Do chimpanzees (Pan troglodytes) understand single invisible displacement?

Previous research suggests that chimpanzees understand single invisible displacement. However, this Piagetian task may be solvable through the use of simple search strategies rather than through mentally representing the past trajectory of an object. Four control conditions were thus administered to two chimpanzees in order to separate associative search strategies from performance based on mental representation. Strategies involving experimenter cue-use, search at the last or first box visited by the displacement device, and search at boxes adjacent to the displacement device were systematically controlled for. Chimpanzees showed no indications of utilizing these simple strategies, suggesting that their capacity to mentally represent single invisible displacements is comparable to that of 18-24-month-old children.     

Taking the task seriously: reflections on measures of color acquisition

The experiments described in the lead articles by Kowalski and Zimiles and by O'Hanlon and Roberson examine factors that lead to color term acquisition. These experiments touch on the debate regarding the relative contributions of language and concepts in word learning. In this reflection, we examine how conclusions concerning the debate depend deeply on the particular task presented to children, and we propose an alternative approach to studying color term acquisition.     

Fear generalization in humans: Impact of verbal instructions

Fear generalization lies at the heart of many anxiety problems, but little is known about the factors that can influence this phenomenon. The present study investigated whether verbal instructions about specific stimulus features can influence conditioned fear generalization. All participants were fear conditioned to a yellow triangle, using an electric shock. Participants had received pre-experimental instructions saying that the shapes (or colours) of the stimuli were informative for the occurrence of shock (group Shape and group Colour, respectively). Next, generalization was tested to presentations of a blue triangle (same shape) as well as a yellow square (same colour). Fear reactions were measured through skin conductance and online ratings of shock-expectancy. The results showed strongest generalization to the same shape stimulus in group Shape, versus the same colour stimulus in group Colour. Hence, the same learning experience can have opposite effects in terms of fear generalization, depending on verbally transmitted information about the relative importance of individual stimulus features.     

Novel labels support 10-month-olds’ attention to novel objects

What is the source of the mutual exclusivity bias whereby infants map novel labels onto novel objects? In an intermodal preferential looking task, we found that novel labels support 10-month-olds’ attention to a novel object over a familiar object. In contrast, familiar labels and a neutral phrase gradually reduced attention to a novel object. Markman (1989, 1990) argued that infants must recall the name of a familiar object to exclude it as the referent of a novel label. We argue that 10-month-olds’ attention is guided by the novelty of objects and labels rather than knowledge of the names for familiar objects. Mutual exclusivity, as a language-specific bias, might emerge from a more general constraint on attention and learning.     

Estimation and visualization of confusability matrices from adaptive measurement data

We present a simple but effective method based on Luce’s choice axiom [Luce, R.D. (1959). Individual choice behavior: A theoretical analysis. New York: John Wiley & Sons] for consistent estimation of the pairwise confusabilities of items in a multiple-choice recognition task with arbitrarily chosen choice-sets. The method combines the exact (non-asymptotic) Bayesian way of assessing uncertainty with the unbiasedness emphasized in the classical frequentist approach.We apply the method to data collected using an adaptive computer game designed for prevention of reading disability. A player’s estimated confusability of phonemes (or more accurately, phoneme-grapheme connections) and larger units of language is visualized in an easily understood way with color cues and explicit indication of the accuracy of the estimates. Visualization of learning-related changes in the player’s performance is considered.The empirical validity of the choice axiom is evaluated using the game data itself. The axiom appears to hold reasonably well although a small systematic violation is observable for the smallest choice-set sizes.     

The exponential learning equation as a function of successful trials results in sigmoid performance

While the exponential learning equation, indicating a gradually diminishing improvement, is one of the standard equations to describe learning, a sigmoid behavior with initially increasing then decreasing improvement has also been suggested. Here we show that the sigmoid behavior is mathematically derived from the standard exponential equation when the independent variable of the equation is restricted to the successful trials alone. It is suggested that for tasks promoting success-based learning, performance is better described by the derived sigmoid curve.     

A Recess Evaluation with the Players: Taking Steps Toward Participatory Action Research

This qualitative study, part of a Canadian national study of fathers’ involvement, opened up First Nations and Métis fathering as a new area of inquiry. Conversational interviews with 80 Indigenous fathers illuminated the socio-historical conditions that have shaped Indigenous men’s experiences of learning to be a father and becoming a man in the context of changing gender relationships and the regeneration of circles of care. Indigenous fathers’ experiences unfold in a socio-historical context fraught with difficulties. However, the study findings suggest cultural strengths and sources of resilience unseen in research and community programs driven by Euro-western perspectives. This research can inform efforts to reduce systemic barriers and reconstitute positive father involvement following disrupted intergenerational transmission of fathering in Canada and elsewhere.     

Familiar and unfamiliar face recognition: A review

Since the 1970s there has been a continuing interest in how people recognise familiar faces (Bruce, 1979 Bruce, V. 1979. Searching for politicians: An information processing approach to face recognition. Quarterly Journal of Experimental Psychology, 31: 373–395. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]; Ellis, 1975 Ellis, H.D. 1975. Recognising faces. British Journal of Psychology, 66: 409–426. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). This work has complemented investigations of how unfamiliar faces are processed and the findings from these two strands of research have given rise to accounts that propose qualitatively different forms of representation for familiar and unfamiliar faces. Evidence to suggest that we process familiar and unfamiliar faces in different ways is available from cognitive neuropsychology, brain scanning, and psychophysics. However, in this review we focus on the evidence, available from experimental investigations of how people recognise faces, for different types of representation existing for each type of face. Factors affecting recognition are evaluated in terms of how they apply to familiar and unfamiliar faces and categorised according to the nature of their impact. In the final section this evidence, along with recent advances in the field, is used to explore the way in which unfamiliar faces may become familiar and the factors that may be important for the development of familiar face representations.     

The effects of local and global processing orientation on eyewitness identification performance

Recent work has demonstrated that performance on a simultaneous target-present photographic line-up can be enhanced by prior global processing orientation, and hindered by prior local processing orientation induced by processing Navon letter stimuli. A series of studies explore the generality of this processing bias effect using either videotaped scenarios or live interactions. Five experiments demonstrate that these effects are seen across a range of test stimuli, test formats, and test instructions. These data inform the processes engaged in by witnesses when making line-up identifications and indicate that it may be possible to improve the accuracy of witnesses making such judgements.     

Bias and learning in temporal binding: Intervals between actions and outcomes are compressed by prior bias

It has consistently been shown that agents judge the intervals between their actions and outcomes as compressed in time, an effect named intentional binding. In the present work, we investigated whether this effect is result of prior bias volunteers have about the timing of the consequences of their actions, or if it is due to learning that occurs during the experimental session. Volunteers made temporal estimates of the interval between their action and target onset (Action conditions), or between two events (No-Action conditions). Our results show that temporal estimates become shorter throughout each experimental block in both conditions. Moreover, we found that observers judged intervals between action and outcomes as shorter even in very early trials of each block. To quantify the decrease of temporal judgments in experimental blocks, exponential functions were fitted to participants’ temporal judgments. The fitted parameters suggest that observers had different prior biases as to intervals between events in which action was involved. These findings suggest that prior bias might play a more important role in this effect than calibration-type learning processes.