Nonhuman primates learn adjacent dependencies but fail to learn nonadjacent dependencies in a statistical learning task with a salient cue.

There is ample evidence that humans and nonhuman animals can learn complex statistical regularities presented within various types of input. However, humans outperform their nonhuman primate counterparts when it comes to recognizing relationships that exist across one or several intervening stimuli (nonadjacent dependencies). This is especially true when the two elements in the dependency do not share any perceptual similarity (arbitrary associations). In the present study, we investigated whether manipulating the saliency of the predictive stimulus would enhance nonadjacent dependency learning in nonhuman primates. Rhesus macaques and tufted capuchins engaged in a computerized signal detection task that included sequences that were random in nature, included an adjacent dependency, or included a nonadjacent dependency. We manipulated the saliency of the predictive stimulus, such that the predictor jittered in place on the screen in some grammar blocks, as well as the transitional probability (the likelihood of the stimulus preceding the target to accurately predict the target's appearance) from block to block. Some monkeys evidenced learning of adjacent dependencies by faster response times to targets that followed a predictive stimulus compared to targets that were not preceded by a predictor. However, consistent with the body of evidence that indicates that nonhuman animals' statistical learning mechanisms are not at the same level of sophistication as humans', there was no evidence that monkeys learned nonadjacent dependencies of arbitrary associations, even when the salient cue was present.

Breaking the link: Distraction from emotional cues reduces the association between trait disinhibition and reactive physical aggression.

Research has implicated biased attention allocation toward emotional cues as a proximal mechanism in the association between trait disinhibition and physical aggression. The current study tested this putative cognitive mechanism by incentivizing a shift of attention from a provoking stimulus to a neutral stimulus during a laboratory aggression paradigm. Participants were 119 undergraduate men. They completed a questionnaire that assessed trait disinhibition, were randomly assigned to a distraction or no-distraction control condition, and completed a shock-based aggression task in which they received low and high provocation from a fictitious opponent. A significant positive association between trait disinhibition and physical aggression was found among non-distracted participants exposed to high, but not low, provocation. Distraction from provoking cues significantly attenuated this association. This study is among the first to provide experimental evidence of (a) the positive relation between trait disinhibition and laboratory-based physical aggression, and (b) a potential method for attenuating this association.

Rhesus monkeys (Macaca mulatta) remember agency information from past events and integrate this knowledge with spatial and temporal features in working memory.

The purpose of the present study was to examine whether rhesus monkeys remember information about their own agency-along with spatial, temporal and contextual properties-from a previously experienced event. In Experiment 1, rhesus monkeys (n = 4) used symbols to reliably indicate whether they had performed or observed an event on a computer screen. In Experiment 2, naïve and experienced monkeys (n = 8) reported agency information when stringent controls for perceptual and proprioceptive cues were included. In Experiment 3, five of the monkeys completed a task in which they reported agency information along with spatial and temporal features of events. Two monkeys performed this agency discrimination when they could not anticipate which memory test they would receive. There was also evidence that these features were integrated in memory. Implications of this research are discussed in relation to working memory, episodic memory and self-awareness in nonhuman animals.

Simians in the Shape School: A comparative study of executive attention.

Executive functions (EF) have been studied extensively in children and adults. However, EF tasks for young children can be difficult to administer and interpret. Espy (1997, Developmental Neuropsychology, 13, 495-499) designed the Shape School task to measure inhibition and switching in preschool-aged children. Shape School presents cartoon-like characters that children must flexibly name by their color, their shape, or both, depending on cues that indicate the appropriate rule. Shape School has been found to be age sensitive as well as predictive of performance on other EF tasks. We presented a computerized analogue of Shape School to seven rhesus macaques. Monkeys were trained to categorize characters by color or shape, or to inhibit this response, depending on whether the characters had eyes open, eyes closed, or wore hats. Monkeys performed above chance on the inhibition and switching components of the task. Long runs of a single classification rule and long runs of noninhibition trials had no significant impact on performance when the rule changed or inhibition was required. This nonverbal adaptation of Shape School can measure EF in nonhuman animals and could be used in conjunction with other EF tasks to provide a clearer picture of both human and nonhuman executive functions.

