Visual artificial grammar learning by rhesus macaques (<Emphasis Type="Italic">Macaca mulatta</Emphasis>): exploring the role of grammar complexity and sequence length

Humans and nonhuman primates can learn about the organization of stimuli in the environment using implicit sequential pattern learning capabilities. However, most previous artificial grammar learning studies with nonhuman primates have involved relatively simple grammars and short input sequences. The goal in the current experiments was to assess the learning capabilities of monkeys on an artificial grammar-learning task that was more complex than most others previously used with nonhumans. Three experiments were conducted using a joystick-based, symmetrical-response serial reaction time task in which two monkeys were exposed to grammar-generated sequences at sequence lengths of four in Experiment 1, six in Experiment 2, and eight in Experiment 3. Over time, the monkeys came to respond faster to the sequences generated from the artificial grammar compared to random versions. In a subsequent generalization phase, subjects generalized their knowledge to novel sequences, responding significantly faster to novel instances of sequences produced using the familiar grammar compared to those constructed using an unfamiliar grammar. These results reveal that rhesus monkeys can learn and generalize the statistical structure inherent in an artificial grammar that is as complex as some used with humans, for sequences up to eight items long. These findings are discussed in relation to whether or not rhesus macaques and other primate species possess implicit sequence learning abilities that are similar to those that humans draw upon to learn natural language grammar.     

“All I remember is the black eye”: A distinctive facial feature harms eyewitness identification

Many crimes occur in which a perpetrator has a distinctive facial feature, such as a tattoo or black eye, but few eyewitness identification (ID) studies have involved such a feature. We conducted an experiment to determine how eyewitness ID performance is impacted by a distinctive facial feature, and how police could deal with this issue. Participants (N = 4,218) studied a target face with or without a black eye, and later viewed a simultaneous photo lineup either containing the target or not. For those who saw a target with a black eye, this feature was either replicated among all lineup members or was removed. The black eye harmed empirical discriminability regardless of replication or removal, which did not differ. However, participants responded more conservatively when the black eye was removed, compared to replication. Lastly, immediate confidence was consistently indicative of accuracy.     

A computational approach to modeling population differences

Four experiments were conducted to determine whether the Hyperspace Analogue to Language (HAL) model of semantic memory could differentiate between two different populations. An analysis of the differences in densities (or average distances between word neighbors in semantic space) in HAL matrices—generated from text corpora derived from younger and older adults—confirmed that HAL was able to distinguish between the two age groups. This difference was again detected when structured interview data were used to build the corpora. A third experiment, designed to test the specificity of HAL in detecting differences between groups, did not detect any difference in the densities of the memory representations when older adults generated both the test corpora. The final experiment, conducted on the language of adults with Alzheimer’s and normal adults, again demonstrated that HAL could discriminate between the two populations. These results suggest that HAL is capable of modeling, on the basis of changes in mean density, some of the differences between populations without modifying the model itself but, rather, by changing the text corpus from which the model creates its representations in semantic space.     

SOCIAL CONFORMITY AND PSYCHOLOGICAL DIFFERENTIATION12

This study examined the role of socialization experiences in the development of psychological differentiation. In each of three countries (Holland, Italy, Mexico) two villages were selected as presenting a contrasting picture with regard to degree of emphasis on conformity to family, religious and political authority. It was hypothesized that within the pair of villages in each country children from the village which stressed social conformity would tend to be more field dependent and show other signs of less developed differentiation than children from the village in which social conformity was less emphasized. In each of the six villages approximately 100 children (boys and girls, aged 9–11 and 13–15) were studied. Differentiation was assessed by a battery of tests of field-dependence-independence and the figure-drawing test. In every comparison of mean test scores between pairs of villages, in each of the three countries, children from the village in which social conformity was stressed obtained scores reflecting less differentiated functioning. Village differences were significant for every measure of differentiation in all three countries. Addition alanalyses of the data from the tests of differentiation and other tests used yielded results essentially consistent with findings from previous studies.     

Weapons and Eye Contact as Instigators or Inhibitors of Aggressive Arousal in Police-Citizen Interaction1

A field experiment was conducted with police officers during the normal course of their traffic patrol duties. The purpose was to determine whether the presence of holstered weapons and mirror sunglasses affected the degree of aggressiveness expressed nonverbally, and reported on a mood scale by citizens halted for an information check (neutral condition) or in order to be given a traffic ticket (negative condition). Results indicated that subjects in the negative condition both expressed and reported more aggressivity when the police officer wore a weapon than when no weapon was visible. The use of sunglasses had no effect on aggressivity but resulted in the officer's being perceived more negatively, though he was not perceived more negatively when he wore a weapon. No sex differences in expressed or reported aggressivity were obtained, although some sex differences on measures of secondary interest did occur. The implications of these findings for research on the “weapons effect” and on policy regarding the visibility of police weapons and the wearing of sunglasses by police officers are discussed.     

Readability of prescription drug labels by older and younger adults

This experiment investigated the readability of medication labels using various combinations of fonts, sizes, and weights of print. Older and younger adult reading speeds and error rates for different print types were compared for both bottle and flat labels. Findings of the study indicated significant differences in reading speed, error rates, and subjective evaluations for print characteristics investigated. Furthermore, the effects of these print characteristics varied for different age groups. Implications of these findings for the design of medication labels for older adults are discussed.     

Similarity Arguments in the Genetic Modification Debate

In the ethical debate on genetic modification (GM), it is common to encounter the claim that some anti-GM argument would also apply an established, ethically accepted technology, and that the anti-GM argument is therefore unsuccessful. The paper discusses whether this argumentative strategy, the Similarity Argument, is sound. It presents a logically valid, generic form of the Similarity Argument and then shows that it is subject to three types of objection: (i) It does not respect the difference between pro tanto reasons and all-things-considered judgments; (ii) it relies on the unproblematic transferability of reasons from one case to another; and (iii) it runs the risk of equivocations, especially in cases where the anti-genetic-modification argument relies on gradable features. The paper then shows how these issues play out in three specific Similarity Arguments that can be found in the literature. Finally, the paper discusses what conclusions we can draw from the fact that genetic modification and established technologies are similar for the ethical status of genetic modification.     

Language as shaped by the brain

It is widely assumed that human learning and the structure of human languages are intimately related. This relationship is frequently suggested to derive from a language-specific biological endowment, which encodes universal, but communicatively arbitrary, principles of language structure (a Universal Grammar or UG). How might such a UG have evolved? We argue that UG could not have arisen either by biological adaptation or non-adaptationist genetic processes, resulting in a logical problem of language evolution. Specifically, as the processes of language change are much more rapid than processes of genetic change, language constitutes a "moving target" both over time and across different human populations, and, hence, cannot provide a stable environment to which language genes could have adapted. We conclude that a biologically determined UG is not evolutionarily viable. Instead, the original motivation for UG--the mesh between learners and languages--arises because language has been shaped to fit the human brain, rather than vice versa. Following Darwin, we view language itself as a complex and interdependent "organism," which evolves under selectional pressures from human learning and processing mechanisms. That is, languages themselves are shaped by severe selectional pressure from each generation of language users and learners. This suggests that apparently arbitrary aspects of linguistic structure may result from general learning and processing biases deriving from the structure of thought processes, perceptuo-motor factors, cognitive limitations, and pragmatics.