Differences in Noun and Verb Processing in Lexical Decision Cannot be Attributed to Word Form and Morphological Complexity Alone

It has been suggested that the effect of word category in noun and verb processing reflects typical word class properties, which can be characterized in terms of semantic as well as syntactic and morphological features. The present study is aimed at differentiating and discussing the relative contribution of these aspects with a main focus on syntactic and morphological processing. Experiment 1 established a processing advantage for nouns in German visual lexical decision, using nouns denoting biological and man-made objects as compared to transitive and intransitive verbs. Experiment 2 showed that the noun advantage persisted even when the morphological differences between word categories were reduced by using identical suffixes in nouns and verbs. Overall results suggest that the processing differences cannot be reduced to variables such as frequency, word form, or morphological complexity. Reaction time differences between transitive and intransitive verbs strengthen the role of syntactic information. In line with previous accounts the observed effects are discussed in terms of a category-specific combination of linguistic parameters.     

Evidence for the activation of sensorimotor information during visual word recognition: the body-object interaction effect

We examined the effects of sensorimotor experience in two visual word recognition tasks. Body-object interaction (BOI) ratings were collected for a large set of words. These ratings assess perceptions of the ease with which a human body can physically interact with a word's referent. A set of high BOI words (e.g., mask) and a set of low BOI words (e.g., ship) were created, matched on imageability and concreteness. Facilitatory BOI effects were observed in lexical decision and phonological lexical decision tasks: responses were faster for high BOI words than for low BOI words. We discuss how our findings may be accounted for by (a) semantic feedback within the visual word recognition system, and (b) an embodied view of cognition (e.g., Barsalou's perceptual symbol systems theory), which proposes that semantic knowledge is grounded in sensorimotor interactions with the environment.     

An information-based approach to action understanding

It has been proposed that the ability to make sense of other agents' behavior relies on the activation of internal mechanisms that map action perception onto action execution. In this study we explored the constraints on this ability introduced by eyeheight-scaled information in the optic array. Short and tall participants provided maximum overhead reaching judgments for themselves and another participant. Perceptual information was manipulated by changing the participants' optically specified eyeheight. Observers were modestly accurate in perceiving maximum overhead reach for themselves and for another actor whose action capabilities differed. Perceived maximum overhead reach increased for both self- and other-judgments when the perceiver's eyeheight was increased. The results suggest an important role of perceptual information that has gone unrecognized in existing accounts of action understanding and prediction.     

Visual working memory capacity for objects from different categories: a face-specific maintenance effect

The capacity of visual working memory was examined when complex objects from different categories were remembered. Previous studies have not examined how visual similarity affects object memory, though it has long been known that similar-sounding phonological information interferes with rehearsal in auditory working memory. Here, experiments required memory for two or four objects. Memory capacity was compared between remembering four objects from a single object category to remembering four objects from two different categories. Two-category sets led to increased memory capacity only when upright faces were included. Capacity for face-only sets never exceeded their nonface counterparts, and the advantage for two-category sets when faces were one of the categories disappeared when inverted faces were used. These results suggest that two-category sets which include faces are advantaged in working memory but that faces alone do not lead to a memory capacity advantage.     

The co-occurrence of multisensory competition and facilitation

Previous studies of multisensory integration have often stressed the beneficial effects that may arise when information concerning an event arrives via different sensory modalities at the same time, as, for example, exemplified by research on the redundant target effect (RTE). By contrast, studies of the Colavita visual dominance effect (e.g., [Colavita, F. B. (1974). Human sensory dominance. Perception & Psychophysics, 16, 409–412]) highlight the inhibitory consequences of the competition between signals presented simultaneously in different sensory modalities instead. Although both the RTE and the Colavita effect are thought to occur at early sensory levels and the stimulus conditions under which they are typically observed are very similar, the interplay between these two opposing behavioural phenomena (facilitation vs. competition) has yet to be addressed empirically. We hypothesized that the dissociation may reflect two of the fundamentally different ways in which humans can perceive concurrent auditory and visual stimuli. In Experiment 1, we demonstrated both multisensory facilitation (RTE) and the Colavita visual dominance effect using exactly the same audiovisual displays, by simply changing the task from a speeded detection task to a speeded modality discrimination task. Meanwhile, in Experiment 2, the participants exhibited multisensory facilitation when responding to visual targets and multisensory inhibition when responding to auditory targets while keeping the task constant. These results therefore indicate that both multisensory facilitation and inhibition can be demonstrated in reaction to the same bimodal event.     

