They might all be marauders.

Circle theory predicts most offenders will reside within the smallest circle that encloses a pattern of offense locations, which defines the offender's crime range. Those who reside within the crime range reflect a marauder decision pattern, with the remainder reflecting a commuter decision pattern. Random simulations of marauders were conducted to determine the failure rate of the smallest circle to correctly identify a marauder decision pattern. Failure rates were higher as the number of offenses was reduced, but were systematic and predictable. Moreover, the published rates of the marauder vs commuter patterns correspond well with the predicted failure rate. A method for estimating the true size of an offender's criminal territory is presented and it is suggested that the vast majority of offenders are likely to be adopting a marauder decision pattern, and that true commuters may be far less than indicated by the circle test.

Intention matters more than attention: Item-method directed forgetting of items at attended and unattended locations.

This study embedded attentional cues in the study phase of an item-method directed forgetting task. We used an unpredictive onset cue (Experiment 1), a predictive onset cue (Experiment 2), or a predictive central cue (Experiments 3-6) to direct attention to the left or right. In Experiments 1-5, this was followed by a pink or blue study word that required a speeded colour discrimination; in Experiment 6, it was followed by a pink or blue word or nonword that required a lexical decision. Each study word was followed by an instruction to Remember or Forget. A yes-no recognition test confirmed better recognition of to-be-remembered words than to-be-forgotten words; a cueing effect confirmed the effectiveness of predictive cues in allocating attentional resources. There was, however, no evidence that the directed forgetting effect differed for attended and unattended words: Encoding depends more on the memory intention formed after a study word has disappeared than on the availability of processing resources when that word first appears.

Cancelling Flash Illusory Line Motion by Cancelling the Attentional Gradient and a Consideration of Consciousness.

Illusory line motion (ILM) refers to the perception of motion in a line that is, in fact, presented in full at one time. One form of this illusion (flashILM) occurs when the line is presented between two objects following a brief luminance change in one of them and flashILM is thought to result from exogenous attention being captured by the flash. Exogenous attention fades with increasing delays, which predicts that flashILM should show a similar temporal pattern. Exogenous attention appears to follow flashILM to become more or less equally distributed along the line.The current study examines flashILM in order to test these predictions derived from the attentional explanation for flashILM and the results were consistent with them. The discussion then concludes with an exploratory analysis approach concerning states of consciousness and decision making and suggests a possible role for attention.

Human Sensory LTP Predicts Memory Performance and Is Modulated by the BDNF Val66Met Polymorphism.

Background: Long-term potentiation (LTP) is recognised as a core neuronal process underlying long-term memory. However, a direct relationship between LTP and human memory performance is yet to be demonstrated. The first aim of the current study was thus to assess the relationship between LTP and human long-term memory performance. With this also comes an opportunity to explore factors thought to mediate the relationship between LTP and long-term memory. The second aim of the current study was to explore the relationship between LTP and memory in groups differing with respect to brain-derived neurotrophic factor (BDNF) Val66Met; a single-nucleotide polymorphism (SNP) implicated in memory function. Methods: Participants were split into three genotype groups (Val/Val, Val/Met, Met/Met) and were presented with both an EEG paradigm for inducing LTP-like enhancements of the visually-evoked response, and a test of visual memory. Results: The magnitude of LTP 40 min after induction was predictive of long-term memory performance. Additionally, the BDNF Met allele was associated with both reduced LTP and reduced memory performance. Conclusions: The current study not only presents the first evidence for a relationship between sensory LTP and human memory performance, but also demonstrates how targeting this relationship can provide insight into factors implicated in variation in human memory performance. It is anticipated that this will be of utility to future clinical studies of disrupted memory function.

Selection for encoding: No evidence of better endogenous orienting following forget than following remember instructions.

