Sexual reinforcement in the female rat.

Sexual reinforcement in the female rat was studied in a preparation that allowed continuous operant responding for access to a male rat leading to intromission. Experiment 1 used a high operant level nose-poke response to test the possible reinforcing effects of some components of access to a male. A simple tone stimulus used as a conditioned reinforcer and two odor stimuli, target male bedding and emulsified preputial gland, were tested. None of these contingent events altered responding above or below operant level. Access to the male, which was always accompanied by intromission, immediately increased response rate when it was made contingent upon the nose-poke response. Performance on fixed-ratio schedules was erratic, and response rate was low in comparison to typical food-reinforced responding. An interresponse-time analysis indicated, however, that some effect of the ratio contingency may have been present. In Experiment 2, several modifications of the procedure were tested with the objective of creating a more tractable preparation for behavior analysis. Response type and the hormone delivery method were changed, and 2 target males were used instead of 1. The latter tripled the average number of reinforcers earned in a single session. Differences between sexual and other reinforcers are discussed in terms of procedural, quantitative, and motivational aspects of the sexual reinforcement procedure.     

Theoretical and methodological consequences of variations in exposure duration in visual laterality studies

The visual system does not instantaneously extract the entire content of a stimulus, and its resolving power is enhanced as the energy in the stimulus increases. This property of the visual system has been overlooked in previous tachistoecopic studies, the consequences of which are examined. Three groups of 12 right-handed males were presented with faces to categorize as “female” or “male,” each group at differentexposure duration, 40, 120, or 200 msec. A shift in visual field superiority was observed, from the left to the right field, as stimulus energy increased IExperiment 1). This result was replicated in Experiment 2, using a within-subject design. In Experiment 3, display energy was kept constant by reciprocally varying the duration of exposure and the level of luminance. The same shift in visual field superiority as in the previous experiments obtained when exposure duration increased. Implications of these results for future tachistoscopic studies and for a model of cerebral laterallzation are discussed. It is suggested that the right and left hemispheres may not require an equal amount of energy to efficiently engage into cognitive processing.     

Providing a sensory basis for models of visual information acquisition

Our major goal is to account for some simple digit-recall data with a theory that integrates two models from two scientific traditions. Therandom-sampling model, founded in the memory and attention literature, holds that (1) stimulus features are randomly sampled throughout the course of stimulus presence and (2) proportion correct recall is equal to the ratio of sampled features to total features.The linear-filter model, founded in the vision and sensation literature, holds that the initial stages of the visual system act as a low-pass temporal filter on the input stimulus, resulting in a time-varyingsensory response in the nervous system. We report two experiments in which a variable-duration, masked, four-digit string had to be immediately recalled. Experiment 1 was designed principally to replicate past data confirming the basic random-sampling model. Like others, we were able to confirm the model only by endowing it with an additionalprocessing-delay assumption: that feature sampling does not begin until the stimulus has been physically present for some minimal duration. Experiment 2 was an extension of Experiment 1 in which the target stimulus was preceded, 250 msec prior to its onset, by a 50-msec pre-presentation ofthe same stimulus called aprime. The Experiment 2 results allowed the following conclusions. First, the initial processing delay found in Experiment 1 is immutably tied to stimulus onset; that is, if there are two stimulus onsets, separated even briefly in time, there are two associated processing delays. Second, processing rate is essentially unaffected by the prime’s presentation. Third, being presented with a 50-msec prime is equivalent, in terms of memory performance, to increasing unprimed stimulus duration by approximately 30 msec; the prime can thus said to beworth 30 msec of additional exposure duration. This third conclusion seems superficially paradoxical, in the sense that one would expect that having seen a 50-msec prime would be equivalent to increasing exposure duration byat least the same 50 msec. However, both the initial processing delays and the 30-msec prime’s worth are natural consequences of our theory that conjoins the random-sampling model with the linear-filter model.     

