The limits of visual mass perception

The theory of direct perception suggests that observers can accurately judge the mass of a box picked up by a lifter shown in a point-light display. However, accurate perceptual performance may be limited to specific circumstances. The purpose of the present study was to systematically examine the factors that determine perception of mass, including display type, lifting speed, response type, and lifter's strength. In contrast to previous research, a wider range of viewing manipulations of point-light display conditions was investigated. In Experiment 1, we first created a circumstance where observers could accurately judge lifts of five box masses performed by a lifter of average strength. In Experiments 2–5, we manipulated the spatial and temporal aspects of the lift, the judgement type, and lifter's strength, respectively. Results showed that mass judgement gets worse whenever the context deviates from ideal conditions, such as when only the lifted object was shown, when video play speed was changed, or when lifters of different strength performed the same task. In conclusion, observers' perception of kinetic properties is compromised whenever viewing conditions are not ideal.     

Parts and wholes in person recognition: developmental trends

This study's aim is the investigation of short-term visual person recognition in 8- and 10-year-olds and adults, within the part-whole paradigm introduced by. Natural unfamiliar whole persons were contrasted with natural unfamiliar faces to test for differences between person processing and face processing. Two experiments showed advantages of whole face recognition over isolated face feature recognition. Also, these was a complete over part probe advantage (CPA, ) for person recognition in all age groups. Thus, recognition became more accurate between 8 years and adulthood, but no developmental shift in visual information processing was observable with face and whole person recognition. I conclude that person recognition does not rely on processes completely different from those of face recognition and that this holds for 8- and 10-year-olds as well as for adults.     

Flexibility over automaticity: Separable representations for colours and words

This study demonstrates that associations between colour words and the colours they denote are not mandatory. Experiments 1–3 used a go/no-go task in which participants responded to one print colour and one word and withheld response from another print colour and another word. In Experiment 1, the content of the words denoted noncolour entities. In Experiment 2 the two words denoted two colours that were different from the target print colours. In Experiment 3, the words denoted the same colours as the target print colours but each response set included incompatible print colour and word (e.g., one response to the print colour blue and the word “green” and another response to the print colour green and the word “blue”). Participants performed equally well in all the experiments. Experiment 4a used Arabic digits and words denoting numbers, two formats that are known to have shared representations. Here, participants had difficulties separating their responses to the digits and words. These results suggest that representations of words are distinct from the content that they represent, supporting the existence of distinct verbal and colour modules.     

Mind-reading without the scanner: Behavioural decoding of working memory content

ABSTRACT

Sophisticated machine learning algorithms have been successfully applied to functional neuroimaging data in order to characterize internal cognitive states. But is it possible to “mind-read” without the scanner? Capitalizing on the robust finding that the contents of working memory guide visual attention toward memory-matching objects, we trained a multivariate pattern classifier on behavioural indices of attentional guidance. Working memory representations were successfully decoded from behaviour alone, both within and between individuals. The current study provides a proof-of-concept for applying machine learning techniques to simple behavioural outputs (e.g., response times) in order to decode information about specific internal cognitive states.     

Disentangling boundary extension and normalization of view memory for scenes

Boundary extension (BE) is a memory error for close-up views of scenes in which participants tend to remember a picture of a scene as depicting a more wide-angle view than what was actually displayed. However, some experiments have yielded data that indicate a normalized memory of the views depicted in a set of scenes, suggesting that memory for the previously studied scenes has become drawn toward the average view in the image set. In previous studies, normalization is only found when the retention interval is very long or when the stimuli no longer appear to represent a spatial expanse. In Experiment 1, we examine whether normalization can influence results for scenes depicting a partial view of space and when the memory test occurs immediately following the study block by manipulating the degree of difference between studied close-up and wide-angle scenes. In Experiment 2, normalization is induced in a set of scenes by creating conditions expected to lead to memory interference, suggesting that this may be the cause of view normalization. Based on the multi-source model of BE, these scenes should be extended during perception (Intraub, H. (2010). Rethinking scene perception: A multisource model. Psychology of Learning and Motivation, 52, 231–265). In Experiment 3, we show that BE is indeed observable if the same scenes are tested differently, supporting the notion that BE is primarily a perceptual phenomenon while normalization is a memory effect.     

Amodal processing of visual speech as revealed by priming

This study investigated the linguistic processing of visual speech (video of a talker's utterance without audio) by determining if such has the capacity to prime subsequently presented word and nonword targets. The priming procedure is well suited for the investigation of whether speech perception is amodal since visual speech primes can be used with targets presented in different modalities. To this end, a series of priming experiments were conducted using several tasks. It was found that visually spoken words (for which overt identification was poor) acted as reliable primes for repeated target words in the naming, written and auditory lexical decision tasks. These visual speech primes did not produce associative or reliable form priming. The lack of form priming suggests that the repetition priming effect was constrained by lexical level processes. That priming found in all tasks is consistent with the view that similar processes operate in both visual and auditory speech processing.     

The processing of auditory and visual recognition of self-stimuli

This study examined self-recognition processing in both the auditory and visual modalities by determining how comparable hearing a recording of one’s own voice was to seeing photograph of one’s own face. We also investigated whether the simultaneous presentation of auditory and visual self-stimuli would either facilitate or inhibit self-identification. Ninety-one participants completed reaction-time tasks of self-recognition when presented with their own faces, own voices, and combinations of the two. Reaction time and errors made when responding with both the right and left hand were recorded to determine if there were lateralization effects on these tasks. Our findings showed that visual self-recognition for facial photographs appears to be superior to auditory self-recognition for voice recordings. Furthermore, a combined presentation of one’s own face and voice appeared to inhibit rather than facilitate self-recognition and there was a left-hand advantage for reaction time on the combined-presentation tasks.     

Are visual features of a looming or receding object processed in a capacity-free manner?

Numerous experiments have examined whether moving stimuli capture spatial attention but none have sought to determine whether visual features of looming and receding objects are extracted in a capacity-free manner. The current experiment (N = 28) used the task-choice procedure originated by Besner and Care (2003) to examine this possibility. Stimuli were presented in 3D space by manipulating retinal disparity. Results indicate that features of an object are extracted in a capacity-free manner for both looming and receding objects for participants who consciously perceive motion but not for participants who do not consciously perceive motion. These results suggest that the cognitive system is biased to process potentially animate objects, perhaps because of the evolutionary advantage this cognitive ability may provide.     

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.