Semantic activation during object naming

Summary The study deals with the processes of semantic activation which accompany the response of naming an object. A general model of semantic activation is presented, characterized by the proposal of the existence of different components of the semantic representations that constitute the conceptual nodes corresponding to objects. Within these, a distinction is made between elements corresponding to physical properties of the stimulus objects, and more abstract, functional elements. Two distinct routes are proposed for the activation of the concept node, a direct and an indirect one. A further distinction made in the present study is between categories characterized predominantly in terms of perceptual properties, and primarily conceptual categories.The study reports two sets of experiments, the first one offering support to the distinction of two activation routes, the second to the notion of the existence of two types of categories. This latter distinction also allows a convincing explanation for various facts reported in the literature, in particular for the difference in categorization and in naming latencies for objects and for words.     

Object perception and object naming in early development

Among our most fundamental capacities are those that allow us to perceive, categorize and name objects. Recently, controversy has surrounded the question of how young children learn names for objects, in particular, the relative roles of perception and higher-level world knowledge. It is well known that adults depend strongly on conceptual knowledge in a variety of categorization tasks, including object naming. We argue, however, that perception may play a special role in early object naming and, in particular, that certain kinds of world knowledge known to guide adult naming may come to guide naming only rather late in development. Building early mechanisms of naming on a perceptual foundation that may be encapsulated, and thus shut off from more reflective processes, may explain in part why young children can easily and rapidly learn names for things from the adults around them, despite the fact that adults and children may possess very different conceptual organizations.     

Semantic distance effects on object and action naming

Graded interference effects were tested in a naming task, in parallel for objects and actions. Participants named either object or action pictures presented in the context of other pictures (blocks) that were either semantically very similar, or somewhat semantically similar or semantically dissimilar. We found that naming latencies for both object and action words were modulated by the semantic similarity between the exemplars in each block, providing evidence in both domains of graded semantic effects.     

The effects of surface detail on object categorization and naming

Three experiments are reported examining the effects of surface colour and brightness/texture gradients (photographic detail) on object classification and naming. Objects were drawn from classes with either structurally similar or structurally dissimilar exemplars. In Experiment 1a, object naming was facilitated by both congruent surface colour and photographic detail, with the effects of these two variables combining under-additively. In addition incongruent colour disrupted naming accuracy. These effects tended to be larger on objects from structurally similar classes than on objects from structurally dissimilar classes. Experiment 1b examined superordinate classification. There were again advantages due to congruent colour and photographic detail on responses to objects from both structurally similar and structurally dissimilar classes. Incongruent colour disrupted classification accuracy on structurally distinct but not structurally similar items. For structurally similar items, the advantages of congruent surface attributes on classification were smaller than on naming, but this was not the case for structurally dissimilar items. Experiment 2 examined subordinate classification of structurally similar objects. Now effects of congruent and incongruent colour, but not of photographic detail, were found. Experiment 3 showed that congruent and incongruent colour effects occur only when the colours occupy the internal surfaces of objects. The results suggest that surface details can affect object recognition and naming, depending upon: (1) the degree to which objects must be differentiated for a correct response to be made, and (2) the nature of the rate-limiting process determining performance.     

The role of visual and semantic codes in object naming

Three experiments investigated the effects of familiarity, practice, and stimulus variability on naming latencies for photographs of objects. Latencies for pictures of objects having the same name decreased most with practice when the same picture was always used to represent a given object (Condition Ps-Ns), less if different views of the same object were used (Condition Pv-Ns), and least if pictures of different objects having the same name were used (Condition Pd-Ns). In all cases, however, the effect of practice was significant. The savings in naming latency associated with practice on Conditions Ps-Ns and Pv-Ns showed almost no transfer to condition Pd-Ns, even though the same responses were being given before and after transfer. However, practice on Condition Ps-Ns transferred completely to Condition Pv-Ns. Name frequency affected latency in all conditions. The frequency effect decreased slightly with practice.These results are related to several alternative models of the coding processes involved in naming objects. It is concluded that at least three types of representation may be necessary: visual codes, nonverbal semantic codes, and name codes. A distinction is made between visual codes that characterize two-dimensional stimuli and those that characterize three-dimensional objects.     