In an item-method directed forgetting task, attentional resources are withdrawn from forget item processing (e.g., Taylor & Fawcett in Attention, Perception, & Psychophysics, 73, 1790-1814, 2011). Taylor and Hamm (Attention, Perception, & Psychophysics, 78, 168-186, 2016) demonstrated that there is no corresponding increase in the proclivity for exogenous attention to be captured following a forget instruction. This means either that the attentional resources withdrawn from the forget item are reallocated immediately (and therefore not especially vulnerable to capture) or that it is not exogenous attention that is withdrawn. Given that endogenous attention is distinct from exogenous attention, we therefore extended the Taylor and Hamm study by using endogenous orienting rather than exogenous orienting. Words appeared individually in a peripheral location (Exp. 1) or in a central location (Exp. 2), followed by an instruction to either remember or forget. After a short (50-ms) or long (250-ms) interstimulus interval (ISI), a central cue (80% accurate) directed participants to allocate their attention to the left or right. This was followed by a discrimination target that appeared at a 1,000-ms cue-target stimulus onset asynchrony. A subsequent yes-no recognition test assessed memory for all study items. In both experiments, we observed better recognition of remember words than forget words-a directed forgetting effect. We also found a cueing effect, revealed as faster reaction times to discriminate cued targets than to discriminate uncued targets. There was not, however, an effect of memory instruction (and/or instruction-cue ISI) on the magnitude of this cueing effect. Thus, neither exogenous attention nor endogenous attention remains in an unengaged state following an instruction to forget.

Comparisons of flashILM, transformational apparent motion, and polarized gamma motion indicate these are three independent and separable illusions.

Illusory line motion (ILM) refers to perceived motion in a bar when it is presented all at once. Explanations for ILM include low-level visual accounts, visual attention, and object tracking. These explanations tend to arise from studies using different protocols to induce ILM, based on the assumption that the same illusion is being generated. Using real motion in the same and in the opposite direction as the ILM quantifies the illusions from all protocols as the area between response curves for the left- and right-side inducers. This common measure enables testing of the assumption that two display configurations result in the same illusion. If there is a common underlying cause, an individual who shows a strong illusion in one situation should show a strong illusion in the other, but illusions that arise through different systems should not correlate. This approach has differentiated ILM induced by a flash (flashILM) from ILM induced by matching the bar to an attribute of the inducing stimuli (transformational apparent motion, TAM). The former is thought to reflect attention, while the latter is thought to reflect object processing. Low-level visual explanations are often offered based on ILM that occurs when the bar is adjacent to only a single inducer (polarized gamma motion, PGM) rather than between two stimuli (flashILM and TAM). The present study replicates the independence of flashILM and TAM and shows that neither is related to PGM, suggesting that all three explanations for ILM are warranted and that the debates in the literature are conflating at least three different illusions.

A grand memory for forgetting: Directed forgetting across contextual changes.

Using an item-method directed forgetting task, we presented homographic homophonic nouns embedded in sentences. At study, each sentence was followed by an instruction to remember or forget the embedded word. On a subsequent yes-no recognition test, each word was again embedded within a sentence. In Experiments 1, 2, and 4 we varied the embedding sentence at test so that it was identical to that at study, changed but retained the meaning of the studied word, or changed to alter the meaning of the studied word. Repeated context - whether the sentence and/or the word meaning - proved to be as useful a retrieval cue for TBF items as for TBR items. In Experiment 3, we demonstrated that physical repetition was insufficient to produce context effects for either TBR or TBF items. And, in Experiment 4, we determined that participants were equally accurate in reporting context repetition/change following the correct recognition of TBR and TBF items. When considered in light of the existing literature, our results suggest that when context can be dissociated from the study item, it is encoded in "one shot" and not vulnerable to subsequent efforts to limit unwanted encoding.

Flash-induced forward and reverse illusory line motion in offset bars.

Illusory line motion (ILM) refers to perception of motion in a bar that onsets or offsets all at once. When the bar onsets or offsets between two boxes after one of the boxes flashes, the bar appears to shoot out of the flashed box (flashILM). If the bar offsets during the flash, it appears to contract into the flashed box (reverse ILM; rILM). Onset bars do not show rILM. Moreover, rILM and flashILM are not correlated, indicating they are two different illusions. To date, rILM has only been studied using a 50-ms flash where the bar offsets 16.7 ms after flash onset. It is not clear if rILM is due to the 16.7-ms flash-bar-removal stimulus onset asynchrony (SOA) or due to the flash offsetting after the bar. The current studies explore these parameters to better understand the conditions that lead to rILM. The results suggest that flashILM is sensitive to the temporal interval between flash onset and bar offset, while rILM appears to arise when the flash offsets after the bar has been removed regardless of the temporal interval between flash onset and bar removal. These results are consistent with flashILM reflecting visual exogenous attention while rILM may reflect the low-level spreading of subthreshold activation radiating from the flashed box. The findings are incorporated into the recent work that suggests that the literature concerning ILM is possibly conflating a number of different illusions of line motion, including polarized gamma motion (PGM), transformational apparent motion (TAM), and exogenous attention induced motion (flashILM).

