Using a sharp instrument to parse apart strategy and consistency: an evaluation of PPT and its assumptions

Potential Performance Theory (PPT) is a general theory for parsing observed performance into the underlying strategy and the consistency with which it is used. Although empirical research has supported that PPT is useful, it is desirable to have more information about the bias and standard errors of PPT findings. It also is beneficial to know the effects of violations of PPT assumptions. The authors present computer simulations that evaluate bias and standard errors at varying levels of strategy, consistency, and number of trials per participant. The simulations show that, when the assumptions are true, there is very little bias and the standard errors are low when there are moderate or large numbers of trials per participant (e.g., N=50 or N=100). But when the independence assumption is violated, PPT provides biased findings, although the bias is quite small unless the violations are large.     

The mental representation of lexical form: a phonological approach to the recognition lexicon

We propose a psycholinguistic model of lexical processing which incorporates both process and representation. The view of lexical access and selection that we advocate claims that these processes are conducted with respect to abstract underspecified phonological representations of lexical form. The abstract form of a given item in the recognition lexicon is an integrated segmental-featural representation, where all predictable and non-distinctive information is withheld. This means that listeners do not have available to them, as they process the speech input, a representation of the surface phonetic realisation of a given word-form. What determines performance is the abstract, underspecified representation with respect to which this surface string is being interpreted. These claims were tested by studying the interpretation of the same phonological feature, vowel nasality, in two languages, English and Bengali. The underlying status of this feature differs in the two languages; nasality is distinctive only in consonants in English, while both vowels and consonants contrast in nasality in Bengali. Both languages have an assimilation process which spreads nasality from a nasal consonant to the preceding vowel. A cross-linguistic gating study was conducted to investigate whether listeners would interpret nasal and oral vowels differently in two languages. The results show that surface phonetic nasality in the vowel in VN sequences is used by English listeners to anticipate the upcoming nasal consonant. In Bengali, however, nasality is initially interpreted as an underlying nasal vowel. Bengali listeners respond to CVN stimuli with words containing a nasal vowel, until they get information about the nasal consonant. In contrast, oral vowels in both languages are unspecified for nasality and are interpreted accordingly. Listeners in both languages respond with CVN words (which have phonetic nasality on the surface) as well as with CVC words while hearing an oral vowel. The results of this cross-linguistic study support, in detail, the hypothesis that the listener's interpretation of the speech input is in terms of an abstract underspecified representation of lexical form.     

Chronically stressed female rats show increased anxiety but no behavioral alterations in object recognition or placement memory: a preliminary examination

Stress, depending on intensity and duration, elicits adaptive or maladaptive physiological effects. Increasing evidence shows those patterns of advantageous versus deleterious physiologic stress effects also exist for some brain functions, including learning and memory. For example, short stress enhances, while chronic stress impairs, performance on numerous cognitive tasks in male rats. In contrast, performance of female rats is enhanced, or not altered, following both short-term and long-term stress exposure on the same behavioral tasks. The current study was designed to better characterize the behavioral effects of sustained chronic restraint stress in female rats. Female Sprague Dawley rats were assigned to a stress (restraint, 6 h/day, 35 days) or control (no stress) condition, weighed weekly, and then tested on open field (OF), object recognition (OR) and object placement (OP) tasks. Stressed females gained less weight during stress than controls. On the OF, there were no group differences in locomotor activity, but stressed females made fewer inner visits than controls, indicating increased anxiety. Both groups successfully performed the OP and OR tasks across all inter-trial delays, indicating intact non-spatial and spatial memory in both control and stress females. The current results provide preliminary evidence that the commonly used chronic restraint stress model may not be an efficient stressor to female rats.     

Equal performance but distinct behaviors: sex differences in a novel object recognition task and spatial maze in a highly social cichlid fish

Animal Cognition - Sex differences in behavior and cognition can be driven by differential selection pressures from the environment and in the underlying neuromolecular mechanisms of...     

Learning to perceive with a visuo-auditory substitution system: localisation and object recognition with 'the vOICe'

We investigated to what extent participants can acquire the mastery of an auditory-substitution-of-vision device ('The vOICe') using dynamic tasks in a three-dimensional environment. After extensive training, participants took part in four experiments. In the first experiment we explored locomotion and localisation abilities. Participants, blindfolded and equipped with the device, had to localise a target by moving a hand-held camera, walk towards the target, and point at it. In the second experiment, we studied the localisation ability in a constrained pointing task. In the third experiment we explored participants' ability to recognise natural objects via their auditory rendering. In the fourth experiment we tested the ability of participants to discriminate objects belonging to the same category. We analysed participants' performance from both an objective and a subjective point of view. The results showed that participants, through sensorimotor interactions with the perceptual scene while using the hand-held camera, were able to make use of the auditory stimulation to obtain the information necessary for locomotor guidance, localisation, and pointing, as well as for object recognition. Furthermore, analysis from a subjective perspective yielded insights into participants' qualitative experience and into the strategies they used to master the device, and thus to pass from a kind of deductive reasoning to a form of immediate apprehension of what is being perceived.     

