Narrative comprehension in adults with right and left hemisphere brain-damage: theme organization.

The effects of delayed presentation of a central theme on the comprehension and interpretation of narratives were investigated in adults with right and left hemisphere brain-damage and normal individuals. The performance of subgroups of the subjects with right and left hemisphere brain-damage also was examined. Right hemisphere brain-damaged groups with anterior and posterior lesions were significantly less accurate and identified significantly fewer central themes when central theme presentation was delayed until the end of a narrative than when the theme was presented at the beginning. Subjects with anterior right hemisphere brain-damage produced significantly more embellishments and confabulations than subjects with posterior damage and non-brain-damaged controls, regardless of theme condition. The performance of non-brain-damaged subjects and subjects with fluent and nonfluent aphasia was unaffected by the organization of the central theme in the narratives.     

Temporal dimensions of consonant and vowel production: an acoustic and CT scan analysis of aphasic speech

This study explored a number of temporal (durational) parameters of consonant and vowel production in order to determine whether the speech production impairments of aphasics are the result of the same or different underlying mechanisms and in particular whether they implicate deficits that are primarily phonetic or phonological in nature. Detailed analyses of CT scan lesion data were also conducted to explore whether more specific neuroanatomical correlations could be made with speech production deficits. A series of acoustic analyses were conducted including voice-onset time, intrinsic and contrastive fricative duration, and intrinsic and contrastive vowel duration as produced by Broca's aphasics with anterior lesions (A patients), nonfluent aphasics with anterior and posterior lesions (AP patients), and fluent aphasics with posterior lesions (P patients). The constellation of impairments for the anterior aphasics including both the A and AP patients suggests that their disorder primarily reflects an inability to implement particular types of articulatory gestures or articulatory parameters rather than an inability to implement particular phonetic features. They display impairments in the implementation of laryngeal gestures for both consonant and vowel production. These patterns seem to relate to particular anatomical sites involving Broca's area, the anterior limb of the internal capsule, and the lowest motor cortex areas for larynx and tongue. The posterior patients also show evidence of subtle phonetic impairments suggesting that the neural instantiation of speech may require more extensive involvement, including the perisylvian area, than previously suggested.     

Disruptive behaviors in the classroom: Initial standardization data on a new teacher rating scale

This study presents initial standardization data on the Sutter- Eyberg Student Behavior Inventory (SESBI), a teacher- completed measure of disruptive classroom behaviors. SESBIs were completed on 1116 children in kindergarten through fifth grade in a rural eastern Washington school district. Various analyses (Cronbach's alpha, corrected item- total correlations, average interitem correlations, principal components analyses) indicated that the SESBI provides a homogeneous measure of disruptive behaviors. Support was also found for three factors within the scale (e.g., overt aggression, oppositional behavior, and attentional difficulties). While the child's age did not have a significant effect on the SESBI, the child's gender did have a significant effect on scale scores as well as on most of the items, with males being rated more problematic than females. The SESBI was also able to discriminate between children in treatment for behavioral problems or learning disabilities and children not in treatment.The authors would like to acknowledge the support of the teachers in the Pullman School District, whose kind help and assistance made the study possible. Special thanks are also extended to Todd Sosna, Christine Ladish, and Lee Sternberger for their helpful comments on earlier versions of the paper. Preparation of this study was supported in part by funds provided to G. Leonard Burns by Washington State University.     

Role of spatial location in integration of pictorial information across saccades

Identification of a fixated object in a visual display is facilitated by integrating information from a preview of that object in the periphery with information extracted on the subsequent foveal fixation (Pollatsek, Rayner, & Collins, 1984). These experiments investigated the extent to which this integration is dependent on the spatial location of the information remaining constant. Two preview objects were presented in the periphery; Ss fixated that region and named a single target object that appeared in the same spatial location in which one of the two preview objects had been presented. Of primary interest was the facilitative effect when a preview object was identical to the target object as a function of whether they were in the same spatial location. The major finding was that although there was a small effect of switching, there was still a substantial preview benefit even when the location of the identical object switched. In addition, the switching effect did not interact with the level of identity between the preview and target. There was also a preview benefit in conditions in which there were no eye movements and the preview and target objects were at least 5 degrees apart. Thus, the data indicate that the process object identification is relatively insensitive to location information and that object information and location information are coded fairly independently.     

