Journal of Experimental Psychology-Animal Learning and Cognition最新文献

Visual search for complex natural targets requires focal attention, either cued by predictive stimulus associations or primed by a representation of the most recently detected target. Because both processes can focus visual attention, cuing and priming were compared in an operant search task to evaluate their relative impacts on performance and to determine the nature of their interaction in combined treatments. Blue jays were trained to search for pairs of alternative targets among distractors. Informative or ambiguous color cues were provided before each trial, and targets were presented either in homogeneous blocked sequences or in constrained random order. Initial task acquisition was facilitated by priming in general, but was significantly retarded when targets were both cued and primed, indicating that the two processes interfered with each other during training. At asymptote, attentional effects were manifested mainly in inhibition, increasing latency in miscued trials and decreasing accuracy on primed trials following an unexpected target switch. A combination of cuing and priming was found to interfere with performance in such unexpected trials, apparently a result of the limited capacity of working memory. Because the ecological factors that promote priming or cuing are rather disparate, it is not clear whether they ever simultaneously contribute to natural predatory search.

In 2 experiments, rats were trained to press a centrally located lever that delivered immediate food reinforcement and turned on a light signal that indicated the location of a further food reward. After rats learned to press the lever and use the light cue to find food, immediate reinforcement for lever pressing was discontinued. In Experiment 1, rats continued to press the lever for information about the location of reward in a T-maze, but control groups yoked to the experimental group for amount of reward, and conditioned reinforcement showed complete extinction of lever pressing. Rats tested on an 8-arm radial maze in Experiment 2 also continued to press a lever that did not yield immediate reinforcement but provided a light cue indicating which randomly chosen arm of the maze contained food; lever pressing declined significantly, however, when the same arm contained food on every trial. Comparisons of testing conditions between and within experiments suggested that probability of lever pressing increased as the amount of information gained increased. The comparative implications of these findings for metacognition are discussed.

In an ever-changing world, the ability to track what significant events occur and where and when is beneficial to a variety of animal species. The purpose of the present studies was to assess the presence of this ability to track what-where-when memory in pigeons based both on when during the day the events occurred and how long ago events occurred. In these studies, pigeons were trained to discriminate between two foods that differed in quality (what), making one more "attractive" than the other. The birds were required to alter their choice of keylights (where) to get these differential foods based on the time of day (Experiments 1-2) or how long ago (Experiments 3-5) they were in a session (when). Pigeons were able to correctly choose the key that yielded the "attractive" food using both time of day and how long ago, indicating a what-where-when memory. However, the pigeons failed to transfer this knowledge to a novel situation, showing limited flexibility in use of the learned what-where-when information. These findings suggest that pigeons have abilities to track what-where-when events as do caching birds and other animal species, but perhaps represented in a more rigid manner.

The face inversion effect is a defection in performance in recognizing inverted faces compared with faces presented in their usual upright orientation typically believed to be specific for facial stimuli. McLaren (1997) was able to demonstrate that (a) an inversion effect could be obtained with exemplars drawn from a familiar category, such that upright exemplars were better discriminated than inverted exemplars; and (b) that the inversion effect required that the familiar category be prototype-defined. In this article, we replicate and extend these findings. We show that the inversion effect can be obtained in a standard old/new recognition memory paradigm, demonstrate that it is contingent on familiarization with a prototype-defined category, and establish that the effect is made up of two components. We confirm the advantage for upright exemplars drawn from a familiar, prototype-defined category, and show that there is a disadvantage for inverted exemplars drawn from this category relative to suitable controls. We also provide evidence that there is an N170 event-related potential signature for this effect. These results allow us to integrate a theory of perceptual learning originally proposed by McLaren, Kaye, and Mackintosh (1989) with explanations of the face inversion effect, first reported by Yin.

Scene gist categorization in humans is rapid, accurate, and tuned to the statistical regularities in the visual world. However, no studies have investigated whether scene gist categorization is a general process shared across species, or whether it may be influenced by species-specific adaptive specializations relying on specific low-level scene statistical regularities of the environment. Although pigeons form many types of categorical judgments, little research has examined pigeons' scene categorization, and no studies have examined pigeons' ability to do so rapidly. In Experiment 1, pigeons were trained to discriminate between either 2 basic-level categories (beach vs. mountain) or a superordinate-level natural versus a manmade scene category distinction (beach vs. street). The birds learned both tasks to a high degree of accuracy and transferred their discrimination to novel images. Furthermore, the pigeons successfully discriminated stimuli presented in the 0.2- to 0.35-s duration range. Therefore, pigeons, a highly divergent species from humans, are also capable of rapid scene categorization, but they require longer stimulus durations than humans. Experiment 2 examined whether pigeons make use of complex statistical regularities during scene gist categorization across multiple viewpoints. Pigeons were trained with the 2 natural categories from Experiment 1 (beach vs. mountain) with zenith (90°), bird's eye (45°), and terrestrial (0°) viewpoints. A sizable portion of the variability in pigeon categorization performance was explained by the systematic variation in scene category-specific statistical regularities, as with humans. Thus, rapid scene categorization is a process that is shared across pigeons and humans, but shows a degree of adaptive specialization.

