Infants' reactions to perceptual paradox during mother–infant interaction.

36 3-mo-old infants interacted with their mothers under conditions in which they could see and hear their mothers (correlated auditory plus visual information: A?+?V), see but not hear their mothers (V), and hear but not see their mothers (A); the latter 2 conditions are termed perceptual paradox. The interactions were videotaped, and the Ss' behavior was judged by naive observers who used a subjective 7-point rating scale of infant affect. For 2 groups of Ss, 3 1-min presentations of the A?+?V condition were alternated with 3 1-min presentations of either A (Group 1) or V (Group 2) conditions. In both groups, Ss were judged as being more distressed during unimodal presentations than during bimodal presentations. In a 3rd group, unimodal (A) presentations were alternated with unimodal (V) presentations. Ss in this group were significantly more distressed when they could hear but not see their mothers than when they could see but not hear their mothers. Results demonstrate the suitability of global subjective ratings of affective state in studies of infant perception. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A principal components analysis of the Rathus Assertiveness Schedule.

Performed a principal components analysis of the Rathus Assertiveness Schedule (RAS) to investigate the adequacy of this inventory as a global measure of assertiveness. The analysis (using 956 undergraduate Ss) indicated that the RAS does not provide a unidimensional index of assertiveness, but rather measures a number of factors including situation-specific assertive behavior, aggressiveness, and a more general assertiveness. The results are discussed in relation to the small number of items comprising the schedule and the rather limited repertoire of different behavioral situations sampled in the items. These problems make it difficult to adequately define the individual factors revealed by the principal components analysis. (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The roles of static depth information and object-image relative motion in perception of heading.

In a series of 6 experiments, two hypotheses were tested: that nominal heading perception is determined by the relative motion of images of objects positioned at different depths (R. F. Wang and J. E. Cutting, 1999) and that static depth information contributes to this determination. By manipulating static depth information while holding retinal-image motion constant during simulated self-movement, the authors found that static depth information played a role in determining perceived heading. Some support was also found for the involvement of R. F. Wang and J. E. Cutting's (1999) categories of object-image relative motion in determining perceived heading. However, results suggested an unexpected functional dominance of information about heading relative to apparently near objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the spatial distribution of visual attention.

A reanalysis of part of P. Podgorny and R. N. Shepard's (see record 1984-03057-001) data shows that reaction times (RTs) to attended and unattended squares are almost identical when the attended areas are nonunitary and that RTs are related to compactness for unitary attended areas but that this relation breaks down when attention is focused on nonunitary areas. The importance of the actual grid location of probes on RTs is also illustrated. The failure of compactness to reflect these aspects of the spatial nature of attention suggests that this metric is deficient when applied to the study of the spatial determinants of attention. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Directions of motion after-effects induced by gratings and plaids

In three experiments the direction of motion after-effect (MAE) is measured following adaptation to two gratings moving in different directions presented in alternation (component-induced MAEs: CMAEs), and to moving plaid patterns composed of superimposed pairs of these gratings (plaid-induced MAEs; PMAEs). These MAEs are compared to: (i) the vector sum direction of the component gratings; (ii) the IOC-predicted direction of the plaids; and (iii) the perceived direction of the plaids as reported by observers. Contrary to previous findings (Burke D, Wenderoth P. Vis Res 1993;33:351-9), directions of PMAEs are shown to approximate the vector sum direction of the components, whereas directions of CMAEs are shown to approximate the mean (unweighted) direction of the components. This difference is attributed to the activity, and adaptation, of an additional population of neurones whose stimulus), or a counterphase moving plaid (a combined Fourier and non-Fourier stimulus), rules out the possibility that the discrepancy between PMAE direction and actual plaid direction is due to the use of test stimuli that do not adequately reflect adaptation by the Fourier and non-Fourier components of the adapting plaids (HR, Ferrera VP, Yo C. Vis Neurosci 1992;9:79-97). Various explanations of this paradoxical result are discussed, including: (i) that MAEs produced by Fourier components out-weigh (and possibly even mask) MAEs produced by non-Fourier plaid components; (ii) PMAEs are influenced by adaptation of a population of component-selective neurones that do not contribute to plaid perception; and, (iii) PMAEs are influenced by component-specific adaptation effects that are weighted according to relative component sensitivity, rather than relative component speed (Pantle A. Vis Res 14;1974:1229-36). We review psychophysical and neurophysiological evidence consistent with these explanations.