How does cognition evolve? Phylogenetic comparative psychology

Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly skillful at adapting methodologies to test multiple species. Meanwhile, evolutionary biologists have generated quantitative approaches to investigate the phylogenetic distribution and function of phenotypic traits, including cognition. In particular, phylogenetic methods can quantitatively (1) test whether specific cognitive abilities are correlated with life history (e.g., lifespan), morphology (e.g., brain size), or socio-ecological variables (e.g., social system), (2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species, and (3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species. 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). Here, we explain how an integration of comparative psychology and evolutionary biology will answer a host of questions regarding the phylogenetic distribution and history of cognitive traits, as well as the evolutionary processes that drove their evolution.     

Are monkeys able to plan for future exchange?

Whether or not non-human animals can plan for the future is a hotly debated issue. We investigate this question further and use a planning-to-exchange task to study future planning in the cooperative domain in two species of monkeys: the brown capuchin (Cebus apella) and the Tonkean macaque (Macaca tonkeana). The rationale required subjects to plan for a future opportunity to exchange tokens for food by collecting tokens several minutes in advance. Subjects who successfully planned for the exchange task were expected to select suitable tokens during a collection period (5/10?min), save them for a fixed period of time (20/30?min), then take them into an adjacent compartment and exchange them for food with an experimenter. Monkeys mostly failed to transport tokens when entering the testing compartment; hence, they do not seem able to plan for a future exchange with a human partner. Three subjects did however manage to solve the task several times, albeit at very low rates. They brought the correct version of three possible token types, but rarely transported more than one suitable token at a time. Given that the frequency of token manipulation predicted transport, success might have occurred by chance. This was not the case, however, since in most cases subjects were not already holding the token in their hands before they entered the testing compartment. Instead, these results may reflect subjects' strengths and weaknesses in their time-related comprehension of the task.     

Great apes infer others’ goals based on context

In previous studies claiming to demonstrate that great apes understand the goals of others, the apes could potentially have been using subtle behavioral cues present during the test to succeed. In the current studies, we ruled out the use of such cues by making the behavior of the experimenter identical in the test phase of both the experimental and control conditions; the only difference was the preceding “context.” In the first study, apes interpreted a human’s ambiguous action as having the underlying goal of opening a box, or not, based on that human’s previous actions with similar boxes. In the second study, chimpanzees learned that when a human stood up she was going to go get food for them, but when a novel, unexpected event happened, they changed their expectation—presumably based on their understanding that this new event led the human to change her goal. These studies suggest that great apes do not need concurrent behavioral cues to infer others’ goals, but can do so from a variety of different types of cues—even cues displaced in time.     

The Impact of Type of Examples on Originality: Explaining Fixation and Stimulation Effects

There are obstacles to creativity: one of them is called fixation effect, the fact that some knowledge about existing or obvious solutions is spontaneously activated and constrains the generation of new solutions. Converging evidence in cognitive psychology has indicated that the ability to generate original ideas can be limited by recently activated knowledge, such as examples of solutions. On the other hand, neuroimaging studies have recently demonstrated that exposure to examples could, on the contrary, have a stimulating effect on originality. To make sense of what seems to be contradictory studies, we hypothesized that two types of examples could have opposite effects on originality: (1) restrictive examples—within the fixation effect—could lead to a reduction in the originality of the solutions, whereas (2) expansive examples—outside the fixation effect—could provoke solutions of higher originality. Results from a total of 160 participants confirmed that the solutions proposed by the group exposed to restrictive examples were less original than those given by the group exposed to expansive examples.     

Perpetrator Abhorrence: Disgust as a Stop Sign

Most contemporary research on disgust can be divided into “disgust advocates” and “disgust skeptics.” The so‐called advocates argue that disgust can have a positive influence on our moral judgment; skeptics warn that it can mislead us toward prejudice and discrimination. This article compares this disagreement to a structurally similar debate in the field of genocide studies concerning the phenomenon of “perpetrator abhorrence.” While some soldiers report having felt strong disgust in the moment of committing or witnessing atrocity, scholars disagree on whether such disgust is moral in nature. These empirical cases provide us with reasons to reconsider the normative features of disgust. Inspired by the conceptualization of disgust in Immanuel Kant and Aurel Kolnai, and as an alternative to both the disgust advocates and the skeptics, this article argues that the analogy of a stop sign can better help us define disgust responses.     

