The acquisition of stimulus control over released pecking by hatchling chicks (Gallus gallus).

Analyzed the spatial and dynamic stimulus characteristics of the pecking arrow display that control simple release and/or learned release of pecking by 254 hatchling chicks in 5 experiments. Findings show (1) a pronounced preference by Ss to peck at red rather than green illuminated lamps, (2) significantly greater pecking by Ss to lamps attached to, and on the floor beneath, the pecking arrow during the display, and (3) little evidence that placement of a stimulus on the arrow, on the floor beneath the arrow, or in both locations differentially affected frequency of pecking to matching stimulus colors. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preference for symmetry is experience dependent in newborn chicks (Gallus gallus).

Spontaneous pecking preferences toward symmetric or asymmetric stimuli were tested in newborn chicks (Gallus gallus). A preference for asymmetric patterns was found in na?ve chicks (either 24 or 48 hours old), although a preference for symmetry appeared at retest after chicks had experienced standard rearing conditions (Experiments 1 and 2). Only food-experienced chicks preferred symmetric patterns; food-deprived and hand-fed chicks did not show any preference (Experiment 3). A key factor that allowed for the emergence of a preference for symmetry may relate to the improving of pecking sensorimotor skills occurring during active food manipulation. Possible explanations are discussed for the late emergence of the preference for symmetry and for the preference for asymmetry found in na?ve chicks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What is needed for a theory of mobility: Direct perceptions and cognitive maps—lessons from the blind.

Proposes a theory of mobility, using nonvisual stimuli and a cognitive control process to augment J. J. Gibson's (1979; see also PA, Vol 33:9697) explanations of visual guidance. This proposed theory of mobility explains the nonvisual processes that underlie travel by both blind and sighted persons. The author stresses: (1) the importance of perceptual or cognitive representations of the environment in controlling mobility; and (2) how the regularities of the human-made environment influence the nature of travel activities and spatial cognition. Mobility can be directed by visual control stimuli in the ambient optic array; by nonvisual control stimuli; and by processes of spatial learning, including stimulus–response rote learning, motor plans, schemas, and cognitive maps. The selection of processes and strategies depends on the availability of particular information or on task demands. Attentional processes select stimuli for locomotor control within any particular modality and select between perceptual and cognitive processes. (109 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nonconscious Influence of Masked Stimuli on Response Selection Is Limited to Concrete Stimulus-Response Associations.

A pattern-masked arrow negatively biased the "free choice" between 2 manual responses or between 2 vocal responses. This apparently nonconscious influence occurred only when the free-choice trials were intermixed randomly with other trials that terminated in fully visible arrows, which directed a response of the same modality (manual vs. vocal) as that involved in the free-choice test trials. This indicates that recent conscious processing of the association between specific stimuli and specific responses is needed to activate the nonconscious influence of masked arrows on response selection. Because this influence occurred only when a concrete association was activated, it appears not to be based on deep comprehension of the stimuli and instead is attributable to simple stimulus-response bonds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of inferotemporal lesions on the behavior of monkeys.

Monkeys with inferotemporal (IT) lesions learn visual discriminations abnormally slowly. The evidence for various explanations of this defect is reviewed. It is concluded that the defect does not result from the disorders of perception, attention, or memory for either visual stimuli or visual associations that have so far been postulated. Two other explanations remain viable: that IT animals have a reduced capacity either to (a) categorize visual stimuli or (b) form associations with them. Since the existing evidence on these 2 hypotheses is inadequate, ways of testing them are suggested. (123 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The what and the where of the pigeon's processing of complex visual stimuli.

Eight pigeons were trained on a go-no go visual discrimination involving I S+ and 15 S–s. The 16 discriminative stimuli were black-and-white line drawings created by the factorial combination of 4 different geometric shapes (wedge, cylinder, cone, handle) in 4 different spatial locations (right, left, above, below) in relation to a common shape (cube). All of the pigeons readily learned this complex visual discrimination. Each bird's pecking behavior was controlled by both attributes of the line drawings, but somewhat stronger stimulus control was exerted by the location of the added component than by its shape. Across all 8 pigeons, there was an inverse relation between stimulus control by component shape and component location. These results document pigeons' joint processing of "what" and "where" information in visual discrimination learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition of Return and Repetition Priming Effects in Localization and Discrimination Tasks.