Removing the own-race bias in face recognition by attentional shift using fixation crosses to diagnostic features: An eye-tracking study

Hills and Lewis (2011) have demonstrated that the own-race bias in face recognition can be reduced or even removed by guiding participants' attention and potentially eye movements to the most diagnostic visual features. Using the same old/new recognition paradigm as Hills and Lewis, we recorded Black and White participants' eye movements whilst viewing Black and White faces following fixation crosses that preceded the bridge of the nose (between the eyes) or the tip of the nose. White faces were more accurately recognized when following high fixation crosses (that preceded the bridge of the nose) than when following low fixation crosses. The converse was true for Black faces. These effects were independent of participant race. The fixation crosses attracted the first fixation but had less effect on other eye-tracking measures. Furthermore, the location of the first fixation was predictive of recognition accuracy. These results are consistent with an attentional allocation model of the own-race bias in face recognition and highlight the importance of the first fixation for face perception (cf. Hsiao & Cottrell, 2008).     

On the representation of events: a study of orientation, recall, and recognition

Examined the representation of real-world events in memory as a function of orientation toward a videotaped sequence in which 2 people play a board game. In 4 experiments, analyzed subjects' segmentation of the videotaped sequence into events, using a technique developed by Newtson (1973). A comparison of segmentation patterns with performance on recognition, recall, and cued-recall tasks indicated that recall of events changed as a function of subjects' orientation toward the videotape, whereas recognition of events did not. The authors conclude that orientation toward an episodic sequence affects how rather than what events are represented in memory. An account of how orientation might affect the encoding and the representation of events is offered.     

Object recognition and object segregation in infancy: historical perspective, theoretical significance, "kinds" of knowledge, and relation to object categorization

Needham (2001, this issue) reports that 4.5-month-old infants can use a short-term familiarization experience with a single object to facilitate the segregation of a visual display consisting of a configurally similar object and a configurally dissimilar adjacent object. We reflect on this finding in the larger context of Needham's systematic research on the development of object perception, a program that has included (1) a series of empirical studies designed to identify the different cues that infants use for object segregation and (2) a theoretical framework in which infants are presumed to integrate these cues to form interpretations of complex visual displays.     

Learning representation hierarchies by sharing visual features: a computational investigation of Persian character recognition with unsupervised deep learning

In humans, efficient recognition of written symbols is thought to rely on a hierarchical processing system, where simple features are progressively combined into more abstract, high-level representations. Here, we present a computational model of Persian character recognition based on deep belief networks, where increasingly more complex visual features emerge in a completely unsupervised manner by fitting a hierarchical generative model to the sensory data. Crucially, high-level internal representations emerging from unsupervised deep learning can be easily read out by a linear classifier, achieving state-of-the-art recognition accuracy. Furthermore, we tested the hypothesis that handwritten digits and letters share many common visual features: A generative model that captures the statistical structure of the letters distribution should therefore also support the recognition of written digits. To this aim, deep networks trained on Persian letters were used to build high-level representations of Persian digits, which were indeed read out with high accuracy. Our simulations show that complex visual features, such as those mediating the identification of Persian symbols, can emerge from unsupervised learning in multilayered neural networks and can support knowledge transfer across related domains.     

Consistent (but not variable) names as invitations to form object categories: new evidence from 12-month-old infants

Recent research documents that for infants just beginning to produce words on their own, novel words highlight commonalities among named objects and, in this way, serve as invitations to form categories. The current experiment identifies more precisely the source of this invitation. We asked whether applying a consistent name to a set of distinct objects is crucial to categorization, or whether variable names might serve the same conceptual function. The evidence suggests that for 12-month-old infants, consistency in naming is critical. Infants hearing a single consistent novel noun for a set of distinct objects successfully formed object categories. Infants hearing different novel nouns for the same set of objects did not. These results lend strength and greater precision to the argument that naming has powerful and rather nuanced conceptual consequences for infants as well as for mature speakers.     

When a face type is perceived as threatening: Using general recognition theory to understand biased categorization of Afrocentric faces

Prior research indicates that stereotypical Black faces (e.g., wide nose, full lips: Afrocentric) are often associated with crime and violence. The current study investigated whether stereotypical faces may bias the interpretation of facial expression to seem threatening. Stimuli were prerated by face type (stereotypical, nonstereotypical) and expression (neutral, threatening). Later in a forced-choice task, different participants categorized face stimuli as stereotypical or not and threatening or not. Regardless of prerated expression, stereotypical faces were judged as more threatening than were nonstereotypical faces. These findings were supported using computational models based on general recognition theory (GRT), indicating that decision boundaries were more biased toward the threatening response for stereotypical faces than for nonstereotypical faces. GRT analysis also indicated that perception of face stereotypicality and emotional expression are dependent, both across categories and within individual categories. Higher perceived stereotypicality predicts higher perception of threat, and, conversely, higher ratings of threat predict higher perception of stereotypicality. Implications for racial face-type bias influencing perception and decision-making in a variety of social and professional contexts are discussed.     

