these relationships remain to be determined, the patterns of association exhibited by pheasants at feeders can be predicted by individual variation in cognitive performances and we suspect these patterns are related to differences in information use. Critically, these resulting patterns of association have fitness consequences for individuals that cannot be explained directly by their cognitive ability, but which could mediate selection on cognition.

No evidence that footedness in pheasants influences cognitive performance in tasks assessing colour discrimination and spatial ability.

The differential specialization of each side of the brain facilitates the parallel processing of information and has been documented in a wide range of animals. Animals that are more lateralized as indicated by consistent preferential limb use are commonly reported to exhibit superior cognitive ability as well as other behavioural advantages. We assayed the lateralization of 135 young pheasants (Phasianus colchicus), indicated by their footedness in a spontaneous stepping task, and related this measure to individual performance in either 3 assays of visual or spatial learning and memory. We found no evidence that pronounced footedness enhances cognitive ability in any of the tasks. We also found no evidence that an intermediate footedness relates to better cognitive performance. This lack of relationship is surprising because previous work revealed that pheasants have a slight population bias towards right footedness, and when released into the wild, individuals with higher degrees of footedness were more likely to die. One explanation for why extreme lateralization is constrained was that it led to poorer cognitive performance, or that optimal cognitive performance was associated with some intermediate level of lateralization. This stabilizing selection could explain the pattern of moderate lateralization that is seen in most non-human species that have been studied. However, we found no evidence in this study to support this explanation.

Unpredictable environments enhance inhibitory control in pheasants.

The ability to control impulsive actions is an important executive function that is central to the self-regulation of behaviours and, in humans, can have important implications for mental and physical health. One key factor that promotes individual differences in inhibitory control (IC) is the predictability of environmental information experienced during development (i.e. reliability of resources and social trust). However, environmental predictability can also influence motivational and other cognitive abilities, which may therefore confound interpretations of the mechanisms underlying IC. We investigated the role of environmental predictability, food motivation and cognition on IC. We reared pheasant chicks, Phasianus colchicus, under standardised conditions, in which birds experienced environments that differed in their spatial predictability. We systematically manipulated spatial predictability during their first 8 weeks of life, by either moving partitions daily to random locations (unpredictable environment) or leaving them in fixed locations (predictable environment). We assessed motivation by presenting pheasants with two different foraging tasks that measured their dietary breadth and persistence to acquire inaccessible food rewards, as well as recording their latencies to acquire a freely available baseline worm positioned adjacent to each test apparatus, their body condition (mass/tarsus3) and sex. We assessed cognitive performance by presenting each bird with an 80-trial binary colour discrimination task. IC was assessed using a transparent detour apparatus, which required subjects to inhibit prepotent attempts to directly acquire a visible reward through the barrier and instead detour around a barrier. We found greater capacities for IC in pheasants that were reared in spatially unpredictable environments compared to those reared in predictable environments. While IC was unrelated to individual differences in cognitive performance on the colour discrimination task or motivational measures, we found that environmental predictability had differential effects on sex. Males reared in an unpredictable environment, and all females regardless of their rearing environment, were less persistent than males reared in a predictable environment. Our findings, therefore, suggest that an individual's developmental experience can influence their performance on IC tasks.

A single factor explanation for associative learning performance on colour discrimination problems in common pheasants (Phasianus colchicus).

It remains unclear whether performance of non-human animals on cognitive test batteries can be explained by domain general cognitive processes, as is found in humans. The persistence of this dispute is likely to stem from a lack of clarity of the psychological or neural processes involved. One broadly accepted cognitive process, that may predict performance in a range of psychometric tasks, is associative learning. We therefore investigated intra-individual performances on tasks that incorporate processes of associative learning, by assessing the speed of acquisition and reversal learning in up to 187 pheasants (Phasianus colchicus) on four related binary colour discrimination tasks. We found a strong, positive significant bivariate relationship between an individual's acquisition and reversal learning performances on one cue set. Weak, positive significant bivariate relationships were also found between an individual's performance on pairs of reversal tasks and between the acquisition and reversal performances on different cue sets. A single factor, robust to parallel analysis, explained 36% of variation in performance across tasks. Inter-individual variation could not be explained by differential prior experience, age, sex or body condition. We propose that a single factor explanation, which we call 'a', summarises the covariance among scores obtained from these visual discrimination tasks, as they all assess capacities for associative learning. We argue that 'a' may represent an underlying cognitive ability exhibited by an individual, which manifests across a variety of tasks requiring associative processes.

Do detour tasks provide accurate assays of inhibitory control?

