Priming of depth-rotated objects depends on attention and part changes

Three priming experiments investigated the role of attention and view changes when common objects were rotated in depth. Objects were shown in prime-probe trial pairs. Experiment 1 extended findings by Stankiewicz, Hummel, and Cooper (1998) showing that attended objects primed themselves in the same but not in a reflected view, whereas ignored objects only primed themselves in the same view. In Experiment 2, depth-rotations produced changes in the visible part structure between prime and probe view of an object. Priming after depth-rotation was more reduced for attended objects than for ignored objects. Experiment 3 showed that other depth rotations that did not change the perceived part structure revealed a priming pattern similar to that in Experiment 1, with equivalent reduction in priming for attended and ignored objects. These data indicate that recognition of attended objects is mediated by a part-based (analytic) representation together with a view-based (holistic) representation, whereas ignored images are recognized in a strictly view-dependent fashion.     

Category effects on the processing of plane-rotated objects

We examined the effects of plane rotations on the identification of exemplars of three semantic categories. In the first two experiments line drawings belonging to three categories (animals, inanimate objects, and vegetables) were presented at four orientations (0 degree, 60 degrees, 120 degrees, and 180 degrees of clockwise rotation). The response time was found to depend on stimulus category. In particular, whereas rotation effects were shown for animals, no effect at all was found for vegetables and only partial effects were found for inanimate objects. The unclear pattern found for inanimate objects was further examined in experiment 3 where the orientation effects on the identification of two subsets of the inanimate category were studied. The hypothesis of view-observation frequency was confirmed. In experiment 4, line drawings of objects at different orientations were presented in physically degraded versions. The minimum amount of visual information necessary to identify rotated stimuli was found to vary as a function of stimulus category as well. Results are discussed, combining current research on both viewpoint-dependence/independence and neural systems involved in category processing.     

Recognition thresholds for plane-rotated pictures of familiar objects

We investigated picture plane rotation effects on the minimum stimulus duration required to recognise pictures of familiar objects in a picture-word verification task. Participants made unspeeded responses, selecting from 126 written alternatives. Longer stimulus durations were needed to identify plane-misoriented views. These orientation effects were non-linear, arguing against a simple mental rotation account of compensation for plane misorientation in identification tasks. Orientation effects were found for almost all items, in particular including those labelled at the basic level (cf. Hamm, McMullen, 1998, Journal of Experimental Psychology: Human Perception and Performance 24, 413-426). We suggest that plane misorientation increases the difficulty of basic level as well as subordinate level identification unless only a small, visually dissimilar set of stimuli are presented. Errors in the task were analysed to provide an alternative, objective measure of perceived visual similarity, by assessing the number and nature of mistaken identifications made to a given target object. We propose that misorientation effects are best understood in terms of the effects of the perceived visual similarity of a target to its set of response alternatives rather than in terms of the level (basic or subordinate) at which the target is to be identified.     

Pigeons discriminate objects on the basis of abstract familiarity

Knowledge of previous encounters with conspecifics is thought to be beneficial as it allows fast and appropriate behavioral responses toward those animals. This level of categorization goes beyond perceptual similarity and requires the individual to refer to a more abstract common referent, namely familiarity. It has been shown that pigeons are able to form functional classes of conspecifics that are based on familiarity. To date, we do not know whether this ability is restricted to the social context (including heterospecifics) or if it can also be used to classify inanimate objects. Furthermore, the factors influencing the formation of this functional class are still unknown. Here, we show that pigeons (Columba livia) are able to use a categorical rule of familiarity to classify previously unseen photographs of objects from their living environment. Pigeons that lacked real-life experience with the objects were not able to do so. This suggests that perceptual features alone were not sufficient for class recognition. To investigate the impact of additional functional properties of the objects, familiar objects were further divided into two subcategories, namely those that were considered functionally relevant to the birds and those that were not. Although the majority of pigeons learned to categorize photographs of objects based on familiarity alone, our results also suggest an unlearned preference for “relevant” familiar objects. The results presented here suggest that pigeons are able to learn to extract the discriminative feature of abstract familiarity from pictures by referring to previous real-life experience but that additional functions of objects lead to a preference of these objects.     

