The effects of complexity on the perception of vibrotactile patterns presented to separate fingers.

Pairs of vibrotactile patterns were presented to subjects' left middle and index fingerpads (unilateral presentation) or left and right index fingerpads (bilateral presentation), using two Optacon arrays. A set of simple (one-line) patterns and a set of complex (two-line) patterns were constructed so that they were equally identifiable when presented individually. In Experiment 1, discrimination performance was lower for two-line patterns than it was for one-line patterns, and it was lower for unilateral presentation than it was for bilateral presentation. Communality, the number of lines that two patterns share in common, was a major factor in reducing discrimination performance for two-line patterns. Subjects' abilities to identify one member of the pair of patterns were measured in Experiment 2. There were no significant differences in performance between pattern sets or type of presentation when subjects attended to a single pattern. However, when subjects were required to attend to both patterns, identification performance was lower for two-line patterns than it was for one-line patterns, and it was lower for unilateral presentation than it was for bilateral presentation. The results suggest that there are limited attentional resources for processing vibrotactile patterns and that more resources are available bilaterally than are available unilaterally.     

Effects of reinforcer delays on choice as a function of income level

Three rats earned their daily food ration by responding during individual trials either on a lever that delivered one food pellet immediately or on a second lever that delivered three pellets after a delay that was continuously adjusted to ensure substantial responding to both alternatives. Choice of the delayed reinforcer increased when the number of trials per session was reduced. This result suggests that models seeking closure on choice effects must include a parameter reflecting how preference changes with sessionwide income. Moreover, models positing that reinforcer probability and immediacy (1/delay) function equivalently in choice are called into question by the finding that probability and immediacy produce opposing effects when income level is changed.     

Towards a postmodern ethics: Sir Isaiah Berlin and John Caputo

Conclusions It may seem to their opponents that they are trying to have their cake and eat it too. Postmodernists admit that their own paradigm must be and will be placed into question by future thinkers. But if they can anticipate an eventual reaffirmation of their paradoxical stand in an ongoing oscillating debate, then cannot it be said that they have arrived at a truth that transcends their time and place in history? And, if so, is not their fallibilist stance in fact self-referentially inconsistent? The response of postmodernists is the claim that each reaffirmation of a fallibilist epistemology and ethics throughout history is in fact sui generis. And this is the case because each reaffirmation has its own unique context within which it is made. Modernists will of course argue that these contextual differences are nonessential and irrelevant. And the debate over the problem of the One and the Many is once again launched in a new context. Thus far from running away from the paradoxical position that what they assert is both true and false, postmodernists revel in such inconsistencies.But does not such an ethical stance resemble the Sisyphean nightmare of being condemned to roll a heavy stone up a cliff only to have it keep falling back to the bottom ad infinitum? If no decision is innocent of doing some harm in the world, why should we bother to play the moral game at all? Indeed, what possible help is a postmodernist ethics when it comes to making some of the complex and crucial decisions we face today if it refuses to say anything substantial beyond the recommendations that we be cautious and balanced?And the postmodernist can only reply that we are letting our neurotic need for solid foundations frighten us. For ethics is an art not a science. There are no absolute rules. If we do not like the way the game is set up, then we are simply revealing our ultimate hubris in the face of a mystery requiring deep humility.     

INTERVIEWER DECISION PROCESSES AND EFFECTIVENESS: AN EXPERIMENTAL POLICY-CAPTURING INVESTIGATION

Using a policy-capturing approach, 29 corporate interviewers evaluated 64 hypothetical candidates for a position in a financial services organization. Six selection criteria were manipulated in a balanced factorial design. Interviewers evaluated candidates' qualifications and made hiring recommendations. The results revealed substantial individual differences in interviewers' decision strategies, as well as their insight into their own decision processes. Data on the effectiveness of the 29 interviewers were collected from 427 hiring managers and the decision processes of effective and ineffective interviewers were compared. The findings indicated that the decision strategies used by effective interviewers were quite similar to one another and relied heavily on two selection criteria. Also, effective interviewers were more likely than ineffective interviewers to use selection criteria in a manner that mirrored their self-reports of the importance of these criteria. Effective interviewers were more aware of their decision processes than ineffective interviewers.     

Haptic probing: perceiving the length of a probe and the distance of a surface probed.

Knowing about the properties of objects by wielding them and knowing about the distances of surfaces by striking them with objects as probes are examples of dynamic or effortful touch. Six experiments focused on the invariant mechanical parameters that couple the time-varying states (displacements, velocities) of hand-held rods to the time-varying torques and forces imposed upon them by wielding and probing. There were three major conclusions. First, when a probe is wielded without contact, perceived probe length is a function of the probe's rotational inertia; however, with contact, perceived probe length is affected by the rotational inertia and the distance of the point of contact from the probe's center of percussion. Second, when a surface is struck with a probe, perceived surface distance is affected by the probe's rotational inertia and the angle of inclination of the probe at contact. Third, under seemingly identical conditions of probing, either probe length or surface distance can be perceived selectively without confusion. Results were discussed in terms of haptic information, haptic attention, and the dynamics of probing.     

