Learning to recalibrate the role of dead reckoning and visual cues in spatial navigation

In Experiment 1, hamsters started from their permanent home at the periphery of a circular arena and headed to a food source at the center. They then returned, fully laden with food, along a direct path to their home. On control trials, in which no manipulation takes place, visual cues outside the arena and dead reckoning (i.e., updated internal references generated during the outward journey to the food source) controlled the return journey. On experimental trials, the arena, with the hamster in its nest, was rotated by 90°, putting dead reckoning at variance with the distal visual environment. The animals were rewarded for going with dead reckoning. At first, they favored the distal cues, but later most of the subjects switched to using dead reckoning. Thus, hamsters are flexible enough to recalibrate the relative weight that they normally attribute to different sets of spatial cues. In Experiment 2, the reliance on dead-reckoning was greatly enhanced when a cue card at the nest entrance was rotated along with the arena, pitting one proximal cue plus dead reckoning against distal cues. Hence, dead reckoning and external cues seem to reinforce each other through their mutual correlation.     

Shortcut ability in hamsters (Mesocricetus auratus): The role of environmental and kinesthetic information

Shortcut ability in hamsters was tested in a complex wheel-shaped maze, in which kinesthetic information could be associated with environmental (proximal and/or distal) cues. The hamsters, previously trained to reach a hidden goal by a circumferential route, were led to the center of the maze to test their ability to take a directional shortcut to that same goal. In Experiment 1, their ability to accurately take a straight-line shortcut to the goal (from among eight possible paths) when distal cues were available was demonstrated. In Experiment 2, environmental information was neutralized in some conditions in order to enhance the relevance of kinesthetic information. When circumferential training runs were not too complex, the hamsters could use kinesthetic information—“path integration” processes—integrated during their previous training to infer the direction of the hidden goal.     

Cognitive reality of multidimensional information processing in knowledge assessment by experts

Two experiments were designed in order to examine the knowledge assessment task accomplished by French teachers assessing essays written by French native secondary school students. The focus of the study bears on the potentially multidimensional nature of the processing of evaluation cues. In the experimental conditions conventionally designed to test multidimensional evaluation models or techniques, information about each object to be evaluated (and hence, the dimensions along which objects are compared with each other) are explicitly provided to the subject from some external source. The experiments presented here were aimed at studying information processing by experts performing an evaluation task in which the experts themselves are required to: (i) define the relevant dimensions to be used in the evaluation and (ii) elaborate the necessary information about each of those dimensions for each object (in this case, native language essays). The question is to find out whether or not the information processing carried out by such subjects is multidimensional. If evaluators do in fact perform multidimensional processing of information, this implies not only that evaluation cues belong to differentiated classes (Experiment 1), but also that cues belonging to the same class are processed with respect to each other before being processed with respect to cues of another class (Experiment 2). The results obtained here support that conclusion. Both experiments used the self-paced display paradigm. Subjects were presented with segments of text on a computer screen, and the display time for each segment was recorded. Random coloration of errors belonging to three evaluator-defined classes was found to increase display time on the corresponding segments.     

Effect of number of trials,interstimulus interval,and dishabituation during CS habituation on subsequent conditioning in a CER paradigm

Three experiments were conducted to investigate the influence of variables during habituation of a CS on a subsequent conditioning to that CS in a conditioned emotional response paradigm. Experiment I varied the number of habituation trials received before conditioning, and it was found that additional habituation trials resulted in a further attenuation of conditioning. Experiment II varied the interstimulus interval of the habituating stimulus, and it was found that the longer intervals produced the greater attenuation in conditioning. Experiment III examined the effect of interpolating another stimulus between habituation and conditioning (dishabituation), and it was found that the dishabituating stimulus augmented subsequent conditioning. It was concluded that manipulations during habituation training that produce the greatest decrement in response to a stimulus, when assessed under equivalent conditions for all animals, have the greatest attenuating effect on subsequent conditioning to that stimulus.     

No evidence for overshadowing or facilitation of spatial pattern learning by visual cues

Two experiments were conducted to examine the effects of redundant and relevant visual cues on spatial pattern learning. Rats searched for hidden food items on the tops of poles that formed a square (Experiment 1) or a checkerboard (Experiment 2) pattern. The experimental groups were trained with visual cues that specified the locations of the baited poles. All groups were tested without visual cues so that any overshadowing or facilitation of spatial pattern learning by visual cues could be detected. Spatial choices were controlled by the spatial pattern and by the visual cues in both experiments. However, there was no evidence of overshadowing or facilitation of spatial pattern learning by visual cues in either experiment. The results are consistent with the idea that the representation of the spatial pattern that guides choices is not controlled by the same learning processes as those that produce associations between visual cues and food locations.     