Searching for inhibition of return in the rat using the covert orienting of attention task

Inhibition of return (IOR) is an important psychological construct describing inhibited responses to previously attended locations. In humans, it is investigated using Posner’s cueing paradigm. This paradigm requires central visual fixation and detection of cued stimuli to the left or right of the fixation point. Stimuli can be validly or invalidly cued, appearing in the same or opposite location to the cue. Although a rat version of the spatial cueing paradigm (the covert orienting of attention task) does exist, IOR has so far not been demonstrated. We therefore investigated whether IOR could be robustly demonstrated in adult male rats using the covert orienting of attention task. This task is conducted in holed wall operant chambers with the central three holes mimicking the set-up for Posner cueing. Across four samples of rats (overall n = 84), we manipulated the following task parameters: stimulus onset asynchronies (Experiments 1–3), cue brightness (Experiment 1b) and the presence of a central reorienting event (Experiment 4). In Experiment 1, we also investigated strain differences by comparing Lister Hooded rats to Sprague–Dawley rats. Although Lister Hooded rats briefly showed evidence of IOR (Experiment 1a, and see Online Resource 1 data), we were unable to replicate this finding in our other experiments using different samples of this strain. Taken together, our findings suggest that IOR cannot be robustly demonstrated in the rat using the covert orienting of attention task conducted in holed wall operant chambers.     

Derived relational responding as generalized operant behavior

The major aim of the present study was to demonstrate that derived relational responding may be viewed as a form of generalized operant behavior. In Experiment 1, 4 subjects were divided into two conditions (2 in each condition). Using a two-comparison matching-to-sample procedure, all subjects were trained and tested for the formation of two combinatorially entailed relations. Subjects were trained and tested across multiple stimulus sets. Each set was composed of novel stimuli. Both Conditions 1 and 2 involved explicit performance-contingent feedback presented at the end of each block of test trials (i.e., delayed feedback). In Condition 1, feedback was accurate (consistent with the experimenter-designated relations) following exposure to the initial stimulus sets. When subjects' responding reached a predefined mastery criterion, the feedback then switched to inaccurate (not consistent with the experimenter-designated relations) until responding once again reached a predefined criterion. Condition 2 was similar to Condition 1, except that exposure to the initial stimulus sets was followed by inaccurate feedback and once the criterion was reached feedback switched to accurate. Once relational responding emerged and stabilized, response patterns on novel stimulus sets were controlled by the feedback delivered for previous stimulus sets. Experiment 2 replicated Experiment 1, except that during Conditions 3 and 4 four comparison stimuli were employed during training and testing. Experiment 3 was similar to Condition 1 of Experiment 1, except that after the mastery criterion was reached for class-consistent responding, feedback alternated from accurate to inaccurate across each successive stimulus set. Experiment 4 involved two types of feedback, one type following tests for mutual entailment and the other type following tests for combinatorial entailment. Results from this experiment demonstrated that mutual and combinatorial entailment may be controlled independently by accurate and inaccurate feedback. Overall, the data support the suggestion, made by relational frame theory, that derived relational responding is a form of generalized operant behavior.     

Stimulus control of schedule-induced activity in pigeons during multiple schedules

Stimulus control of schedule-induced general activity was demonstrated with pigeons using multiple schedules of response-independent food delivery. In Experiment 1, the introduction of food during a multiple variable-time 30-second variable-time 30-second schedule produced a tenfold increase in activity above the no-food baseline. Each pigeon developed stable differential activity rates during the components (correlated with red and green lights) of a multiple variable-time 30-second extinction schedule. Lengthening the extinction component from 1 to 7 minutes increased the rate differences and produced a reliable pattern of responding during S− (the stimulus correlated with extinction): Activity rate was high immediately following the change from S+ (the stimulus correlated with variable-time 30-second) to S−, then decreased abruptly and remained low throughout the middle of the interval, and subsequently showed a positively accelerated increase until the stimulus changed to S+. In Experiment 2, three pigeons were exposed to a mixed variable-time extinction schedule prior to a multiple variable-time extinction schedule. Auditory rather than visual stimuli were used to determine the generality of Experiment 1 results. The multiple- versus mixed-schedule results indicated that stimulus control of activity occurred for two of the birds, but rate differences between S+ and S− were much less than those demonstrated with visual stimuli. A direct comparison of visual and auditory stimulus control in Experiment 3 supported this conclusion. These parallels between the stimulus control of reinforced responding and that of schedule-induced activity suggest that the stimulus control of induced activity may be a factor in operant stimulus control.     

