GUIDED VISUAL SEARCH IS A LEFT-HEMISPHERE PROCESS IN SPLIT-BRAIN PATIENTS

Abstract— Previous research has shown that split-brain (callosotomy) patients search through visual displays twice as fast as normal observers when items are divided evenly between visual hemifields, as though each disconnected hemisphere possessed its own attentional scanning system (Luck, Hillyard, Mangun, & Gazzaniga, 1989, 1994) Results from 3 split-brain patients in the present study indicate that the ability to limit search to a relevant subset of the visual display is lateralized to the left cerebral hemisphere. This ability to perform guided search was not shown in the right hemisphere, even when the search time in that hemisphere was superior to search time in the left Furthermore, guided search was observed for both hemifields in normal control observers. These findings suggest that, as with higher cognitive processes such as language, strategic visuospatial attentional processes are preferentially lateralized to the left cerebral hemisphere. The findings also imply that the callosum mediates guided search in the right hemisphere of normal subjects     

REFLECTIONS ON AFFIRMATIVE ACTION GOALS IN PSYCHOLOGY ADMISSIONS

Four goals of affirmative action in higher education are described as they relate to psychology admissions. Broadly conceived, these goals are compensating for past injustice, correcting present inequity, promoting intellectual diversity, and enhancing the presence of role models. It is argued that the four goats differ in their underlying assumptions about the purposes of affirmative action and that these differences can result in disparate admission decisions. Data from three experiments on decision making in graduate psychology admissions are presented to illustrate the analysis. In these studies, academic psychologists rated the admissibility of hypothetical graduate student applicants who varied on a number of characteristics (e g., ethnicity, social class, interest in minority research) pertinent to affirmative action. A consistent pattern of ethnic group differences in admissibility ratings was documented, illustrating that compensation for past injustice can be interpreted as a salient affirmative action goal in graduate admissions decisions. Implications of the analysis for clarifying admissions decisions guided by affirmative action goals are discussed.     

False memories of childhood experiences

We conducted two experiments to investigate if college students would create false memories of childhood experiences in response to misleading information and repeated interviews. In both experiments we contacted parents to obtain information about events that happened to the students during childhood. In a series of interviews we asked the students to recall the parent-reported events and one experimenter-created false event. In the second experiment we varied the age at which we claimed the false event occurred. In both experiments we found that some individuals created false memories in these circumstances and in the second experiment we found no effect of age of attempted incorporation. In the second experiment we also found that those who discussed related background knowledge during the early interviews were more likely to create a false recall. Generalizations to therapy contexts are discussed.     

The modification of auditory hallucinations

The ABAB withdrawal design was used to document the effectiveness of a behavioral treatment package in reducing the duration of auditory hallucinations of a chronically mentally ill inpatient. Results revealed clear functional control of the treatment package over the occurrence of the subject's auditory hallucinations during a 2-hr time period.     

Direct comparisons between residential and community students on school performance measures in a public school setting

The purpose of the current study was to evaluate the school performance of residential youth who attended a public school setting. Direct comparisons were made between the residential youth and students in the community on a number of school measures. Results from a multivariate analysis of covariance indicated that the residential students had significantly lower grades, participated in significantly fewer extracurricular activities, and exhibited more problematic behaviors such as tardies and absences. These findings were consistent with previous research which found that many residential youth have a number of behavioral, social, and academic difficulties that interfere with school functioning. A number of recommendations were made regarding educational placement for residential youth.     

Stereotyped movement disorder in an adult following acquired brain injury: Effect of environmental stimulation

In the present study, a naturalistic functional analysis procedure was used to assess the effect of environmental stimulation on the stereotypic behavior (body rocking) of an adult whose stereotypy appeared to be induced by an acquired brain injury. Environmental stimulation, operationalized in terms of both physical and social characteristics, resulted in only minimal changes in the occurrence of body rocking. Body rocking occurred in excess of 50% of the observations in all environmental stimulation conditions and in a naturally occurring baseline condition. To our knowledge, this is the first published report of a functional analysis of stereotypy associated with acquired brain injury.     

Evaluating pediatric psychology consultation services in a medical setting: An example

We examined the nature of referrals to a health center-based pediatric psychology service from 1990 to 1993 and assessed the satisfaction of health professionals with these services. Archival evaluation of 1467 records showed that over half of the consultation requests came from general pediatrics, pediatric neurology, and surgical services and that 70% of the psychological services were delivered on an outpatient basis. The most frequent referrals were for cognitive/neuropsychological evaluation and externalizing behavior problems. Pediatric psychology trainees were involved in 94% of the consultations. Survey of health professionals (n = 143) indicated very high overall satisfaction with the quality of services delivered. Presenting problems yielding the greatest likelihood for future consultation requests were behavior problems, child abuse, coping with illness, and depression/suicide. Results are discussed in the context of previous evaluations of pediatric psychology services and recommendations for future evaluation research.     

Non-heart-beating organ donation: a reply to Campbell and Weber.

In the preceding commentary, Campbell and Weber raise two valid and important issues concerning non-heart-beating organ donation (NHBOD). First, because the procedure links withdrawal of life support and the potential for subsequent organ donation, the desire for organs may create a situation in which care of the dying individual has relatively less importance and the dying may receive suboptimal care. Second, even if concerns about care of the dying were dealt with adequately, there will not be enough non-heart-beating donors to significantly decrease the organ shortage that exists, making the procedure not worth the risk. We agree that attention to the important details of caring for the dying are, and must be, the primary concern of all health care workers caring for those individuals. Ensuring the patients' comfort, dignity, and autonomy, and providing for family and social support are the mainstays of this care. All policies for NHBOD should clearly support and mandate these concepts. Regarding the second concern, we agree that NHBOD is currently rare; however, evidence is increasing that this type of donation has great potential. Continued growth of the practice in this country will depend largely on public acceptance, which we believe will be directly influenced by whether the public perceives that care of the dying is not compromised by this procedure.     

The box alignment illusion: An orientation illusion induced by pictorial depth

In four experiments, observers attempted to align two sets of oblique edges to parallel. The contexts for these alignments included lines in isolation (2-D control), lines embedded in orthogonal drawings of same-oriented and different-oriented boxes (3-D objects), and each of these viewed against backgrounds depicting strong linear perspective (3-D backgrounds). A consistent distortion was observed in the alignments of different-oriented boxes relative to control lines, indicating that the parallel lines in these stimuli appeared to diverge toward the top of the picture. Furthermore, thisbox alignment illusion decreased with interstimulus distance, whereas alignment distortions in control lines and same-oriented boxes increased with distance. Viewing the stimuli against 3-D backgrounds produced a dramatic reversal of the illusion, with control lines now appearing to converge more than the boxes. These results suggest that the illusion reflects basic processes involved in pictorial depth perception.     

Book reviews

Integrative Psychological and Behavioral Science -