Judgments of Monkey's (Macaca mulatta) Facial Expressions by Humans: Does Housing Condition "Affect" Countenance?

The ability to interpret facial expressions of others is one of the more important abilities possessed by humans. However, is it possible for humans to accurately interpret the facial expressions of another species of primate, namely rhesus monkeys (Macaca mulatta)? We investigated this possibility by taking digital photos of four rhesus monkeys housed either singly or socially and allowing thirty-one participants to judge these photographs as representing either a happy, sad, or neutral monkey. Results indicated that the photographs of monkeys that were socially housed were more likely to be rated as happy or neutral than were photographs of singly housed monkeys. We suggest that these results imply important parallels between the perception of human and nonhuman primate facial expressions as well as introduce a potential new method for assessing nonhuman primate well-being.

Do monkeys choose to choose?

Both empirical and anecdotal evidence supports the idea that choice is preferred by humans. Previous research has demonstrated that this preference extends to nonhuman animals, but it remains largely unknown whether animals will actively seek out or prefer opportunities to choose. Here we explored the issue of whether capuchin and rhesus monkeys choose to choose. We used a modified version of the SELECT task-a computer program in which monkeys can choose the order of completion of various psychomotor and cognitive tasks. In the present experiments, each trial began with a choice between two icons, one of which allowed the monkey to select the order of task completion, and the other of which led to the assignment of a task order by the computer. In either case, subjects still had to complete the same number of tasks and the same number of task trials. The tasks were relatively easy, and the monkeys responded correctly on most trials. Thus, global reinforcement rates were approximately equated across conditions. The only difference was whether the monkey chose the task order or it was assigned, thus isolating the act of choosing. Given sufficient experience with the task icons, all monkeys showed a significant preference for choice when the alternative was a randomly assigned order of tasks. To a lesser extent, some of the monkeys maintained a preference for choice over a preferred, but computer-assigned, task order that was yoked to their own previous choice selection. The results indicated that monkeys prefer to choose when all other aspects of the task are equated.

Overcoming cognitive set bias requires more than seeing an alternative strategy.

Determining when to switch from one strategy to another is at the heart of adaptive decision-making. Previous research shows that humans exhibit a 'cognitive set' bias, which occurs when a familiar strategy occludes-even much better-alternatives. Here we examined the mechanisms underlying cognitive set by investigating whether better solutions are visually overlooked, or fixated on but disregarded. We analyzed gaze data from 67 American undergraduates (91% female) while they completed the learned strategy-direct strategy (LS-DS) task, which measures their ability to switch from a learned strategy (LS) to a more efficient direct strategy (DS or shortcut). We found that, in the first trial block, participants fixated on the location of the shortcut more when it was available but most (89.6%) did not adopt it. Next, participants watched a video demonstrating either the DS (N = 34 Informed participants) or the familiar LS (N = 33 Controls). In post-video trials, Informed participants used the DS more than pre-video trials and compared to Controls. Notably, 29.4% of Informed participants continued to use the LS despite watching the DS video. We suggest that cognitive set in the LS-DS task does not stem from an inability to see the shortcut but rather a failure to try it.

Rhesus monkeys (Macaca mulatta) adaptively monitor uncertainty while multi-tasking.

As researchers explore animals' capacity for metacognition and uncertainty monitoring, some paradigms allow the criticism that animal participants-who are always extensively trained in one stimulus domain within which they learn to avoid difficult trials-use task-specific strategies to avoid aversive stimuli instead of responding to a generalized state of uncertainty like that humans might use. We addressed this criticism with an uncertainty-monitoring task environment in which four different task domains were interleaved randomly trial by trial. Four of five macaques (Macaca mulatta) were able to make adaptive uncertainty responses while multi-tasking, suggesting the generality of the psychological signal that occasions these responses. The findings suggest that monkeys may have an uncertainty-monitoring capacity that is like that of humans in transcending task-specific cues and extending simultaneously to multiple domains.

