Stimulus control in the use of landmarks by pigeons in a touch-screen task

Cue combination in human spatial navigation

This project investigated the ways in which visual cues and bodily cues from self-motion are combined in spatial navigation. Participants completed a homing task in an immersive virtual environment. In Experiments 1A and 1B, the reliability of visual cues and self-motion cues was manipulated independently and within-participants. Results showed that participants weighted visual cues and self-motion cues based on their relative reliability and integrated these two cue types optimally or near-optimally according to Bayesian principles under most conditions. In Experiment 2, the stability of visual cues was manipulated across trials. Results indicated that cue instability affected cue weights indirectly by influencing cue reliability. Experiment 3 was designed to mislead participants about cue reliability by providing distorted feedback on the accuracy of their performance. Participants received feedback that their performance with visual cues was better and that their performance with self-motion cues was worse than it actually was or received the inverse feedback. Positive feedback on the accuracy of performance with a given cue improved the relative precision of performance with that cue. Bayesian principles still held for the most part. Experiment 4 examined the relations among the variability of performance, rated confidence in performance, cue weights, and spatial abilities. Participants took part in the homing task over two days and rated confidence in their performance after every trial. Cue relative confidence and cue relative reliability had unique contributions to observed cue weights. The variability of performance was less stable than rated confidence over time. Participants with higher mental rotation scores performed relatively better with self-motion cues than visual cues. Across all four experiments, consistent correlations were found between observed weights assigned to cues and relative reliability of cues, demonstrating that the cue-weighting process followed Bayesian principles. Results also pointed to the important role of subjective evaluation of performance in the cue-weighting process and led to a new conceptualization of cue reliability in human spatial navigation.

Blocking between landmarks during 2-D (touchscreen) and 3-D (ARENA) search tasks with pigeons

Many studies investigating cue competition have focused on the blocking effect. We investigated the blocking effect with pigeons using a landmark-based spatial search task in both a touchscreen preparation (Exp. 1a) and an automated remote environmental navigation apparatus (Exp. 1b). In Phase 1, two landmarks (LMs: A and Z) appeared on separate trials as colored circles among a row of eight (touchscreen) or six (ARENA) identical response units. Subjects were rewarded for pecking at a target response unit to the right of LM A and to the left of an extraneous LM, Z. During the blocking trials in Phase 2, LM X was presented in compound with a second LM (A) that had been previously trained. On control trials, LM Y was presented in compound with LM B and a target in the same manner as in the trials of AX, except that neither landmark had previously been trained with the target. All subjects were then tested with separate trials of A, X, B, and Y. Testing revealed poor spatial control by X relative to A and Y. We report the first evidence for a spatial-blocking effect in pigeons and additional support for associative effects (e.g., blocking) occurring under similar conditions (e.g., training sessions, spatial relationships, etc.) in 3-D and 2-D search tasks.

Scene-based contextual cueing in pigeons

Repeated pairings of a particular visual context with a specific location of a target stimulus facilitate target search in humans. We explored an animal model of such contextual cueing. Pigeons had to peck a target, which could appear in 1 of 4 locations on color photographs of real-world scenes. On half of the trials, each of 4 scenes was consistently paired with 1 of 4 possible target locations; on the other half of the trials, each of 4 different scenes was randomly paired with the same 4 possible target locations. In Experiments 1 and 2, pigeons exhibited robust contextual cueing when the context preceded the target by 1 s to 8 s, with reaction times to the target being shorter on predictive-scene trials than on random-scene trials. Pigeons also responded more frequently during the delay on predictive-scene trials than on random-scene trials; indeed, during the delay on predictive-scene trials, pigeons predominately pecked toward the location of the upcoming target, suggesting that attentional guidance contributes to contextual cueing. In Experiment 3, involving left-right and top-bottom scene reversals, pigeons exhibited stronger control by global than by local scene cues. These results attest to the robustness and associative basis of contextual cueing in pigeons.

