Brain, Behavior, and the Emergence of Cognitive Competence

A program-project grant supported by the National Institute of Child Health and Human Development (HD-38051)

Research Updates:

PROJECT DESCRIPTIONS

Brain, Behavior, and Emergence of Cognitive Competence is a Program-Project (supported by NICHD grant HD38051) comprised of an administrative core and five independent but interrelated research projects outlined below:

ADMINISTRATIVE CORE

THE EMERGENCE OF COGNITIVE CONTROL

THE EMERGENCE OF SYMBOLIC PROCESSING

COMPARATIVE STUDIES OF PRIMATE SPATIAL COGNITION AND MEMORY

THE EMERGENCE OF UNCERTAINTY MONITORING AND METACOGNITION

NEUROANATOMICAL AND NEUROFUNCTIONAL CORRELATES OF COGNITIVE COMPETENCE

COMPARATIVE STUDIES OF NUMERICAL COGNITION

ADMINISTRATIVE CORE

This program-project reflects a direct outgrowth of previous research at the Language Research Center on the biobehavioral foundations of human language and cognition, supported by NICHD. It builds on the psychological principles articulated from that research and uses methods developed and proven there. However, the present proposal is not focused on language acquisition. Rather, the present proposal is comprised of six separate projects designed to elucidate the emergence of cognitive competence as it is manifest across primate species, developmental periods, and other grouping variables, and in correspondence with brain structure, activity and function.

The present proposal also benefits from substantial overlap, complementarity, and convergence between the separate projects, such that the scientific promise of the entire program greatly exceeds the sum of the anticipated scientific gains of each of these strong individual projects. The psychological processes being investigated (attention, executive function, memory, spatial problem solving, numerical cognition, metacognition) are closely inter-related, and the study of any one process requires understanding its relation to language and the other constructs. Further, cognitive competence can be studied from different levels of analysis, and the present proposal aims to elucidate the correspondence between the psychological and the neurobiological levels.

The synthesis of these projects and the administration of this team of investigators will be supported by a core. Images of brain structure and activity will benefit all of the investigations in this program-project, just as care of the nonhuman primates and maintenance of laboratory resources will be to the advantage of all of the proposals. Its core support and functions will ensure that the ambitious program of research proposed here is conducted in an efficient and integrative way, using our unique and limited animal resources to yield the greatest scientific gains. (Rumbaugh, Washburn)

THE EMERGENCE OF COGNITIVE CONTROL

The control of attention is an interaction of environmental, experiential, and executive constraints. Preliminary data suggest that species differences corresponding with differences brain complexity exist in the capacity for executive control of attention. Monkeys are relatively susceptible to environmental constraints (i.e., stimulus control) on attention and subsequent behavior. In the present proposal, five series of studies are proposed (a) to describe the similarities and differences in the attention skills of human adults and children and rhesus monkeys; (b) to study the determinants of attention and the within- and between-species differences in the endogenous versus exogenous control of attention; (c) to relate the control of attention to species differences in working memory and executive function; (d) to assess the role of language in attention and executive function--in part by determining the degree to which monkeys and chimpanzees without language can attend, plan, and monitor, and in part by examining the improvement in these skills that follow language training; to identify procedures that promote controlled attention and relational learning in monkeys and chimpanzees; (e) to identify training or practice techniques that improve the endogenous control of attention; and (f) to relate these behavioral data to patterns of brain activity revealed through imaging, stimulation, and biochemical procedures. In all experiments, participants will respond to computer-generated stimuli (pictures, words, forms) by manipulating a joystick or similar response device. Response time, response accuracy, response topography, eye movements and other performance measures will be recorded as a series of variables are manipulated. Species, age, diagnostic category, and other grouping variables (e.g., memory span, attention profile) will also be used in the analyses. It is anticipated that the results of these experiments will elucidate the utility of nonhuman primate models of attention, and will improve theories of attention as it is manifest across primate species. (Washburn, Kane, Roitblat, Kleinman, Putney)