Effects of perceptual quality on the processing of human faces presented to the left and right cerebral hemispheres

Three experiments examined the effects of stimulus duration, retinal eccentricity, and visual noise on the processing of human faces presented to the left visual field/right hemisphere (LVF-RH) and right visual field/left hemisphere (RVF-LH). In Experiment 1 observers identified which of 10 similar male faces was presented on a screen. The single face was presented for 10, 55, or 100 ms at 1 degree, 4 degrees, or 9 degrees of visual angle to the left or right of fixation. Decreasing stimulus duration and increasing retinal eccentricity lowered face recognition. The effect of duration was the same for LVF-RH and RVF-LH trials, but the detrimental effect of increasing retinal eccentricity was larger on LVF-RH trials than on RVF-LH trials. In Experiment 2 observers indicated whether a single face from this same set was a member of a memorized set of five positive faces. The probe face on each trial was presented alone or embedded in visual noise. Visual noise increased the error rate more on LVF-RH trials than on RVF-LH trials. This effect was replicated in Experiment 3, which also required observers to make a much easier discrimination between male and female faces. In the male/female task visual noise tended to impair performance more on RVF-LH trials than on LVF-RH trials, opposite the effect for the male/male task. These results are discussed in terms of hemispheric asymmetry for global versus local features of faces, the level of feature analysis demanded by a task, and the level of feature analysis most disrupted by perceptual degradation.     

Muscimol,AP5, or scopolamine infused into perirhinal cortex impairs two-choice visual discrimination learning in rats

The perirhinal cortex (PRh) has been strongly implicated in object recognition memory and visual stimulus representation. Studies of object recognition have revealed evidence for the involvement of several neurotransmitter subsystems, including those involving NMDA (N-methyl-d-aspartic acid) and muscarinic cholinergic receptors. In the present study, we assessed the possible involvement of PRh and related receptor subsystems in two-choice visual discrimination learning by Lister Hooded rats tested in touchscreen-equipped operant boxes. In Experiment 1, daily pre-training inactivation of PRh with the GABA_A receptor agonist muscimol (0.5 μg/hemisphere) significantly impaired acquisition of the two-choice visual discrimination. In Experiment 2, daily pre-training blockade of either NMDA or muscarinic receptors in PRh with AP5 (5.9 μg/hemisphere) or scopolamine (10 μg/hemisphere), respectively, impaired task acquisition. These results parallel the findings from object recognition studies and suggest a generality of neurotransmitter receptor involvement underlying the role of PRh in both object recognition memory and visual discrimination learning. The involvement of PRh in both types of tasks may be related to its role in complex visual stimulus representation.     

Evaluation of infant vocal conditioning.

The use of the operant conditioning paradigm, as it has been applied to infant social, vocal behavior, reflects a failure to take into account the social nature of human infants over and above the rigid theoretical rationale of the paradigm. It is argued that: (1) the baseline procedure used in operant conditioning studies is methodologically and conceptually invalid; (2) the reinforcing stimulus used in social conditioning studies elicits the very response that it is assigned to reinforce; and (3) the effect of the response-reinforcer relationship is not the reinforcement (strengthening) of vocal response rate.     