Transparent Cylinder and Barrier tasks are used to purportedly assess inhibitory control in a variety of animals. However, we suspect that performances on these detour tasks are influenced by non-cognitive traits, which may result in inaccurate assays of inhibitory control. We therefore reared pheasants under standardized conditions and presented each bird with two sets of similar tasks commonly used to measure inhibitory control. We recorded the number of times subjects incorrectly attempted to access a reward through transparent barriers, and their latencies to solve each task. Such measures are commonly used to infer the differential expression of inhibitory control. We found little evidence that their performances were consistent across the two different Putative Inhibitory Control Tasks (PICTs). Improvements in performance across trials showed that pheasants learned the affordances of each specific task. Critically, prior experience of transparent tasks, either Barrier or Cylinder, also improved subsequent inhibitory control performance on a novel task, suggesting that they also learned the general properties of transparent obstacles. Individual measures of persistence, assayed in a third task, were positively related to their frequency of incorrect attempts to solve the transparent inhibitory control tasks. Neophobia, Sex and Body Condition had no influence on individual performance. Contrary to previous studies of primates, pheasants with poor performance on PICTs had a wider dietary breadth assayed using a free-choice task. Our results demonstrate that in systems or taxa where prior experience and differences in development cannot be accounted for, individual differences in performance on commonly used detour-dependent PICTS may reveal more about an individual's prior experience of transparent objects, or their motivation to acquire food, than providing a reliable measure of their inhibitory control.

A novel continuous inhibitory-control task: variation in individual performance by young pheasants (Phasianus colchicus).

Inhibitory control enables subjects to quickly react to unexpectedly changing external demands. We assessed the ability of young (8 weeks old) pheasants Phasianus colchicus to exert inhibitory control in a novel response-inhibition task that required subjects to adjust their movement in space in pursuit of a reward across changing target locations. The difference in latencies between trials in which the target location did and did not change, the distance travelled towards the initially indicated location after a change occurred, and the change-signal reaction time provided a consistent measure that could be indicative of a pheasant's inhibitory control. Between individuals, there was a great variability in these measures; these differences were not correlated with motivation either to access the reward or participate in the test. However, individuals that were slower to reach rewards in trials when the target did not change exhibited evidence of stronger inhibitory control, as did males and small individuals. This novel test paradigm offers a potential assay of inhibitory control that utilises a natural feature of an animal's behavioural repertoire, likely common to a wide range of species, specifically their ability to rapidly alter their trajectory when reward locations switch.

Disentangling learning from knowing: Does associative learning ability underlie performances on cognitive test batteries?

Are the mechanisms underlying variations in the performance of animals on cognitive test batteries analogous to those of humans? Differences might result from procedural inconsistencies in test battery design, but also from differences in how animals and humans solve cognitive problems. We suggest differentiating associative-based (learning) from rule-based (knowing) tasks to further our understanding of cognitive evolution across species.

Transfer of physical understanding in a non-tool-using parrot.

Physical cognition has generally been assessed in tool-using species that possess a relatively large brain size, such as corvids and apes. Parrots, like corvids and apes, also have large relative brain sizes, yet although parrots rarely use tools in the wild, growing evidence suggests comparable performances on physical cognition tasks. It is, however, unclear whether success on such tasks is facilitated by previous experience and training procedures. We therefore investigated physical comprehension of object relationships in two non-tool-using species of captive neotropical parrots on a new means-end paradigm, the Trap-Gaps task, using unfamiliar materials and modified training procedures that precluded procedural cues. Red-shouldered macaws (Diopsittaca nobilis) and black-headed caiques (Pionites melanocephala) were presented with an initial task that required them to discriminate between pulling food trays through gaps while attending to the respective width of the gaps and size of the trays. Subjects were then presented with a novel, but functionally equivalent, transfer task. Six of eight birds solved the initial task through trial-and-error learning. Four of these six birds solved the transfer task, with one caique demonstrating spontaneous comprehension. These findings suggest that non-tool-using parrots may possess capacities for sophisticated physical cognition by generalising previously learned rules across novel problems.

Spatial memory predicts home range size and predation risk in pheasants.

