Biomedical subjects

Steven P Tipper

Publications and source records attributed to Steven P Tipper.

At least 19 recordsLinked to original sources

PubMed2006

Focusing on body sites: the role of spatial attention in action perception.

Humans use the same representations to code self-produced and observed actions. Neurophysiological evidence for this view comes from the discovery of the so-called mirror neurons in premotor cortex of the macaque monkey. These neurons respond when the monkey performs a particular action but also when it observes the same behavior in another individual. In humans, such direct links between perception and action seem to mediate action priming, where a response is facilitated when a similar action is observed. An issue that has not been fully resolved concerns the role of selective attention in these processes. Action priming appears to be an automatic process in the sense that the observed action can be irrelevant to the observer's task and nevertheless prime similar responses. However, it is not known whether attention has to be oriented to the action for these processes to be engaged. It is demonstrated here that spatial attention indeed has to be oriented to the action related body site for action priming to take place. Furthermore, if attention is oriented to the appropriate body site, there need be no visual cues to action for action priming to emerge.

Accommodation, Ocular↗

PubMed2006

Affective evaluations of objects are influenced by observed gaze direction and emotional expression.

Gaze direction signals another person's focus of interest. Facial expressions convey information about their mental state. Appropriate responses to these signals should reflect their combined influence, yet current evidence suggests that gaze-cueing effects for objects near an observed face are not modulated by its emotional expression. Here, we extend the investigation of perceived gaze direction and emotional expression by considering their combined influence on affective judgments. While traditional response-time measures revealed equal gaze-cueing effects for happy and disgust faces, affective evaluations critically depended on the combined product of gaze and emotion. Target objects looked at with a happy expression were liked more than objects looked at with a disgust expression. Objects not looked at were rated equally for both expressions. Our results demonstrate that facial expression does modulate the way that observers utilize gaze cues: Objects attended by others are evaluated according to the valence of their facial expression.

Adult↗

PubMed2006

Inhibition of return and action affordances.

Previous work has shown that inhibition of return (IOR) operates on identity-specific object representations and does not spread to semantically related items (Morgan et al. in Eur J Cogn Psychol 17(4):499-520, 2005). The current study further examines the representations underlying IOR by investigating whether IOR is influenced by action-related properties of objects. An exogenous cue appeared on the side of an object that was either compatible or incompatible with the action afforded by the object. Then a target requiring a rapid key-press or reach localisation response appeared on the cued or uncued side. Responses were slower to cued versus uncued targets, but this IOR effect did not interact with action-compatibility. These results show that IOR does not appear to operate on visuomotor representations.

Adolescent↗

PubMed2006

Implicit action encoding influences personal-trait judgments.

When an observed action (e.g., kicking) is compatible to a to be produced action (e.g., a foot-key response as compared to a finger-key response), then the self-produced action is more fluent, that is, it is more accurate and faster. A series of experiments explore the notion that vision-action compatibility effects can influence personal-trait judgments. It is demonstrated that when an observed individual carries out an action that is compatible with the participants' response, (1) this individual is identified more fluently, and (2) the observed individual's personality is attributed with the properties of the observed action. For example, if it is easier to identify one individual with a foot-response when he is seen kicking a ball, as compared to typing, he is perceived to be more 'sporty'. In contrast, if it is easier to identify one individual with a finger response when he is seen typing as compared to kicking a ball, he is associated with the 'academic' trait. These personal-trait judgment effects can be observed with explicit measures, where participants are asked to rate the sporty/academic nature of the person on a scale. They are also obtained when implicit measures are taken in a priming task, where participants are never explicitly asked to rate the personalities of the individuals. A control experiment rules out that these personal-trait effects are merely due to an association of motor responses (foot, finger) to individuals while identifying them, but that these effects depend on a prior manipulation of vision-action fluency.

Adolescent↗

PubMed2006

Spatial negative priming in early Alzheimer's disease: evidence for reduced cognitive inhibition.