Memory for spatial and local cues: A comparison of a storing and a nonstoring species

Two passerine species, black-capped chickadees (Parus atricapillus, a food-storing bird) and darkeyed juncos (Junco hyemalis, a nonstoring bird) were compared in a task in which they inspected four feeders in an aviary. Different feeders and different spatial locations were used on each trial. One of the feeders was baited. The subjects returned after a 5-min retention interval to find the baited feeder. Tests with transformations of the feeder array made it possible to determine what cues controlled the food-finding behavior. Chickadees responded to spatial cues preferentially over local color and pattern cues associated with the feeder (Experiments 2–4). The same ordering of responding was found in Experiment 1, a food-storing version of the food-finding task outlined above. Experiment 5 tested juncos on the food-finding task. Juncos responded to all types of information equally. The results are discussed in relation to the notion that because of their food-storing lifestyle, chickadees may need to rely more heavily on spatial cues than do juncos.     

Acquired equivalence of cues in pigeon autoshaping: Effects of training with common consequences and with common antecedents

In three experiments, we sought evidence for the acquired equivalence of cues in pigeons trained in an autoshaping paradigm. In Experiment 1, presentations of each of a pair of cues (different keylight stimuli) preceded a common consequence (a different keylight stimulus). The pattern of response then established by further training given to one member of the pair was found to generalize preferentially to the other, demonstrating equivalence between cues that had shared a common consequence. The same test procedure was used in Experiment 2, but with a training procedure in which each cue of a pair was preceded by a given stimulus. This too resulted in enhanced generalization between members of the pair, showing that equivalence can be established when cues have been experienced along with a common antecedent. Both training procedures were combined in Experiment 3 to confirm the reliability of the effects previously obtained. The discussion is focused on ways in which the associative explanation offered for cases of equivalence mediated by a common consequence might be extended to accommodate equivalence mediated by a common antecedent.     

Interaction between conflicting memories in the rat: Contextual pretest cuing reverses control of behavior by testing context

Two experiments were run in order to investigate the influence of external contextual cues on the interaction between two conflicting memories. Rats were trained, in the same apparatus, on a passive-avoidance task and, 10 min later, on an active-avoidance task, then submitted to a 24-h delayed test (without reinforcement). When contextual cues remained unchanged throughout these three phases, the animals exhibited proactive interference, as shown by longer response latencies than those of control animals that had learned only the active-avoidance task (Experiment 1). When training contexts were made slightly different from one task to the other (by the presence of a continuous tone during either the first or the second task), the animals behaved at subsequent testing in accordance with the response contingencies present in the context exactly similar to the test context; this control of behavior by testing context was demonstrated both when the tone was absent (Experiments 1 and 2) and present (Experiment 2) at testing. A cuing procedure—a 90-sec exposure to the tone in the experimental room 5 min prior to testing—led the animals to behave in accordance with the response previously acquired in the presence of the tone (Experiments 1 and 2), exactly in the same way as animals tested in the presence of the tone (Experiment 2). The same cuing treatment was ineffective when administered 1 h before testing (Experiment 2). These results are interpreted in terms of a dual function of contextual cues at the time of retrieval: the general contextual information present during testing or during pretest cuing is assumed to induce concurrent reactivation of both memories. Consequently, the experimentally manipulated contextual cue (the tone) would have a discriminative function, leading the animals to choose between the two equally available representations.     

External stimulus control of target-directed attack and biting elicited by tailshock

Two experiments evaluating the effects of external stimuli on attack and biting in rats elicited by electric tailshock are reported. In the first experiment, stimuli presented to four groups of test subjects consisted of a stimulus animal, a stimulus animal plus taped vocalizations of a rat experiencing shock, an inanimate object, and an inanimate object plus taped vocalizations. Subjects in a fifth (control) group were tested in the absence of these stimuli. The presence of another animal in the test situation significantly increased the amount of target-directed responding. A decrease in responding, rather than increase, was shown by the subjects tested under the stimulus-object plus taped-vocalization conditions. Experiment 2 investigated the salient features of the stimulus animal and found a combination of both olfactory and visual cues to be most effective in eliciting target-directed responding. These studies indicate that the amount of target-directed attack and biting shown in this situation may be related causally to the type of sensory input received by the test animal.     

Why don’t guiding cues always guide in behavior chains?

