The 36th Sir Frederick Bartlett Lecture: An associative analysis of spatial learning

The ability of animals to find important goals in their environment has been said to require a form of learning that is qualitatively different from that normally studied in the conditioning laboratory. Such spatial learning has been said to depend upon the construction of a global representation of the environment, and the acquisition of knowledge about the position of goals with reference to this representation is said to be unaffected by the presence of other cues or landmarks. To evaluate the first of these claims, experiments are described that investigated the extent to which the effects of training in one environment transfer to another. To evaluate the second claim, experiments are described that investigated whether cue competition effects normally found in conditioning studies can be found in spatial tasks. Overall, the results indicate that most of the phenomena of spatial learning can be explained by the principles of associative learning. The implications of the reported results for an understanding of the neural mechanisms of spatial learning are considered.     

Effects of visual cue and response assignment on spatial stimulus coding in stimulus–response compatibility

Tlauka and McKenna (2000 Tlauka, M. and McKenna, F. P. 2000. Hierarchical knowledge influences stimulus–response compatibility effects. Quarterly Journal of Experimental Psychology, 53A: 85–103.  [Google Scholar]) reported a reversal of the traditional stimulus–response compatibility (SRC) effect (faster responding to a stimulus presented on the same side than to one on the opposite side) when the stimulus appearing on one side of a display is a member of a superordinate unit that is largely on the opposite side. We investigated the effects of a visual cue that explicitly shows a superordinate unit, and of assignment of multiple stimuli within each superordinate unit to one response, on the SRC effect based on superordinate unit position. Three experiments revealed that stimulus–response assignment is critical, while the visual cue plays a minor role, in eliciting the SRC effect based on the superordinate unit position. Findings suggest bidirectional interaction between perception and action and simultaneous spatial stimulus coding according to multiple frames of reference, with contribution of each coding to the SRC effect flexibly varying with task situations.     

The modulation of spatial congruency by object-based attention: Analysing the “locus” of the modulation

In a diffusion model, performance as measured by latency and accuracy in two-choice tasks is decomposed into different parameters that can be linked to underlying cognitive processes. Although the diffusion model has been utilized to account for lexical decision data, the effects of stimulus manipulations in previous experiments originated from just one parameter: the quality of the evidence. Here we examined whether the diffusion model can be used to effectively decompose the underlying processes during visual-word recognition. We explore this issue in an experiment that features a lexical manipulation (word frequency) that we expected to affect mostly the quality of the evidence (the drift rate parameter), and a perceptual manipulation (stimulus orientation) that presumably affects the nondecisional time (the T_er parameter, time of encoding and response) more than it affects the drift rate. Results showed that although the manipulations do not affect only one parameter, word frequency and stimulus orientation had differential effects on the model's parameters. Thus, the diffusion model is a useful tool to decompose the effects of stimulus manipulations in visual-word recognition.     

Up north and down south: Implicit associations between topography and cardinal direction

Route planners show a reliable tendency to select south- relative to north-going routes between two horizontally (east/west) aligned landmarks, suggesting the application of a north-is-up heuristic (Brunyé, Mahoney, Gardony, & Taylor, 2010). The source of this north-is-up bias remains unknown, and there is no strong evidence to suggest that it is due to explicit strategy use. In four experiments, we attempt to further elucidate the source of this effect by testing whether it can be attributed to implicit associations between cardinal direction (north/south) and topography (mountainous/level terrain). Experiments 1 and 2 used an adapted Implicit Association Test and demonstrate automatically activated judgements that associate north with mountainous and south with relatively level terrain. Experiment 3 rules out the possibility that this effect is due to the local topography of New England by replicating in participants from the topographically dissimilar Midwestern United States. Finally, Experiment 4 tests the relative contribution of implicit versus explicit associations between cardinal direction and topography in predicting route-planning asymmetries; we show that implicit associations are a stronger predictor of southern route biases than explicit processes. Overall, results demonstrate that the conceptualization of space can be driven by physically unfounded implicit associations between cardinal directions and topographical features, and these associations are at least partially responsible for southern route preferences.     

