Conditioned suppression as a sensitive baseline for social facilitation

The key pecking of pigeons maintained on a variable-interval schedule of food reinforcement was suppressed during occasional presentations of a warning stimulus paired with electric shock. On alternate sessions, a co-actor pigeon was visible in an adjoining chamber where it emitted the same food-reinforced key peck during the warning stimulus that signalled shock for the subject. With no shock and at low shock intensities, where the subject's responding was not suppressed or suppressed only slightly, the co-actor had little effect. At the higher shock intensities, where the subject's responding was reduced by at least 40%, the response rate during the warning stimulus was consistently higher when the co-actor was present. One explanation of these results assumes a special relationship between social stimuli and aversive stimuli in which the presence of another animal reduces emotional reactions and thereby allows operant responses to increase. This was not the case here because the mere presence of the co-actor did not maintain social facilitation. Rather, the present results, taken in conjunction with previous findings, suggest that changes in social and non-social variables which affect the rate of food-reinforced responding may produce proportionately larger changes in responding when that responding is suppressed by aversive stimulation than when it is not.     

Conditioned suppression in goldfish as a function of shock-reinforcement schedule

The conditioned suppression technique (Estes and Skinner, 1941) was employed to study the effects of partial-shock reinforcement in the goldfish. Lever-pressing behavior of hungry goldfish was suppressed in the presence of a flashing light that had been previously paired with electric shocks. Fish that acquired the suppression under 50% and 100% shock-reinforcement, respectively, were subjected to repeated presentations of the flashing light alone. This procedure revealed a more rapid extinction of the suppressed behavior in the 50% than in the 100% shocked group. The finding was compared with those from other experiments and possible reasons for the differences were examined.     

Conditioned suppression as a psychophysical technique for the cat

A modified conditioned suppression paradigm coupled with a new training apparatus has been applied to gathering sensory data in the cat. The method excels in that training, data collection, and reliability are quickly achieved and it can be used with subtle stimulus changes.     

Paired baseline performance as a behavioral ideal

Several recent theories view performance under the constraints of a schedule as an attempt to approach the basepoint, the total amount of the instrumental response and the total amount of the contingent response seen in the absence of schedule constraint. Some new analyses of experiments on concurrent ratio schedules, and simple ratio schedules offering an optional magnitude of contingent reward, tested this view directly. In each of the five experiments examined the organism rejected the chance of a closer approach to the basepoint, and thereby failed in addition to maximize the rate of reinforcement.     

Conditioned suppression of behavior maintained by intracranial stimulation as a function of stimulation intensity.

Conditioned suppression was demonstrated in two experiments with rats lever pressing on a fixed-ration 1 schedule for lateral hypothalamic intracranaial stimulation (ICS)'n Experiment I, conditioned suppression of responding for low-intensity ICS was obtained with a moderate intensity of foot shock, In Experiment II, low and high intensities of ICS were alternated within the same session and the same animal The suppression that was exhibited with low intensity ICS was minimal or absent with high-intensity stimulation, despite the pairing of foot shock with each warning stimulus. Conditioned suppression was a function of ICS intensity, and was independent of response rates. The inverse relationship between ICS intensity and degree os suppression is consistent with a motivational analysis of conditioned suppression. Previous reports of resistance to suppression of behaviors maintained by ICS may now be attributed to the use of high-intensity stimulation.     

Conditioned suppression with extinction as the signalled stimulus

The key pecking of pigeons that was maintained by a 60-sec random-interval schedule of food reinforcement was suppressed during a variable-duration warning stimulus that signalled a 5-min extinction period. The onset of the extinction period immediately followed the termination of the warning signal and was independent of the subject's responses. All subjects eventually showed nearly complete suppression of responding during the warning stimulus.     

Conditioned reinforcement as a function of duration of stimulus

Pigeons were provided with three keys. Pecking the center key produced grain on a schedule that alternated at unpredictable times between a variable-interval component and extinction. On concurrent variable-interval schedules, pecking either side key produced a stimulus associated with the variable-interval component on the center key provided that said schedule was currently in effect. The independent variable was the length of time this stimulus remained on the keys. Pecking one side key produced the stimulus for 27 seconds, whereas the duration produced by pecking the other key varied for successive blocks of sessions. For the first four birds, the values tested were 3, 9, 27, and 81 seconds. For the second group, numbering three birds, the values tested were 1, 3, 9, and 27 seconds. The dependent variable was the proportion of total side key pecks that occurred on the variable key. For all birds, the function was positive in slope and negative in acceleration. This finding supports a formulation that ascribes the maintenance of observing responses in a normal setting to the fact that the subject exposes itself to the positive discriminative stimulus for a longer mean duration than it does to the negative stimulus.     