The effects of familiarity and practice on naming pictures of objects

Ss were given a paired-associate learning task, using nonsense shapes as stimuli and object names which varied in Thorndike-Lorge frequency as responses. Between each block of learning trials, Ss named the nonsense shapes and a set of line drawings of objects. While naming latencies for the shapes were unaffected by name frequency, there was an effect of frequency on naming a control set of pictures of objects. The frequency effect for the pictures decreased significantly with practice. When the Ss were asked to name pictures of the objects having the names previously learned for the nonsense shapes, an effect of frequency appeared, the size of the effect being the same as that found for the control pictures after practice. The frequency effect disappeared when the shapes were reintroduced.     

Unconscious masked priming depends on temporal attention

The cognitive processes at work in masked priming experiments are usually considered automatic and independent of attention. We provide evidence against this view. Three behavioral experiments demonstrate that the occurrence of unconscious priming in a number–comparison task is determined by the allocation of temporal attention to the time window during which the prime–target pair is presented. Both response–congruity priming and physical repetition priming vanish when temporal attention is focused away from this time window. These findings are inconsistent with the concept of a purely automatic spreading of activation during masked priming.     

The role of attention and familiarity in face identification

How is attention allocated during face identification? Previous work using famous and unfamiliar faces suggests that either no attention or a special attentional mechanism is required. We used a conventional attentional blink (AB) procedure to measure face identification with temporarily reduced attention. The participants viewed a rapid series of face images with one embedded nonface abstract pattern (T1). They judged the texture of T1 and then detected a prespecified face (T2) presented at varying lags after T1. T2 was either famous or unfamiliar, as were distractor faces. Regardless of distractor type, detection of an unfamiliar T2 face was significantly impaired at short versus long T1-T2 lags, indicating an attentional requirement for face identification. Detection of a famous T2 face was unaffected by lag, suggesting that familiarity protects against atemporal attentional bottleneck These findings do not support propositions that face identification is "special" in its need for attentional control     

Priming of reach and grasp actions by handled objects

Pictures of handled objects such as a beer mug or frying pan are shown to prime speeded reach and grasp actions that are compatible with the object. To determine whether the evocation of motor affordances implied by this result is driven merely by the physical orientation of the object's handle as opposed to higher-level properties of the object, including its function, prime objects were presented either in an upright orientation or rotated 90° from upright. Rotated objects successfully primed hand actions that fit the object's new orientation (e.g., a frying pan rotated 90° so that its handle pointed downward primed a vertically oriented power grasp), but only when the required grasp was commensurate with the object's proper function. This constraint suggests that rotated objects evoke motor representations only when they afford the potential to be readily positioned for functional action.     

Perception of facial expression depends on prior attention

Attending versus ignoring a stimulus can later determine how it will be affectively evaluated. Here, we asked whether attentional states could also modulate subsequent sensitivity to facial expressions of emotion. In a dual-task procedure, participants first rapidly searched for a gender-defined face among two briefly displayed neutral faces. Then a test face with the previously attended or ignored face’s identity was presented, and participants judged whether it was emotionally expressive (happy, angry, or fearful) or neutral. Intensity of expression in the test face was varied so that an expression detection threshold could be determined. When fearful or angry expressions were judged, expression sensitivity was worse for faces bearing the same identity as a previously ignored versus attended face. When happy expressions were judged, sensitivity was unaffected by prior attention. These data support the notion that the motivational value of stimuli may be reduced by processes associated with selective ignoring.     

Short-term storage capacity for visual objects depends on expertise

Visual short-term memory (VSTM) has traditionally been thought to have a very limited capacity of around 3-4 objects. However, recently several researchers have argued that VSTM may be limited in the amount of information retained rather than by a specific number of objects. Here we present a study of the effect of long-term practice on VSTM capacity. We investigated four age groups ranging from pre-school children to adults and measured the change in VSTM capacity for letters and pictures. We found a clear increase in VSTM capacity for letters with age but not for pictures. Our results indicate that VSTM capacity is dependent on the level of expertise for specific types of stimuli.     