Quantitative scores of normal and abnormal subjects on Initial-letter Word-association Test.

The quotient of the mean quantitative score on Initial-letter Word-association Test for 193 normal subjects was significantly higher than the quotient of the mean quantitative score of 44 abnormal (psychotic) subjects. This is interpreted as meaning that, in general, the normal subjects have predominantly a positive attitude towards their surrounding world in contradistinction to the abnormal subjects whose attitude was predominantly negative, ambivalent, and repressive. On the other hand, the mean of the quotients of the quantitative scores of the 44 abnormal subjects was higher than the mean of the quotients of the quantitative scores of the normal subjects which suggests increased oral tendencies of the abnormal subjects expressed much as the unwarranted optimism of small children.     

Perceptual-motor coordination and style in healthy boys and those with minimal brain dysfunction.

Differences in visual-motor tracking by 8- to 9-yr.-old boys diagnosed with Minimal Brain Dysfunction or healthy have been analyzed. The subject's task was to use two computer keys to control a cursor line within a target which moved horizontally in two directions over the display. Target size and speed were the experimental variables. Off-target incidences and durations were measured and evaluated. The latter were longer and the former were more frequent on small targets for boys with brain dysfunction than for healthy boys. The two measures correlated negatively in most situations. The perceptual-motor style expressed by means of the distribution of coincidences of the two measures being over or under a criterion set equal to the corresponding averages of the healthy boys was different in the two groups. Brain-damaged boys were characterized mostly by the combination of high incidence of low duration misses for small and fast targets and by high incidence of high duration misses for large and slow targets, whereas most healthy boys showed a few misses of low duration for large and slow targets and few misses of high duration for small and fast targets.     

An automated test development of parallel tests from a seed test

Binary programming models are presented to generate parallel tests from an itembank. The parallel tests are created to match item for item an existing seed test and match user supplied taxonomic specifications. The taxonomic specifications may be either obtained from the seed test or from some other user requirement. An algorithm is presented along with computational results to indicate the overall efficiency of the process. Empirical findings based on an itembank for the Arithmetic Reasoning section of the Armed Services Vocational Aptitude Battery are given.The Office of Naval Research, Program in Cognitive Science, N00014-87-C-0696 partially supported the work of Douglas H. Jones. The Rutgers Research Resource Committee of the Graduate School of Management partially supported the work of Douglas H. Jones and Ing-Long Wu. A Thomas and Betts research fellowship partially supported the work of Ing-Long Wu. The Human Resources Laboratory, United States Air Force, partially supported the work of Ronald Armstrong. The authors benefited from conversations with Dr. Wayne Shore, Operational Technologies, San Antonio, Texas. The order of authors' names is alphabetical and denotes equal authorship.     

Reaction time and temporal serial judgment: corroboration or dissociation?]

Dissociations between a motor response and the subject's verbal report have been reported from various experiments that investigated special experimental effects (e.g., metacontrast or induced motion). To examine whether similar dissociations can also be observed under standard experimental conditions, we compared reaction times (RT) and temporal order judgments (TOJ) to visual and auditory stimuli of three intensity levels. Data were collected from six subjects, each of which served for nine sessions. The results showed a strong, highly significant modality dissociation: While RTs to auditory stimuli were shorter than RTs to visual stimuli, the TOJ data indicated longer processing times for auditory than for visual stimuli. This pattern was found over the whole range of intensities investigated. Light intensity had similar effects on RT and TOJ, while there was a marginally significant tendency of tone intensity to affect RT more strongly than TOJ. It is concluded that modality dissociation is an example of "direct parameter specification", where the pathway from stimulus to response in the simple RT experiment is (at least partially) separate from the pathway that leads to a conscious, reportable representation. Two variants of this notion and alternatives to it are discussed.     

Slow alpha in the EEG power spectrum as an indicator for conceptual arousal]

Based on previous findings (B?sel et al., 1990) it was assumed that in concept learning tasks generating on hypotheses on a concept which has to be developed is accompanied by increases of the Alpha 1 power (7.5-10 Hz) in the spontaneous EEG activity. In this study 16 subjects performed five problem solving tasks with similar processing requirements. EEG data were analyzed by means of post hoc comparisons of subjects differing in performance quality. Additionally, four control tasks were employed in which, based on previous studies, variations in the Theta frequency range were expected. An effect in the Alpha 1 frequency band was observed in tasks requiring reconstructive recall or testing the usefulness of an mathematical algorithm. The creation of a rank order or mental map is accompanied by power increases in the lower portions of the Alpha 1 frequency band (7.5-8.5 Hz). Moreover a high amount of controlled variance (eta2 up to 34%) was obtained for this effect. Increases in EEG Theta power, which presumably indicate subjects' component analysis, were found before the subjects recognized parts of geometric figures or before relevant features in the "buddhist monk problem" were discriminated. The dynamics of EEG power over time is in examples of frequency/time plots in a figure, illustrated.