The task-specific nature of domain-general reasoning

This paper develops a theory of how interpretative processes constrain inferential performance on conditional reasoning tasks. Experiment 1 investigated the hypothesis that performance on common reasoning tasks is mediated by different interpretive variables. Necessity and sufficiency relations predicted performance on the conditional arguments task, whereas on the Wason task, performance was predicted by whether the conditional statement instantiated a deontic or a factual relation. Performance on the truth-table task was predicted by both sets of variables. Experiment 2 explored the mapping relation between interpretation, representation, and inference. It was observed that conditional responses to the Wason and arguments tasks were based on different representations of the conditional relationship. These data rule out a simple model of the interplay between interpretation and reasoning in which the interpretation of a statement is driven solely by its content, and instead, indicate that the interpretation of conditional relations is task-specific.     

An interval size illusion: the influence of timbre on the perceived size of melodic intervals

In four experiments, we investigated the influence of timbre on perceived interval size. In Experiment 1, musically untrained participants heard two successive tones and rated the pitch distance between them. Tones were separated by six or seven semitones and varied in timbre. Pitch changes were accompanied by a congruent timbre change (e.g., ascending interval involving a shift from a dull to a bright timbre), an incongruent timbre change (e.g., ascending interval involving a shift from a bright to a dull timbre), or no timbre change. Ratings of interval size were strongly influenced by timbre. The six-semitone interval with a congruent timbre change was perceived to be larger than the seven-semitone interval with an incongruent timbre change (interval illusion). Experiment 2 revealed similar effects for musically trained participants. In Experiment 3, participants compared the size of two intervals presented one after the other. Effects of timbre were again observed, including evidence of an interval illusion. Experiment 4 confirmed that timbre manipulations did not distort the perceived pitch of tones. Changes in timbre can expand or contract the perceived size of intervals without distorting individual pitches. We discuss processes underlying interval size perception and their relation to pitch perception mechanisms.     

The influence of restricted viewing conditions on egocentric distance perception: implications for real and virtual indoor environments

We carried out three experiments to examine the influence of field of view and binocular viewing restrictions on absolute distance perception in real-world indoor environments. Few of the classical visual cues provide direct information for accurate absolute distance judgments to points in the environment beyond about 2 m from the viewer. Nevertheless, in previous work it has been found that visually directed walking tasks reveal accurate distance estimations in full-cue real-world environments to distances up to 20 m. In contrast, the same tasks in virtual environments produced with head-mounted displays (HMDs) show large compression of distance. Field of view and binocular viewing are common limitations in research with HMDs, and have been rarely studied under full pictorial-cue conditions in the context of distance perception in the real-world. Experiment 1 showed that the view of one's body and feet on the floor was not necessary for accurate distance perception. In experiment 2 we manipulated the horizontal and the vertical field of view along with head rotation and found that a restricted field of view did not affect the accuracy of distance estimations when head movement was allowed. Experiment 3 showed that performance with monocular viewing was equal to that with binocular viewing. These results have implications for the information needed to scale egocentric distance in the real-world and reduce the support for the hypothesis that a limited field of view or imperfections in binocular image presentation are the cause of the underestimation seen with HMDs.     

"Tip of the fingers" experiences by deaf signers: insights into the organization of a sign-based lexicon

The "tip of the fingers" phenomenon (TOF) for sign language parallels the "tip of the tongue" phenomenon (TOT) for spoken language. During a TOF, signers are sure they know a sign but cannot retrieve it. Although some theories collapse semantics and phonology in sign language and thus predict that TOFs should not occur, TOFs were elicited in the current study. Like TOTs, TOFs often resolve spontaneously, commonly involve targets that are proper names, and frequently include partial access to phonology. Specifically, signers were more likely to retrieve a target sign's handshape, location, and orientation than to retrieve its movement. Signers also frequently recalled the first letter of a finger-spelled word. The existence of TOFs supports two-stage retrieval and a division between semantics and phonology in American Sign Language. The partial phonological information available during TOFs suggests that phonological features are accessed more simultaneously during lexical access for signed language than during lexical access for spoken language.     