Stimulus familiarity,dogmatism, and the duration of attention

Thirtyeight males and 30 females viewed each of 30 black and white photographs for as long as they wished. Half the photographs were judged by the Es to be unfamiliar to college students. The remaining photographs were judged to be familiar. After the looking task all Ss cotnpleted the Dogmatism Scale. It was predicted that the open-minded Ss would spend more time looking at the novel stimuli than the closed-minded Ss, and, that all Ss would spend more time looking at novel stimuli than familiar stimuli. The results failed to confirm the hypothesis that open-minded Ss would look longer at the novel stimuli than closed-minded Ss. However, it was found that Ss spent more time looking at novel stimuli than familiar stimuli regardless of the degree to which their belief systems were opened or closed. The adwwtage of manipulating stimulus familiarity by E-selection of the stimuli was discussed.     

Speech segmentation by statistical learning depends on attention

We addressed the hypothesis that word segmentation based on statistical regularities occurs without the need of attention. Participants were presented with a stream of artificial speech in which the only cue to extract the words was the presence of statistical regularities between syllables. Half of the participants were asked to passively listen to the speech stream, while the other half were asked to perform a concurrent task. In Experiment 1, the concurrent task was performed on a separate auditory stream (noises), in Experiment 2 it was performed on a visual stream (pictures), and in Experiment 3 it was performed on pitch changes in the speech stream itself. Invariably, passive listening to the speech stream led to successful word extraction (as measured by a recognition test presented after the exposure phase), whereas diverted attention led to a dramatic impairment in word segmentation performance. These findings demonstrate that when attentional resources are depleted, word segmentation based on statistical regularities is seriously compromised.     

Unconscious semantic activation depends on feature-specific attention allocation

We examined whether semantic activation by subliminally presented stimuli is dependent upon the extent to which participants assign attention to specific semantic stimulus features and stimulus dimensions. Participants pronounced visible target words that were preceded by briefly presented, masked prime words. Both affective and non-affective semantic congruence of the prime-target pairs were manipulated under conditions that either promoted selective attention for affective stimulus information or selective attention for non-affective semantic stimulus information. In line with our predictions, results showed that affective congruence had a clear impact on word pronunciation latencies only if participants were encouraged to assign attention to the affective stimulus dimension. In contrast, non-affective semantic relatedness of the prime-target pairs produced no priming at all. Our findings are consistent with the hypothesis that unconscious activation of (affective) semantic information is modulated by feature-specific attention allocation.     

Reflexive joint attention depends on lateralized cortical connections

Joint attention, the tendency to spontaneously direct attention to where someone else is looking, has been thought to occur because eye direction provides a reliable cue to the presence of important events in the environment. We have discovered, however, that adults will shift their attention to where a schematic face is looking—even when gaze direction does not predict any events in the environment. Research with 2 split-brain patients revealed that this reflexive joint attention is lateralized to a single hemisphere. Moreover, although this phenomenon could be inhibited by inversion of a face, eyes alone produced reflexive shifts of attention. Consistent with recent functional neuroimaging studies, these results suggest that lateralized cortical connections between (a) temporal lobe subsystems specialized for processing upright faces and gaze and (b) the parietal area specialized for orienting spatial attention underlie human reflexive shifts of attention in response to gaze direction.     

Allocation of visual attention depends on type of precue

To distinguish between theoretical concepts of how attention is allocated, participants were presented with different types of precues in 6 experiments. In 1 condition with 100% valid precues (Experiments 1 and 2), the time course of attention effects revealed that (a) higher accuracy was obtained with dynamic multiple-element precues (MEPs in which the unique element was defined by apparent motion) than with static MEPs, in which the elements did not move once they were presented (Cheal & Chastain, 1998); (b) a longer precue-target interval (stimulus-onset asynchrony; SOA) was needed to reach asymptote accuracy with dynamic MEPs than with dynamic single-element precues (SEPs); and (c) all dynamic precues (both MEPs and SEPs) resulted in a decline in accuracy at long SOAs. These results suggest that static and dynamic MEPs result in delayed engagement of attention relative to SEPs. Further, a decline in accuracy at long intervals is associated with static and dynamic SEPs and dynamic MEPs, but not with static MEPs. With irrelevant precues (Experiments 3 to 5), there was capture by precues in which the unique element moved briskly, smoothly, or abruptly, or simply flashed on and off, although there were differences in the amount of capture. The strongest capture occurred with smooth movement in static background elements and the weakest with smooth movement in abruptly moving background elements. It was shown in Experiment 6 that a static MEP will not capture attention if one element changes to a unique brightness near the time of precue onset, but if the element changes after 1,000 ms, it will capture attention. The authors suggest that different types of precues result in unequal influence of endogenous and exogenous components of attention, even when the same targets are used. In addition, they show that neither singleton detection mode nor contingent involuntary orienting is necessary for the capture of attention.     