Testing the embodied account of object naming: A concurrent motor task affects naming artifacts and animals

Embodied theories of object representation propose that the same neural networks are involved in encoding and retrieving object knowledge. In the present study, we investigated whether motor programs play a causal role in the retrieval of object names. Participants performed an object-naming task while squeezing a sponge with either their right or left hand. The objects were artifacts (e.g. hammer) or animals (e.g. giraffe) and were presented in an orientation that favored a grasp or not. We hypothesized that, if activation of motor programs is necessary to retrieve object knowledge, then concurrent motor activity would interfere with naming manipulable artifacts but not non-manipulable animals. In Experiment 1, we observed naming interference for all objects oriented towards the occupied hand. In Experiment 2, we presented the objects in more ‘canonical orientations’. Participants named all objects more quickly when they were oriented towards the occupied hand. Together, these interference/facilitation effects suggest that concurrent motor activity affects naming for both categories. These results also suggest that picture-plane orientation interacts with an attentional bias that is elicited by the objects and their relationship to the occupied hand. These results may be more parsimoniously accounted for by a domain-general attentional effect, constraining the embodied theory of object representations. We suggest that researchers should scrutinize attentional accounts of other embodied cognitive effects.     

Age of acquisition,not word frequency,affects object naming,not object recognition

Word frequency is widely believed to affect object naming speed, despite several studies in which it has been reported that frequency effects may be redundant upon age of acquisition. We report, first, a reanalysis of data from the study by Oldfield and Wingfield (1965), which is standardly cited as evidence for a word frequency effect in object naming; then we report two new experiments. The reanalysis of Oldfield and Wingfield shows that age of acquisition is the major determinant of naming speed, and that frequency plays no independent role when its correlation with other variables is taken into account. In Experiment 1, age of acquisition and phoneme length proved to be the primary determinants of object naming speed. Frequency, prototypicality, and imageability had no independent effect. In Experiment 2, subjects classified objects into two semantic categories (natural or man-made). Prototypicality and semantic category were the only variables to have a significant effect on reaction time, with no effect of age of acquisition, frequency, imageability, or word length. We conclude that age of acquisition, not word frequency, affects the retrieval and/or execution of object names, not the process of object recognition. The locus of this effect is discussed, along with the possibility that words learned in early childhood may be more resistant to the effects of brain injury in at least some adult aphasics than words learned somewhat later.     

Resolving competition when naming an object in a multiple-object display

Naming an object in the context of other objects requires the selection and processing of the target object at different levels, while the processing of competing representations activated by context objects has to be constrained. At what stage are these competing representations attenuated? To address this question, we presented pairs of target and context objects that were either similar in visual shape (e.g., umbrella–palm tree) or dissimilar in visual shape (e.g., umbrella–ladder), so that the context object would attract various amounts of attention. The activation of the context object at different levels of processing was assessed by means of auditory distractors (semantically related, or phonologically related, or unrelated to the context object). Semantic and phonological distractor effects were observed for shape-related object pairs, but not for unrelated object pairs. This finding suggests that context objects do not activate their associated lexical representations to any substantial amount, unless they capture attention. In that case, they undergo full lexical processing up to a phonological level. Implications for models of word production are discussed.     

The role of axes of elongation and symmetry in rotated object naming

Many theorists have postulated that axes of elongation and/or symmetry play an important role in the recognition of objects. In this paper, evidence is presented that mitigates this claim from independent assessments of the effects of axes of elongation or symmetry on the time to name rotated line drawings of common objects. This conclusion was further supported in a stronger test in which both of these variables were orthogonally controlled, the aspect ratio of elongation was manipulated,and only objects that were completely geometrically symmetrical or asymmetrical were used. In all the experiments, objects were named for several blocks to determine the influence of these variables on effects of orientation with practice. Symmetry was found to diminish the effects of orientation after practice in naming the object set, and the effects of the most extreme orientation tested (120 degrees from upright) were diminished when both axes defined the same orientation, relative to when they defined different orientations. Contrary to many theories, these findings relegate the axes of symmetry and elongation to relatively minor roles during object identification.     