Conditioned suppression in the gerbil

The present report describes apparatus and procedures for investigating conditioned suppression of a running response in the gerbil. Data are presented which demonstrate that the conditioned suppression observed in this situation is not an artifact of alpha responses, pseudoconditioning, or sensitization. An analysis of differential conditioning indicated that cue similarity and US intensity are negatively related to cue-specific differential responding.     

Social facilitation as a function of the mere presence of others

According to R. B. Zajonc's (1965) drive theory of social facilitation, the mere presence of others increases arousal and, thereby, the frequency of dominant responses (i.e., responses with the greatest habit strength). In the present experiment, U.S. undergraduates performed a stimulus discrimination task under 1 of 2 conditions: in the presence of another individual (audience) or alone. The mere presence condition was designed to make it difficult for the participants to attend directly to the audience. The task was designed to minimize the likelihood that the specific response (numerical preference) would be attributable to a desire to respond appropriately to the audience. There was a significant difference in the mean number of dominant responses between the participants in the audience condition and those in the alone condition. The results provide support for Zajonc's mere presence drive theory of social facilitation.     

Conditioned suppression of free-operant avoidance

The responses of white rats were maintained on an unsignalled free-operant avoidance schedule. Superimposed on the avoidance schedule was a blinking white light followed immediately by response-independent electric shock. Duration of the light stimulus was either 1 or 3 min. Avoidable shock was 1.5 mA; response-independent shock was 7.5 mA. Suppression of responding during the light stimulus (both durations) developed over sessions. Responding immediately following the response-independent light-shock sequence was neither suppressed nor accelerated. The similarity is noted between the present result and findings of “positive conditioned suppression”.     

Latency facilitation in temporal-order judgments: time course of facilitation as a function of judgment type

The paper is concerned with two models of early visual processing which predict that priming of a visual mask by a preceding masked stimulus speeds up conscious perception of the mask (perceptual latency priming). One model ascribes this speed-up to facilitation by visuo-spatial attention [Scharlau, I., & Neumann, O. (2003a). Perceptual latency priming by masked and unmasked stimuli: Evidence for an attentional explanation. Psychological Research 67, 184-197], the other attributes it to nonspecific upgrading mediated by retino-thalamic and thalamo-cortical pathways [Bachmann, T. (1994). Psychophysiology of visual masking: The fine structure of conscious experience. Commack, NY: Nova Science Publishers]. The models make different predictions about the time course of perceptual latency priming. Four experiments test these predictions. The results provide more support for the attentional than for the upgrading model. The experiments further demonstrate that testing latency facilitation with temporal-order judgments may induce a methodological problem resulting in fairly low estimates. A method which provides a more exhaustive measure is suggested and tested.     

Fixed-time schedule effects as a function of baseline reinforcement rate

Using an arbitrary response, we evaluated fixed-time (FT) schedules that were either similar or dissimilar to a baseline (response-dependent) reinforcement schedule and extinction. Results suggested that both FT schedules and extinction resulted in decreased responding. However, FT schedules were more effective in reducing response rates if the FT reinforcer rate was dissimilar to baseline reinforcer rates. Possible reasons for this difference were evaluated with data analysis methods designed to identify adventitious response-reinforcer relations.     

Semantic facilitation in lexical decision as a function of prime-target association

Using a lexical decision task, the relationship between magnitude of semantic facilitation and degree of prime-target relatedness was examined as a function of amount of attention allocated to the prime and the prime-target interval. In none of the conditions studied did amount of facilitation vary with prime-target relatedness, a finding which was seen as inconsistent with the spread of activation account of the association effect in lexical decision. Both forward (prime to target) and backward (target to prime) associations were effective in producing semantic facilitation. Backward associates, however, were effective only during earlier stages of the experiment and forward associations only during later stages. The implications of these findings for the processes underlying the association effect was discussed.     

Conditioned suppression of an avoidance response

A signal followed by shock was presented at irregular intervals during a free-operant avoidance schedule. The effects of this procedure were studied in terms of the rate of unavoided shock in the presence and absence of the signal and the rate of response before and during the signal. Three shock intensities were employed. Response enhancement as well as response suppression were observed; irrespective of changes in responding, shock rates substantially increased during signalled periods compared to non-signalled periods. Shock rates in non-signalled periods were generally higher than during training.