Function transfer in human operant experiments: the role of stimulus pairings

Although function transfer often has been studied in complex operant procedures (such as matching to sample), whether operant reinforcement actually produces function transfer in such settings has not been established. The present experiments, with high school students as subjects, suggest that stimulus pairings can promote function transfer in conditions that closely approximate those of matching to sample. In Experiment 1, the subjects showed transfer of operant responding from three geometric figures (C1, C2, C3) to three colored shapes (B1, B2, B3) when the latter were paired with the former. Experiment 2 involved two groups of subjects. In the matching group, subjects matched the colored shapes with the geometric figures; in the yoked group, the shapes were merely paired with the geometric figures, and the schedule of stimulus pairing was yoked to the performance of the subjects in the matching group. Both groups of subjects showed function transfer. Experiment 3 documented function transfer from C stimuli to B stimuli through indirect stimulus pairings (A-B, A-C). In Experiment 4, function transfer was obtained even though the subjects vocalized continuously during the pairing trials, presumably preventing covert verbalization that might mediate transfer effects. Our results are consistent with a Pavlovian account and raise difficulties for current operant theories of function transfer.     

One-trial appetitive conditioning in the sexual behavior system

One-trial Pavlovian conditioning has been demonstrated with aversive reinforcers such as electric shock and lithium chloride. The present experiments using male Japanese quail were conducted to determine if an appetitive unconditioned stimulus (US), the opportunity to copulate with a female quail, can also generate one-trial learning. In Experiment 1, subjects were exposed to a contextual conditioned stimulus (CS) for 35 sec and then given copulatory opportunity. In Experiment 2, male birds were given 0, 2, or 4 min of exposure to the contextual CS before presentation of a female. In both cases, control groups received comparable exposure to both the contextual CS and the sexual US, but in an unpaired fashion. Subjects were tested for sexual learning by reintroducing them to the experimental context in the presence of a test object that incorporated the taxidermically prepared head of a female quail. In both Experiments 1 and 2, subjects for whom the contextual CS and sexual US had been paired displayed significantly more approach to the test object than did unpaired subjects.     

Operant and Pavlovian factors in cross-response transfer of inhibitory stimulus control

Experiment 1 used a within-response procedure to compare inhibitory stimulus control of the extinction cue in multiple variable interval-extinction (mult VI EXT) and the variable time cue in multiple variable interval-variable time (mult VI VT). Experiment 2A made the same comparison using a crossresponse procedure. In addition, Experiment 2A also tested the extinction cue in multiple variable time-extinction (mult VT EXT), and Experiment 2B tested the variable time cue in mult VT EXT. Unlike the mult VI EXT and mult VI VT conditions, the mult VT EXT condition was administered in the absence of a response manipulandum. The main findings of the present study were: (1) cross-response suppression by the variable time cue in mult VI VT; (2) greater response suppression by the extinction cue in mult VI EXT than by either the variable time cue in mult VI VT or the extinction cue in mult VT EXT; and (3) response facilitation by the variable time cue in mult VT EXT. These findings indicate that inhibitory stimulus control based on an operant source (i.e., absence of an R-S contingency) does transfer across responses, and that such transfer cannot be explained in terms of competing responses. These findings also indicate that operant and Pavlovian sources of stimulus control summate algebraically to determine the inhibitory strength of the extinction cue in mult VI EXT. Finally, the third finding is not consistent with notions that emphasize the importance of location and localization of cues explicitly paired with positive events.     