Retrieval of names in face and object naming in an interference study

Two experiments using the interference paradigm are reported. In the first experiment, the participants spoke aloud the names of celebrities and the names of objects when presented with pictures while hearing distractors. In the case of proper names, we replicated the data obtained by Izaute and Bonin (2001) using the interference paradigm with a proper name written naming task. In the case of common names, the results replicated those obtained by Shriefers, Meyer, and Levelt (1990). In the second experiment, the participants produced the names of celebrities when presented with their faces while hearing distractors that were either proper names associated with the celebrities (associate condition), that belonged to a different professional category (different condition), or that corresponded to the proper names of the celebrities (identical condition). For negative SOAs, "associate" distractors were found to increase latencies compared to the "different category" condition. The implications of the findings for proper name retrieval are briefly discussed.     

Retrieval of names in face and object naming in an interference study

Two experiments using the interference paradigm are reported. In the first experiment, the participants spoke aloud the names of celebrities and the names of objects when presented with pictures while hearing distractors. In the case of proper names, we replicated the data obtained by Izaute and Bonin (2001) using the interference paradigm with a proper name written naming task. In the case of common names, the results replicated those obtained by Shriefers, Meyer, and Levelt (1990). In the second experiment, the participants produced the names of celebrities when presented with their faces while hearing distractors that were either proper names associated with the celebrities (associate condition), that belonged to a different professional category (different condition), or that corresponded to the proper names of the celebrities (identical condition). For negative SOAs, “associate” distractors were found to increase latencies compared to the “different category” condition. The implications of the findings for proper name retrieval are briefly discussed.     

Gesturing and naming: the use of functional knowledge in object identification

Studies using functional imaging show reliable activation of premotor cortex when observers view manipulable objects. This result has led to the view that knowledge of object function, particularly the actions associated with the typical use of objects, may play a causal role in object identification. To obtain relevant evidence regarding this causal role, we asked subjects to learn gesture-color associations and then attempt to identify objects presented in colors denoting functional gestures that were congruent or incongruent with the objects' use. A strong congruency effect was observed when subjects gestured the use of an object, but not when they named an object. We conclude that our procedure constitutes a sensitive measure of the recruitment and causal role of functional knowledge and that this recruitment is not present during object naming. Preliminary evidence, however, indicates that gestures evoked by the volumetric shape of an object do contribute to object naming.     

Perceptual differentiation as a source of category effects in object processing: Evidence from naming and object decision

The locus of category effects in picture recognition and naming was examined in two experiments with normal subjects. Subjects carried out object decision (deciding whether the stimulus is a “real” object or not) and naming tasks with pictures of clothing, furniture, fruit, and vegetables. These categories are distinguished by containing either relatively many exemplars with similar perceptual structures (fruit and vegetables;structurally similar categories), or relatively few exemplars with similar perceptual structures (clothing and furniture;structurally dissimilar categories). In Experiment 1, responses to the stimuli from the structurally similar categories were slower than responses to stimuli from the structurally dissimilar categories, and this effect was larger in the naming than in the object decision task. Further, prior object decisions to stimuli from structurally similar categories facilitated their subsequent naming. In Experiment 2, we orthogonally manipulated object decision and naming as prime and target tasks, again with stimuli from the four categories. Category effects, with responses slower to objects from structurally similar categories, were again larger in naming than in object decision, and these category effects in naming were reduced by priming with both naming and object decision. We interpret the data to indicate that category effects in object naming can reflect visually based competition which is reduced by the preactivation of stored structural knowledge for objects.     