Pigeons exhibit contextual cueing to both simple and complex backgrounds

Repeated pairings of a particular visual context with a specific location of a target stimulus facilitate target search in humans. We explored an animal model of this contextual cueing effect using a novel Cueing-Miscueing design. Pigeons had to peck a target which could appear in one of four possible locations on four possible color backgrounds or four possible color photographs of real-world scenes. On 80% of the trials, each of the contexts was uniquely paired with one of the target locations; on the other 20% of the trials, each of the contexts was randomly paired with the remaining target locations. Pigeons came to exhibit robust contextual cueing when the context preceded the target by 2s, with reaction times to the target being shorter on correctly-cued trials than on incorrectly-cued trials. Contextual cueing proved to be more robust with photographic backgrounds than with uniformly colored backgrounds. In addition, during the context-target delay, pigeons predominately pecked toward the location of the upcoming target, suggesting that attentional guidance contributes to contextual cueing. These findings confirm the effectiveness of animal models of contextual cueing and underscore the important part played by associative learning in producing the effect. This article is part of a Special Issue entitled: SQAB 2013: Contextual Con.

Behaviorism, latent learning, and cognitive maps: needed revisions in introductory psychology textbooks

This paper critically assesses the scholarship in introductory psychology textbooks in relation to the topic of latent learning. A review of the treatment of latent learning in 48 introductory psychology textbooks published between 1948 and 2004, with 21 of these texts published since 1999, reveals that the scholarship on the topic of latent learning demonstrated in introductory textbooks warrants improvement. Errors that persist in textbooks include the assertion that the latent learning experiments demonstrate unequivocally that reinforcement was not necessary for learning to occur, that behavioral theories could not account for the results of the latent learning experiments, that B. F. Skinner was an S-R association behaviorist who argued that reinforcement is necessary for learning to occur, and that because behavioral theories (including that of B. F. Skinner) were unable explain the results of the latent learning experiments the cognitive map invoked by Edward Tolman is the only explanation for latent learning. Finally, the validity of the cognitive map is typically accepted without question. Implications of the presence of these errors for students and the discipline are considered. Lastly, remedies are offered to improve the scholarship found in introductory psychology textbooks.

Associative Basis of Landmark Learning and Integration in Vertebrates

Early work on spatial navigation evaluated what stimuli (kinesthetic or extra-maze) support small-scale navigation and the nature of the underlying learning (place versus response) process. Contemporary research has focused primarily on how cues interact to determine spatial search. This review covers three general findings from research on landmark-based spatial search in vertebrates. First, pigeons and rats encode simple spatial maps in both open-field and touchscreen environments. Second, a nascent literature shows how simple maps can be integrated into complex maps through higher-order associative processes. The spatial-integration hypothesis provides an associative mechanism for spatial mapping that serves as an alternative to a previously posed configural mechanism. Finally, the evidence for associative cue-competition phenomena in landmark learning is reviewed-focusing on blocking and overshadowing. These findings support a role for associative learning in spatial tasks and provide a powerful explanatory framework for understanding cue integration and competition effects in landmark learning.

An echolocation visualization and interface system for dolphin research

The present study describes the development and testing of a tool for dolphin research. This tool was able to visualize the dolphin echolocation signals as well as function as an acoustically operated "touch screen." The system consisted of a matrix of hydrophones attached to a semitransparent screen, which was lowered in front of an underwater acrylic panel in a dolphin pool. When a dolphin aimed its sonar beam at the screen, the hydrophones measured the received sound pressure levels. These hydrophone signals were then transferred to a computer where they were translated into a video image that corresponds to the dynamic sound pressure variations in the sonar beam and the location of the beam axis. There was a continuous projection of the image back onto the hydrophone matrix screen, giving the dolphin an immediate visual feedback to its sonar output. The system offers a whole new experimental methodology in dolphin research and since it is software-based, many different kinds of scientific questions can be addressed. The results were promising and motivate further development of the system and studies of sonar and cognitive abilities of dolphins.

Evidence against integration of spatial maps in humans

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.

Small-scale spatial cognition in pigeons

Roberts and Van Veldhuizen's [Roberts, W.A., Van Veldhuizen, N., 1985. Spatial memory in pigeons on the radial maze. J. Exp. Psychol.: Anim. Behav. Proc. 11, 241-260] study on pigeons in the radial maze sparked research on landmark use by pigeons in lab-based tasks as well as variants of the radial-maze task. Pigeons perform well on open-field versions of the radial maze, with feeders scattered on the laboratory floor. Pigeons can also be trained to search precisely for buried food. The search can be based on multiple landmarks, but is sometimes controlled by just one or two landmarks, with the preferred landmarks varying across individuals. Findings are similar in landmark-based searching on a computer monitor and on a lab floor, despite many differences between the two kinds of tasks. A number of general learning principles are found in landmark-based searching, such as cue competition, generalization and peak shift, and selective attention. Pigeons also learn the geometry of the environment in which they are searching. Neurophysiological studies have implicated the hippocampal formation (HF) in avian spatial cognition, with the right hippocampus hypothesized to play a more important role in the spatial recognition of goal locations. Most recently, single-cell recording from the pigeon's hippocampal formation has revealed cells with different properties from the classic 'place' cells of rats, as well as differences in the two sides of the hippocampus.

