Size and orientation cue figure-ground segregation in infants

ABSTRACT

Adult perceivers segregate figure from ground based on image cues such as small size and main axis orientation. The current study examined whether infants can use such cues to perceive figure-ground segregation. Three- to 7-month-olds were familiarized with a pie-shaped stimulus in which some pieces formed a?+?and other pieces formed an x. The infants were then presented with a novelty preference test pairing the?+?and x. The bases for the pieces forming the?+?or x were size and orientation (Experiment 1), size (Experiment 2), and orientation (Experiment 3). In each experiment, infants responded as if they recognized as familiar the shape specified by small size, main axis orientation, or their combination. Control conditions showed that infant performance could not be attributed to spontaneous preference. The findings suggest that infants can achieve figure-ground segregation based on some of the same cues used by adults.     

Attributions for Memory Performance in Adulthood: Age Differences and Mediation Effects

We examined age differences in attributions to internal (controllable and uncontrollable), external (uncontrollable), and unstable factors for performance on a free recall memory task in 149 young, middle-aged, and older adults. Attributions varied by age and by level of memory performance. Middle-aged and older adults rated internal, uncontrollable factors (ability and genes) as more influential for high performance than for low performance, and they were less likely than young adults to attribute low performance to these factors. Within age groups, only the older adults rated memory ability as more influential than strategy use, even though they were as likely as the other age groups to use a categorization strategy. Attributions to both internal controllable (strategy use) and uncontrollable (ability) factors as well as to health were associated with better memory performance. These attributions partially mediated the relationship between age and memory performance. Thus, attributions may provide some insight into sources of age differences in memory performance.     

The Influence of Reduced Visual Acuity on Age-Related Decline in Spatial Working Memory: An Investigation

ABSTRACT

To investigate the relationship between visual acuity and cognitive function with aging, we compared low-vision and normally-sighted young and elderly individuals on a spatial working memory (WM) task. The task required subjects to memorise target locations on different matrices after perceiving them visually or haptically. The haptic modality was included as a control to look at the effect of aging on memory without the confounding effect of visual deficit. Overall, age and visual status did not interact to affect WM accuracy, suggesting that age does not exaggerate the effects of visual deprivation. Young participants performed better than the elderly only when the task required more operational processes (i.e., integration of information). Sighted participants outperformed the visually impaired regardless of testing modality suggesting that the effect of the visual deficit is not confined to only the most peripheral levels of information processing. These findings suggest that vision, being the primary sensory modality, tends to shape the general supramodal mechanisms of memory.     

A non-auditory measure of interference predicts distraction by competing speech in older adults

ABSTRACT

In this study, older adults monitored for pre-assigned target sounds in a target talker's speech in a quiet (no noise) condition and in a condition with competing-talker noise. The question was to which extent the impact of the competing-talker noise on performance could be predicted from individual hearing loss and from a cognitive measure of inhibitory abilities, i.e., a measure of Stroop interference. The results showed that the non-auditory measure of Stroop interference predicted the impact of distraction on performance, over and above the effect of hearing loss. This suggests that individual differences in inhibitory abilities among older adults relate to susceptibility to distracting speech.     

Lay Perceptions of Psychotherapists in South Africa

The study investigated South African layperson perceptions of psychotherapists. Participants were 10 males and 25 females (Whites = 23, Blacks = 10, Coloreds = 2; age range 20 to 59). Semi structured interviews were used to study expectations, attitudes and stereotypical beliefs and behavior towards psychotherapists. Laypersons perceived psychotherapists negatively, and would personally not want any assistance from psychotherapists.     

Carrying the height of the world on your ankles: Encumbering observers reduces estimates of how high an actor can jump

The authors investigated how changes in action capabilities affect estimation of affordances for another actor. Observers estimated maximum jumping-reach height for themselves and another actor. Half of the observers wore ankle weights that reduced their jumping ability. The ankle weights reduced estimates of maximum jumping-reach height that observers made for themselves and for the other actor, but only after observers had the opportunity to walk while wearing the weights. Changes in estimates closely matched changes in actual jumping-reach ability. Results confirm and extend recent investigations that indicate that perception of the spatial layout of surfaces in the environment is scaled to an observer's capacity to act, and they link that approach to another embodied cognition perspective that posits a link between one's own action capabilities and perception of the actions of other agents.     

Location- and object-based inhibition of return are affected by different kinds of working memory

Castel, Pratt, and Craik (2003) have shown that inhibition of return (IOR, the delayed response to a recently cued item) is disrupted by a secondary task that involves spatial working memory (WM), and they suggest that IOR is mediated by spatial WM. However, they did not specify what kind of IOR was involved. We used a dual-task paradigm to examine whether the two kinds of IOR (location- and object-based IOR) are affected by two kinds of secondary task that involve spatial and nonspatial WM, respectively. The results show that location-based IOR was disrupted by a spatial secondary task while the object-based IOR was disrupted by a nonspatial secondary task. The present study further elaborates the conclusion of Castel et al. (2003) by differentiating the effect of the two kinds of WM (spatial vs. nonspatial) on the two kinds of IOR (location based vs. object based).     

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.     

Motor simulation in verbal knowledge acquisition

Recent research highlights the importance of motor processes for a wide range of cognitive functions such as object perception and language comprehension. It is unclear, however, whether the involvement of the motor system goes beyond the processing of information that is gathered through active action experiences and affects also the representation of knowledge acquired through verbal learning. We tested this prediction by varying the presence of motor interference (i.e., squeezing a ball vs. oddball detection task) while participants verbally acquired functional object knowledge and examined the effects on a subsequent object detection task. Results revealed that learning of functional object knowledge was only impaired when participants performed an effector-specific motor task while training. The present finding of an effector-specific motor interference effect on object learning demonstrates the crucial role of the motor system in the acquisition of novel object knowledge and provides support for an embodied account to perception and cognition.