With his memory magnetically erased, a monkey knows he is uncertain.

Although intelligence is associated with what one knows, it is also important to recognize and to respond adaptively when one is uncertain. This competency has been examined developmentally and comparatively, but it is difficult to distinguish between objective versus subjective cues to which organisms may respond. In this study, transcranial magnetic stimulation was used to disrupt cognitive processing by a rhesus monkey (Macaca mulatta) in a computerized divided visual field memory task. When magnetic stimulation disrupted neural activity in the cerebral hemisphere that initially processed the visual images, recognition accuracy declined and use of the uncertain response significantly increased, relative to control conditions. Thus, the monkey tended to respond adaptively when he did not know the answer--where uncertainty was produced by targeted disruption of the neural processing of a stimulus--even in the absence of external, objective cues to corroborate his subjective, metacognitive assessment of uncertainty.

Martha Helson Wilson (1929-2020).

Memorializes Martha Helson Wilson (1929-2020), a physiological psychologist. Martha enrolled at Yale University for doctoral study in 1952, where she studied the physiological aspects of sensation with Burton Rosner. She also developed skills in electrophysiology under the direction of Karl Pribram, who became her career-long mentor, collaborator, and friend. In Pribram's Laboratory of Neurophysiology at the Institute of Living in Hartford, Connecticut, Martha met William A. Wilson, another lifelong collaborator as well as her husband for 62 years. Her behavioral investigations of intersensory learning were mainstream comparative psychology, as were her innovative studies of category learning that bridged animal research and human clinical neuropsychology, a field Wilson entered via her 1979 sabbatical with Brenda Milner at the Montreal Neurological Institute. Martha Wilson used this broad knowledge and experience to lead APA Division 6 (Physiological and Comparative Psychology)as its secretary-treasurer, executive committee member-at-large, representative to the Council of Representatives, president-elect, president (1986 -1987), and past president. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Strategy use in probabilistic categorization by rhesus macaques (Macaca mulatta) and capuchin monkeys (Cebus [Sapajus] apella).

Probabilistic categorization tasks present the learner with a set of possible responses and imperfect cue evidence of which response will be rewarded. A single, optimal integration of all available cues into an optimal response is possible given any set of evidence. In contrast, there are many possible uses of the cues that offer the learner suboptimal (but better than chance) responding. We presented a classic probabilistic categorization task to 3 rhesus macaques (Macaca mulatta) and 13 capuchin monkeys (Cebus [Sapajus] apella) to explore what strategies for integration of imperfectly predictive stimulus information would be used by the animals. Using the strategy analysis models that have been previously used to describe human strategy use in probabilistic categorization tasks, we fit each of thousands of blocks of responses to 25 types of response strategies ranging from complex cognitive strategies (e.g., optimal integration of all evidence) to heuristic strategies (e.g., identify a highly predictive cue and respond based only on its presence or absence) to rote behavior (e.g., choosing the same response every trial). Inferences about strategy use were highly stable within animals and were heterogeneous across animals, with some animals never using cue information and others using it fruitfully. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Memory for "what", "where", and "when" information in rhesus monkeys (Macaca mulatta).

The present study examined working memory for what, where, and when information in rhesus monkeys (Macaca mulatta) using a computerized task. In Experiment 1, monkeys completed three delayed matching-to-sample (DMTS) tasks: (1) identity DMTS, (2) spatial DMTS, and (3) temporal DMTS. In Experiment 2, the identity and spatial tasks were combined so that monkeys had to report both what and where information about an event. In Experiment 3, the identity, spatial, and temporal tasks were combined to examine what-where-when memory integration. The rhesus monkeys reported all three components of the events, and there was some evidence suggesting that these components were integrated in working memory.

