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Reynhout, I. C., Cornelissen, J. J. L. M., & Nolte, R. J. M. (2007). Self-assembled architectures from biohybrid triblock copolymers. J Am Chem Soc, 129(8), 2327–2332.
Abstract: The synthesis and self-assembly behavior of biohybrid ABC triblock copolymers consisting of a synthetic diblock, polystyrene-b-polyethylene glycol (PSm-b-PEG113), where m is varied, and a hemeprotein, myoglobin (Mb) or horse radish peroxidase (HRP), is described. The synthetic diblock copolymer is first functionalized with the heme cofactor and subsequently reconstituted with the apoprotein or the apoenzyme to yield the protein-containing ABC triblock copolymer. The obtained amphiphilic block copolymers self-assemble in aqueous solution into a large variety of aggregate structures. Depending on the protein and the polystyrene block length, micellar rods, vesicles, toroids, figure eight structures, octopus structures, and spheres with a lamellar surface are formed.
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Watanabe, S., & Troje, N. F. (2006). Towards a “virtual pigeon”: a new technique for investigating avian social perception. Anim. Cogn., 9(4), 271–279.
Abstract: The purpose of the present study is to examine the applicability of a computer-generated, virtual animal to study animal cognition. Pigeons were trained to discriminate between movies of a real pigeon and a rat. Then, they were tested with movies of the computer-generated (CG) pigeon. Subjects showed generalization to the CG pigeon, however, they also responded to modified versions in which the CG pigeon was showing impossible movement, namely hopping and walking without its head bobbing. Hence, the pigeons did not attend to these particular details of the display. When they were trained to discriminate between the normal and the modified version of the CG pigeon, they were able to learn the discrimination. The results of an additional partial occlusion test suggest that the subjects used head movement as a cue for the usual vs. unusual CG pigeon discrimination.
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Lacreuse, A., Martin-Malivel, J., Lange, H. S., & Herndon, J. G. (2007). Effects of the menstrual cycle on looking preferences for faces in female rhesus monkeys. Anim. Cogn., 10(2), 105–115.
Abstract: Fluctuations of ovarian hormones across the menstrual cycle influence a variety of social and cognitive behaviors in primates. For example, female rhesus monkeys exhibit heightened interest for males and increased agonistic interactions with other females during periods of high estrogen levels. In the present study, we hypothesized that females' preference for males during periods of high estrogen levels is also expressed at the level of face perception. We tested four intact females on two face-tasks involving neutral portraits of male and female rhesus monkeys, chimpanzees and humans. In the visual preference task (VP), monkeys had to touch a button to view a face image. The image remained on the screen as long as the button was touched, and the duration of pressing was taken as an index of the monkey's looking time for the face stimulus. In the Face-Delayed Recognition Span Test (Face-DRST), monkeys were rewarded for touching the new face in an increasing number of serially presented faces. Monkeys were tested 5 days a week across one menstrual cycle. Blood was collected every other day for analysis of estradiol and progesterone. Two of the four females were cycling at the time of testing. We did not find an influence of the cycle on Face-DRST, likely due to a floor effect. In the VP however, the two cycling individuals looked longer at conspecific male faces than female faces during the peri-ovulatory period of the cycle. Such effects were absent for human and chimpanzee faces and for the two noncycling subjects. These data suggest that ovarian hormones may influence females' preferences for specific faces, with heightened preference for male faces during the peri-ovulatory period of the cycle. Heightened interest for stimuli of significant reproductive relevance during periods of high conception risk may help guide social and sexual behavior in the rhesus monkey.
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Neiworth, J. J., Hassett, J. M., & Sylvester, C. J. (2007). Face processing in humans and new world monkeys: the influence of experiential and ecological factors. Anim. Cogn., 10(2), 125–134.