The relationship between flash based illusory line motion and exogenous visual attention.

If a bar suddenly appears between 2 squares after 1 of the squares flashes the bar appears to shoot away from the flashed square toward the other. This occurs despite the bar actually having been presented all at once. This illusory motion is sufficiently strong to cancel real motion drawn in the opposite direction. One explanation for the illusion in these displays is based upon the prior entry benefits generated by exogenous attention at the flashed location. These prior entry benefits can be offset by real motion in the opposite direction, which enables 1 to quantify the illusion based upon the area between the response curves following left and right flashes. The influence of attention can be quantified as the costs plus benefits during an exogenous cuing study involving target discrimination. The current study required participants to complete motion direction discrimination trials and a set of target discrimination trials following noninformative peripheral cues. If attention is involved in the motion illusion during these displays then those who show large effects of attention during cuing should also show large illusions. Correlation analyses confirmed a positive relationship existed between the costs plus benefits of exogenous attention and the illusory motion. (PsycINFO Database Record

Musical training increases functional connectivity, but does not enhance mu suppression.

Musical training provides an ideal platform for investigating action representation for sound. Learning to play an instrument requires integration of sensory and motor perception-action processes. Functional neuroimaging studies have indicated that listening to trained music can result in the activity in premotor areas, even after a short period of training. These studies suggest that action representation systems are heavily dependent on specific sensorimotor experience. However, others suggest that because humans naturally move to music, sensorimotor training is not necessary and there is a more general action representation for music. We previously demonstrated that EEG mu suppression, commonly implemented to demonstrate mirror-neuron-like action representation while observing movements, can also index action representations for sounds in pianists. The current study extends these findings to a group of non-musicians who learned to play randomised sequences on a piano, in order to acquire specific sound-action mappings for the five fingers of their right hand. We investigated training-related changes in neural dynamics as indexed by mu suppression and task-related coherence measures. To test the specificity of training effects, we included sounds similar to those encountered in the training and additionally rhythm sequences. We found no effect of training on mu suppression between pre- and post-training EEG recordings. However, task-related coherence indexing functional connectivity between electrodes over audiomotor areas increased after training. These results suggest that long-term training in musicians and short-term training in novices may be associated with different stages of audiomotor integration that can be reflected in different EEG measures. Furthermore, the changes in functional connectivity were specifically found for piano tones, and were not apparent when participants listened to rhythms, indicating some degree of specificity related to training.

Mental rotation: an examination of assumptions.

Since first presented by Shepard and Metzler, Science 1971, 171: 701-703, mental rotation has been described as a rotary transformation of a visual stimulus allowing it to be represented in a new orientation. For a given stimulus, the transformation is thought to occur at a constant speed, though speed may vary between stimuli; three-dimensional abstract shapes made out of blocks tend to be rotated much more slowly than alphanumeric characters or line drawings of common objects. Rotation is also presumed to be performed through the shortest angle. These assumptions are based upon the fact that response times tend to increase with angle of rotation, peaking at 180° of separation for abstract block figures or from upright for common objects and alphanumeric stimuli. The symmetry about 180° provides evidence supporting rotation through the shortest angle. In order to determine the shortest direction, the current orientation of the stimulus is assumed to be known prior to mental rotation. Moreover, in order to determine the current orientation of a common object or alphanumeric stimulus, it is assumed the stimulus is identified prior to mental rotation because the current orientation is defined by what the object is. In mirror/normal discriminations or left/right facing discriminations of rotated stimuli response times are often examined by collapsing over response options as this variable is assumed to be uninteresting in terms of mental rotation. This article examines these assumptions, and suggests that many of them are not entirely safe. WIREs Cogn Sci 2017, 8:e1443. doi: 10.1002/wcs.1443 For further resources related to this article, please visit the WIREs website.

A comparison of colour, shape, and flash induced illusory line motion.

When a bar suddenly appears between two boxes, the bar will appear to shoot away from the box that matches it in colour or in shape-a phenomenon referred to as attribute priming of illusory line motion (ILM; colourILM and shapeILM, respectively). If the two boxes are identical, ILM will still occur away from a box if it changes luminance shortly before the presentation of the bar (flashILM). This flash condition has been suggested to produce the illusory motion due to the formation of an attentional gradient surrounding the flashed location. However, colourILM and shapeILM cannot be explained by an attentional gradient as there is no way for attention to select the matching box prior to the presentation of the bar. These findings challenge the attentional gradient explanation for ILM, but only if it is assumed that ILM arises for the same underlying reason. Two experiments are presented that address the question of whether or not flashILM is the same as colourILM or shapeILM. The results suggest that while colourILM and shapeILM reflect a common illusion, flashILM arises for a different reason. Therefore, the attentional gradient explanation for flashILM is not refuted by the occurrence of colourILM or shapeILM, which may reflect transformational apparent motion (TAM).

