Sensory and cognitive components of visual information acquisition.

Describes a theory of visual information acquisition and visual memory. The theory has 2 major components. First, the visual system's initial sensory response to a short-duration, low-contrast stimulus is generated by a linear, low-pass temporal filter that operates on the stimulus's temporal waveform. Second, information is acquired from a stimulus through an independent-sampling process whose sampling rate at time t following stimulus onset is jointly proportional to (1) the magnitude by which the sensory response exceeds some threshold and (2) the proportion of still unacquired information. The theory was successfully tested in 5 variants of a digit recall task in which temporal waveform of the stimulus was systematically manipulated. In a final experiment, the theory simultaneously accounted for performance in detection and identification tasks. Implications for visual information processing, low-contrast detection, and binocular combination of information are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binocular information acquisition and visual memory.

Mechanisms underlying the binocular combination of visual information were investigated within the context of a visual information acquisition theory proposed by G. R. Loftus et al (e.g., as described by T. A. Busey and G. R. Loftus, 1994). A central assumption of the theory is that of a sensory threshold, which engenders an information loss such that information processing subsequent to the threshold is assumed to occur only when the magnitude of a sensory representation triggered by the stimulus exceeds the threshold. The presumed sensory threshold may be situated prior to or subsequent to the point at which the information from the two eyes combines. The location of this threshold was investigated in 3 experiments that provided conclusions about the location of the sensory thresholds and the mechanisms of binocular combination. It is concluded that a linear summation mechanism, an independent sampling information acquisition model, and both pre- and postcombinatorial sources of information loss are required to account for the data. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Set-size effects for identification versus localization depend on the visual search task.

In both behavior and neuroscience research, it is debated whether the processing of identity and location is closely bound throughout processing. One aspect of this debate is the possibly privileged processing of identity or location. For example, processing identity may have unlimited capacity, while processing location does not. The authors have investigated the possibility of such privileged processing by measuring set-size effects for a variety of identification and localization tasks. In particular, set-size effects in accuracy visual search are measured with either 1 or 2 possible targets. For 1-target tasks, set-size effects are smaller for identification than localization; for 2-target tasks, set-size effects are larger for identification than localization. The observed crossover interaction is inconsistent with a privileged processing hypothesis for either identity or location. Furthermore, this interaction is predicted by an independent channel model based on signal detection theory, in which the details of each decision determine the relative magnitude of the set-size effects. This result is consistent with the similar processing of identity and location, and it refutes the privileged processing hypothesis for either identity or location. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multidimensional models and iconic decay: Reply to di Lollo and Dixon.

Discusses 2 issues raised by V. di Lollo and P. Dixon (see record 1992-33922-001). First, the authors formalize the notion of "informational dimensionality" and demonstrate that G. R. Loftus's extraction-rate model is equivalent to di Lollo and Dixon's "dual-decay model" with respect to dimensionality. Second, the authors describe how the extraction-rate model can be modified to apply it to 2 data sets reported by di Lollo and Dixon. The major modifications involve (1) the assumption of capacity limitations in short-term memory and (2) the assumption of differential information-extraction rates prior to and after probe presentation in a partial-report paradigm. The authors demonstrate that although the model can account qualitatively for di Lollo and Dixon's data, it cannot account for them quantitatively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accounts of blending, distinctiveness, and typicality in the false recognition of faces.

The false recognition of distractor faces created from combinations of studied faces has been attributed to the creation of novel traces in memory, although familiarity accounts are also plausible. In 3 experiments, participants studied parent faces and then were tested with a distractor that was created by morphing 2 parents. These produced high false-alarm rates but no effects of a temporal separation manipulation. In a forced-choice version, participants chose the distractor over the parents. R. M. Nosofsky's (1986) Generalized Context Model and variants could account for some but not all aspects of the data. A new model, SimSample, can account for the effects of typicality and distinctiveness, but not for the morph false alarms unless explicit prototypes are included. The conclusions are consistent with an account of memory in which novel traces are created in memory; alternative explanations are also explored. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the role of individual items in recognition memory and metacognition: Challenges for signal detection theory.

The authors tested the role of individual items in recognition memory using a forced-choice paradigm with face stimuli. They constructed distractor stimuli using morphing procedures that were similar to two parent faces and then compared a studied morph against an unstudied morph that was similar to two studied parents. The similarity of the parent faces was carefully balanced so that the choosing rates for the studied and unstudied morphs were approximately equal. Despite being equally likely to choose the studied and the unstudied morph, participants were systematically more confident when choosing the studied morph. This result is incompatible with Gaussian signal detection theory, even with unequal variances for targets and distractors. The authors propose an extension of an extant sampling model, SimSample, which provides a qualitative and quantitative account of the confidence and recognition dissociation. The results suggest that observers make contact with individual items when making recognition judgments with faces and that the structure of the sampling and decision process naturally leads to this dissociation of confidence and recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects in rats and guinea pigs of short-term exposures to sulfuric acid mist, ozone, and their combination

Ozone and the oxides of sulfur are common environmental pollutants. The acute pulmonary lesions caused by ozone and sulfuric acid mist in rats and guinea pigs have been characterized. Rats are not affected by sulfuric acid mist in concentrations up to 100 mg/m3 except for reduced body weight at the higher doses. A true alveolitis develops in guinea pigs exposed to more than 20 mg/m3 sulfuric acid mist. The ozone lesion is primarily confined to the terminal bronchioles and proximal alveoli. In combination studies with up to 2 ppm ozone and up to 10 mg/m3 sulfuric acid mist, the pulmonary lesion and lung/body weight data were essentially the same as in exposure to ozone alone, and the number of statistically significant synergistic effects in rats and guinea pigs was about what one would expect to observe by chance alone.