Inhibition of return (IOR) refers to slower responding to a stimulus that is presented at the same, rather than a different location as a preceding, spatially nonpredictive, stimulus. Repetition priming refers to speeded responding to a stimulus that duplicates the visual characteristics of a stimulus that precedes it. IOR and repetition priming effects interact in nonspatial discrimination tasks but not in localization tasks; three experiments examined whether this is due to processing differences or due to response differences between tasks. Two stimuli, S1 and S2, occurred on each trial. In Experiment 1, S1 and S2 were both peripheral arrows; in Experiment 2, S1 was a central arrow and S2 was a peripheral nondirectional rectangle; in Experiment 3, S1 was a peripheral nondirectional rectangle and S2 was a peripheral arrow. S1 never required a response; S2 required a localization or a discrimination response. Despite evidence that form information was likely extracted from the arrow stimuli, the localization task revealed no repetition priming: IOR occurred regardless of shared visual identity of the S1 and S2 arrows. The discrimination task revealed IOR only when the visual identity changed from S1 to S2; otherwise, facilitation occurred. These results suggest that IOR is masked by repetition priming only when the response depends on the explicit processing of form information; repetition priming does not occur when such information is extracted automatically but is task (and response) irrelevant. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Forgetting of visual discriminations by pigeons.

Three experiments examined the forgetting of visual discriminations by 48 Silver King pigeons. The problems consisted of feature discriminations, with dot displays as the discriminative stimuli, and involved a successive go/no-go pecking response. In all 3 experiments, Ss trained to refrain from pecking an S– display resumed pecking at this display after retention intervals. It is argued that these data represent the 1st direct demonstration of forgetting of a discrimination by pigeons. Exp I also showed that the amount of forgetting progressively increased, in a negatively accelerated fashion, over intervals of 1, 10, and 20 days. Also, more S– responses occurred during relearning a reverse discrimination than after relearning a nonreverse discrimination. In Exp II, acquisition was retarded and more forgetting occurred for discriminations that involved more highly similar stimuli. In Exp III, a change in contextual cues between acquisition and retention testing enhanced forgetting when the contextual cues present during original acquisition were conspicuous; when these cues were relatively inconspicuous, a change in context had no effect on forgetting. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissecting the conditioned pecking response: an integrated system for the analysis of pecking response parameters

The conventional pecking response key, although an excellent transducer of response rate, can provide minimal information on the topography, coordination, or localization of conditioned pecking. We describe the hardware and software components of a system that, in addition to recording response rates, permits simultaneous "on-line" monitoring of head acceleration, jaw movement, terminal peck location, and duration of pecking response. Head movements are monitored with a miniature accelerometer, jaw movements with a magnetosensitive transducer, and peck location with modified touch screen technology. Initial experiments with the system suggest that it will be useful in studies of response differentiation, acquisition and maintenance of complex discriminations, and interaction of conditioned and unconditioned stimuli in the control of pecking response probability and response topography.     

Inhibition of return: Effects of attentional cuing on eye movement latencies.

Inhibition of return refers to a bias against attending to and/or detecting visual stimuli at recently attended locations. A total of 57 Ss participated in 5 experiments, in which Ss were slower to initiate eye movements to previously attended locations. Furthermore, there was more inhibition when a peripheral (exogenous) flash signaled the target, compared with when a central (endogenous) arrow cue was used as an imperative stimulus. That pattern suggests that some of the inhibition is due to processes involved in detecting visual stimuli, and some of the inhibition is related to the movement of the eye. Subsequent experiments showed that the eye-movement component of the inhibition is not object-centered and does not move if the previously attended object moves, although the stimulus-detection component is object-centered. Results have implications for visual attention in general and for the link between overt and covert orienting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Directed attention prolongs the perceived duration of a brief stimulus

Stelmach, Herdman, and McNeil (1994) suggested recently that the perceived duration for attended stimuli is shorter than that for unattended ones. In contrast, the attenuation hypothesis (Thomas & Weaver, 1975) suggests the reverse relation between directed attention and perceived duration. We conducted six experiments to test the validity of the two contradictory hypotheses. In all the experiments, attention was directed to one of two possible stimulus sources. Experiments 1 and 2 employed stimulus durations from 70 to 270 msec. A stimulus appeared in either the visual or the auditory modality. Stimuli in the attended modality were rated as longer than stimuli in the unattended modality. Experiment 3 replicated this finding using a different psychophysical procedure. Experiments 4-6 showed that the finding applies not only to stimuli from different sensory modalities but also to stimuli appearing at different locations within the visual field. The results of all six experiments support the assumption that directed attention prolongs the perceived duration of a stimulus.     