Priming problem solving with conceptual processing of relevant objects

In the present study, the author explored the effect of processing relevant information on producing solutions to brief insight problems. She hypothesized that the conceptual processing of objects relevant to the target solution would facilitate that solution relative to unrelated objects or the shallow processing of words. The author also explored the effect of knowledge of the relationship between the initial object-processing task and the problem-solving task. The results showed that participants who conceptually processed objects related to the target solution (Experiment 1), but not those who shallowly processed words related to the target solution (Experiment 2), were more likely to produce the solution relative to the control; and knowledge of the relationship between objects and solutions made no difference in the frequency of target solutions produced. The results of Experiment 3 showed that conceptual processing of an object could prime a nondominant solution for an ambiguously worded problem. Taken together, the results of the studies supported the effect of conceptual processing on facilitating insight in problem solving.     

Segmentation, attention and phenomenal visual objects

Issues concerning selective attention provoke new questions about visual segmentation, and vice-versa. We illustrate this by describing our recent work on grouping under conditions of inattention, on change blindness for background events and the residual processing of undetected background changes, on modal versus amodal completion in visual search, and the differential effects of these two forms of completion on attentional processes, and on attentional modulation of lateral interactions thought to arise in early visual cortex. Many of these results indicate that segmentation processes substantially constrain attentional processes, but the reverse influence is also apparent, suggesting an interactive architecture. We discuss how the 'proto-objects' revealed by studies of segmentation and attention (i.e. the segmented perceptual units which constrain selectivity) may relate to other object-based notions in cognitive science, and we wrestle with their relation to phenomenal visual awareness.     

The structuralist view of mathematical objects

This paper is based on lectures given to meetings of the Society for Exact Philosophy in Toronto, May 17, 1985, and of the Association for Symbolic Logic in Washington, DC, December 29, 1985. Some of the material had been presented in lectures at Dartmouth College in 1981 and at the University of Padua in 1983. I am indebted to comments from all four audiences, and also to correspondence with Michael Resnik and especially W. W. Tait. This paper was written while I was at Columbia University, to which I and it owe much. Support of the John Simon Guggenheim Memorial Foundation is gratefully acknowledged.     

Pigeons' recognition of partially occluded objects depends on specific training experience

DiPietro et al (2002 Perception 31 1299-1312) reported a dramatic improvement in pigeons' recognition of partially occluded objects after the birds had been trained to recognize objects that were placed on top of another surface. Here, we investigated whether training with partially erased stimuli or with notched stimuli that had a thin gap between the object and another surface would similarly enhance pigeons' recognition of partially occluded objects. We found that erased training had no effect on the birds' recognition of partially occluded objects. Training pigeons to recognize notched objects improved their performance with the same objects when they were partially occluded; but this improvement did not transfer to novel objects, a result that DiPietro et al reported after on-top training. Together, the present results and those of DiPietro et al implicate prior experience as a key factor in pigeons' recognition of partially occluded objects. Training experiences which improve recognition of partially occluded objects may do so because they improve decomposition of complex two-dimensional scenes by pigeons into separate entities.     

Objects of attention, objects of perception

Four experiments were conducted, to explore the notion of objects in perception. Taking as a starting point the effects of display content on rapid attention transfer and manipulating curvature, closure, and processing time, a link between objects of attention and objects of perception is proposed. In Experiment 1, a number of parallel, equally spaced, straight lines facilitated attention transfer along the lines, relative to transfer across the lines. In Experiment 2, with curved, closed-contour shapes, no "same-object" facilitation was observed. However, when a longer time interval was provided, in Experiment 3, a same-object advantage started to emerge. In Experiment 4, using the same curved shapes but in a non-speeded distance estimation task, a strong effect of objects was observed. It is argued that attention transfer is facilitated by line tracing but that line tracing is encouraged by objects.