Effects of Damage to Right-Hemisphere Brain Structures on Spontaneous Emotional and Social Judgments

Recent work in cognitive and social neuroscience has focused on the neural substrates of social judgment. The present study explores the effects of damage to the right-hemisphere somatosensory cortices (RSS), a region known for its role in emotion recognition. Seven subjects with RSS damage were shown a short movie depicting objects that move in socially suggestive ways, a stimulus that typically elicits spontaneous social and emotional attributions from normal subjects. The spontaneous verbal responses of RSS-damaged subjects to this movie were compared to those of normal subjects as well as brain-damaged control subjects; the data were derived using a word count and categorization computer program. This method measures spontaneous social and emotional judgments rather than the more typical rating and labeling measures used in neuropsychological studies of social judgment. As predicted, relative to brain-damaged and normal controls, subjects with RSS damage reacted to the stimulus movie with fewer words in categories describing emotional and social processes, despite using a similar total number of words (and slightly more words describing movement, a control category). These results provide further evidence for the role of the RSS in social/emotional processing and identify a role for the RSS in automatic representation in ourselves of body states of others to foster emotion recognition and social cognition.     

Signed difference analysis: Theory and application

Psychological constructs can only be measured indirectly in terms overt behavior, often by means of changes in the level of performance on tasks they are presumed to affect. However, the exact relationship between constructs and the tasks they are presumed to affect is usually not known, which often requires non-essential auxiliary assumptions to be added to a psychological model to allow it to contact the data. Signed difference analysis is a method of deriving testable consequences from psychological models under the general assumption that the relationship between task performance and the constructs or combinations of constructs postulated by the model is at least monotonic. The predictions derived using signed difference analysis do not depend upon estimation of either model parameters or explicit functional relationships. In the present paper, the mathematical theory of signed difference analysis is presented and applied to illustrative problems drawn from research in memory, spatial attention, and reading. The relationships between signed difference analysis and related inferential procedures such as conjoint measurement, state-trace analysis, and double dissociation are discussed.     

Comparing excitatory backward and forward conditioning

Three Pavlovian lick suppression studies with rats were conducted to compare the role of the conditioning context in excitatory backward and forward conditioning. The experiments explored the possibility that excitatory backward conditioning, but not forward conditioning, is mediated by the context. That is, in excitatory backward conditioning, the conditioning context may function as an excitatory mediator, which supports second-order conditioning of the target cue. This possibility contrasts with traditional accounts, which suggests that common processes underlie excitatory backward and forward conditioning. Experiment 1 found that conditioned responding following backward conditioning was attenuated as a result of posttraining extinction of the training context, but the same manipulation elevated responding after forward conditioning. Experiments 2 and 3 found that posttraining and pretraining associative inflation of the context (presenting unsignalled USs) increased conditioned responding to the target of a backward conditioning procedure but either had no effect or reduced responding to the target of a forward conditioning procedure. Thus, excitatory backward and forward conditioning appear to differ in their dependence on the status of the conditioning context.     

Retroactive interference in rats: Independent effects of time and similarity of the intervening event with respect to acquisition

Events occurring during the retention intervals for a 5-min delayed alternation task were used to investigate the factors that influence retroactive interference. Appetitive reinforcement in an E-maze was employed to train rats on the delayed alternation task consisting of a forced-choice (target event) trial followed by a free-choice (test) trial. Occasional probe trials added a potentially interfering event either at the beginning, middle, or end of the retention period. These events also varied in similarity to the target events, ranging from low similarity to the converse of the target event. Interference increased both with the interval between the target and intervening events and with the similarity between the converse of the target event and the intervening event; however, there was no tendency, significant or otherwise, towards an interaction between stimulus similarity and the interval between the target and intervening events. Control groups demonstrated that the interference was of an associative nature and that the interval between the intervening event and the test trial was little consequence. These results are discussed in terms of two separate types of interference: similarity interference which depends on stimulus similarity of the intervening event to the converse of the target event but not on the temporal location of the intervening event, and processing interference which depends on the temporal location of the intervening event but not on its similarity to the converse of the target event.