This research focused on the changes in stimulus control that influence an animal’s ability to master a behavioral skill. We assessed stimulus control by (a) predictive environmental cues (panel lights) and (b) practice cues resulting from the subject’s own behavior, as rats learned to complete a left–right lever-press sequence. Following a demonstration of overshadowing by Reid, Nill, and Getz (Behavioural Processes 84: 511–515, 2010), in which stimulus control by the panel lights overshadowed control by practice cues, four additional experiments replicated and assessed this overshadowing effect. In Experiment 1, we discovered a powerful asymmetry: Rats failed to adapt to a lights → reversed-lights transition, but adapted immediately to a reversed-lights → lights transition. Experiment 2 was designed to measure the interactions between these stimulus conditions and practice cues. In Experiment 3, we measured the effect of these stimulus conditions on acquisition rates. Finally, in Experiment 4 an ABA design was used to assess the effects of prior exposure to condition A on B → A transitions, and we found that prior exposure generally reversed the effects observed in B → A transitions presented first or in isolation. We discuss feature-positive bias and spatial S–R compatibility as potential explanations of the observed insensitivity to cues that should be, at face value, highly predictive of food during the acquisition of a behavioral skill. Perfectly predictive cues in behavior chains do not always guide behavior.     

Infant responsivity to curvature.

The reactions of 112 10-month-old male infants to the property of curvature were examined using a habituation paradigm with lever pressing as an instrumental response. 4 levels of curvature (straightt line, minimal curve, moderate curve, large curve) each served as a standard (habituation) stimulus and as a transformation stimulus in 9 separate experimental conditions. Results revealed a greater initial dishabituation of reinforced instrumental responding in those conditions crossing the curved/straight boundary; furthermore, this initial dishabituation was sustained throughout the transformation phase of the experiment in those conditions which involved changes from straight to curved, but not curved to straight. Results are interpreted as implying a special attention-recruiting value for curvature in 10-month old infants.     

The role of injection cues in the production of the morphine preexposure effect in taste aversion learning

The attenuation of an LiCl-induced conditioned taste aversion (CTA) by LiCl preexposure is mediated primarily by associative blocking via injection-related cues. Given that preexposure to morphine attenuates morphine-induced CTAs, it was of interest to determine whether injection cues also mediate this effect. Certain morphine-induced behaviors such as analgesic tolerance are controlled associatively, via injection-related cues. Accordingly, animals in the present experiments were preexposed to morphine (or vehicle) every other day for five total exposures, followed by an extinction phase, in which the subjects were given saline injections (or no treatment) for 8 (Experiment 1) or 16 (Experiment 2) consecutive days. All of the animals then received five CTA trials with morphine (or vehicle). The morphine-preexposed animals in Experiment 1 displayed an attenuation of the morphine CTA that was unaffected by extinction saline injections, suggesting that blocking by injection cues during morphine preexposure does not mediate this effect. All of the morphine-preexposed subjects in Experiment 2 displayed a weakened preexposure effect, an effect inconsistent with a selective extinction of drug-associated stimuli. The attenuating effects of morphine preexposure in aversion learning are most likely controlled by nonassociative mechanisms, like drug tolerance.     

Factors affecting conditional discrimination learning by pigeons: II. Physical and temporal characteristics of stimuli

Four experiments were performed to determine the stimulus characteristics that favor the development of conditional stimulus control in the single reversal paradigm with pigeon subjects. In Experiment 1, pigeons were trained on a successive discrimination between tone frequencies ranging from 350 to 3500 Hz in a particular houselight context condition (houselight-on or -off). The subjects then were trained on the reversal of the tone discrimination in the alternative context. Subsequent tone-frequency generalization testing in the two contexts indicated that they had failed to gain conditional control over the pigeons’ discriminative performance. Such control was obtained in Experiment 2, in which the two problems were alternated daily for 32 sessions of training. The gradients then peaked at the appropriate S+ value in each context. In Experiment 3, the key colors (blue vs. red) served as contexts while pigeons learned a successive discrimination in which the discriminative cues were houselight-on versus houselight-off conditions. This was followed by a reversal of the discrimination in the alternative key-color context condition. The key colors were effective conditional cues in this situation. In a previous experiment (Thomas, McKelvie, & Mah, 1985), key color had been ineffective as a conditional cue when the discriminative cues were lines superimposed on the colored background. In Experiment 4, key color was effective when the color and lines were presented on a single key as in the earlier experiment, but were sequenced such that the onset of the key color preceded and then overlapped the presentation of the lines. We concluded that conditional discriminations are easiest for pigeons when visual cues are used, but the conditional and discriminative cues must be presented in such a way that they do not combine to form a psychological compound.     

Action speaks louder than words: young children differentially weight perceptual, social, and linguistic cues to learn verbs

This paper explores how children use two possible solutions to the verb-mapping problem: attention to perceptually salient actions and attention to social and linguistic information (speaker cues). Twenty-two-month-olds attached a verb to one of two actions when perceptual cues (presence/absence of a result) coincided with speaker cues but not when these cues were placed into conflict (Experiment 1), and not when both possible referent actions were perceptually salient (Experiment 2). By 34 months, children were able to override perceptual cues to learn the name of an action that was not perceptually salient (Experiment 3). Results demonstrate an early reliance on perceptual information for verb mapping and an emerging tendency to weight speaker information more heavily over developmental time.     