Illusory line motion in onset and offset bars.

Illusory line motion (ILM) refers to the perception of motion in a bar that is presented all at once next to an inducing stimulus. The experimental methods for producing and quantifying ILM are varied, and the resulting explanations are likewise at odds. The current study examined the explanations for ILM away from the inducing stimulus (bright or dark flash) using bars that either suddenly appear (onset bars) or suddenly disappear (offset bars). Real motion is used to cancel ILM, providing three measures to quantify ILM: the consistency of responding to only ILM in the absence of real motion; the distance between the points of subjective equality between ILM and the real motion; and the area between the curves relating perception of motion to the real and illusory conditions. ILM quantities for onset and offset bars are strongly correlated when the bar change occurs after the flash. However, onset bars presented during the flash do not show any evidence of ILM, whereas offset bars removed during the flash result in reverse ILM (rILM). Moreover, rILM and ILM are not correlated, suggesting they reflect two separate illusions. These results are consistent over the various measures of ILM.

Mu rhythm suppression demonstrates action representation in pianists during passive listening of piano melodies.

Musicians undergo extensive training which enhances established neural links between auditory and motor areas of the brain. Long-term training develops, strengthens and enables flexibility in these connections allowing proficiency in performance. Previous research has indicated that passive listening of trained music results in the recruitment of premotor areas. It has been argued that this sound-action representation may rely on activity in mirror neuron systems and that these systems are heavily dependent on actual sensorimotor experience. Action observation studies using electroencephalography have associated changes in mu rhythm activity with the mirror neuron system in the visuomotor domain. We aimed to investigate similar effects in the audiomotor domain. We utilised a mu suppression method in our action-listening study to detect involuntary motor coactivation when pianists passively listened to piano melodies. Wavelet analysis revealed sensorimotor mu rhythm suppression while pianists listened passively to piano melodies. Thus, we show that this spectral analysis method can also be used to demonstrate that auditory stimuli can activate the human mirror neuron system when sounds are linked to actions. Mu suppression could be a useful index for further research on action representation and training-induced plasticity.

Selection for encoding: No evidence of greater attentional capture following forget than remember instructions.

We measured attentional orienting in an item-method-directed forgetting task. Words appeared singly, followed by an instruction to remember or forget. In Experiment 1, study words appeared at center; in Experiments 2 and 3, they appeared to the left and right. In all three experiments, there was a delay of 50 ms or 250 ms, after which a cue appeared to the left or right of fixation. This was followed at a fixed 100-ms stimulus onset asynchrony by a target in the cued or uncued location. Attentional capture was measured by evaluating the speed to localize (Experiments 1 and 2) or discriminate (Experiment 3) targets in cued versus uncued locations. A subsequent yes-no recognition test confirmed a directed forgetting effect. Even though attention is purported to withdraw more readily after forget instructions than after remember instructions, we obtained no evidence for the corollary: Attention is not more readily captured by events that follow forget instructions. A forget instruction must therefore impact attention only insofar as withdrawal is needed to instantiate the intention to forget, without instigating a longer lasting distractibility.

Asymmetric response time functions during left-/right-facing discriminations of rotated objects: The short and the long of it.

When deciding if a rotated object would face to the left or to the right, if imagined at the upright, mental rotation is typically assumed to be carried out through the shortest angular distance to the upright prior to determining the direction of facing. However, the response time functions for left- and right-facing objects are oppositely asymmetric, which is not consistent with the standard explanation. Using Searle and Hamm's individual differences adaption of Kung and Hamm's Mixture Model, the current study compares the predicted response time functions derived when assuming that objects are rotated through the shortest route to the upright with the predicted response time functions derived when assuming that objects are rotated in the direction they face. The latter model provides a better fit to the majority of the individual data. This allows us to conclude that, when deciding if rotated objects would face to the left or to the right if imagined at the upright, mental rotation is carried out in the direction that the objects face and not necessarily in the shortest direction to the upright. By comparing results for mobile and immobile object sets we can also conclude that semantic information regarding the mobility of an object does not appear to influence the speed of mental rotation, but it does appear to influence pre-rotation processes and the likelihood of employing a mental rotation strategy.