Most animals confine their activities to a discrete home range, long assumed to reflect the fitness benefits of obtaining spatial knowledge about the landscape. However, few empirical studies have linked spatial memory to home range development or determined how selection operates on spatial memory via the latter's role in mediating space use. We assayed the cognitive ability of juvenile pheasants (Phasianus colchicus) reared under identical conditions before releasing them into the wild. Then, we used high-throughput tracking to record their movements as they developed their home ranges, and determined the location, timing and cause of mortality events. Individuals with greater spatial reference memory developed larger home ranges. Mortality risk from predators was highest at the periphery of an individual's home range in areas where they had less experience and opportunity to obtain spatial information. Predation risk was lower in individuals with greater spatial memory and larger core home ranges, suggesting selection may operate on spatial memory by increasing the ability to learn about predation risk across the landscape. Our results reveal that spatial memory, determined from abstract cognitive assays, shapes home range development and variation, and suggests predation risk selects for spatial memory via experience-dependent spatial variation in mortality.

Spatial cognitive ability is associated with transitory movement speed but not straightness during the early stages of exploration.

Memories about the spatial environment, such as the locations of foraging patches, are expected to affect how individuals move around the landscape. However, individuals differ in the ability to remember spatial locations (spatial cognitive ability) and evidence is growing that these inter-individual differences influence a range of fitness proxies. Yet empirical evaluations directly linking inter-individual variation in spatial cognitive ability and the development and structure of movement paths are lacking. We assessed the performance of young pheasants (Phasianus colchicus) on a spatial cognition task before releasing them into a novel, rural landscape and tracking their movements. We quantified changes in the straightness and speed of their transitory paths over one month. Birds with better performances on the task initially made slower transitory paths than poor performers but by the end of the month, there was no difference in speed. In general, birds increased the straightness of their path over time, indicating improved efficiency independent of speed, but this was not related to performance on the cognitive task. We suggest that initial slow movements may facilitate more detailed information gathering by better performers and indicates a potential link between an individual's spatial cognitive ability and their movement behaviour.

Heritability and correlations among learning and inhibitory control traits.

To understand the evolution of cognitive abilities, we need to understand both how selection acts upon them and their genetic (co)variance structure. Recent work suggests that there are fitness consequences for free-living individuals with particular cognitive abilities. However, our current understanding of the heritability of these abilities is restricted to domesticated species subjected to artificial selection. We investigated genetic variance for, and genetic correlations among four cognitive abilities: inhibitory control, visual and spatial discrimination, and spatial ability, measured on >450 pheasants, Phasianus colchicus, over four generations. Pheasants were reared in captivity but bred from adults that lived in the wild and hence, were subject to selection on survival. Pheasant chicks are precocial and were reared without parents, enabling us to standardize environmental and parental care effects. We constructed a pedigree based on 15 microsatellite loci and implemented animal models to estimate heritability. We found moderate heritabilities for discrimination learning and inhibitory control (h2 = 0.17-0.23) but heritability for spatial ability was low (h2 = 0.09). Genetic correlations among-traits were largely positive but characterized by high uncertainty and were not statistically significant. Principle component analysis of the genetic correlation matrix estimate revealed a leading component that explained 69% of the variation, broadly in line with expectations under a general intelligence model of cognition. However, this pattern was not apparent in the phenotypic correlation structure which was more consistent with a modular view of animal cognition. Our findings highlight that the expression of cognitive traits is influenced by environmental factors which masks the underlying genetic structure.

Serial reversal learning and cognitive flexibility in two species of Neotropical parrots (Diopsittaca nobilis and Pionites melanocephala).

Serial reversal learning of colour discriminations was assessed as an index of cognitive flexibility in two captive species of Neotropical parrots. Both species showed similar performances across serial reversals and no between species differences were observed. In a second task subjects' performances were assessed after they experienced either a low or high pre-reversal learning criterion. If reversal performances improve through processes of associative learning, a high pre-reversal criterion is expected to strengthen previously learned associations and hence impede post-reversal performances. Conversely, highly reinforced associations may facilitate the use of conditional rules that can be generalised across reversals and improve post-reversal performances. We found that high criterion subjects made fewer post-reversal errors and required fewer trials to reach criterion, than low criterion subjects. Red-shouldered macaws and black-headed caiques may therefore demonstrate capacities for solving serial reversal problems by applying conditional rules, rather than learning solely by associative processes. Such performances coincide with findings in great apes, but contrast with findings in monkeys and prosimians, which generally show impaired reversal performances when trained to a highly rigorous pre-reversal criterion. Overall, these findings suggest an evolutionary convergence of cognitive flexibility between parrots and non-human great apes.

Group social rank is associated with performance on a spatial learning task.