Epistemic states and traits: preschoolers appreciate the differential informativeness of situation-specific and person-specific cues to knowledge

Previous research has demonstrated that preschoolers can use situation-specific (e.g., visual access) and person-specific (e.g., prior accuracy) cues to infer what others know. The present studies investigated whether 4- and 5-year-olds appreciate the differential informativeness of these types of cues. In Experiment 1 (N = 50), children used others' prior labeling accuracy as a cue when learning labels for, but not the visual identity of, hidden objects. In Experiment 2 (N = 64), with both cues present, children attended more to visual access than prior accuracy when learning the visual identity of, but not labels for, hidden objects. These findings demonstrate that children appreciate the difference between situation- and person-specific cues and flexibly evaluate these cues depending on what information they are seeking.     

Competition among spatial cues in a naturalistic food-carrying task

Rats collected nuts from a container in a large arena in four experiments testing how learning about a beacon or cue at a goal interacts with learning about other spatial cues (place learning). Place learning was quick, with little evidence of competition from the beacon (Experiments 1 and 2). Rats trained to approach a beacon regardless of its location were subsequently impaired when the well-learned beacon was removed and other spatial cues identified the location of the goal (Experiment 3). The competition between beacon and place cues reflected learned irrelevance for place cues (Experiment 4). The findings differ from those of some studies of associative interactions between cue and place learning in other paradigms.     

Postevent cues bias recognition performance in pigeons

In the present study, we examined whether the presentation of postevent cues would bias recognition in a visual delayed matching-to-sample task with pigeons. Postevent cues were either consistent with the original target stimulus (i.e., they were the same as the correct choice option at recognition), inconsistent (i.e., they were the same as the incorrect recognition option), or neutral (i.e., they were different from both the correct and the incorrect recognition options). In Experiment 1, a single colored light served as the target stimulus. In Experiment 2, the target stimulus was one of three lights presented in a sequence. Both experiments demonstrated that recognition choices were biased toward the option corresponding to the postevent cue, but only if the cue occurred at the end of the delay interval. The present results mirror those found using the misinformation paradigm with human subjects.     

The effect of subadditive pretraining on blocking: limits on generalization

Recent evidence indicates that prior learning about a set of cues may determine how new cues are processed. If subjects are taught that two reliable predictors of an outcome do not summate when the cues are presented together (i.e., subadditive pretraining), the subjects will tend to show a less profound blocking effect when trained with different cues. Three experiments investigated the conditions necessary for subadditive pretraining to generalize to new cues. Experiment 1 demonstrated that subadditive pretraining is less effective in reducing blocking when it is experienced in a context other than that in which the blocking training is experienced. In Experiment 2, the effectiveness of subadditive pretraining waned with time. Experiment 3 showed that subadditive pretraining is more effective when the temporal characteristics of pretraining cues are similar to those of the cues used in blocking training. These results provide information concerning the conditions under which learning will generalize from one set of cues to another.     

Perception of kinetic illusory contours by two-month-old infants

Perception of kinetic illusory contours by 2-month-old infants was explored with sparse random-dot displays depicting an illusory shape against a background. In Experiment 1, 24 infants were habituated to a shape specified by accretion and deletion of background texture and relative motion, and exhibited a novelty preference when presented with luminance-defined familiar and novel shapes. Subsequent experiments explored kinetic cues in isolation. In Experiment 2 (n = 24), relative motion information was removed, leaving accretion and deletion of texture and luminance cues, and in Experiment 3 (n = 24), only relative motion information was available. In both these experiments the novelty preference obtained in Experiment 1 was replicated. Results from a control condition (n = 12) mitigated against the likelihood of an inherent preference for either of the test shapes. These findings reveal an early capacity to perceive shape solely from kinetic information, and suggest a mechanism geared toward spatiotemporal boundary formation that is functional shortly after birth. Theories of development of edge and motion discrimination are discussed.     

An eye tracking comparison of external pointing cues and internal continuous cues in learning with complex animations

Two experiments used eye tracking to investigate a novel cueing approach for directing learner attention to low salience, high relevance aspects of a complex animation. In the first experiment, comprehension of a piano mechanism animation containing spreading-colour cues was compared with comprehension obtained with arrow cues or no cues. Eye tracking data revealed differences in learner attention patterns between the different experimental conditions. The second experiment used eye tracking with synchronized and non-synchronized cues to investigate the role of dynamic direction of attention in cueing effectiveness. Results of Experiment 1 showed that spreading-colour cues resulted in better targeting of attention to thematically relevant aspects and in higher comprehension scores than arrow cues or no cues. For Experiment 2, superior comprehension after the synchronized version together with eye tracking data indicated that cue effectiveness depended on attention direction being spatially and temporally coordinated with onsets of animation events having high thematic relevance to the learning task. The findings suggest the importance of perceptual cues and bottom-up processing.