Suppression of Regional Cerebral Blood during Emotional versus Higher Cognitive Implications for Interactions between Emotion and Cognition

Brain mapping studies using dynamic imaging methods demonstrate areas regional cerebral blood flow (rCBF) decreases, as well as areas where increases, during performance of various experimental tasks. Task holds for both sets of cerebral blood flow changes (CBF), providing the opportunity to investigate areas that become and “activated” in the experimental condition relative to control state. Such data yield the intriguing observation that in areas in emotional processing, such as the amygdala, the posteromedial cortex, and the ventral anterior cingulate cortex, although flow as expected during specific emotion-related tasks, flow decreases performance of some attentionally demanding, cognitive tasks. Conversely, in some of the areas that appear to subserve cognitive functions, as the dorsal anterior cingulate and the dorsolateral prefrontal cortices, increases while performing attentionally demanding cognitive tasks, but during some experimentally induced and pathological emotional Although the specific nature of such reciprocal patterns of regional remains unclear, they may reflect an important cross-modal interaction during mental operations. The possibility that neural activity is less in areas required in emotional processing during some higher cognitive processes holds implications for the mechanisms underlying interactions cognition and emotion. Furthermore, the possibility that neural in some cognitive-processing areas is suppressed during intense states suggests mechanisms by which extreme fear or severe may interfere with cognitive performance.     

Positive Emotions Speed Recovery from the Cardiovascular Sequelae of Negative Emotions

Two studies tested the hypothesis that certain positive emotions speed recovery from the cardiovascular sequelae of negative emotions. In Study 1, 60 subjects (Ss) viewed an initial fear-eliciting film, and were randomly assigned to view a secondary film that elicited: (a) contentment; (b) amusement; (c) neutrality; or (d) sadness. Compared to Ss who viewed the neutral and sad secondary films, those who viewed the positive films exhibited more rapid returns to pre-film levels of cardiovascular activation. In Study 2, 72 Ss viewed a film known to elicit sadness. Fifty Ss spontaneously smiled at least once while viewing this film. Compared to Ss who did not smile, those who smiled exhibited more rapid returns to pre-film levels of cardiovascular activation. We discuss these findings in terms of emotion theory and possible health-promoting functions of positive emotions.     

The influence of only on syntactic processing of "long" relative clause sentences

We report an eye movement experiment investigating the influence of the focus operator only on syntactic processing of "long" relative clause sentences. Paterson, Liversedge, and Underwood (1999) found that readers were garden pathed by "short" reduced relative clause sentences containing the focus operator only . They argued that due to thematic differences between "short" and "long" relative clause sentences, garden path effect might not occur when "long" reduced relative clause sentences are read. Eye-tracking data show that garden path effects found during initial processing of the disambiguating verb of "long" reduced sentences without only were absent or delayed in the case of counterparts with only . We discuss our results in terms of current theories of sentence processing.     

AN EMPIRICAL APPRAISAL OF THE PRCA FOR MEASURING ORAL COMMUNICATION APPREHENSION

Since 1970 about 80% of the research on oral communication apprehension has used one of two versions of McCroskey's Personal Report of Communication Apprehension. The original 20-item PRCA was introduced for the purpose of measuring apprehension beyond the traditional public speaking context. Although the PRCA-20 is reliable, some serious criticism of it has centered on its ability to tap interpersonal behavior outcomes. In an attempt to bolster its interpersonal applicability, five “interpersonally-oriented” items were added to form the PRCA-25. The studies reported herein demonstrate that both versions fail to possess sufficient reliable variance to be applicable to contexts other than public settings. In addition, it was found that the interpersonal items are a separate component of the PRCA, and as such, do not justify being treated equal in terms of additivity and, therefore, reduce the construct integrity of the PRCA.     

Assessing potential reinforcement-like effects of brief stimuli unrelated to food reinforcers

It is widely assumed that reinforcers are biologically relevant stimuli, or stimuli that have been associated with biologically relevant stimuli. However, brief, arbitrary stimuli have also been reported to have reinforcement-like effects, despite being unrelated to biologically relevant stimuli like food. The present study explored the potential reinforcement-like effects of brief stimuli across 5 experiments. In Experiments 1 through 4, pigeon subjects responded for food reinforcement and brief stimulus presentations in a 2-component multiple schedule. Neither baseline response rates nor resistance to change during disruption tests were systematically greater in a component with versus without brief stimulus presentations. Increasing the rate and duration of brief stimulus presentations in Experiment 4 did not reveal reinforcement-like effects when compared directly with food. In Experiment 5, pigeons chose between independent terminal links in a concurrent-chains procedure. Across conditions, varying the location, duration, and rate of brief stimulus presentations in the terminal links had no systematic effects on preference. In contrast, varying rates of food reinforcers resulted in large and reliable shifts in preference. Therefore, the present study found no systematic evidence that brief stimuli unrelated to food reliably increase response rates, resistance to change, or preference. These data demonstrate the value of systematic replication, and a behavioral momentum approach to assessing potential reinforcement-like effects.     

Selective attention and stimulus-reinforcer interactions in the pigeon

The study supplies further evidence that non-associative effects and temporal-spatial similarities between certain combinations of cue and consequence cannot explain all instances of stimulus-reinforcer interactions. Pigeons were trained to press a treadle in the presence of a discriminative compound stimulus either to avoid shock or to obtain a food reinforcer. The compound stimulus was composed of diffuse tone and light cues which had identical temporal patterns of onset, duration and offset. With the avoidance schedule the auditory cue acquired more control than the visual cue; however, when food was the reinforcer, the visual cue exerted more control. This pattern of stimulus control on the appetitive schedule did not change if random shocks were also added, even though these shocks were equal in density to the food presentations and equal in magnitude to those used for the avoidance schedule. Other changes in the appetitive procedure, such as making the tone spatially contiguous with food and removing the light in the food hopper, also failed to alter the relative control by the different cues. Prior training with a food reinforcer did not produce any change in the relative control by the two cues when the birds were retrained on the shock-avoidance schedule. The results suggest that some frequently stated alternatives to selective associability are not adequate explanations of this instance of a stimulus-reinforcer interaction.     

Successive negative contrast in one-way avoidance learning in rats

In three experiments, successive negative contrast was examined in one-way avoidance learning. Reward magnitude in first (pre-shift) and second (post-shift) phases was manipulated by time spent in the safe compartment. Experiment 1 demonstrated that when time in the danger compartment was held constant, a group shifted from a large reward--30 sec spent in the safe compartment--to a small reward--1 sec--showed poor performance and longer response latency than a group conditioned with the small reward in both phases. Experiment 2 replicated this effect with a less intense shock and also demonstrated that a group shifted from large to small reward performed more poorly than a group exposed to large reward--30 sec--in both phases. Finally, Experiment 3 showed that changes in intertrial interval, defined as total time spent in the safe compartment and the danger compartment before the onset of the warning signal, were not responsible for this contrast effect. These results suggest that time spent in a safe place can act as appetitive incentive during one-way avoidance learning.