What meaning means for same and different: Analogical reasoning in humans (Homo sapiens), chimpanzees (Pan troglodytes), and rhesus monkeys (Macaca mulatta).

Thus far, language- and token-trained apes (e.g., D. Premack, 1976; R. K. R. Thompson, D. L. Oden, & S. T. Boysen, 1997) have provided the best evidence that nonhuman animals can solve, complete, and construct analogies, thus implicating symbolic representation as the mechanism enabling the phenomenon. In this study, the authors examined the role of stimulus meaning in the analogical reasoning abilities of three different primate species. Humans (Homo sapiens), chimpanzees (Pan troglodytes), and rhesus monkeys (Macaca mulatta) completed the same relational matching-to-sample (RMTS) tasks with both meaningful and nonmeaningful stimuli. This discrimination of relations-between-relations serves as the basis for analogical reasoning. Meaningfulness facilitated the acquisition of analogical matching for human participants, whereas individual differences among the chimpanzees suggest that meaning can either enable or hinder their ability to complete analogies. Rhesus monkeys did not succeed in the RMTS task regardless of stimulus meaning, suggesting that their ability to reason analogically, if present at all, may be dependent on a dimension other than the representational value of stimuli.

Ordinal judgments of symbolic stimuli by capuchin monkeys (Cebus apella) and rhesus monkeys (Macaca mulatta): the effects of differential and nondifferential reward.

Ordinal learning was investigated in capuchin monkeys (Cebus apella) and rhesus monkeys (Macaca mulatta). In Experiment 1, both species were presented with pairings of the Arabic numerals 0 to 9. Some monkeys were given food rewards equal to the value of the numeral selected and some were rewarded with a single pellet only for choosing the higher numeral within the pair. Both species learned to select the larger numeral, but only rhesus monkeys that were differentially rewarded performed above chance levels when presented with novel probe pairings. In Experiment 2, the monkeys were first presented with arrays of 5 familiar numerals (from the range 0 to 9) and then arrays of 5 novel letters (from the range A to J) with the same reward outcomes in place as in Experiment 1. Both species performed better with the numerals, suggesting that an ordinal sequence of all stimuli had been learned during Experiment 1, rather than a matrix of two-choice discriminations.

Duane M. Rumbaugh (1929-2017).

Presents an obituary of Duane M. Rumbaugh (1929-2017). Rumbaugh was an experimental psychologist known for his many contributions toward understanding primate learning and behavior. His ape-language research with Lana and other chimpanzees, comparative studies of quantitative and qualitative hallmarks of primate intelligence, and numerous methodological innovations helped usher in the field of comparative cognition. Rumbaugh's scientific legacy is extensive. The computerized language keyboard invented for the Lana Project would subsequently be employed to teach other nonhuman primates, as well as humans with intellectual challenges to communicate. (PsycINFO Database Record

A computerized testing system for primates: Cognition, welfare, and the Rumbaughx.

Innovations in apparatus technology come about for a variety of reasons such as the need to use the same methodology with various species, the opportunity to present dynamic and carefully controlled stimuli, the goal of using automation to make data collection more precise or efficient, and the need to control for and/or eliminate the presence of experimenters in the testing context. At the Language Research Center (LRC) of Georgia State University, a computer-based system has been developed and used extensively with nonhuman primate species. This system involves the animal working in an enclosure that provides visual access to a computer screen, access to a joystick to control a cursor on the screen, and access to a food dish where pellets are delivered for correct responses. Here we will describe the history and development of this system as well as some considerations that might be applied to expanding this apparatus to a new environment, including the mobility of test stations, equipment needs, training protocols, and the cost and considerations for initial set up of such a system. A variety of computer based programs have been developed for use with this system. These programs have allowed insight into many nonhuman primate cognitive abilities and we highlight some that have been the focus of study at the LRC such as metacognition, numerical cognition, inhibitory processes, prospective memory, attention, and cognitive control. In addition, this cognitive testing apparatus has been shown to create a stimulating and enriching environment for the animals. We advocate that the computerized testing apparatus is useful for advancing our understanding of nonhuman animal cognition and may be uniquely suited to optimizing animal welfare. This area of research is already rapidly expanding in zoos, and we hope to offer some insight from one journey of designing, implementing and adapting a computerized testing paradigm.

