Influence of the cost of responding

In three experiments, the effect of costs associated with responding on judgments of the causal effectiveness of the response was examined. In Experiment 1, the temporal interval between outcomes was matched on a variable interval (VI) and a variable ratio (VR) schedule. When each response was made at some “cost,” and outcomes represented some “gain” for the subject, the rating of causal effectiveness for responses was higher on the VR than on the VI schedule. This relationship was absent when the outcome was a triangle Hash. In Experiment 2, the number of responses required per outcome on a VI and a VR schedule were matched, and responses on the VR schedule were rated as more causally effective. In Experiment 3, a VI-to-VR yoking procedure was used. With minimal response costs, judgments were similar on the VI and VR schedules, but with greater response costs, responses performed on the VR schedule were rated as more causally effective than those emitted on the VI schedule.     

Analysis of potentiation and overshadowing effects in the instrumental performance of pigeons

In each of two experiments, pigeons were trained on a multiple VI (variable interval) schedule with a 3-s delay of reinforcement. Different components were associated with different key colors. Experiment 1 (stage 2) confirmed a previous finding that the response rate is higher in a component having a signal (illumination of the houselight) filling the delay interval than in a component lacking the signal. This potentiation effect was replaced by an overshadowing effect (i.e., the rate was low in the signaled component) when in stage 1 of Experiment 1 the birds received concurrent experience of a component containing houselight presentations not correlated with reinforcement. In Experiment 2 it was found that this overshadowing effect was abolished when the signal used was the presentation of a pattern on the response key rather than illumination of the houselight. These results are interpreted in terms of an interaction between the rate-enhancing properties of the signal (perhaps a consequence of its conditioned reinforcing power) and the tendency of the signal in some conditions to evoke behavior that competes with the response being recorded.     

A Framework and Themes for Social Network Intervention

This paper is concerned with the development and application of social network concepts in clinical practice. A framework of network levels and sets for ordering data and observations is proposed; the phenomenon of truncated networks is considered and two emphases in network intervention (gathering and connecting forms) are proposed to conceptualize network characteristics and practice that follows from such characteristics. A number of current examples of network practice are placed within the framework, and several advantages of utilizing a network perspective as a complement to existing models of family therapy are noted.     

Phonetic disintegration in aphasia: Acoustic analysis of spectral characteristics for place of articulation

In this study, we attempted to determine whether phonetic disintegration of speech in Broca's aphasia affects the spectral characteristics of speech sounds as has been shown for the temporal characteristics of speech. To this end, we investigated the production of place of articulation in Broca's aphasics. Acoustic analysis of the spectral characteristics for stop consonants were conducted. Results indicated that the static aspects of speech production were preserved, as Broca's aphasics seemed to be able to reach the articulatory configuration for the appropriate place of articulation. However, the dynamic aspects of speech production seemed to be impaired, as their productions reflected problems with the source characteristics of speech sounds and with the integration of articulatory movements in the vocal tract. Listener perceptions of the aphasics' productions were compared with acoustic analyses for these same productions. The two measures were related; that is, the spectral characteristics of the utterances provided salient cues for place of articulation perception. An analysis of the occurrences of errors along the dimensions of voicing and place showed that aphasics rarely produce utterances containing both voice and place substitutions.     

Signaled Delay of Reinforcement: Effects of Postconditioning Manipulation of Context Associative Strength on Instrumental Performance

Two experiments examined the influence of postconditioning treatments of contextual cues on instrumental responding acquired with a signaled delay of reinforcement schedule. In Experiment 1, mere exposure to the conditioning context after instrumental training resulted in an attenuated response rate during an extinction test. In the second experiment, responding was decreased by exposure to the contextual cues or sessions in which signaled noncontingent reinforcements occurred. The greatest response decrement, however, occurred following unsignaled noncontingent food presentations. The results are discussed with respect to the different roles of contextual cues on operant responding.     

On the analysis of studies of choice

In a review of 103 sets of data from 23 different studies of choice, Baum (1979) concluded that whereas undermatching was most commonly observed for responses, the time measure generally conformed to the matching relation. A reexamination of the evidence presented by Baum concludes that undermatching is the most commonly observed finding for both measures. Use of the coefficient of determination by both Baum (1979) and de Villiers (1977) for assessing when matching occurs is criticized on statistical grounds. An alternative to the loss-in-predictability criterion used by Baum (1979) is proposed. This alternative statistic has a simple operational meaning and is related to the usual F-ratio test. It can therefore be used as a formal test of the hypothesis that matching occurs. Baum (1979) also suggests that slope values of between .90 and 1.11 can be considered good approximations to matching. It is argued that the establishment of a fixed interval as a criterion for determining when matching occurs, is inappropriate. A confidence interval based on the data from any given experiment is suggested as a more useful method of assessment.     

Anxiety and aggression of high and low assertive persons following conflict

This experiment examined changes in anxiety and differences in aggression for high and low assertive women when different degrees of conflict were encountered. As predicted, low assertive women were intially more uneasy or anxious than high assertive women when they were placed in a conflictual situation. When the level of actual conflict was low, the level of anxiety of low assertive women decreased. However, when the actual level of conflict was high the anxiety level of low assertive women remained unchanged. These results were taken as support for the fear of conflict hypothesis which predicted that the reduction in anxiety for low assertive persons is contingent upon whether or not the anticipated conflict is actually encountered. The results also indicated that high assertive women were not significantly more aggressive than low assertive women. This finding provided support for Galassi's position that assertiveness and aggression are distinct concepts.