Frames of reference for the light-from-above prior in visual search and shape judgements

Faced with highly complex and ambiguous visual input, human observers must rely on prior knowledge and assumptions to efficiently determine the structure of their surroundings. One of these assumptions is the 'light-from-above' prior. In the absence of explicit light-source information, the visual system assumes that the light-source is roughly overhead. A simple, low-cost strategy would place this 'light-from-above' prior in a retinal frame of reference. A more complex, but optimal strategy would be to assume that the light-source is gravitationally up, and compensate for observer orientation. Evidence to support one or other strategy from psychophysics and neurophysiology has been mixed. This paper pits the gravitational and retinal frames against each other in two different visual tasks that relate to the light-from-above prior. In the first task, observers had to report the presence or absence of a target where distractors and target were defined purely by shading. In the second task, observers made explicit shape judgements of similar stimuli. The orientation of the stimuli varied across trials and the observer's head was fixed at 0, +/-45 or +/-60 degrees . In both tasks the retinal frame of reference dominated. Visual search behaviour with shape-from-shading stimuli (SFS) was modulated purely by stimulus orientation relative to the retina. However, the gravitational frame of reference had a significant effect on shape judgements, with a 30% correction for observer orientation. In other words, shading information is processed quite differently depending on the demands of the current task. When a 'quick and dirty' representation is required to drive fast, efficient search, that is what the visual system provides. In contrast, when the task is to explicitly estimate shape, extra processing to compensate for head orientation precedes the perceptual judgment. These results are consistent with current neurophysiological data on SFS if we re-frame compensation for observer orientation as a cue-combination problem.     

Attending to threat: Race-based patterns of selective attention

The present research investigated the extent to which the stereotype that young Black men are threatening and dangerous has become so robust and ingrained in the collective American unconscious that Black men now capture attention, much like evolved threats such as spiders and snakes. Specifically, using a dot-probe detection paradigm, White participants revealed biased attention toward Black faces relative to White faces (Study 1). Because the faces were presented only briefly (30-ms), the bias is thought to reflect the early engagement of attention. The attentional bias was eliminated, however, when the faces displayed averted eye-gaze (Study 2). That is, when the threat communicated by the Black faces was attenuated by a relevant, competing socio-emotional cue—in this case, averted eye-gaze—they no longer captured perceivers’ attention. Broader implications for social cognition, as well as public policies that reify these prevailing perceptions of young Black men are discussed.     

Development and Validation of the Clutter Image Rating

Few instruments are available to assess compulsive hoarding and severity of clutter. Accuracy of assessment is important to understanding the clinical significance of the problem. To overcome problems associated with over- and under-reporting of hoarding symptoms, the clutter image rating (CIR) was developed. This pictorial scale contains nine equidistant photographs of severity of clutter representing each of three main rooms of most people’s homes: living room, kitchen, and bedroom. The psychometric properties of this measure were examined in two studies. Internal consistency, test–retest, and interobserver reliabilities were good and convergent validity with other questionnaire and interview measures was also good. The CIR correlated more strongly with measures of clutter than with other hoarding and psychopathology scales. The CIR’s very brief pictorial assessment method makes it useful in clinical and treatment contexts for measuring the clutter dimension of compulsive hoarding. The Clutter Image Rating (CIR) is available in conjunction with the following publication: Steketee, G., & Frost, R.O. (2007). Treatment of compulsive hoarding. New York: Oxford University Press at .     

Visual categorization of natural stimuli by domestic dogs

One of the fundamental issues in the study of animal cognition concerns categorization. Although domestic dogs (Canis familiaris) are on the brink to become one of the model animals in animal psychology, their categorization abilities are unknown. This is probably largely due to the absence of an adequate method for testing dogs’ ability to discriminate between large sets of pictures in the absence of human cueing. Here we present a computer-automated touch-screen testing procedure, which enabled us to test visual discrimination in dogs while social cueing was ruled out. Using a simultaneous discrimination procedure, we first trained dogs (N = 4) to differentiate between a set of dog pictures (N = 40) and an equally large set of landscape pictures. All subjects learned to discriminate between the two sets and showed successful transfer to novel pictures. Interestingly, presentation of pictures providing contradictive information (novel dog pictures mounted on familiar landscape pictures) did not disrupt performance, which suggests that the dogs made use of a category-based response rule with classification being coupled to category-relevant features (of the dog) rather than to item-specific features (of the background). We conclude that dogs are able to classify photographs of natural stimuli by means of a perceptual response rule using a newly established touch-screen procedure. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Female degus (Octodon degus) monitor their environment while foraging socially

Vigilance or scanning involves interruptions in foraging behavior when individuals lift their heads and conduct visual monitoring of the environment. Theoretical considerations assume that foraging with the "head down", and scanning ("head up") are mutually exclusive activities, such that foraging precludes vigilance. We tested this generalization in a socially foraging, small mammal model, the diurnal Chilean degu (Octodon degus). We studied spontaneous bouts of scanning of captive degus when foraging in pairs of female sibs and non-sibs. We examined the extent to which foraging (head down postures) and scanning (head up postures) were mutually exclusive in subjects exposed to none, partial, and complete lateral visual obstruction of their partners. In addition, we monitored the orientation of their bodies to examine the target of attention while foraging and scanning. Lastly, we examined the temporal occurrence of scanning events to assess the extent of scanning coordination, and whether this coordination is kin-biased. Visual obstruction had a significant influence on degu vigilance. Focal degus increased their quadrupedal and semi-erect scanning when foraging under a partially obstructed view of their partners. Degus oriented their bodies toward partners when foraging and scanning. Despite this, degus did not coordinate scanning bouts; instead, they scanned independently from one another. Relatedness among cage mates did not influence any aspect of degu behavior. Contrary to theoretical expectations, these results indicate that foraging and vigilance are not mutually exclusive, and that kinship per se does not influence scanning behavior and coordination.