Dominant individuals differ from subordinates in their performances on cognitive tasks across a suite of taxa. Previous studies often only consider dyadic relationships, rather than the more ecologically relevant social hierarchies or networks, hence failing to account for how dyadic relationships may be adjusted within larger social groups. We used a novel statistical method: randomized Elo-ratings, to infer the social hierarchy of 18 male pheasants, Phasianus colchicus, while in a captive, mixed-sex group with a linear hierarchy. We assayed individual learning performance of these males on a binary spatial discrimination task to investigate whether inter-individual variation in performance is associated with group social rank. Task performance improved with increasing trial number and was positively related to social rank, with higher ranking males showing greater levels of success. Motivation to participate in the task was not related to social rank or task performance, thus indicating that these rank-related differences are not a consequence of differences in motivation to complete the task. Our results provide important information about how variation in cognitive performance relates to an individual's social rank within a group. Whether the social environment causes differences in learning performance or instead, inherent differences in learning ability predetermine rank remains to be tested.

Intra-individual variation in performance on novel variants of similar tasks influences single factor explanations of general cognitive processes.

Intra-individual variation in performance within and across cognitive domains may confound interpretations of both domain-general and domain-specific abilities. Such variation is rarely considered in animal test batteries. We investigate individual consistency in performance by presenting pheasant chicks (n = 31), raised under standardized conditions, with nine different cognitive tasks. Among these tasks were two replicated novel variants of colour learning and colour reversal problems, tests of positional learning and memory, as well as two different tasks that captured multiple putative measures of inhibitory control and motor-related performance. These task variants were also used to compare subjects' performance on alternative test batteries comprised of different task combinations. Subjects' performance improved with experience, yet we found relatively little consistency in their performance, both within similar tasks using different paradigms and across different tasks. Parallel analysis revealed non-significant factors when all nine tasks were included in a principal axis factor analysis. However, when different combinations of six of the nine tasks were included in principal axis factoring, 14 of 84 combinations revealed significant main factors, explaining between 28 and 35% of the variance in task performance. While comparable findings have been suggested to reflect domain-general intelligence in other species, we found no evidence to suggest that a single factor encompassed a diverse range of cognitive abilities in pheasants. Instead, we reveal how single factor explanations of cognitive processes can be influenced by test battery composition and intra-individual variation in performance across tasks. Our findings highlight the importance of conducting multiple tests within specific domains to ensure robust cognitive measures are obtained.

Individuals in larger groups are more successful on spatial discrimination tasks.

To understand how natural selection may act on cognitive processes, it is necessary to reliably determine interindividual variation in cognitive abilities. However, an individual's performance in a cognitive test may be influenced by the social environment. The social environment explains variation between species in cognitive performances, with species that live in larger groups purportedly demonstrating more advanced cognitive abilities. It also explains variation in cognitive performances within species, with larger groups more likely to solve novel problems than smaller groups. Surprisingly, an effect of group size on individual variation in cognitive performance has rarely been investigated and much of our knowledge stems from impaired performance of individuals reared in isolation. Using a within-subjects design we assayed individual learning performance of adult female pheasants, Phasianus colchicus, while housed in groups of three and five. Individuals experienced the group sizes in a different order, but were presented with two spatial discrimination tasks, each with a distinct cue set, in a fixed order. We found that across both tasks individuals housed in the large groups had higher levels of success than individuals housed in the small groups. Individuals had higher levels of success on their second than their first task, irrespective of group size. We suggest that the expression of individual learning performance is responsive to the current social environment but the mechanisms underpinning this relationship require further investigation. Our study demonstrates that it is important to account for an individual's social environment when attempting to characterize cognitive capacities. It also demonstrates the flexibility of an individual's cognitive performance depending on the social context.

The quick are the dead: pheasants that are slow to reverse a learned association survive for longer in the wild.

Cognitive abilities probably evolve through natural selection if they provide individuals with fitness benefits. A growing number of studies demonstrate a positive relationship between performance in psychometric tasks and (proxy) measures of fitness. We assayed the performance of 154 common pheasant (Phasianus colchicus) chicks on tests of acquisition and reversal learning, using a different set of chicks and different set of cue types (spatial location and colour) in each of two years and then followed their fates after release into the wild. Across all birds, individuals that were slow to reverse previously learned associations were more likely to survive to four months old. For heavy birds, individuals that rapidly acquired an association had improved survival to four months, whereas for light birds, slow acquirers were more likely to be alive. Slow reversers also exhibited less exploratory behaviour in assays when five weeks old. Fast acquirers visited more artificial feeders after release. In contrast to most other studies, we showed that apparently 'poor' cognitive performance (slow reversal speed suggesting low behavioural flexibility) correlates with fitness benefits in at least some circumstances. This correlation suggests a novel mechanism by which continued exaggeration of cognitive abilities may be constrained.This article is part of the theme issue 'Causes and consequences of individual differences in cognitive abilities'.