Ideomotor compatibility in the psychological refractory period effect: 29 years of oversimplification.

Four experiments examined whether the psychological refractory period (PRP) effect can be eliminated with ideomotor compatible (IM) but not stimulus-response compatible (SR) tasks, as reported by A. G. Greenwald and H. G. Shulman (1973). Their tasks were used: a left or right movement to a left- or right-pointing arrow (IM) or to the word left or right (SR) for Task 1; saying "A" or "B" (IM) or "1" or "2" (SR) to an auditory A or B for Task 2. The stimulus onset asynchronies were 0, 100, 200, 300, 500, and 1,000 ms in Experiment 1, and only 0, 100, 200, and 1,000 ms in Experiments 2-4. The arrow was in the center of the screen in Experiments 1-3 and to the left or right in Experiment 4. As in Greenwald and Shulman's Experiment 2, the instructions stated that most often the 2 stimuli would be presented simultaneously. A PRP effect was obtained in all conditions, most likely because response-selection decisions are required even for IM tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discrimination of video images by zebra finches (Taeniopygia guttata): Direct evidence from song performance.

Adult male zebra finches (Taeniopygia guttata) were found to work for the reward of viewing silent video images. In addition, birds that were exposed either passively or contingently upon key pecking to an array of moving images randomly displayed on a video monitor responded with song, depending on the content of the images. In both Experiment 1 (with full-screen images) and Experiment 2 (with sections of images), the subjects clearly discriminated between bird and nonbird pictures. Stimulus movement was found to affect the response only when bird pictures were presented, thus ruling out the evidence for species recognition. The methodology offers a new behavioral assay for investigating categorical perception of pictorial stimuli by songbirds. It has also the potential to provide further insights into the role of visual cues in song learning and social interactions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of food recognition in young chicks: I. Maturation and nutrition.

Investigated age and food ingestion as factors influencing food recognition in 5 experiments with a total of 338 Burmese Red Junglefowl chicks. Newly hatched chicks pecked indiscriminately at sand and food; by 3 days of age, pecks were directed primarily at food. Pecking at food or sand had little effect on subsequent pecking at either stimulus until the chicks were 2-3 days old. Ingestion of food then served to facilitate pecking, but such facilitation did not occur until 10 min to 1 hr after ingestion. The effects that occurred on Day 3 were not specific to the stimulus pecked, but pecking at food and sand increased in frequency when the chicks had ingested food. Control experiments using a forced-feeding technique showed that these effects were due to ingestion of food and occurred only if food ingestion was associated with pecking. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Similarity of approach and pecking preferences for spectral stimuli in domestic chicks: Absence of a mirror-image relation.

Reports that the results of H. H. Schaefer and E. H. Hess (1959) showing that White Rock chicks described mirror-image response functions to spectral stimuli in approach and pecking behavior could not be replicated using 10 Cornish-Cross chicks under more controlled conditions. Present results show similar blue-orange bimodal functions for both behavioral responses, resembling the approach data of Schaefer and Hess and the earlier pecking data of Hess and others, but not the pecking data reported by Schaefer and Hess. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual load alters visual excitability.

Increasing perceptual load reduces the processing of visual stimuli outside the focus of attention, but the mechanism underlying these effects remains unclear. Here we tested an account attributing the effects of perceptual load to modulations of visual cortex excitability. In contrast to stimulus competition accounts, which propose that load should affect simultaneous, but not sequential, stimulus presentations, the visual excitability account makes the novel prediction that load should affect detection sensitivity for both simultaneous and sequential presentations. Participants fixated a stimulus stream, responding to targets defined by either a color (low load) or color and orientation conjunctions (high load). Additionally, detection sensitivity was measured for a peripheral critical stimulus (CS) presented occasionally. Increasing load at fixation reduced sensitivity to the peripheral CSs; this effect was similar regardless of whether CSs were presented simultaneously with central stimuli or during the (otherwise empty) interval between them. Controls ruled out explanations of the results in terms of strategic task prioritization. These findings support a cortical excitability account for perceptual load, challenging stimulus competition accounts. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Visual stimulation: Effects on vestibular habituation.