Crowded and sparse domains in object recognition: consequences for categorization and naming

Some models of object recognition propose that items from structurally crowded categories (e.g., living things) permit faster access to superordinate semantic information than structurally dissimilar categories (e.g., nonliving things), but slower access to individual object information when naming items. We present four experiments that utilize the same matched stimuli: two examine superordinate categorization and two examine picture naming. Experiments 1 and 2 required participants to sort pictures into their appropriate superordinate categories and both revealed faster categorization for living than nonliving things. Nonetheless, the living thing superiority disappeared when the atypical categories of body parts and musical instruments were excluded. Experiment 3 examined naming latency and found no difference between living and nonliving things. This finding was replicated in Experiment 4 where the same items were presented in different formats (e.g., color and line-drawn versions). Taken as a whole, these experiments show that the ease with which people categorize items maps strongly onto the ease with which they name them.     

Conceptual coherence affects phonological activation of context objects during object naming

In 4 picture-word interference experiments, speakers named a target object that was presented with a context object. Using auditory distractors that were phonologically related or unrelated either to the target object or the context object, the authors assessed whether phonological processing was confined to the target object or not. Phonological activation of the context objects was reliably observed if the target and context objects were embedded in a conceptually coherent scene (e.g., if the picture showed a mouse eating some cheese), regardless of whether the target was cued by its thematic role (agent vs. patient) or by color. However, this activation dissipated if the two objects were presented in an arbitrary object array (e.g., if the cheese was presented along with a finger). These findings suggest that conceptual coherence among multiple objects affects the information flow in the conceptual-lexical system during speech planning.     

The spatial frame of reference in object naming and discrimination of left-right reflections

The effects of stimulus rotation and observer's head-tilt position on various pattern-recognition tasks were investigated to compare the external directions most closely aligned with the spatial frame of reference. Specifically, the effects of these factors on the time to name objects were compared with their effects on the time to discriminate left-facing from right-facing lateral views of these objects, as well as with their effects on the time to discriminate normal from mirror-imaged alphanumeric characters. The naming task relied upon a reference frame more closely aligned with retinal directions than with environmental directions. In contrast, both discrimination tasks relied upon a frame aligned more closely with environmental directions. Overall, the nature of the task exerts a greater influence on the directions with which the frame of reference is aligned than do the stimulus attributes.     

The interplay of bottom-up and top-down mechanisms in visual guidance during object naming

An ongoing issue in visual cognition concerns the roles played by low- and high-level information in guiding visual attention, with current research remaining inconclusive about the interaction between the two. In this study, we bring fresh evidence into this long-standing debate by investigating visual saliency and contextual congruency during object naming (Experiment 1), a task in which visual processing interacts with language processing. We then compare the results of this experiment to data of a memorization task using the same stimuli (Experiment 2). In Experiment 1, we find that both saliency and congruency influence visual and naming responses and interact with linguistic factors. In particular, incongruent objects are fixated later and less often than congruent ones. However, saliency is a significant predictor of object naming, with salient objects being named earlier in a trial. Furthermore, the saliency and congruency of a named object interact with the lexical frequency of the associated word and mediate the time-course of fixations at naming. In Experiment 2, we find a similar overall pattern in the eye-movement responses, but only the congruency of the target is a significant predictor, with incongruent targets fixated less often than congruent targets. Crucially, this finding contrasts with claims in the literature that incongruent objects are more informative than congruent objects by deviating from scene context and hence need a longer processing. Overall, this study suggests that different sources of information are interactively used to guide visual attention on the targets to be named and raises new questions for existing theories of visual attention.     

Color makes a difference: two-dimensional object naming in literate and illiterate subjects

Previous work has shown that illiterate subjects are better at naming two-dimensional representations of real objects when presented as colored photos as compared to black and white drawings. This raises the question if color or textural details selectively improve object recognition and naming in illiterate compared to literate subjects. In this study, we investigated whether the surface texture and/or color of objects is used to access stored object knowledge in illiterate subjects. A group of illiterate subjects and a matched literate control group were compared on an immediate object naming task with four conditions: color and black and white (i.e., grey-scaled) photos, as well as color and black and white (i.e., grey-scaled) drawings of common everyday objects. The results show that illiterate subjects perform significantly better when the stimuli are colored and this effect is independent of the photographic detail. In addition, there were significant differences between the literacy groups in the black and white condition for both drawings and photos. These results suggest that color object information contributes to object recognition. This effect was particularly prominent in the illiterate group.