Capuchins (<Emphasis Type="Italic">Cebus apella</Emphasis>) fail to show an asymmetric dominance effect

The asymmetric dominance effect (ADE) occurs when the introduction of a partially dominated decoy option increases the choice share of its dominating alternative. The ADE is a violation of regularity and the constant-ratio rule, which are two derivations of the independence of irrelevant alternatives axiom, a core tenant of rational choice. The ADE is one of the most widely reported human choice phenomena, leading researchers to probe its origins by studying a variety of non-human species. We examined the ADE in brown capuchin monkeys (Cebus apella), a species that displays many other decision biases. In Experiment 1, we used a touchscreen method to elicit choice-based preferences for food rewards in asymmetrically dominated choice sets. In Experiments 2 and 3, we distinguished between different types of judgments and used a free selection task to elicit consumption-based preferences for juice rewards. However, we found no evidence for the ADE through violations of regularity or the constant-ratio rule, despite the similarity of our stimuli to other human and non-human experiments. While these results appear to conflict with existing literature on the ADE in non-human species, we point out methodological differences—notably, the distinction between value-based and perception-based stimuli—that have led to a collection of phenomena that are difficult to understand under a unitary theoretical framework. In particular, we highlight key differences between the human and non-human research and provide a series of steps that researchers could take to better understand the ADE.     

The effect of social learning on avoidance of aposematic prey in juvenile great tits (<Emphasis Type="Italic">Parus major</Emphasis>)

Social learning plays an important role in acquiring new foraging skills and food preferences in many bird species but its potential role in learning to avoid aposematic prey has never been studied. We tested the effect of social learning on the acquisition of avoidance of aposematic insect prey (firebug Pyrrhocoris apterus; Heteroptera) in juvenile, hand-reared great tits (Parus major). Behaviour towards aposematic prey was compared between two groups of birds: (1) the observers that were, prior to encounter with firebugs, allowed to watch the experienced conspecific demonstrator repeatedly refuse to attack the prey, and (2) the control birds that lacked this opportunity. Observing an experienced demonstrator was not sufficient for learning complete avoidance, because birds from both groups attacked at least the first firebug they had encountered in avoidance training. However, the opportunity to observe the avoidance behaviour of another bird significantly increased the rate of subsequent individual learning of observers in comparison with control birds. Social learning also decreased mortality of firebugs killed by the birds during the avoidance learning. Socially enhanced learning to avoid aposematic prey might be a mechanism important especially for naive juvenile birds learning from their parents, but it could also enhance learning in adults from their more experienced flock mates. Because social learning of avoidance may also lead to decreased mortality of aposematic prey, its effect should be taken into account in scenarios considering evolution and maintenance of prey warning signals.     

Do ‘literate’ pigeons (<Emphasis Type="Italic">Columba livia</Emphasis>) show mirror-word generalization?

Many children pass through a mirror stage in reading, where they write individual letters or digits in mirror and find it difficult to correctly utilize letters that are mirror images of one another (e.g., b and d). This phenomenon is thought to reflect the fact that the brain does not naturally discriminate left from right. Indeed, it has been argued that reading acquisition involves the inhibition of this default process. In the current study, we tested the ability of literate pigeons, which had learned to discriminate between 30 and 62 words from 7832 nonwords, to discriminate between words and their mirror counterparts. Subjects were sensitive to the left–right orientation of the individual letters, but not the order of letters within a word. This finding may reflect the fact that, in the absence of human-unique top-down processes, the inhibition of mirror generalization may be limited.     

No evidence for self-recognition in a small passerine,the great tit (<Emphasis Type="Italic">Parus major</Emphasis>) judged from the mark/mirror test

Self-recognition is a trait presumed to be associated with high levels of cognition and something previously considered to be exclusive to humans and possibly apes. The most common test of self-recognition is the mark/mirror test of whether an animal can understand that it sees its own reflection in a mirror. The usual design is that an animal is marked with a colour spot somewhere on the body where the spot can only be seen by the animal by using a mirror. Very few species have passed this test, and among birds, only magpies have been affirmatively demonstrated to pass it. In this study, we tested great tits (Parus major), small passerines, that are known for their innovative foraging skills and good problem-solving abilities, in the mirror self-recognition test. We found no indication that they have any ability of this kind and believe that they are unlikely to be capable of this type of self-recognition.     

Enhanced music sensitivity in 9-month-old bilingual infants

This study explores the influence of bilingualism on the cognitive processing of language and music. Specifically, we investigate how infants learning a non-tone language perceive linguistic and musical pitch and how bilingualism affects cross-domain pitch perception. Dutch monolingual and bilingual infants of 8–9 months participated in the study. All infants had Dutch as one of the first languages. The other first languages, varying among bilingual families, were not tone or pitch accent languages. In two experiments, infants were tested on the discrimination of a lexical (N = 42) or a violin (N = 48) pitch contrast via a visual habituation paradigm. The two contrasts shared identical pitch contours but differed in timbre. Non-tone language learning infants did not discriminate the lexical contrast regardless of their ambient language environment. When perceiving the violin contrast, bilingual but not monolingual infants demonstrated robust discrimination. We attribute bilingual infants’ heightened sensitivity in the musical domain to the enhanced acoustic sensitivity stemming from a bilingual environment. The distinct perceptual patterns between language and music and the influence of acoustic salience on perception suggest processing diversion and association in the first year of life. Results indicate that the perception of music may entail both shared neural network with language processing, and unique neural network that is distinct from other cognitive functions.     

Linguistic asymmetry,egocentric anchoring,and sensory modality as factors for the observed association between time and space perception

Temporal and spatial representations have been consistently shown to be inextricably intertwined. However, the exact nature of time–space mapping remains unknown. On the one hand, the conceptual metaphor theory postulates unilateral, asymmetric mapping of time onto space, that is, time is perceived in spatial terms but the perception of space is relatively independent of time. On the other hand, a theory of magnitude assumes bilateral and symmetric interactions between temporal and spatial perceptions. In the present paper, we argue that the concepts of linguistic asymmetry, egocentric anchoring, and sensory modality provide potential explanations for why evidences favoring both asymmetry and symmetry have been obtained. We first examine the asymmetry model and suggest that language plays a critical role in it. Next, we discuss the symmetry model in relation to egocentric anchoring and sensory modality. We conclude that since these three factors may jointly account for some conflicting past results regarding the strength and directionality of time–space mapping, they should be taken into serious consideration in future test designs.     

Betting on transitivity in probabilistic causal chains

Causal reasoning is crucial to people’s decision making in probabilistic environments. It may rely directly on data about covariation between variables (correspondence) or on inferences based on reasonable constraints if larger causal models are constructed based on local relations (coherence). For causal chains an often assumed constraint is transitivity. For probabilistic causal relations, mismatches between such transitive inferences and direct empirical evidence may lead to distortions of empirical evidence. Previous work has shown that people may use the generative local causal relations A → B and B → C to infer a positive indirect relation between events A and C, despite data showing that these events are actually independent (von Sydow et al. in Proceedings of the thirty-first annual conference of the cognitive science society. Cognitive Science Society, Austin, 2009, Proceedings of the 32nd annual conference of the cognitive science society. Cognitive Science Society, Austin, 2010, Mem Cogn 44(3):469–487, 2016). Here we used a sequential learning scenario to investigate how transitive reasoning in intransitive situations with negatively related distal events may relate to betting behavior. In three experiments participants bet as if they were influenced by a transitivity assumption, even when the data strongly contradicted transitivity.