Disconnect in concept learning by rhesus monkeys (Macaca mulatta): judgment of relations and relations-between-relations.

The authors investigated the role that entropy measures, discriminative cues, and symbolic knowledge play for rhesus monkeys (Macaca mulatta) in the acquisition of the concepts of same and different for use in a computerized relational matching-to-sample task. After repeatedly failing to perceive relations between pairs of stimuli in a 2-choice discrimination paradigm, monkeys rapidly learned to discriminate between 8-element arrays. Subsequent tests with smaller arrays, however, suggested that, although important for the initial acquisition of the concept, entropy is not a variable on which monkeys are dependent. Not only do monkeys choose a corresponding relational pair in the presence of a cue, but they also choose the cue itself in the presence of the relational pair--in essence, labeling those relations. Subsequent failure in the judgment of relations-between-relations, however, suggests that perhaps a qualitatively different cognitive component exists that prevents monkeys from behaving analogically.

Ordinal-list integration for symbolic, arbitrary, and analog stimuli by rhesus macaques (Macaca mulatta).

Two numeral-trained monkeys learned to produce 3 5-item lists of Arabic numerals, colors, and arbitrary signs in the correct sequence. The monkeys then responded at above-chance levels when the authors tested them with nonrewarded pair-wise comparisons of items from different lists, indicating their use of ordinal-position information. The authors also tested the monkeys with nonrewarded pair-wise comparisons of an analog quantity and an item from 1 of the 3 learned lists. Although the monkeys were not trained to serially order analog quantities, 1 monkey correctly integrated the analog quantities with the lists of numerals, colors, and signs. The consistent use of an ordinal rule, despite different types of training and varying degrees of experience with the 4 types of stimuli, suggested that the monkey had a robust concept of ordinality.

A Stroop-like effect in color-naming of color-word lexigrams by a chimpanzee (Pan troglodyte).

The Stroop effect (J. R. Stroop, 1935) reflects the difficulty in ignoring irrelevant, but automatically processed, semantic information that is inherent in certain stimuli. With humans, researchers have found this effect when they asked participants to name the color of the letters that make up a word that is incongruent with that color. The authors tested a chimpanzee that had learned to associate geometric symbols called lexigrams with specific colors. When the chimpanzee had to make different responses that depended on the color of stimuli presented to her, she showed a Stroop-like effect when researchers presented to her the previously learned symbols for colors in incongruent font colors. Her accuracy performance was significantly poorer with these stimuli than with congruent color-referent lexigrams, noncolor-referent lexigrams, and nonlexigram stimuli, although there were not any significant differences in response latency. The authors' results demonstrated color-word interference in a Stroop task with a nonhuman animal.

The effects of prayer on attention resource availability and attention bias.

Two experiments were used to measure the effects of prayer, contemplation, or a control activity on attention resource capacity and attention bias. Results from a dual-task test in Experiment 1 indicated that allowing participants to pray about an issue in their lives improved subsequent task performance, but only for individuals who score highly on a measure of religiosity. Experiment 2 suggested that praying about a problem can bias attention in a word-search task. Similar effects were not observed for control activities. Thus, at least for people most likely to engage in religious behavior, praying about a problem appeared to liberate cognitive resources that are presumably otherwise consumed by worry and rumination, leaving individuals better able to process other information, and additionally to bias attention to favor detection of problem-relevant information. These effects suggest one cognitive process (attention) that may underlie how people come to perceive answers to prayers.