THE EMERGENCE OF SYMBOLIC PROCESSING

The proposed experiments examine: 1) the numerical competencies of nonhuman primates and human children when directly compared on counting tasks for performance level, strategies employed to attain success, and transfer of skills from one counting task to another, 2) the extent to which symbols are learned and retained within long-term memory by nonhuman primates, and 3) the effect of symbols on episodic memory in human and nonhuman primates. The present project regarding symbolic representation in monkeys, apes, and humans has the following specific aims:

(1) To compare the numerical capacities of nonhuman primates to those of human children of various developmental stages when both are exposed to the identical testing paradigms. These paradigms include computerized counting tasks and real world situations involving the creation of sets of items. (2) To investigate whether counting capacities in monkeys, apes, and human children are dependent on formal training or whether these capacities emerge from a predisposed sense of "number". On computerized tasks, some individuals will be trained to sequence Arabic numerals in the correct order for counting while other individuals are only presented with target numbers for which they must select an equal quantity of items. (3) To investigate the impact of known and unknown symbols on computerized episodic memory tasks.

(4) To investigate the long term retention of symbols that one chimpanzee has not used for more than 20 years. (5) To investigate the learning of symbols by language-trained chimpanzees with and without explicit training. (6) To investigate the use of planning by humans and nonhuman primates on symbolic and non-symbolic tasks.

These experiments will provide valuable comparative data of numerical competencies, episodic memory, long-term retention, and the acquisition of symbols. The experiments also will provide the opportunity for functional brain imaging of nonhuman primate cognitive skills in the areas of language, numerical competence, planning, and memory. (Pate, Beran, Rumbaugh)

COMPARATIVE STUDIES OF PRIMATE SPATIAL COGNITION AND MEMORY

The first aim of this research is to determine some of the information that chimpanzees recall and convey about the nature, location and temporal availability of objects in outdoor environments. The research will obtain measures of recall that are independent of an animal's path of travel. Four chimpanzees will be tested. The animals are uniquely well-suited for studies of recall memory. They have learned arbitrary visual symbols (lexigrams) that refer to foods and objects. The following method will be used to assess recall. An animal sees an experimenter place an object in an outdoor location. Later, in its indoor cage, the animal can indicate to an uninformed person the type and location of the object. Delays between the cue-giving and response phase of the trial will range up to 4 weeks. The ability to recall information about features of the environment not present to the senses is important in human thinking.

The second aim of this research is to study the movements of capuchins, macaques and chimpanzees in computer-presented foraging, barrier and maze tasks. Tasks that an animal can solve in an outdoor enclosure will be modeled for presentation to the animal in a digital format. Animals will move a joystick to make a cursor hit a target on a computer monitor. In one study, barriers and/or targets will disappear as soon as the animal begins to move. Questions are how much detail the animal remembers about the positions of targets, landmarks, and barriers, and how efficient its route is. Each animal's route will be compared on a jump-by-jump basis to an optimal routing. In a further study, barriers and targets will remain visible during trials. To assess planning ahead, eye movements will be analyzed. Planning during initial solutions of novel mazes by maze-naive capuchins, macaques, and chimpanzees will be studied. The development of planning over a series of mazes will be examined, in accord with Bidell & Fischer's theory of the development of planning skills.

THE EMERGENCE OF UNCERTAINTY MONITORING AND METACOGNITION

Humans respond intelligently to uncertainty and difficulty, grounding the extensive literatures on uncertainty monitoring and metacognition. But there is a lack of comparative research in this area, research that could explore animals' analogous capacities, that could sharpen the constructs of uncertainty and monitoring in human psychology, that could suggest the evolutionary antecedents of humans' cognitive self-awareness, and that could promote more facilitative ways to train metacognitive capacities in young children and children with special educational challenges. The proposed research explores uncertainty monitoring and metacognition comparatively using simple, behavioral paradigms that let animals cope with difficulty by using an uncertainty response to bail out of chosen trials. The experiments deliberately challenge animals' monitoring capacities--in order to reveal their limitations and constraints--by asking whether uncertainty responses transcend control by stimuli and reinforcements, whether they transfer flexibly and generalize broadly, and whether animals can quantify their uncertainty or judge it prospectively. The experiments also explore uncertainty within the symbolic domains of number and language. If animals successfully run this uncertainty gauntlet it will strengthen a higher-level interpretation of their uncertainty. One might discover a metacognitive capacity in them, informing the literatures on self-awareness and theory of mind. If animals sometimes falter and reveal their uncertainty "blind spots," it will suggest the character of less sophisticated monitoring capacities, and possibly let one trace the evolutionary emergence of human metacognition. This research could also let one trace the developmental emergence of human metacognition. It is a current concern that existing assays of metacognition underestimate children's true metacognitive capacities and veil their earliest metacognitive attainments. Our simple, behavioral paradigms could help address this concern. Moreover, children with special learning problems often fail to monitor uncertainty and comprehension in existing tasks. Our procedures could help assess these children's true monitoring capacities and yield more facilitative training methods. (Smith, Shields, Washburn)

