The psychologist's role in assessing and facilitating patients' knowledge of advance directives in medical settings: A preliminary investigation

In a time of budgetary shortfalls in the medical industry, an aging population, and an increased emphasis on health care choices, psychologists are being called upon to administer advance medical directive programs to patients. This study reports preliminary findings from a program to assess and facilitate patients' knowledge of advance directives (ADs) by the Psychology Service at the Ann Arbor VA Medical Center. The participant pool included 243 male veteran patients admitted to medical and surgical wards at the hospital. The intervention included the use of a computer-generated prompt for consultation, which was sent to the psychology staff in response to a patient inquiry regarding ADs. It also involved an increased emphasis on the delivery of written material on ADs by the admissions clerks. The intervention appeared to result in a modest increase in patients' knowledge of advance directives. Suggestions are offered for areas that should be emphasized in future attempts to increase patients' knowledge and utilization of advance directives.     

Multidimensional same--different judgments: evidence against independent comparisons of dimensions

Commonly discussed models of performance in the multidimensional same-different task are based on the assumption that independent same-different decisions are reached for each of the stimulus dimensions used in an experiment. In these models, a higher level mechanism examines th outcome of these independent decisions in order to determine whether the stimuli are the same or different overall. Previous evidence indicating that these models are inconsistent with results from same trials is summarized, and a new test of the above assumption using data from different trials is proposed. Detailed analysis of reaction times from different trials is shown, at least for some pairs of dimensions, to be incompatible with the view that separate same-different decisions are reached for each dimension. The major finding is that there are more relatively fast responses in a condition with two dimensions different, compared with the two conditions with only one of the dimensions different, than any processing model treating the dimensions separately could predict. The results suggest that partial information may be combined across dimensions in order to reach a "different" judgment.     

Iconic memory and visible persistence

There are three senses in which a visual stimulus may be said to persist psychologically for some time after its physical offset. First, neural activity in the visual system evoked by the stimulus may continue after stimulus offset (“neural persistence”). Second, the stimulus may continue to be visible for some time after its offset (“visible persistence”). Finally, information about visual properties of the stimulus may continue to be available to an observer for some time after stimulus offset (“informational persistence”). These three forms of visual persistence are widely assumed to reflect a single underlying process: a decaying visual trace that (1) consists of afteractivity in the visual system, (2) is visible, and (3) is the source of visual information in experiments on decaying visual memory. It is argued here that this assumption is incorrect. Studies of visible persistence are reviewed; seven different techniques that have been used for investigating visible persistence are identified, and it is pointed out that numerous studies using a variety of techniques have demonstrated two fundamental properties of visible persistence: theinverse duration effect (the longer a stimulus lasts, the shorter is its persistence after stimulus offset) and theinverse intensity effect (the more intense the stimulus, the briefer its persistence). Only when stimuli are so intense as to produce afterimages do these two effects fail to occur. Work on neural persistences is briefly reviewed; such persistences exist at the photoreceptor level and at various stages in the visual pathways. It is proposed that visible persistence depends upon both of these types of neural persistence; furthermore, there must be an additional neural locus, since a purely stereoscopic (and hence cortical) form of visible persistence exists. It is argued that informational persistence is defined by the use of the partial report methods introduced by Averbach and Coriell (1961) and Sperling (1960), and the term “iconic memory” is used to describe this form of persistence. Several studies of the effects of stimulus duration and stimulus intensity upon the duration of iconic memory have been carried out. Their results demonstrate that the duration of iconic memory is not inversely related to stimulus duration or stimulus intensity. It follows that informational persistence or iconic memory cannot be identified with visible persistence, since they have fundamentally different properties. One implication of this claim that one cannot investigate iconic memory by tasks that require the subject to make phenomenological judgments about the duration of a visual display. In other words, the so-called “direct methods” for studying iconic memory do not provide information about iconic memory. Another implication is that iconic memory is not intimately tied to processes going on in the visual system (as visible persistence is); provided a stimulus is adequately legible, its physical parameters have little influence upon its iconic memory. The paper concludes by pointing out that there exists an alternative to the usual view of iconic memory as a precategorical sensory buffer. According to this alternative, iconic memory is post-categorical, occurring subsequent to stimulus identification. Here, stimulus identification is considered to be a rapid automatic process which does not require buffer storage, but which provides no information about episodic properties of a visual stimulus. Information about these physical stimulus properties must, in some way, be temporarily attached to a representation of the stimulus in semantic memory; and it is this temporarily attached physical information which constitutes iconic memory.     

Children’s use of phonological encoding when reading for meaning

The role of phonological recoding in children’s reading was investigated by means of a task requiring comprehension of sentence meaning: The child’s task was to decide whether a sequence of printed letter strings was a meaningful sentence or not. Meaningless sentences that are meaningful when phonologically recoded (e.g., “He ran threw the street”) produced more incorrect responses than did meaningless sentences that remain meaningless when phonologically recoded (e.g., “He ran sew the street”). The difference in error rates between the two sentence types diminished as a function of age. Control experiments showed that these results were not due to visual similarity effects, nor to imperfect ability to spell homophones. It was concluded that very young readers rely extensively on phonological recoding when reading for meaning; as they grow older, reliance on visual encoding becomes progressively more important.     

The effect of set size on hemifield asymmetries in letter recognition

Single letters were presented tachistoscopically in the left or right hemifield to right-handed observers. Superior recognition of letters on the right was found for letters chosen from subsets containing four items, but no differences were found when any letter, or any symmetrical letter, could appear. In a second experiment, the right hemifield advantage was found under conditions requiring the subject to determine the subset only when the subset chosen was appropriate. Results were discussed in terms of the adequacy of language-based explanations of hemifield asymmetries in letter recognition.     

Irrelevant differences in the "same"--"different" task

This article examines the effects of irrelevant information on the multidimensional "same"--"different" task. Subjects were instructed to compare two geometric figures with respect to certain attributes but to ignore other attributes in making the "same"--"different" decision. The irrelevant attributes were chosen in such a way that they could not easily be ignored to see how the existence of irrelevant differences would affect the comparison process. As expected, the overall latencies were longer than is usually found in tasks with no irrelevant differences. However, the nature of the comparison process appeared unchanged. The usual finding of a "fast-same" phenomenon persisted even when irrelevant information was present. The similarity of the results in this task to results in the "same"--"different" task with no irrelevant features supports the idea that the same comparison mechanism is used whether or not irrelevant differences are present in the stimulus pairs. The results suggest a more general-purpose comparison mechanism than is usually included in models of this task. Two-process models of visual comparisons are thus ruled out entirely. A modified version of Krueger's noisy-operator theory does appear consistent with the results.