Some studies of negative priming and other tasks assumed to reflect inhibitory functions suggest a decline in inhibitory processes in Alzheimer's disease. However, none of the measures used in previous studies can be interpreted as an unambiguous reflection of distractor inhibition. The present study investigates whether reductions in negative priming associated with Alzheimer's disease reflect reduced distractor inhibition, rather than perceptual review processes. Individuals with early Alzheimer's disease were predicted to show reduced negative priming on a spatial localization task designed to provide an unambiguous measure of distractor inhibition. Sixteen clinical participants showed significantly less negative priming than old and young healthy control groups, which is interpreted as evidence for reduced distractor inhibition in early dementia. A second analysis indicated that, within the clinical sample only, negative priming effect size was significantly correlated with prime trial response speed. Clinical participants showing the least negative priming were slower to respond to an initial stimulus. The results may mean that people with early Alzheimer's disease have a reduced capacity to use excitatory as well as inhibitory processes in selection.

Age Factors↗

PubMed2006

Bend it like Beckham: embodying the motor skills of famous athletes.

Observing an action activates the same representations as does the actual performance of the action. Here we show for the first time that the action system can also be activated in the complete absence of action perception. When the participants had to identify the faces of famous athletes, the responses were influenced by their similarity to the motor skills of the athletes. Thus, the motor skills of the viewed athletes were retrieved automatically during person identification and had a direct influence on the action system of the observer. However, our results also indicated that motor behaviours that are implicit characteristics of other people are represented differently from when actions are directly observed. That is, unlike the facilitatory effects reported when actions were seen, the embodiment of the motor behaviour that is not concurrently perceived gave rise to contrast effects where responses similar to the behaviour of the athletes were inhibited.

Adolescent↗

PubMed2006

Predictive gaze cues and personality judgments: Should eye trust you?

Although following another person's gaze is essential in fluent social interactions, the reflexive nature of this gaze-cuing effect means that gaze can be used to deceive. In a gaze-cuing procedure, participants were presented with several faces that looked to the left or right. Some faces always looked to the target (predictive-valid), some never looked to the target (predictive-invalid), and others looked toward and away from the target in equal proportions (nonpredictive). The standard gaze-cuing effects appeared to be unaffected by these contingencies. Nevertheless, participants tended to choose the predictive-valid faces as appearing more trustworthy than the predictive-invalid faces. This effect was negatively related to scores on a scale assessing autistic-like traits. Further, we present tentative evidence that the "deceptive" faces were encoded more strongly in memory than the "cooperative" faces. These data demonstrate the important interactions among attention, gaze perception, facial identity recognition, and personality judgments.

Adult↗

PubMed2006

Gaze cues evoke both spatial and object-centered shifts of attention.

When someone observes another individual suddenly shifting gaze, the observer's attention automatically and rapidly orients to the same location. Such gaze cuing of attention has properties similar to those of exogenous cuing. We investigated whether gaze cuing is also like exogenous cuing in that it is observed for both spatial and object-/head-centered frames of reference. That is, when the face that produces the gaze cue is presented on its side, tilted 90 degrees from upright, will attention be simultaneously directed to where the eyes would have been looking if the face had been presented upright and toward the actual spatial direction of gaze? It is demonstrated that gaze cues do indeed orient attention in both spatial and object-centered frames, that these effects are of similar magnitude, and that such orienting is relatively rapidly computed.

Adult↗

PubMed2006

Vision-for-action: the effects of object property discrimination and action state on affordance compatibility effects.

When a person views an object, the action the object evokes appears to be activated independently of the person's intention to act. We demonstrate two further properties of this vision-to-action process. First, it is not completely automatic, but is determined by the stimulus properties of the object that are attended. Thus, when a person discriminates the shape of an object, action affordance effects are observed; but when a person discriminates an object's color, no affordance effects are observed. The former, shape property is associated with action, such as how an object might be grasped; the latter, color property is irrelevant to action. Second, we also show that the action state of an object influences evoked action. Thus, active objects, with which current action is implied, produce larger affordance effects than passive objects, with which no action is implied. We suggest that the active object activates action simulation processes similar to those proposed in mirror systems.

Adult↗

PubMed2005

Implicitly evoked actions modulate visual selection: evidence from parietal extinction.