A phenomenological survey of auditory verbal hallucinations in the hypnagogic and hypnopompic states

The phenomenology of auditory verbal hallucinations (AVHs) occurring in hypnagogic and hypnopompic (H&H) states has received little attention. In a sample of healthy participants (N = 325), 108 participants reported H&H AVHs and answered subsequent questions on their phenomenology. AVHs in the H&H state were found (1) to be more likely to only feature the occasional clear word than to be clear, (2) to be more likely to be one-off voices than to be recurrent voices, (3) to be more likely to be voices of people known to the individual than unknown persons, (4) to be more likely to talk directly to the person rather than not, and (5) to only rarely give commands, ask questions, or to result in an interactive conversation. Their phenomenology was similar to normative AVHs in wakefulness (as established by previous research) in that the voice-hearer was usually the target of the voice, and the voice was more likely to be of a recognized person. However, H&H AVHs differed from AVHs in wakefulness in that commands and questions were rare, and there was typically no dialogical engagement with the voice. We conclude by proposing that two distinct types of H&H AVHs may exist (which we term “dialogic” and “monologic”), based on an analysis of the phenomenology of the experience, and suggest avenues for future research.     

The Effect of Plausible Versus Implausible Balance Scale Feedback on the Expectancies of 3- to 4-Year-Old Children

Previous studies (Case, 1985 Case , R. ( 1985 ). Intellectual development: Birth to adulthood . New York , NY : Academic . [Google Scholar]; Siegler, 1981 Siegler , R. S. ( 1981 ). Developmental sequences within and between concepts . Monographs of the Society for Research in Child Development , 46 , 1 – 84 . [Google Scholar]) have shown that children under the age of 5 years have little understanding of balance scales when required to encode the influence of weight or distance from the fulcrum. More recently, however, Halford, Andrews, Dalton, Boag, and Zielinski (2002 Halford , G. S. , Andrews , G. , Dalton , C. , Boag , C. , & Zielinski , T. ( 2002 ). Young children's performance on the balance scale: The influence of relational complexity . Journal of Experimental Child Psychology , 81 , 417 – 445 .[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) noted that an understanding based on weight alone is present even in 2-year-olds. In all these experiments, weight was varied using multiple objects of the same weight. Consequently, the children's decisions could have been based upon visual features (size, number) without necessarily taking the weight into account. The present study investigated whether young children are able to correctly encode the relevance of weight in influencing the behavior of a balance scale. We studied how well 3- to 4-year-old children learn to use one of two different weights (of equal appearance) to tip the scale. In the plausible condition, the heavy weight produced the desired outcome. In the implausible condition, the light weight caused the scale to tip. Only 4-year-olds' performance differed between conditions by learning more effectively in the plausible than the implausible condition. Our results suggest that children younger than 4 years of age have not yet developed clear expectations of the role of weights on the movements of a balance scale.     

Compression as a Universal Principle of Animal Behavior

A key aim in biology and psychology is to identify fundamental principles underpinning the behavior of animals, including humans. Analyses of human language and the behavior of a range of non‐human animal species have provided evidence for a common pattern underlying diverse behavioral phenomena: Words follow Zipf's law of brevity (the tendency of more frequently used words to be shorter), and conformity to this general pattern has been seen in the behavior of a number of other animals. It has been argued that the presence of this law is a sign of efficient coding in the information theoretic sense. However, no strong direct connection has been demonstrated between the law and compression, the information theoretic principle of minimizing the expected length of a code. Here, we show that minimizing the expected code length implies that the length of a word cannot increase as its frequency increases. Furthermore, we show that the mean code length or duration is significantly small in human language, and also in the behavior of other species in all cases where agreement with the law of brevity has been found. We argue that compression is a general principle of animal behavior that reflects selection for efficiency of coding.