Categorical perception of familiar objects

We report three experiments where the categorical perception of familiar, three-dimensional objects was investigated. A continuum of shape change between 15 pairs of objects was created and the images along the continuum were used as stimuli. In Experiment 1 participants were first required to discriminate pairs of images of objects that lay along the shape continuum. Then participants were asked to classify each morph-image into one of two pre-specified classes. We found evidence for categorical perception in some but not all of our object pairs. In Experiment 2 we varied the viewpoint of the objects in the discrimination task and found that effects of categorical perception generalized across changes in view. In Experiment 3 similarity ratings for each object pair were collected. These similarity scores correlated with the degree of perceptual categorization found for the object pairs. Our findings suggest that some familiar objects are perceived categorically and that categorical perception is closely tied to inter-object perceptual similarity.     

Five-year-olds' handling of reference and description in the domains of language and mental representation

Children's concurrent success on false belief tasks and their handling of two labels for one object (e.g., bunny/rabbit) has been interpreted as demonstrating understanding about the essential features of representation. Three experiments reveal the limitations in 5-year-olds' understanding for both mental and linguistic representations. We report relatively poor performance on a task involving two labels for one object (e.g., dice/eraser) which required children to treat another's knowledge as representing only some of the feature of its real referent: Dice but not eraser. Five year olds who made errors also had difficulty handling the fact that a written word 'dice' referring to such a dice/eraser, can also be applied to a standard dice but not to a standard eraser. These children lacked metalinguistic awareness of words as entities that both refer and describe.     

The epistemic benefits of trait-consistent mood states: an analysis of extraversion and mood

One must consider both trait and state affect to predict individual differences in emotional processing. The present results document a novel trait-state interaction that is consistent with proposals concerning the epistemic functions of affect (A. R. Damasio, 1994). Four studies tested the effects of extraversion and mood on motivation-relevant processing. Study 1 measured naturally occurring mood, whereas Studies 2-4 manipulated mood. Extraverts were faster to link events to their personal motivations when in a positive mood state, whereas introverts were faster to do so in a neutral or negative mood state. Further findings indicate that this interaction affects attitude accessibility rather than event elaboration. Overall, the authors suggest that there are pragmatic benefits to trait-consistent moods, particularly for processing motivation-relevant stimuli.     

The subjects as a simple random effect fallacy: subject variability and morphological family effects in the mental lexicon

This is a methodological study addressing the appropriateness of standard by-subject and by-item averaging procedures for the analysis of repeated-measures designs. By means of a reanalysis of published data (Schreuder & Baayen, 1997), using random regression models, we present a proof of existence of systematic variability between participants that is ignored in the standard psycholinguistic analytical procedures. By applying linear mixed effects modeling (Pinheiro & Bates, 2000), we call attention to the potential lack of power of the by-subject and by-item analyses, which in this case study fail to reveal the coexistence of a facilitatory family size effect and an inhibitory family frequency effect in visual and auditory lexical processing.     

A rule-based categorization deficit in Alzheimer's disease?

This study examined the categorization processes that Alzheimer's disease (AD) patients use during assessments of semantic memory. Rule-based categorization involves the careful, analytic processing of strict criteria to determine category membership, particularly for items from graded categories with ambiguous category membership; similarity-based categorization requires an overall comparison of a test stimulus with a prototype or remembered exemplar of the category and is relatively effective for the rapid categorization of items with unambiguous category membership. To assess these processes in AD, patients were asked to decide the category membership of test stimuli for categories with poorly defined or fuzzy boundaries (e.g., VEGETABLE) and for categories with well-defined boundaries (e.g., FEMALE) and then to judge the representativeness of the test stimulus for its chosen category. A subgroup of AD patients demonstrated a typical pattern of impaired semantic memory compared to healthy control subjects; that is, difficulty deciding the category membership of test items from fuzzy categories. Among these patients, we found no deficit in category membership decisions about items taken from well-defined categories. We also found that AD patients and healthy controls do not differ in their representativeness judgments of items within a correctly judged category. These findings are most consistent with the hypothesis that rule-based categorization difficulty limits semantic memory in AD.     

Sigmund Koch--philosophically speaking

Sigmund Koch's legacy is not merely a record of robust criticism aimed at (now mostly failed) dominant perspectives in psychology. Rather, his prescient and tutored thought captured particular habits of mind and institutionalized modes of inquiry likely to retard progress in psychology indefinitely. In important respects, it is Koch's critical assessments of his own earlier commitments and enthusiasms that exemplify his project for any "scientific" psychology worth having. It is in these self-criticisms that Koch discloses both the source and the costs of trimming and reducing reality merely to prosecute research of the approved type. Furthermore, it is in these self-criticisms that Koch exemplifies the integrity and disinterested judiciousness so characteristic of science at its best.     

Differentiation of fluid, visual, and simultaneous cognitive tasks

The constructs of fluid reasoning and spatial visualization (Horn, 1989) as well as the construct of simultaneous processing (Luria, 1966) have been tapped by various cognitive assessment batteries. In order to determine whether these constructs could be differentiated from one another, factor analyses of subtest scores from six cognitive tasks were conducted. Fluid reasoning, spatial visualization, and simultaneous processing emerged as separate factors in the analysis, supporting the hypothesis that these constructs can be differentiated in psychoeducational testing. These results extend the findings of a preliminary study which found factorial differentiation between fluid and simultaneous reasoning.     

Academic, motivational, and emotional correlates of adolescent dating

This study is an examination of the relationship between dating status and academic achievement, academic motivation, depression, and self-esteem; it is an investigation of the differential effects wielded by gender and age (grade level) of the dating adolescent in each of these domains. Participants were a relatively large gender-balanced adolescent group (N = 380) from Grades 8, 10, and 12. Dating status was studied first as a binary variable (frequent versus infrequent dating) and second as a dating spectrum, including steady, frequent, and infrequent dating. Results showed that adolescents who dated frequently (more than once or twice a month), whether they were boys or girls, relatively young (8th grade) or more mature (l0th and 12th grades), exhibited consistently and significantly lower levels of academic achievement and academic motivation and higher levels of depressive symptoms. There were no significant effects of dating status on global self-esteem, but, as hypothesized, subscale analyses revealed important subscale-differentiated effects.