Second-order conditioning with diffuse auditory reinforcers in the pigeon

Pigeon subjects were used in five experiments investigating second-order conditioning with visual second-order and diffuse auditory first-order stimuli. Experiment 1 used a discriminative conditioning procedure to demonstrate reliable and substantial second-order conditioning with these stimuli. In Experiments 2 and 3, extinction of the auditory first-order stimulus after second-order conditioning had little effect upon responding to the second-order stimulus, when compared to a stimulus whose reinforcer was maintained. Experiment 4 compared directly the susceptibility of second-order responding to extinction of the first-order reinforcing stimulus as a function of the modality of that reinforcer. When a visual second-order stimulus was paired with a visual reinforcer, and the response to the latter was extinguished, then second-order responding was greatly reduced relative to control levels. In contrast, when that reinforcer was an auditory stimulus, second-order responding was not affected by the current value of the first-order stimulus after conditioning. Finally, in Experiment 5 the auditory stimulus was established as a reinforcer through discriminative-operant training. Following second-order conditioning, extinction of responding to this stimulus again had little impact upon responding to the second-order stimulus with which it had been paired. These results are discussed in terms of previous work on second-order conditioning with rat and pigeon subjects.     

Selective sensitivity of schedule-induced activity to an operant suppression contingency.

The sensitivity of pigeons' schedule-induced activity to operant consequences was studied in two experiments. During a 30-s interval between food presentations, a keylight stimulus brightened incrementally. Stable terminal key pecking and interim locomotor activity developed. An operant "setback" contingency was applied to activity. The contingency arranged for locomotor movements (detected by a nine-panel floorboard) to be followed by a resetting of the keylight brightness to a dimmer value and a 1-s delay of reinforcement (for individual responses). Experiment 1 showed that activity patterns were highly sensitive to their operant consequences. Accompanying key-peck rates were only transiently affected. In Experiment 2, the setback contingency was imposed during restricted portions of the trial, and differential operant control of activity was demonstrated. However, birds in this study produced higher rates of key pecking as activity rates were reduced. These results suggest that although schedule-induced activity arises in response to the temporal arrangement of stimulus events, this behavior may retain considerable sensitivity to response-consequence relations.     

Contextual conditioning and the control of copulatory behavior by species-specific sign stimuli in male Japanese quail

Three experiments were conducted to identify species-specific sign stimuli sufficient to elicit copulatory behavior in male Japanese quail and to determine how learning is involved in the control of behavior by these sign stimuli. In Experiment 1, sexually experienced subjects were tested for copulatory behavior with a live female quail and with a model consisting of a female quail's head and neck mounted in front of a foam pad. Comparable levels of copulatory behavior were observed in the two tests, indicating that static visual cues provided by a female quail's head and neck are sufficient to elicit copulatory behavior in this species. Experiment 2 showed that male birds that previously received numerous opportunities to copulate with a live female quail in the test situation were significantly more likely to copulate with the head + neck model than were sexually inexperienced subjects. Experiment 3 showed that prior sexual experience with live quail facilitated responding to the head + neck model only if the sexual experience was provided in the same place where subjects were later tested with the model. This last finding suggests that sexual experience facilitates control of copulatory behavior by species-specific sign stimuli through contextual conditioning. Contextual conditioning may lower the threshold for sexual behavior with the result that a stimulus as impoverished as an immobile model containing only the head and neck of a female quail becomes sufficient to elicit normal levels of copulatory behavior. The results are also discussed as an example of conditioned stimulus facilitation of responding to an unconditioned stimulus.     

EVALUATION OF A BRIEF STIMULUS PREFERENCE ASSESSMENT

We evaluated the utility of a brief (5-min) stimulus preference assessment for individuals with developmental disabilities. Participants had noncontingent (free) access to an array of stimuli and could interact with any of the stimuli at any time. Stimuli were never withdrawn or withheld from the participants during a 5-min session. In Experiment 1, the brief preference assessment was conducted for 10 participants to identify differentially preferred stimuli, and reinforcer assessments were conducted to test the reinforcing efficacy of those stimuli identified as highly preferred. In Experiment 2, a comparison was conducted between the brief preference assessment and a commonly used paired-stimulus preference assessment. Collectively, results demonstrated that the brief preference assessment identified stimuli that functioned as reinforcers for a simple operant response, identified preferred stimuli that were differentially effective as reinforcers compared to nonpreferred stimuli, was associated with fewer problem behaviors, and required less time to complete than a commonly used paired-stimulus preference assessment.     