Studied the influence of various forms of visual stimulation presented during the course of vestibular habituation to a caloric stimulus, using 32 adult cats. Eye movements which were either complimentary or in opposition to the induced vestibular nystagmus were produced with an optokinetic drum. In addition, the effect of visual fixation during vestibular-response periods was studied. In all cases, Ss that received visual stimulation during the majority of the caloric trials habituated more slowly than did Ss that received all the habituation trials in total darkness. Data conflict with previous reports of vestibular-visual interactions. Possible explanations for the discrepancy include species differences, distraction provided by the visual stimuli, and the transfer of learning from the dark to light conditions. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Superadditive effects of multiple lesions in a connectionist architecture: Implications for the neuropsychology of optic aphasia.

Neuropsychological disorders have traditionally been understood in terms of a focal lesion to a single component of a cognitive architecture. Optic aphasia (OA) defies explanation in this way. In OA, naming of visual stimuli is impaired in the absence of general visual agnosia or anomia. OA has been explained by positing multiple semantic systems or multiple functional pathways to visual naming. M. J. Farah (1990) instead sketched a parsimonious account based on multiple lesions—to pathways mapping visual input to semantics and semantics to naming responses—and the assumption that the effects of the lesions are superadditive. The authors demonstrate superadditive effects of damage in a connectionist architecture and model other phenomena associated with OA. Multiple lesions with superadditivity provide a novel class of explanations for neuropsychological deficits that previously seemed to imply the existence of highly specialized processing components. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interaction between drug discriminative stimuli and exteroceptive, sensory signals.

Interactions between drug discriminative stimuli based on 5.6 and 10 mg/kg sodium pentobarbital (ip) and exteroceptive stimuli (visual and auditory) were studied in 27 male Sprague-Dawley rats in a T-maze. In 3 groups, visual stimuli (light vs dark) were differentially paired with drug stimuli; the 4th group discriminated combinations of tonal frequencies (1 kHz or 10 kHz) and the presence or absence of pentobarbital (10 mg/kg). In general, visual stimuli controlled choice behavior (left or right turn) to a greater extent than did the drug training stimuli, whereas the auditory stimuli exerted no apparent control over the pentobarbital stimulus in Group 4. Tests with higher doses (13.75 and 17.5 mg/kg) indicated augmented stimulus control by the drug dimension in 2 groups (Group 1, 10 mg/kg pentobarbital vs saline; Group 2, 5.6 mg/kg vs 10 mg/kg pentobarbital) but not in the 3rd group (5.6 mg/kg pentobarbital vs saline) in the "conflict" situation, in which the exteroceptive conditions signaled one response whereas the drug stimulus signaled the opposite response. Discrimination training with only one of the stimulus dimensions resulted in stimulus control in the following order: 10 mg/kg vs saline?>?5.6 mg/kg vs saline?>?1 kHz vs 10 kHz. This indicates that the auditory stimuli were of marginal significance. It is concluded drugs can compete with exteroceptive, visual stimuli for associative strength. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus control of lingual predatory luring and related foraging tactics of mangrove saltmarsh snakes (nerodia clarkii compressicauda).

Knowledge of the various cues that elicit natural behavior is important to our understanding of why and when animals behave as they do. In order to gain insight into the behavior and ecology of Nerodia clarkii compressicauda, a piscivorous snake that uses a unique form of predatory luring as a foraging tactic, we observed 22 juvenile subjects in the presence of visual and chemical prey stimuli in a repeated-measures design. The use of video playback as a visual stimulus in this experiment permitted complete isolation from tactile and chemical cues. Snakes were more sedentary and used lingual luring more when both cue types were present than when none or only one of the cues was available. Subjects also attacked more often in the presence of both stimuli. Predatory attacks by prey-na?ve subjects directed to video cues when only visual prey stimuli were available demonstrated that snakes can identify prey visually without prior experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)