Do locally defined feature discontinuities capture attention?

Results from previous visual search studies have suggested that abrupt onsets produce involuntary shifts of attention (i.e., attentional capture), but discontinuities in simple features such as color and brightness do not (Jonides & Yantis, 1988). In the present study we tested whether feature discontinuities (i.e., “singletons”) can produce attentional capture in a visual search task if defined “locally” or over a small spatial range. On each trial, a variable number of letters appeared, one of which differed from the others in color or intensity. The location of this singleton was uncorrelated with target location. Local discontinuities were created by embedding the letters in a dot texture. In Experiment 1, display size effects for singleton targets were not reduced with the addition of a background dot texture. Similar results were obtained in Experiment 2, regardless of variations in texture density. Experiment 3 confirmed that when targets are defined by a color or intensity singleton, they are detected preattentively, and that increasing texture density yields faster detection. We conclude that the spatial range over which feature discontinuities are defined may influence the guidance of spatial attention, but it has no influence on their ability to capture attention.     

Discrimination of auditory temporal patterns

Two same-different discrimination experiments were performed for click patterns having a total duration of about 4 sec and interclick intervals ofn × 250 msec, withn a random integer. In Experiment 1, the influence of the physical click group structure on discrimination performance was investigated. In Experiment 2, the effect of the strength of an induced internal clock on discrimination performance was measured. Performance was poor if the group structure of clicks was maintained during a change in click pattern and also if the induced infernal clack strength was low. The performance of about 70% of the subjects improved significantly if either a change in click grouping structure occurred or a strong internal clock could be induced. These results cannot be accounted for with simple models based an single-interval duration discrimination or between-pattern correlation statistics.     

Intuitive Perceptions of Decision-making Strategy: Naive Assessors' Concepts of Integrative Complexity

Although there are measurable differences in integrative complexity among solutions that individuals generate in dealing with problems, it is uncertain to what extent people comprehend, recognize, and have preferences among different levels of complexity. Integrative complexity is a function of differentiation (the perception of several attributes within, or perspectives about, a topic) and integration (combining the differentiated characteristics in an interactive or synthesizing solution). The current paper reports two experiments dealing with how university students perceive, interpret, and choose among solutions differing in complexity. Experiment 1 showed that subjects accurately rated the complexity of described solutions differing along the continuum, but that their assessment of their own responses differed from the results of expert scoring. Their self-estimated complexity was highly correlated with their preferences, and preferred complexity was reliably higher than either expert- or self-assessed complexity of subject-generated solutions. Subjects were able to hypothesize quite accurately about environmental and endogenous factors likely to affect complexity. Experiment 2 found that in response to problem scenarios, solutions selected as being potentially most effective were consistently more complex than solutions that participants considered themselves most likely to use. The idea of complexity seems to be intuitively recognizable and understandable by untrained subjects: They can and do distinguish among problem solutions (self-generated or presented) that vary on that dimension, and are able to assess accurately the effects of relevant variables. Such subjects also share the bias shown by experts in favour of the superiority of more complex approaches.     

Relevant implication and the case for a weaker logic

We collect together some misgivings about the logic R of relevant inplication, and then give support to a weak entailment logic DJ^d. The misgivings centre on some recent negative results concerning R, the conceptual vacuousness of relevant implication, and the treatment of classical logic. We then rectify this situation by introducing an entailment logic based on meaning containment, rather than meaning connection, which has a better relationship with classical logic. Soundness and completeness results are proved for DJ^d with respect to a content semantics, which embraces the concept of meaning containment.Dedicated to Robert K. Meyer on the occasion of his 60th birthdayThis paper was presented to the Australasian Association for Logic Conference, A.N.U., Canberra, in July, 1992. This Conference commemorated the 60th birthday of Robert K. Meyer, in recognition of the enormous contribution he has made to Logic, especially to Relevant Logic, and of the general lift he has given to the field in his adopted country, Australia. This paper owes its inspiration to Robert Meyer's Farewell to Entailment [37] and his earlier Why I am not a Relevantist [35]. This paper also owes a great deal to Richard Sylvan who has consistently supported weaker relevant logics at a time when stronger relevant logics were in vogue (see especially [47], Chapter 3). In writing this paper, I have also benefited from conversations with Nuel Belnap, Michael Dunn, Kit Fine and Alasdair Urquhart during a period of study leave in 1991. I also thank Robert Meyer, Michael Dunn, Martin Bunder and John Slaney for useful comments on my conference paper. I would also like to thank the referees of this Journal for their helpful comments, which led me to make substantial improvements to this paper.     

Appraisals of Child Behavior by Mothers of Problem and Nonproblem Toddlers

Mothers of problem and nonproblem toddlers rated videotapes of their own and unfamiliar children's behavior. They classified the behaviors as positive, negative, or neutral, and evaluated the intensity of the positive or negative behaviors. Ratings did not differ by problem status; however, all mothers classified their own children's behavior as less negative than did an independent observer. Mothers also evaluated all children's negative behavior as less aversive than did the observer. Finally, mothers mistakenly classified less of their own children's behavior as negative and more as positive when compared to their biases in classifying unfamiliar children's behavior.     

Traditional Ideologies,Nontraditional Lives

This study examined how blue-collar couples whoalternate work shifts and share the care of theirchildren reconcile their traditional gender ideologieswith their nontraditional lives. In-depth interviews were conducted with twenty-three alternatingshift couples in which the husband was a blue-collarworker. Ninety-six per cent of the participants wereWhite, and the remainder were Hispanic. The results suggested that despite their nontraditionalbehavior, these couples maintained traditional genderidentities by adherence to three central beliefs abouttheir families: 1) the father was still the breadwinner; 2) the mother only worked in the paid laborforce because of financial pressures; and 3) the motherwas still the central parent. The ways in which each ofthese myths is constructed, and the functions they serve of both maintaining traditionalgender identity, and of obscuring potential conflictsbetween husbands and wives over identity arediscussed.     

Prevalence of ADHD and comorbid disorders among elementary school children screened for disruptive behavior

In the context of a school-based prevention of conduct disorder program, 7,231 first- through fourth-grade children were screened for cross-setting disruptive behavior. Frequencies of DSM-III-R psychiatric disorders and patterns of comorbidity were assessed. We also examined the association of psychiatric diagnosis with child and parent characteristics to determine differential risk based on diagnostic subgroups. Attention deficit hyperactivity disorder (ADHD) and oppositional-defiant disorder (ODD) were the most frequent diagnoses. Mood and anxiety disorders were infrequent as single diagnoses. Patterns of comorbidity demonstrated that both externalizing and internalizing disorders commonly cooccurred with ADHD. More severe degrees of psychopathology and psychosocial risk accrued to the subgroup of youths with ADHD plus a comorbid externalizing disorder.This study was supported by grant MN-46584 from the National Institute of Mental Health.