It has been proposed that the mental representation of a graspable object involves not only a description of its visual properties but also encodings of the motor programs to act upon it. Thus, observing a handle automatically primes the motor programs responsible for reaching and grasping it. Here, we provide neurological evidence that such action-related object features can bias visual selection. Two patients with visual extinction after right-parietal injury detected cups with left- or right-oriented handles, briefly displayed in either or both visual fields. People with this disorder have deficient awareness for stimuli toward the contralesional, left side of space, especially when competing stimuli appear further to the right. This contralesional extinction was significantly reduced when cups had handles affording a left-hand grasp, even though no hand response was required. No effect was found when handles were replaced with patches equated for position, size, and mean luminance. These data suggest that action-related information may be correctly extracted by the visual system, even though they are unavailable for conscious report. It is proposed that an object affordance for grasping modulates attentional selection by activating specific motor schema that, in turn, enhance the competitive strength of that object representation.

Aged, 80 and over↗

PubMed2005

Sex differences in eye gaze and symbolic cueing of attention.

Observing a face with averted eyes results in a reflexive shift of attention to the gazed-at location. Here we present results that show that this effect is weaker in males than in females (Experiment 1). This result is predicted by the 'extreme male brain' theory of autism (Baron-Cohen, 2003), which suggests that males in the normal population should display more autism-like traits than females (e.g., poor joint attention). Indeed, participants' scores on the Autism-Spectrum Quotient (Baron-Cohen, Wheelwright, Stott, Bolton, & Goodyear, 2001) negatively correlated with cueing magnitude. Furthermore, exogenous orienting did not differ between the sexes in two peripheral cueing experiments (Experiments 2a and 2b). However, a final experiment showed that using nonpredictive arrows instead of eyes as a central cue also revealed a large gender difference. This demonstrates that reduced orienting from central cues in males generalizes beyond gaze cues. These results show that while peripheral cueing is equivalent in the male and female brains, the attention systems of the two sexes treat noninformative symbolic cues very differently.

Adolescent↗

PubMed2005

Long-term negative priming: support for retrieval of prior attentional processes.

Negative priming reveals that participants respond slowly to a probe target that was a task-irrelevant distractor in the preceding prime display (e.g., Tipper, 1985) and is thought to reflect processes mediating short-term behaviour. However, since the first surprising reports that negative priming is found with meaningless stimuli across delays of 30 days (e.g., DeSchepper & Treisman, 1996), researchers have questioned the existence of long-term negative priming effects. Because long-term negative priming could indicate that task-irrelevant information leaves a memory trace that impacts performance over time, such a finding is of immense theoretical importance. Indeed, the current research finds support for the existence of long-term negative priming as well as its generality across different stimuli and conditions. The authors propose that the initial processes that prevent response to irrelevant stimuli may be stored in memory, where retrieval of these processes can mediate behaviour over time.

Adolescent↗

PubMed2005

Attentional inhibition has social-emotional consequences for unfamiliar faces.

Visual attention studies often rely on response time measures to show the impact of attentional facilitation and inhibition. Here we extend the investigation of the effects of attention on behavior and show that prior attentional states associated with unfamiliar faces can influence subsequent social-emotional judgments about those faces. Participants were shown pairs of face images and were asked to withhold a response if a transparent stop-signal cue appeared over one of the faces. This served to associate the cued face with an inhibitory state. Later, when asked to make social-emotional choices about these face pairs, participants chose uncued faces more often than cued faces as "more trustworthy" and chose cued faces more often than uncued faces as "less trustworthy." For perceptual choices, there was no effect of how the question was framed (which face is "on a lighter background" vs. "on a darker background"). These results suggest that attentional inhibition can be associated with socially relevant stimuli, such as faces, and can have specific, deleterious effects on social-emotional judgments.

Attention↗

PubMed2005

Gaze and arrow cueing of attention reveals individual differences along the autism spectrum as a function of target context.