Abstract: This study tests whether the face-processing system of humans and a nonhuman primate species share characteristics that would allow for early and quick processing of socially salient stimuli: a sensitivity toward conspecific faces, a sensitivity toward highly practiced face stimuli, and an ability to generalize changes in the face that do not suggest a new identity, such as a face differently oriented. The look rates by adult tamarins and humans toward conspecific and other primate faces were examined to determine if these characteristics are shared. A visual paired comparison (VPC) task presented subjects with either a human face, chimpanzee face, tamarin face, or an object as a sample, and then a pair containing the previous stimulus and a novel stimulus was presented. The stimuli were either presented all in an upright orientation, or all in an inverted orientation. The novel stimulus in the pair was either an orientation change of the same face/object or a new example of the same type of face/object, and the stimuli were shown either in an upright orientation or in an inverted orientation. Preference to novelty scores revealed that humans attended most to novel individual human faces, and this effect decreased significantly if the stimuli were inverted. Tamarins showed preferential looking toward novel orientations of previously seen tamarin faces in the upright orientation, but not in an inverted orientation. Similarly, their preference to look longer at novel tamarin and human faces within the pair was reduced significantly with inverted stimuli. The results confirmed prior findings in humans that novel human faces generate more attention in the upright than in the inverted orientation. The monkeys also attended more to faces of conspecifics, but showed an inversion effect to orientation change in tamarin faces and to identity changes in tamarin and human faces. The results indicate configural processing restricted to particular kinds of primate faces by a New World monkey species, with configural processing influenced by life experience (human faces and tamarin faces) and specialized to process orientation changes specific to conspecific faces.
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Sturz, B. R., Bodily, K. D., & Katz, J. S. (2006). Evidence against integration of spatial maps in humans. Anim. Cogn., 9(3), 207–217.
Abstract: A dynamic 3-D virtual environment was constructed for humans as an open-field analogue of Blaisdell and Cook's (2005) pigeon foraging task to determine if humans, like pigeons, were capable of integrating separate spatial maps. Participants used keyboard keys and a mouse to search for a hidden goal in a 4x4 grid of raised cups. During Phase 1 training, a goal was consistently located between two landmarks (Map 1: blue T and red L). During Phase 2 training, a goal was consistently located down and left of a single landmark (Map 2: blue T). Transfer trials were then conducted in which participants were required to make choices in the presence of the red L alone. Cup choices during transfer assessed participants' strategies: association (from Map 1), generalization (from Map 2), or integration (combining Map 1 and 2). During transfer, cup choices increased to a location which suggested an integration strategy and was consistent with results obtained with pigeons. However, additional analyses of the human data suggested participants initially used a generalization strategy followed by a progressive shift in search behavior away from the red L. This shift in search behavior during transfer was responsible for the changes in cup choices across transfer trials and was confirmed by a control condition. These new analyses offer an alternative explanation to the spatial integration account proposed for pigeons.
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Kaminski, J., Call, J., & Tomasello, M. (2004). Body orientation and face orientation: two factors controlling apes' behavior from humans. Anim. Cogn., 7(4), 216–223.
Abstract: A number of animal species have evolved the cognitive ability to detect when they are being watched by other individuals. Precisely what kind of information they use to make this determination is unknown. There is particular controversy in the case of the great apes because different studies report conflicting results. In experiment 1, we presented chimpanzees, orangutans, and bonobos with a situation in which they had to request food from a human observer who was in one of various attentional states. She either stared at the ape, faced the ape with her eyes closed, sat with her back towards the ape, or left the room. In experiment 2, we systematically crossed the observer's body and face orientation so that the observer could have her body and/or face oriented either towards or away from the subject. Results indicated that apes produced more behaviors when they were being watched. They did this not only on the basis of whether they could see the experimenter as a whole, but they were sensitive to her body and face orientation separately. These results suggest that body and face orientation encode two different types of information. Whereas face orientation encodes the observer's perceptual access, body orientation encodes the observer's disposition to transfer food. In contrast to the results on body and face orientation, only two of the tested subjects responded to the state of the observer's eyes.
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Fragaszy, D., Johnson-Pynn, J., Hirsh, E., & Brakke, K. (2003). Strategic navigation of two-dimensional alley mazes: comparing capuchin monkeys and chimpanzees. Anim. Cogn., 6(3), 149–160.