Visual landmark orientation by flying bats at a large-scale touch and walk screen for bats, birds and rodents

Orientation depends on multi-modal information about the locally perceptible environment (local view) in many situations. We developed a behavioural paradigm for investigating visual orientation of flying bats based on a large-scale touch screen (1.2 m x 1.8 m). It functions by a grid of rows and columns of infra-red beams just in front of a screen with back-projected visual stimuli. Approaching animals interrupt the beams and thus permit automatic recording of the time and place of an animal's locational choice. We used it as a vertical touch surface. Installed as a horizontal walk surface, it may also serve as a more natural 'firm ground', circular arena analogue to the 'Morris water maze' for investigating orientation behaviour and spatial cognition from rodents to birds while offering automatic real-time recording of paths, times and latencies with enhanced possibilities to score details of motor behaviour and to control stimuli interactively. Bats offer a unique possibility to investigate the use of both echo-acoustic and visual information processing pathways for the process of self-localization and orientation. In our first experiment, a bat was presented with five identical targets, one central and four peripheral and had to choose the central target. After task acquisition, the array was shifted by the distance between targets, so that a formerly peripheral landmark was now in the absolute location of the formerly central target. At small inter-target distances, the bat 'went with' the array, and chose the new central target (at a new absolute location). With 30 cm or more of inter-target distance (60 cm across the landmark configuration), however, the bat went with absolute location, and chose a peripheral target. In experiment 2, the bat was presented with two landmarks 30 cm apart and an unmarked target located at midline beneath them. On tests, the landmarks either maintained training distance or were expanded to 50 cm apart. On such expansion tests, the bat chose most the location at the correct vector from the right landmark. This showed that the bat first identified a single landmark by the configuration and then applied a previously learnt vector (angle and distance) to locate the target. Glossophaga did not orient by pure angular geometry between landmarks and target.

Shape Parameters Explain Data From Spatial Transformations: Comment on Pearce et al. (2004) and Tommasi & Polli (2004)

In 2 recent studies on rats (J. M. Pearce, M. A. Good, P. M. Jones, & A. McGregor, see record 2004-12429-006) and chicks (L. Tommasi & C. Polli, see record 2004-15642-007), the animals were trained to search in 1 corner of a rectilinear space. When tested in transformed spaces of different shapes, the animals still showed systematic choices. Both articles rejected the global matching of shape in favor of local matching processes. The present authors show that although matching by shape congruence is unlikely, matching by the shape parameter of the 1st principal axis can explain all the data. Other shape parameters, such as symmetry axes, may do even better. Animals are likely to use some global matching to constrain and guide the use of local cues; such use keeps local matching processes from exploding in complexity.

Predicting the extension of equivalence classes from primary generalization gradients: the merger of equivalence classes and perceptual classes

In Experiment 1, 6 college students were given generalization tests using 25 line lengths as samples with a long line, a short line, and a "neither" option as comparisons. The neither option was to be used if a sample did not go with the other comparisons. Then, four-member equivalence classes were formed. Class 1 included three nonsense words and the short line. Class 2 included three other nonsense words and the long line. After repeating the generalization test for line length, additional tests were conducted using members of the equivalence classes (i.e., nonsense words and lines) as comparisons and intermediate-length lines as samples. All Class 2 comparisons were selected in the presence of the test lines that also evoked the selection of the long line in the generalization test that had been given before equivalence class formation. Class 1 yielded complementary findings. Thus, the preclass primary generalization gradient predicted which test lines acted as members of each equivalence class. Regardless of using comparisons that were nonsense words or lines, the post-class-formation gradients overlapped, showing the substitutability of class members. Experiment 2 assessed the discriminability of the intermediate-length test lines from the Class 1 (shortest) and Class 2 (longest) lines. The test lines that functioned as members of an equivalence class were discriminable from the line that was a member of the same class by training. Thus, these test lines also acted as members of a dimensionally defined class of "long" or "short" lines. Extension of an equivalence class, then, involved its merger with a dimensionally defined class, which converted a close-ended class to an open-ended class. These data suggest a means of predicting class membership in naturally occurring categories.