Observing averted gaze results in a reflexive shift of attention to the gazed-at location. In two experiments, participants scoring high and low on the Autism-Spectrum Quotient questionnaire (AQ; Baron-Cohen, Wheelwright, Skinner, Martin, & Clubley, 2001) observed arrow and gaze cues to investigate cueing effect magnitude as a function of the context in which peripheral targets could appear. While identical cueing effects were found with gaze and arrow cues, the more striking results concerned target stimuli. In Experiment 1, targets could appear on a peripheral face, or on scrambled face parts. Overall, greater cueing effects were found when the target appeared on a face. However, this face bias was only observed in participants with low AQ scores, whereas high AQ scorers oriented more to scrambled features. Experiment 2 found equal cueing to targets appearing on tools, as compared with tool parts. However, individual differences were again observed, where low AQ scorers showed larger cueing towards tools, while high scorers oriented more to scrambled parts, as in Experiment 1. These results support the idea that low AQ individuals orient strongly to objects attended by others. However, since the same results were found for arrow cues, this effect may generalize to all central cues to attention. High AQ scorers possessing many more autistic-like traits tended to orient more to scrambled shapes, perhaps reflecting a bias for orienting to local details.

Adult↗

PubMed2005

Inhibition of object identity in inhibition of return: implications for encoding and retrieving inhibitory processes.

Inhibition of return (IOR) effects, in which participants detect a target in a cued box more slowly than one in an uncued box, suggest that behavior is aided by inhibition of recently attended irrelevant locations. To investigate the controversial question of whether inhibition can be applied to object identity in these tasks, in the present research we presented faces upright or inverted during cue and/or target sequences. IOR was greater when both cue and target faces were upright than when cue and/or target faces were inverted. Because the only difference between the conditions was the ease of facial recognition, this result indicates that inhibition was applied to object identity. Interestingly, inhibition of object identity affected IOR both when encoding a cue face and retrieving information about a target face. Accordingly, we propose that episodic retrieval of inhibition associated with object identity may mediate behavior in cuing tasks.

Adolescent↗

PubMed2004

Orienting of attention via observed eye gaze is head-centred.

Observing averted eye gaze results in the automatic allocation of attention to the gazed-at location. The role of the orientation of the face that produces the gaze cue was investigated. The eyes in the face could look left or right in a head-centred frame, but the face itself could be oriented 90 degrees clockwise or anticlockwise such that the eyes were gazing up or down. Significant cueing effects to targets presented to the left or right of the screen were found in these head orientation conditions. This suggests that attention was directed to the side to which the eyes would have been looking towards, had the face been presented upright. This finding provides evidence that head orientation can affect gaze following, even when the head orientation alone is not a social cue. It also shows that the mechanism responsible for the allocation of attention following a gaze cue can be influenced by intrinsic object-based (i.e. head-centred) properties of the task-irrelevant cue.

Adolescent↗

PubMed2004

Orienting attention via observed gaze shift evokes longer term inhibitory effects: implications for social interactions, attention, and memory.

One component of successful social interactions is joint attention. It is now well established that when a gaze shift is observed, the observer's attention rapidly and automatically orients to the same location in space. It is also established that such attention shifts via gaze are relatively transient and do not evoke subsequent inhibition processes. In contrast to this conventional view, the authors conducted a series of studies that showed that these properties of gaze attention shift are not necessarily the case in all situations. The article demonstrates (a) gaze cuing over longer intervals than previously observed, (b) that these longer term effects can be inhibitory, and (c) that the longer term gaze cuing effects do not appear to be contingent on retrieval associated with a particular face identity.

Adult↗

PubMed2004

Revealing effects of noninformative spatial cues: an EEG study of inhibition of return.

Simple responses to noninformatively cued spatial stimuli can be delayed whenever a cue has been briefly presented at the location of the subsequent target. This phenomenon (inhibition of return) might be due to a mechanism that inhibits irrelevant information. However, with sustained cues no inhibition is observed. It has been hypothesised that in the latter, task inhibition is masked by an excitation process. ERP measures support the inhibition-excitation account: (a) P1 suppression, assumed to reflect inhibition, was observed for all targets presented at a cued location. (b) A later negative component (Nd250) was increased with sustained cues, and hence might reflect the excitation process. (c) A negative component at right parietal electrode sites (Nd310) appeared only when inhibition of return was observed. A second study confirmed the link between these ERP components and mechanisms involved in inhibition of return.

Adult↗