Influence of Physical Activity on Human Sensory Long-Term Potentiation.

A growing body of literature has explored the influence of physical activity on brain structure and function. While the mechanisms of this relationship remain largely speculative, recent research suggests that one of the effects of physical exercise is an increase in synaptic long-term potentiation (LTP). This has not yet been explored directly in humans due to the difficulty of measuring LTP non-invasively. However, we have previously established that LTP-like changes in visual-evoked potentials (VEPs) can be measured in humans. Here, we investigated whether physical fitness status affects the degree of visual sensory LTP. Using a self-report measure of physical activity, participants were split into two groups: a high-activity group, and a low-activity group. LTP was measured and compared between the two groups using the previously established electroencephalography-LTP paradigm, which assesses the degree to which the N1b component of the VEP elicited by a sine grating is potentiated (enhanced) following a rapid "tetanic" presentation of that grating. Both groups demonstrated increased negativity in the amplitude of the N1b component of the VEP immediately after presentation of the visual "tetanus," indicating potentiation. However, after a 30-min rest period, the N1b for the high-activity group remained potentiated while the N1b for the low-activity group returned to baseline. This study presents the first evidence for the impact of self-reported levels of physical activity on LTP in humans, and sheds light on potential neurological mechanisms underlying the relationship between physical fitness and cognition.

Behavioural and electrophysiological effects related to semantic violations during braille reading.

This study investigated the potential to detect event related potentials (ERPs) occurring in response to a specific task in braille reading. This would expand current methodologies for studying the cognitive processes underlying braille reading. An N400 effect paradigm was utilised, whereby proficient blind braille readers read congruent- and incongruent-ending braille sentences. Kinematic and electroencephalography (EEG) data were obtained simultaneously and synchronised. The ERPs differed between the incongruent and congruent sentences in a manner consistent with the N400 effect found with a previous sighted reading paradigm, demonstrating that ERPs can be obtained during braille reading. The frequency of finger reversals and the degree of intermittency in the finger velocity were significantly higher when reading incongruent versus congruent sentence endings. Both reversals and the potential N400 effect may reflect processes involved in semantic unification. These findings have significant implications for the modelling of braille reading. The refinement of the technique will enable other ERPs to be identified and related to behavioural responses, to further our understanding of the braille reading process.

Neural correlates of illusory line motion.

Illusory line motion (ILM) refers to a motion illusion in which a flash at one end of a bar prior to the bar's instantaneous presentation or removal results in the percept of motion. While some theories attribute the origin of ILM to attention or early perceptual mechanisms, others have proposed that ILM results from impletion mechanisms that reinterpret the static bar as one in motion. The current functional magnetic resonance imaging study examined participants while they made decisions about the direction of motion in which a bar appeared to be removed. Preceding the instantaneous removal of the bar with a flash at one end resulted in a motion percept away from the flash. If this flash and the bar's removal overlapped in time, it appeared that the bar was removed towards the flash (reverse ILM). Independent of the motion type, brain responses indicated activations in areas associated with motion (MT+), endogenous and exogenous attention (intraparietal sulcus, frontal eye fields, and ventral frontal cortex), and response selection (ACC). ILM was associated with lower percept scores and higher activations in ACC relative to real motion, but no differences in shape-selective areas emerged. This pattern of brain activation is consistent with the attentional gradient model or bottom-up accounts of ILM in preference to impletion.

Effects of memory instruction on attention and information processing: Further investigation of inhibition of return in item-method directed forgetting.

In the item-method directed-forgetting paradigm, the magnitude of inhibition of return (IOR) is larger after an instruction to forget (F) than after an instruction to remember (R). In the present experiments, we further investigated this increased magnitude of IOR after F as compared to R memory instructions (dubbed the F > R IOR difference), in order to understand both the consequences for information processing and the purpose of the differential withdrawal of attention that results in this difference. Words were presented in one of four peripheral locations, followed by either an F or an R memory instruction. Then, a target appeared in either the same location as the previous word or one of the other locations. The results showed that the F > R IOR difference cannot be explained by attentional momentum (Exp. 1), that the spatial compatibility of the response options with target locations is not necessary for the F > R IOR difference to emerge (Exp. 2), and that the F > R IOR difference is location-specific rather than response-specific (Exp. 3). These results are consistent with the view that F > R IOR represents a bias against responding to information emanating from an unreliable source (Taylor & Fawcett, 2011).