Assessment of the Use and Feasibility of Video to Supplement the Genetic Counseling Process: A Cancer Genetic Counseling Perspective

Cancer genetic counselors use a variety of teaching modalities for patient education. This survey of cancer genetic counselors assessed their use of educational videos and their recommendations for content of future videos. Thirty percent of respondents use videos for patient education. Cited benefits included reinforcement of information for clients and increased counselor efficiency. Of the 70% who do not use videos, predominant barriers included the perceived lack of an appropriate video, lack of space and/or equipment, and concern that videos are impersonal. Most respondents desired a video that is representative of the genetic counseling session, but emphasized the importance of using broad information. Content considered critical included the pros and cons of genetic testing, associated psychosocial implications, and genetic discrimination. The results of this exploratory study provide data relevant for the development of a cancer genetics video for patient education, and suggestions are made based on aspects of information processing and communication theories.     

Basic processes in reading: Is visual word recognition obligatory?

Visual word recognition is commonly argued to be automatic in the sense that it is obligatory and ballistic. The present experiments combined Stroop and visual search paradigms to provide a novel test of this claim. An array of three, five, or seven words including one colored target (a word in Experiments 1 and 2, a bar in Experiment 3) was presented to participants. An irrelevant color word also appeared in the display and was either integrated with or separated from the colored target. The participants classified the color of the single colored item in Experiments 1 and 3 and determined whether a target color was present or absent in Experiment 2. A Stroop effect was observed in Experiment 1 when the color word and the color target were integral, but not when the color word and the color target were separated. No Stroop effect was observed in Experiment 2. Visual word recognition is contingent on both the distribution of spatial attention and task demands.     

Stimulus-response compatible orienting and the effect of an action not taken: Perception delayed is automaticity denied

Orienting to a signal source is widely viewed asautomatic in the sense that it is triggered by the stimulus. However, this behavior is typically assessed in a context in which the subject knows beforehand what he or she has to do. In the present experiments, the role of task set was investigated by having the response vary randomly from trial to trial. On some trials, a cue signaled the subject to respond, and on the remaining trials, another cue signaled the subject to withhold a response. Stimulus contrast and temporal overlap between task cue and target were manipulated. The effect of a reduction in stimulus contrast was sometimes absorbed into the time taken to decode the cue, but critically, other times not. These results highlight the theoretical importance of considering task set as an essential element in processing, and they undermine the theoretical claim that putatively automatic processes are not subject to interference from other mental activities.     

Effects of 3-D complexity on the perception of 2-D depictions of objects

In a recent study, Pelli (1999 Science 285 844-846) performed a set of perceptual experiments using portrait paintings by Chuck Close. Close's work is similar to the 'Lincoln' portraits of Harmon and Julesz (1973 Science 180 1194-1197) in that they are composite images consisting of coarsely sampled, individually painted, mostly homogeneous cells. Pelli showed that perceived shape was dependent on size, refuting findings that perception of this type is scale-invariant. In an attempt to broaden this finding we designed a series of experiments to investigate the interaction of 2-D scale and 3-D structure on our perception of 3-D shape. We present a series of experiments where field of view, 3-D object complexity, 2-D image resolution, viewing orientation, and subject matter of the stimulus are manipulated. On each trial, observers indicated if the depicted objects appeared to be 2-D or 3-D. Results for face stimuli are similar to Pelli's, while more geometrically complex stimuli show a further interaction of the 3-D information with distance and image information. Complex objects need more image information to be seen as 3-D when close; however, as they are moved further away from the observer, there is a bias for seeing them as 3-D objects rather than 2-D images. Finally, image orientation, relative to the observer, shows little effect, suggesting the participation of higher-level processes in the determination of the 'solidness' of the depicted object. Thus, we show that the critical image resolution depends systematically on the geometric complexity of the object depicted.     

Verb deficits in Alzheimer's disease and agrammatism: implications for lexical organization

This study examined the nature of verb deficits in 14 individuals with probable Alzheimer's Disease (PrAD) and nine with agrammatic aphasia. Production was tested, controlling both semantic and syntactic features of verbs, using noun and verb naming, sentence completion, and narrative tasks. Noun and verb comprehension and a grammaticality judgment task also were administered. Results showed that while both PrAD and agrammatic subjects showed impaired verb naming, the syntactic features of verbs (i.e., argument structure) influenced agrammatic, but not Alzheimer's disease patients' verb production ability. That is, agrammatic patients showed progressively greater difficulty with verbs associated with more arguments, as has been shown in previous studies (e.g., Kim & Thompson, 2000; Thompson, 2003; Thompson, Lange, Schneider, & Shapiro, 1997), and suggest a syntactic basis for verb production deficits in agrammatism. Conversely, the semantic complexity of verbs affected PrAD, but not agrammatic, patients' performance, suggesting "bottom-up" breakdown in their verb lexicon, paralleling that of nouns, resulting from the degradation or loss of semantic features of verbs.