A model of character recognition and legibility

This article presents a model of character recognition and the experiments used to develop and test it. The model applies to foveal viewing of blurred or unblurred characters and to tactile sensing of raised characters using the fingerpad. The primary goal of the model is to account for variations in legibility across character sets; a secondary goal is to account for variations in the cell entries of the confusion matrix for a given character set. The model consists of two distinct processing stages. The first involves transformation of each stimulus into an internal representation; this transformation consists of linear low-pass spatial filtering followed by nonlinear compression of stimulus intensity. The second stage involves both template matching of the transformed test stimulus with each of the stored internal representations of the characters within the set and response selection, which is assumed to conform to the unbiased choice model of Luce (1963). Though purely stimulus driven, the model accounts quite well for differences in the legibility of character sets differing in character type, size of character, and number of characters within the set; it is somewhat less successful in accounting for the details of each confusion matrix.     

Attentional processing and the independence of color and orientation

Judgments of the color and shape of a stimulus specified by a cue indicating its location demonstrate stochastic independence. Evidence for the independence of color and orientation was obtained when the cue followed stimulus offset immediately, the cue followed stimulus offset by 2 s, and when either a central or peripheral precue focused attention on the cued stimulus at the time of its presentation. It appears that an object's color and orientation are represented independently even following the attentional focusing thought to support feature integration.     

On the relation between metacontrast masking and suppression of visible persistence

Does the introduction of additional contours in a display sequence (an operation known to reduce the strength of suppression in metacontrast) also reduce suppression of visible persistence? In three experiments, duration of visible persistence was estimated by a method in which successful performance depends on the temporal integration of a pattern whose elements are displayed in two successive frames. In this procedure, the arrival of the trailing frame is known to exert a suppressive influence on the visible persistence of the leading frame. Embedding the elements of the leading frame within additional contours (a line grid) reduced the degree of suppression exerted by the trailing frame. This did not occur when the grid was part of the trailing display. We conclude that suppression of visible persistence and metacontrast masking belong to the same class of events.     

Retraction of Ross and LoLordo findings concerning blocking in serial feature-positive discriminations.

Findings concerning the effectiveness of stimuli from various conditioning procedures in blocking conditioned excitation and occasion-setting functions of an added stimulus in a serial feature-postive discrimination training procedure (LoLordo & Ross, 1987; Ross & LoLordo, 1986, 1987) are retracted. Videotapes on which the published data were based were rescored by 2-5 people, most of whom were uninformed about group memberships of the subjects. In no case did the rescoring confirm any of the orginal findings of blocking. Possible factors contributing to the discrepancies are discussed. The experiments should be repeated with feature stimuli that are less similar to each other and with several scorers, at least one of whom is unaware of the group assignment of the subjects.     

Discriminative properties of morphine that modulate associations between tastes and lithium chloride

Wistar rats learned to withhold consumption of a target solution when morphine preceded presentation of the target solution and lithium chloride (LiCl) and to consume the same target solution when saline preceded the presentation of the solution. After this serial feature discrimination training, morphine did not block the formation of a Pavlovian association between saccharin and LiCl but did suppress consumption of familiar tap water. After Pavlovian conditioning, morphine blocked the formation of an association between saccharin and LiCl but did not suppress consumption of a familiar tap water solution. The roles of morphine and saline can be interchanged. It appears that the morphine discriminative stimulus is calling up a representation of neither the conditioned stimulus nor the unconditional stimulus alone, but rather a modified representation of some aspect of their association.     

Ethanol-mediated taste aversions and state-dependency in preweanling (16-day-old) rats

Requirements for conditioning of an ethanol-mediated taste aversion in 16-day-old rat pups were examined. Experiment 1 demonstrated that preweanling rats are capable of acquiring, in two trials, an aversion to a 15% sucrose solution when followed by intragastric intubation of a 1.2 g/kg dose of 17% v/v ethanol, but not when followed by a 0.4 g/kg dose. Comparison was with control animals given sucrose followed by an equivalent volume isocaloric Half and Half. When the 0.4 g/kg dose of ethanol preceded sucrose presentation by 30 min (Experiment 2), the aversion was learned, suggesting that the effective delay between the sucrose and the critical consequences of the ethanol had been too long with the former procedure. Expression of the sucrose aversion required, however, the reinstatement of the context of intoxication--state-dependent retention. Finally, the results of Experiment 3B indicated that, in addition to the association between the sucrose and the aversive consequences of alcohol intoxication, the orosensory cues resulting from alcohol's direct elimination, via such processes as respiration and salivation, became associated with the appetitive properties of the sucrose. This was evidenced by a conditioned increase in preference for ethanol odor. Possible age-related differences in the ability to associate stimuli with alcohol's unconditioned consequences, and in state dependency are discussed.