Hierarchical classes: Model and data analysis

A discrete, categorical model and a corresponding data-analysis method are presented for two-way two-mode (objects × attributes) data arrays with 0, 1 entries. The model contains the following two basic components: a set-theoretical formulation of the relations among objects and attributes; a Boolean decomposition of the matrix. The set-theoretical formulation defines a subset of the possible decompositions as consistent with it. A general method for graphically representing the set-theoretical decomposition is described. The data-analysis algorithm, dubbed HICLAS, aims at recovering the underlying structure in a data matrix by minimizing the discrepancies between the data and the recovered structure. HICLAS is evaluated with a simulation study and two empirical applications.This research was supported in part by a grant from the Belgian NSF (NFWO) to Paul De Boeck and in part by NSF Grant BNS-83-01027 to Seymour Rosenberg. We thank Iven Van Mechelen for clarifying several aspects of the Boolean algebraic formulation of the model and Phipps Arabie for his comments on an earlier draft.     

Interactions between area and numerosity

Summary The concept of filled area, i.e. the impressionistic ensemble of parts of a stimulus field occupied by dots, is used to account for various kinds of numerosity illusions due to perceptual interaction between a number of dots and their spatial arrangement. A measure of filled area is derived from a model for the perceptual clustering of dots on the basis of relative proximity. It is shown that the quantified concept of filled area successfully predicts illusion data from earlier studies. Subsequently, a two-alternatives forced-choice numerosity experiment is reported, the data of which gave further evidence of the predictive power of the filled-area hypothesis. Our approach is discussed with respect to spatial features of dot stimuli that might be in rivalry with the filled-area factor in numerosity-estimation tasks.     

Above suspicion: Cognitive and intentional aspects of the ability to lie

This paper looks at the attribution of the ability to lie and not at lying or lies. It also departs from more familiar approaches by focussing on the appraisal of an ability and not on the ability in itself. We believe that this attribution perspective is required to bring out the cognitive and intentional basis of the ability to lie.     

Local and global contextual constraints on the identification of objects in scenes.

Objects likely to appear in a given real-world scene are frequently found to be easier to recognize. Two different sources of contextual information have been proposed as the basis for this effect: global scene background and individual companion objects. The present paper examines the relative importance of these two elements in explaining the context-sensitivity of object identification in full scenes. Specific sequences of object fixations were elicited during free scene exploration, while fixation times on designated target objects were recorded as a measure of ease of target identification. Episodic consistency between the target, the global scene background, and the object fixated just prior to the target (the prime), were manipulated orthogonally. Target fixation times were examined for effects of prime and background. Analyses show effects of both factors, which are modulated by the chronology and spatial extent of scene exploration. The results are discussed in terms of their implications for a model of visual object recognition in the context of real-world scenes.     

Diurnal variation,morningness-eveningness,and momentary affect

The research questions of this study are the following: To what degree can results such as those of Thayer and colleagues (1978a, 1985, 1986, 1988) concerning diurnal variation and differences between diurnal types, obtained for energetic and tense arousal, be (1) replicated, (2) extended to elation and pleasantness, and (3) generalized to positive and negative affect? With regard to energetic arousal, all results were in line with those of Thayer and colleagues. However, regarding tense arousal, there was an unexpected main effect for time of day. For energetic arousal, elation, pleasantness, positive affect, and negative affect, there was (a) a significant main eflect for time of day, (b) a quadratic trend for diurnal variation, and (c) a significant Diurnal Type × Time of Day interaction, There were no significant sex differences in diurnal variation. Two final hypothetical statements are made about the diurnal variation and differences between diurnal types with regard to state scales: (a) the diurnal variation of a state scale cannot be described with a quadratic function if that scale is completely unrelated to energetic arousal; and (b) the characteristic differences between morning types and evening types, especially when measured in the morning and in the evening, will not manifest themselves on a state scale if that scale is entirely unrelated to energetic arousal. Finally, the possible usefulness of the results of this study for practical applications and the development of theories are discussed.