Abstract: Planning is an important component of cognition that contributes, for example, to efficient movement through space. In the current study we presented novel two-dimensional alley mazes to four chimpanzees and three capuchin monkeys to identify the nature and efficiency of planning in relation to varying task parameters. All the subjects solved more mazes without error than expected by chance, providing compelling evidence that both species planned their choices in some manner. The probability of making a correct choice on mazes designed to be more demanding and presented later in the testing series was higher than on earlier, simpler mazes (chimpanzees), or unchanged (capuchin monkeys), suggesting microdevelopment of strategic choice. Structural properties of the mazes affected both species' choices. Capuchin monkeys were less likely than chimpanzees to take a correct path that initially led away from the goal but that eventually led to the goal. Chimpanzees were more likely to make an error by passing a correct path than by turning onto a wrong path. Chimpanzees and one capuchin made more errors on choices farther in sequence from the goal. Each species corrected errors before running into the end of an alley in approximately 40% of cases. Together, these findings suggest nascent planning abilities in each species, and the prospect for significant development of strategic planning capabilities on tasks presenting multiple simultaneous or sequential spatial relations. The computerized maze paradigm appears well suited to investigate movement planning and spatial perception in human and nonhuman primates alike.
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Leighty, K. A., & Fragaszy, D. M. (2003). Primates in cyberspace: using interactive computer tasks to study perception and action in nonhuman animals. Anim. Cogn., 6(3), 137–139.
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Leighty, K. A., & Fragaszy, D. M. (2003). Joystick acquisition in tufted capuchins (Cebus apella). Anim. Cogn., 6(3), 141–148.
Abstract: A number of nonhuman primate species have demonstrated the ability to use a joystick to control a cursor on a computer screen, yet the acquisition of this skill has not been the focus of systematic inquiry. Here, we examined joystick acquisition in four tufted capuchins under two directional relationships of joystick movement and resultant cursor displacement, isomorphic and inverted. To document the natural history of the acquisition of this skill, we recorded the development of visual tracking of the cursor and body tilting. Rates of acquisition were comparable between the two conditions. After mastering the task in one condition, subjects remastered the task at an accelerated rate in the opposing condition. All subjects significantly increased or maintained high proportions of cursor tracking throughout acquisition. All subjects demonstrated a postural tilt while moving the cursor from the mid-phase of acquisition through task mastery. In the isomorphic condition, all subjects tilted significantly more often in the direction of goal location than in the opposite direction. In three of the four series of tilting that were scored for subjects in the inverted condition, tilting occurred significantly more often toward the direction of goal location than the direction of required hand movement. Together these findings suggest that body tilting participates in the organization of directional movement of the cursor rather than reflecting merely the motoric requirements of the task (to manipulate a joystick).
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Iversen, I. H., & Matsuzawa, T. (2003). Development of interception of moving targets by chimpanzees (Pan troglodytes) in an automated task. Anim. Cogn., 6(3), 169–183.
Abstract: The experiments investigated how two adult captive chimpanzees learned to navigate in an automated interception task. They had to capture a visual target that moved predictably on a touch monitor. The aim of the study was to determine the learning stages that led to an efficient strategy of intercepting the target. The chimpanzees had prior training in moving a finger on a touch monitor and were exposed to the interception task without any explicit training. With a finger the subject could move a small “ball” at any speed on the screen toward a visual target that moved at a fixed speed either back and forth in a linear path or around the edge of the screen in a rectangular pattern. Initial ball and target locations varied from trial to trial. The subjects received a small fruit reinforcement when they hit the target with the ball. The speed of target movement was increased across training stages up to 38 cm/s. Learning progressed from merely chasing the target to intercepting the target by moving the ball to a point on the screen that coincided with arrival of the target at that point. Performance improvement consisted of reduction in redundancy of the movement path and reduction in the time to target interception. Analysis of the finger's movement path showed that the subjects anticipated the target's movement even before it began to move. Thus, the subjects learned to use the target's initial resting location at trial onset as a predictive signal for where the target would later be when it began moving. During probe trials, where the target unpredictably remained stationary throughout the trial, the subjects first moved the ball in anticipation of expected target movement and then corrected the movement to steer the ball to the resting target. Anticipatory ball movement in probe trials with novel ball and target locations (tested for one subject) showed generalized interception beyond the trained ball and target locations. The experiments illustrate in a laboratory setting the development of a highly complex and adaptive motor performance that resembles navigational skills seen in natural settings where predators intercept the path of moving prey.
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