Sexual-discrimination learning in male Japanese quail (Coturnix coturnix japonica)

We investigated how male Japanese quail (Coturnix coturnix japonica) learn through extensive social and sexual experience to discriminate between male and female conspecifics. Opportunity for heterosexual copulation was important for this learning, but even extensive copulatory opportunity was not sufficient to produce a sexual discrimination; subjects also required exposure to other males. Exposure to females after copulatory opportunity did not produce a sexual discrimination but facilitated its acquisition. Time or exposure to only the visual features of male birds (provided by taxidermic models) after copulatory opportunity did not result in differential responding to male and female conspecifics. Finally, presenting stimulus birds one at a time proved to be a more sensitive test of sexual-discrimination learning than presenting two stimulus birds at the same time. The results indicate that sexual-discrimination learning is similar to conventional associative learning.     

Newborn habituation to visual stimuli: a sex difference in novelty detection

Thirty-six newborn human infants were repeatedly exposed to one of two visual stimuli, a four-square or 144-square black and white checkerboard target, until a set criterion of habituation was demonstrated, as measured by a decrement in visual fixation time. When the habituation criterion was reached, independent groups of Ss were either presented with the same target or with a target of either moderate or large discrepancy from the standard habituation stimulus. Results indicated that (1) there was habituation of visual attention, which replicated previous findings, and suggests that some infants soon after birth are capable of storing simple visual information, and (2) following habituation female infants displayed greater recovery of attention than male infants when the moderate stimulus change was introduced.     

Interactions between the effects of food and water motivating operations on food‐ and water‐reinforced responding in mice

Two experiments examined interactions between the effects of food and water motivating operations (MOs) on the food‐ and water‐reinforced operant behavior of mice. In Experiment 1, mice responded for sucrose pellets and then water reinforcement under four different MOs: food deprivation, water deprivation, concurrent food and water deprivation, and no deprivation. The most responding for pellets occurred under food deprivation and the most responding for water occurred under water deprivation. Concurrent food and water deprivation decreased responding for both reinforcers. Nevertheless, water deprivation alone increased pellet‐reinforced responding and food deprivation alone likewise increased water‐reinforced responding relative to no deprivation. Experiment 2 demonstrated that presession food during concurrent food and water deprivation increased in‐session responding for water relative to sessions where no presession food was provided. Conversely, presession water during concurrent food and water deprivation did not increase in‐session responding for pellets. These results suggest that a) the reinforcing value of a single stimulus can be affected by multiple MOs, b) a single MO can affect the reinforcing value of multiple stimuli, and c) reinforcing events can also function as MOs. We consider implications for theory and practice and suggest strategies for further basic research on MOs.     

Sex stereotypes and implicit personality theory. II. A trait-inference approach to the assessment of sex stereotypes

Two experiments were conducted to assess sex stereotypes using the trait-inference method originated by Asch (1946). In both, subjects were asked to make inferences about the personality of a male or a female stimulus target who was introduced by a brief list of traits. In Experiment 1 this trait list described the target as either good or bad in intellectual activities and as either warm or cold while in Experiment 2 the introductory list comprised traits which are relatively neutral in terms of evaluation. Subjects rated the stimulus persons on adjective scales selected to reflect dimensions of personality perception reported in previous research. In both studies, male targets were rated significantly higher than females in terms of the Intellectual Desirability dimension. In addition, female targets tended to be rated higher on Communion in Experiment 1 (p<.06), and lower than males on Potency in Experiment 2 (p<.07). No differences as a function of stimulus sex were obtained for Social Desirability, Activity, and Agency. The results suggest that the dimension of implicit personality theory most closely associated with perceived sex differences is a combination of Intellectual Desirability and Potency. The male end of this dimension is relatively well defined by traits which convey a hard-headed, rational approach to problem solving. The female end is much less elaborated and consists of traits reflecting soft-heartedness.