The transition of object to mental manipulation: beyond a species-specific view of intelligence

Animal Cognition - Many attempts have been made to classify and evaluate the nature of intelligence in humans and other species (referred to as the ‘g’ factor in the former and the G...     

Making two responses to a single object: implications for the central attentional bottleneck.

Experiments with two stimuli and two responses have revealed a central attentional bottleneck and pointed to response selection as its primary locus; however, little has been said about the underlying reasons for this bottleneck. Here we explore these reasons. In the first three experiments, Ss made two separate responses to different aspects of the same object. Interference between selection of the responses persisted, ruling out the possibility that the dual-task bottleneck is caused by the input to the response-selection mechanism being limited to one object at a time. The next four experiments examined what happens when two responses are made to the same attribute of a single object. These experiments show that only one response selection occurred. Hence, the central mechanism is not limited to picking one motor action at a time. Several possible theories about the nature of the bottleneck are discussed.     

Infants' attention to an adult's demonstration of object functions: evidence for a comparator process

The present study was motivated by a concern with the cognitive processes that infants bring to bear on stimulation offered by adults. As previous studies have highlighted the importance of parental stimulation with objects, this study consisted of an experimental investigation of this context of stimulation. It was hypothesized that adults' actions that demonstrate the functions of toys activate a comparator process in 9-month-old infants. It was predicted that prior exposure to the toy in a stationary state would increase attention to a demonstrative action, as the comparator process requires time over and above the local processing of an event. This prediction was borne out: 9-month-olds infants' attention to the demonstration of the functions of a toy was augmented by immediate prior exposure to the toy in a stationary state. By contrast, attention to other actions which did not demonstrate specific functions was either significantly reduced by prior exposure to the toy, or unaffected. Moreover, 16-month-olds who are better able to perform a broad range of actions with objects, did not show increased attention to a demonstration of functions when prior exposure to the toy was provided. © 1998 John Wiley & Sons, Ltd.     

The importance of interhemispheric transfer for foveal vision: a factor that has been overlooked in theories of visual word recognition and object perception

In this special issue of Brain and Language, we examine what implications the division between the left and the right brain half has for the recognition of words presented in the center of the visual field. The different articles are a first indication that taking into account the split between the left and the right cerebral hemisphere need not be an inescapable nuisance in models of visual word recognition but may in fact form the clue to the solution of a longstanding problem within this literature. Also, the fact that interhemispheric transfer has implications for foveal word recognition should interest laterality researchers, as it makes their findings more central to normal reading. In this introductory article, I first present a rough picture of the current (lack of) evidence for a bilateral representation of the fovea and the absence of a callosal delay. I then briefly discuss the suggestions made by the different authors on how to integrate the foveal split within current models of visual word recognition.     

Cued recall from image and sentence memory: a shift from episodic to identical elements representation

The applicability of the identical elements (IE) model of arithmetic fact retrieval (T. C. Rickard, A. F. Healy, & L. E. Bourne, 1994) to cued recall from episodic (image and sentence) memory was explored in 3 transfer experiments. In agreement with results from arithmetic, speedup following even minimal practice recalling a missing word from an episodically bound word triplet did not transfer positively to other cued recall items involving the same triplet. The shape of the learning curve further supported a shift from episode-based to IE-based recall, extending some models of skill learning to cued recall practice. In contrast with previous findings, these results indicate that a form of representation that is independent of the original episodic memory underlies cued-recall performance following minimal practice.     

ADPROCLUS: a graphical user interface for fitting additive profile clustering models to object by variable data matrices

In many areas of psychology, one is interested in disclosing the underlying structural mechanisms that generated an object by variable data set. Often, based on theoretical or empirical arguments, it may be expected that these underlying mechanisms imply that the objects are grouped into clusters that are allowed to overlap (i.e., an object may belong to more than one cluster). In such cases, analyzing the data with Mirkin’s additive profile clustering model may be appropriate. In this model: (1) each object may belong to no, one or several clusters, (2) there is a specific variable profile associated with each cluster, and (3) the scores of the objects on the variables can be reconstructed by adding the cluster-specific variable profiles of the clusters the object in question belongs to. Until now, however, no software program has been publicly available to perform an additive profile clustering analysis. For this purpose, in this article, the ADPROCLUS program, steered by a graphical user interface, is presented. We further illustrate its use by means of the analysis of a patient by symptom data matrix.