Nonblurred regions show priority for gaze direction over spatial blur

The human eye continuously forms images of our 3D environment using a finite and dynamically changing depth of focus. Since different objects in our environment reside at different depth planes, the resulting retinal images consist of both focused and spatially blurred objects concurrently. Here, we wanted to measure what effect such a mixed visual diet may have on the pattern of eye movements. For that, we have constructed composite stimuli, each containing an intact photograph and several progressively blurred versions of it, all arranged in a 3?×?3 square array and presented simultaneously as a single image. We have measured eye movements for 7 such composite stimuli as well as for their corresponding root mean square (RMS) contrast-equated versions to control for any potential contrast variations as a result of the blurring. We have found that when observers are presented with such arrays of blurred and nonblurred images they fixate significantly more frequently on the stimulus regions that had little or no blur at all (p?<?.001). A similar pattern of fixations was found for the RMS contrast-equated versions of the stimuli indicating that the observed distributions of fixations is not simply the result of variations in image contrasts due to spatial blurring. Further analysis revealed that, during each 5 second presentation, the image regions containing little or no spatial blur were fixated first while other regions with larger amounts of blur were fixated later, if fixated at all. The results contribute to the increasing list of stimulus parameters that affect patterns of eye movements during scene perception.     

The spatial representation of numerical and non-numerical ordered sequences: Insights from a random generation task

It is widely believed that numbers are spatially represented from left to right on the mental number line. Whether this spatial format of representation is specific to numbers or is shared by non-numerical ordered sequences remains controversial. When healthy participants are asked to randomly generate digits they show a systematic small-number bias that has been interpreted in terms of “pseudoneglect in number space”. Here we used a random generation task to compare numerical and non-numerical order. Participants performed the task at three different pacing rates and with three types of stimuli (numbers, letters, and months). In addition to a small-number bias for numbers, we observed a bias towards “early” items for letters and no bias for months. The spatial biases for numbers and letters were rate independent and similar in size, but they did not correlate across participants. Moreover, letter generation was qualified by a systematic forward direction along the sequence, suggesting that the ordinal dimension was more salient for letters than for numbers in a task that did not require its explicit processing. The dissociation between numerical and non-numerical orders is consistent with electrophysiological and neuroimaging studies and suggests that they rely on at least partially different mechanisms.     

Adults see vision to be more informative than it is

Humans gain a wide range of knowledge through interacting with the environment. Each aspect of our perceptual experiences offers a unique source of information about the world—colours are seen, sounds heard and textures felt. Understanding how perceptual input provides a basis for knowledge is thus central to understanding one's own and others' epistemic states. Developmental research suggests that 5-year-olds have an immature understanding of knowledge sources and that they overestimate the knowledge to be gained from looking. Without evidence from adults, it is not clear whether the mature reasoning system outgrows this overestimation. The current study is the first to investigate whether an overestimation of the knowledge to be gained from vision occurs in adults. Novel response time paradigms were adapted from developmental studies. In two experiments, participants judged whether an object or feature could be identified by performing a specific action. Adult participants found it disproportionately easy to accept looking as a proposed action when it was informative, and difficult to reject looking when it was not informative. This suggests that adults, like children, overestimate the informativeness of vision. The origin of this overestimation and the implications that the current findings bear on the interpretation of children's overestimation are discussed.     

Miracles in Sport: Finding the ‘Ears to Hear’ and the ‘Eyes to See’

Paralympic Games (PG), involving people with disabilities (PWD), are a manifestation of excellence in sport. They show that athletics performed by PWD counts as genuine sport. They also support a wider meaning of the term ‘health,’ understood not just like a utopian state of perfection, but like the ability to realize oneself in the projects and activities of one’s own choosing. Notwithstanding these virtues, PG—in their current form—may paradoxycally reinforce social prejudice against PWD. This is due to the fact that PG and Olympic Games (OG) are now two distinct events. In this article, I argue that PG should be integrated in the OG, just like women’s and ‘minor’ sports, because the separation of PG and OG indicates a morally arbitrary separation between people with and without disabilities. I also propose to remove the word ‘Para-lympic’ because it stigmatizes the sport performed by PWD as an appendix of ‘normal’ sport. Athletes with disabilities deserve special attention because they have special needs; but they also deserve an arena where their excellence is offered to the public, and this arena should not be different from that of normal-bodied athletes.     

Similarity chains in the transformational paradigm

Rips’ (1989) results with the transformational paradigm have often been cited as supporting accounts of categorisation not based on similarity, such as involving necessary or sufficient features (or a belief in such features), which guarantee a categorisation outcome once their presence has been established. We discuss a similarity account of the transformational paradigm based on similarity chains, which predicts that when the transformation is more gradual the identity of the transformed object is less likely to change. Conversely, we suggest that an essentialist approach to categorisation predicts that essences are more likely to change in gradual transformations, across generations, as is the case with evolutionary change of species. In two experiments we examined the scope of the similarity versus the essentialist account in the transformational paradigm. With space aliens, the similarity account was superior to the essentialist one, but the converse was true with earth creatures. We suggest that an essentialist mode of categorisation is more likely than a similarity one for stimuli that are in better correspondence with our naïve understanding of the world.