Previous research has shown rapid learning of multiple temporal relations between signals and food by pigeons when these relations are changed unpredictably each session (Kyonka & Grace, 2007). The goal of the present study was to test whether contextual temporal cues-that is, an alternative signal-food delay that was a valid predictor of a target signal-food delay-facilitated acquisition by the target contingency. Four pigeons responded in a multiple peak-interval procedure in which red and green keys signaled separate fixed-interval (FI) schedules with occasional extinction probes (peak trials). The schedule parameters of the FIs either summed to 30 s (correlated condition; ρ = -1.0) or were not restricted to sum to 30 s (uncorrelated condition; ρ = 0.0). Comparing stop times obtained from peak trials in the 2 conditions revealed no effect of context: Temporal control of responding was acquired at the same rate and with the same precision regardless of whether the schedule values were correlated. These results suggest that pigeons learn about multiple signal-food delays independently.

Most theories and experimental investigations of discrimination learning and categorization, in both humans and animals, hypothesize that attention must be allocated to the relevant attributes of the training stimuli for learning to occur. Attention has conventionally been inferred after learning has transpired rather than examined while learning is transpiring. We presented pigeons with a visual categorization task in which we monitored their choice accuracy through their responses to different report buttons; critically, we tracked the location of the pigeons' pecks to both the relevant and irrelevant attributes of the training stimuli using touchscreen technology, in order to find out where the birds may have been attending during the course of categorization learning. Pigeons readily mastered the categorization task; most importantly, as training progressed, they increasingly concentrated their pecks on the relevant features of the category exemplars, suggesting that the birds were tracking the relevant information to solve the task. When either new irrelevant features were introduced (Experiment 1) or when new relevant features were introduced and later the discriminative value of these new relevant features was reversed (Experiment 2), pigeons' choice accuracy and peck tracking were strongly affected. These results help elucidate the dynamics and interplay of attention and learning; they also suggest that peck tracking can be a suitable measure of the allocation of attention in pigeons, much as eyetracking is deemed to be a suitable measure of attention in humans.

In 4 experiments that investigated latent spatial learning, rats were repeatedly placed on a submerged platform in a corner of a square swimming pool with walls of different brightness. When they were subsequently released into the pool for a test trial in the absence of the platform, they spent the majority of time in the corner used for placement training-the correct corner. This effect was observed in Experiment 1, even when the test trial took place in a transformed version of the training arena. Experiments 2 and 3 indicated that the correct corner was identified by local cues based on the walls creating the corner. Experiment 4 demonstrated that distal cues created by the two walls that did not surround the platform during placement training could also be used to identify the correct corner. There was no evidence of learning about the relationship between global cues provided by the entire arena and the goal. The absence of the opportunity to develop instrumental, stimulus-response associations during placement training indicates that stimulus-stimulus associations acquired during this training were sufficient to guide rats to the platform when they were eventually released into the pool.

Previous research has suggested that changing the context after instrumental (operant) conditioning can weaken the strength of the operant response. That result contrasts with the results of studies of Pavlovian conditioning, in which a context switch often does not affect the response elicited by a conditioned stimulus. To begin to make the methods more similar, Experiments 1-3 tested the effects of a context switch in rats on a discriminated operant response (R; lever pressing or chain pulling) that had been reinforced only in the presence of a 30-s discriminative stimulus (S; tone or light). As in Pavlovian conditioning, responses and reinforcers became confined to presentations of the S during training. However, in Experiment 1, after training in Context A, a switch to Context B caused a decrement in responding during S. In Experiment 2, a switch to Context B likewise decreased responding in S when Context B was equally familiar, equally associated with reinforcement, or equally associated with the training of a discriminated operant (a different R reinforced in a different S). However, there was no decrement if Context B had been associated with the same response that was trained in Context A (Experiments 2 and 3). The effectiveness of S transferred across contexts, whereas the strength of the response did not. Experiment 4 found that a continuously reinforced response was also disrupted by context change when the same response manipulandum was used in both training and testing. Overall, the results suggest that the context can have a robust general role in the control of operant behavior. Mechanisms of contextual control are discussed.

This study examined affective consequences of an active avoidance response. Catching a fleeting stimulus with a rapid key press secured a monetary reward in a reward condition or avoided a monetary loss in an avoidance condition. Outcomes of wins, missed wins, losses, and avoided losses were signaled with color patches that were evaluated explicitly (via evaluative rating) and implicitly (via an affective priming task). Liking scores in each condition were compared with those in yoked-control conditions in which wins and avoided losses were presented without the requirement of an active response. In the explicit measure, colors associated with an avoided loss were rated positively and colors associated with a missed win were judged negatively, irrespective of whether the outcome was self-generated. In the implicit measure, outcomes of missed wins and avoided losses were evaluated differently only when they were self-generated. The results confirm a qualitative affective equivalence between an avoided loss and an achieved win. Implications for avoidance theories are discussed.