NEUROANATOMICAL AND NEUROFUNCTIONAL CORRELATES OF COGNITIVE COMPETENCE

The proposed studies will examine the neurobiological basis of cognitive functions from a comparative perspective. Both structural and functional differences in brain organization will be investigated in relation to various cognitive functions in primates. The focus of this application is on the emergence of hemispheric specialization in relation to the evolution of overall brain organization and cognitive functions from a comparative primate perspective. Specifically, in addition to global changes in size and neocortical organization, the brain has become increasingly lateralized in both function and structure in primate evolution. One aim of the proposed studies is comparatively to examine global brain organization and lateralization in relation to cognition in monkeys and chimpanzees. Neuroanatomic and cognitive data will be collected in the same subjects and therefore will resolve the existing problem of mixing data sets from different investigators. A second aim of this study is to derive measures of functional asymmetry in monkeys and chimpanzees for specific cognitive functions and to map these performance asymmetries onto structural measures of asymmetry. A third aim of this research is to determine localized and lateralized cognitive functions in monkeys and chimpanzees using rapid-sequence transcranial magnetic stimulation (rTMS). In addition, individual and species variations in lateralized cognitive functions using rTMS will be correlated with area differences in corpus callosum morphology and neuroanatomical asymmetry. In part, this determination will be made by disrupting attention, executive functioning, or symbolic processing by stimulating specific regions of the cortex in monkeys and chimpanzees. Of particular interest will be the determination of whether language-trained chimpanzees have the functional equivalent of Broca's and Wernicke's areas. These studies will elucidate distal mechanisms involved in the evolution of human cognition including language and will provide for a better understanding of neural mechanisms involved in higher-order cognitive functions. (Hopkins, Washburn, Cohen, Rapoport, Epstein)

COMPARATIVE STUDIES OF NUMERICAL COGNITION

We will determine whether children (3 ½ and 5 years of age) and nonhuman primates (chimpanzees and rhesus monkeys) reliably select the largest of multiple sets of items when those items are presented in a one-by-one manner into opaque containers. We predict that they can, even when trials occur over extended periods of time (from 10 minutes up to 8 hours), and we predict that performance will not be limited to small numbers of items but will be limited by the relative size of one set compared to another (indicative of analog magnitude estimation rather than exact representation of numerosity). We will examine potential sources of interference in these numerousness judgments by presenting secondary cognitive tasks that must be performed during these trials, and we predict that concurrent computerized tasks that require processing of numerical attributes of stimuli will interfere with this long-term memory for set sizes more than will non-numerical memory tasks or tasks of motor control. We will vary surface area and item size within these numerousness judgment tasks, and we predict that responding will be made with reference to numerosity, and not amount, in most cases. We will use a computerized task equivalent to that used with children and nonhuman primates with adult humans who are prevented from using formal counting procedures to determine whether adult human performance is similar to that of children and nonhuman primates when estimating set sizes. We will determine whether nonhuman primates can make a specific number of responses when presented with a symbol for numerosity, and we will examine whether this process of enumeration shows similar attributes to that for making numerousness judgments. Thus, we predict that chimpanzees, rhesus monkeys, children, and adult humans (when prevented from counting) represent numerosity approximately rather than exactly. The data will be highly informative in understanding the role of estimation in these groups as well as the potential mechanisms underlying such estimation. The comparative analyses will illustrate whether numerical representation reflects cognitive continuity within these species, and the data will provide insight into potential difficulties children experience with formal arithmetic instruction. (Beran, Johnson-Pynn)