Examining inhibition of return with onset and offset cues in the multiple-cuing paradigm

Location-cued visual selection-Placeholder dots improve target identification

Visual cues help to select a target and attract attention to it. In the present study, a 50-ms exogenous cue was presented to select one of 80 tilted lines, and attention effects at various delays were measured as the time observers needed to identify this target. Like in earlier detection studies, there was a transient cuing effect; targets presented soon after the cue (delays of 50-300 ms) were identified particularly fast. This benefit was followed by a continuous decay of performance toward longer delays (measured up to 5 s), at which the necessary presentation time to identify the target was strongly increased. The decay was substantially reduced when placeholder dots were shown during the delay, at subsequent line positions. The simple presentation of a structured background in the form of random dots did not have this effect. When the presentation times for constant performance were taken to compute the presumed strength of underlying neural responses, the effect of placeholders was seen as a nearly constant addition to the cued target signals, with an additional transient peak about 100 ms after cue (and placeholders) onset.

Placeholders dissociate two forms of inhibition of return

Decades of research using Posner's classic spatial cueing paradigm has uncovered at least two forms of inhibition of return (IOR) in the aftermath of an exogenous, peripheral orienting cue. One prominent dissociation concerns the role of covert and overt orienting in generating IOR effects that relate to perception- and action-oriented processes, respectively. Another prominent dissociation concerns the role of covert and overt orienting in generating IOR effects that depend on object- and space-based representation, respectively. Our objective was to evaluate whether these dichotomies are functionally equivalent by manipulating placeholder object presence in the cueing paradigm. By discouraging eye movements throughout, Experiments 1A and 1B validated a perception-oriented form of IOR that depended critically on placeholders. Experiment 2A demonstrated that IOR was robust without placeholders when eye movements went to the cue and back to fixation before the manual response target. In Experiment 2B, we replicated Experiment 2A's procedures except we discouraged eye movements. IOR was observed, albeit only weakly and significantly diminished relative to when eye movements were involved. We conclude that action-oriented IOR is robust against placeholders but that the magnitude of perception-oriented IOR is critically sensitive to placeholder presence when unwanted oculomotor activity can be ruled out.

Directional interactions between current and prior saccades

One way to explore how prior sensory and motor events impact eye movements is to ask someone to look to targets located about a central point, returning gaze to the central point after each eye movement. Concerned about the contribution of this return to center movement, Anderson et al. (2008) used a sequential saccade paradigm in which participants made a continuous series of saccades to peripheral targets that appeared to the left or right of the currently fixated location in a random sequence (the next eye movement began from the last target location). Examining the effects of previous saccades (n−x) on current saccade latency (n), they found that saccadic reaction times (RT) were reduced when the direction of the current saccade matched that of a preceding saccade (e.g., two left saccades), even when the two saccades in question were separated by multiple saccades in any direction. We examined if this pattern extends to conditions in which targets appear inside continuously marked locations that provide stable visual features (i.e., target “placeholders”) and when saccades are prompted by central arrows. Participants completed 3 conditions: peripheral targets (PT; continuous, sequential saccades to peripherally presented targets) without placeholders; PT with placeholders; and centrally presented arrows (CA; left or right pointing arrows at the currently fixated location instructing participants to saccade to the left or right). We found reduced saccadic RT when the immediately preceding saccade (n−1) was in the same (vs. opposite) direction in the PT without placeholders and CA conditions. This effect varied when considering the effect of the previous 2–5 (n−x) saccades on current saccade latency (n). The effects of previous eye movements on current saccade latency may be determined by multiple, time-varying mechanisms related to sensory (i.e., retinotopic location), motor (i.e., saccade direction), and environmental (i.e., persistent visual objects) factors.

Multiple cueing dissociates location- and feature-based repetition effects

There is an extensive literature on the phenomenon of inhibition of return (IOR): When attention is drawn to a peripheral location and then removed, response time is delayed if a target appears in the previously inspected location. Recent research suggests that non-spatial attribute repetition (i.e., if a target shares a feature like color with the earlier, cueing, stimulus) can have a similar inhibitory effect, at least when the target appears in the previously cued location. What remains unknown is whether location- and feature-based inhibitory effects can be dissociated. In the present study, we used a multiple cueing approach to investigate the properties of location- and feature-based repetition effects. In two experiments (detection, and discrimination), location-based IOR was absent but feature-based inhibition was consistently observed. Thus, the present results indicate that feature- and location-based inhibitory effects are dissociable. The results also provide support for the view that the attentional consequences of multiple cues reflect the overall center of gravity of the cues. We suggest that the repetition costs associated with feature and location repetition may be best understood as a consequence of the pattern of activation for object files associated with the stimuli present in the displays.

Spatial distribution of attentional inhibition is not altered in healthy aging

Inhibition of return (IOR) is a phenomenon of attentional orienting that is indexed by slower responses to targets presented at previously attended locations. The purpose of this study was to examine adult age differences in the distribution of IOR to multiple locations. In three experiments, young adults (ages 18-30 years) and older adults (ages 60-87 years) completed an IOR task that varied in the number of simultaneous onset cues (one to seven) and the number of display locations (four or eight). Analyses were conducted to explore whether IOR patterns were most consistent with limited inhibitory resources, with regional distribution of inhibition, or with vector averaging of cues. The IOR effects were most consistent with vector averaging, such that multiple cues initiated a directional gradient of inhibition centered on the average direction of the cues. The IOR patterns varied minimally with age, consistent with the conclusion that older adults and young adults distributed inhibition in a similar manner.

Inhibitory interaction: the effects of multiple non-predictive visual cues

When the interval between a non-predictive cue and a target appearing at the same spatial location is longer than about 200 ms, target performance is typically poorer than when the cue and target appear at different locations. Recent studies have shown that this effect, known as inhibition of return (IOR), can occur at multiple cued locations, and is enhanced when multiple cues are presented at the same spatial location. However, little is known about how the magnitude of IOR at one spatial location is influenced by a subsequent or preceding cue presented at a different spatial location. We investigated this issue by presenting single or multiple cues at varying inter-cue intervals prior to target onset. Results suggest that the magnitude of IOR at a given location is influenced by the presentation of a preceding cue, but that once IOR occurs, it is unaffected by the presentation of a subsequent cue.

Better late than never: how onsets and offsets influence prior entry and exit

The three experiments presented in the paper examine visual prior entry (determining which of two stimuli appeared first) and prior exit (determining which of two stimuli disappeared first) effects with a temporal order judgment (TOJ) task. In addition to using onset and offset targets, the preceding cues also consisted of either onset or offset stimuli. Typical, and equivalent, prior entry effects were found when either onset or offset cues preceded the onset targets. Unexpectedly large prior exit effects where found with the offset targets, with offset cues producing greater capture effects than onset cues. These findings are consistent with the notion that more attention is allocated to searching the visual field when targets are more difficult to find. In addition, the results indicate that attentional control settings may be more likely to occur with more difficult searches. In addition, these findings demonstrate that TOJ tasks provide extremely precise measures of the allocation of attention and are very sensitive to a range of task manipulations.

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.

Latency facilitation in temporal-order judgments: time course of facilitation as a function of judgment type

The paper is concerned with two models of early visual processing which predict that priming of a visual mask by a preceding masked stimulus speeds up conscious perception of the mask (perceptual latency priming). One model ascribes this speed-up to facilitation by visuo-spatial attention [Scharlau, I., & Neumann, O. (2003a). Perceptual latency priming by masked and unmasked stimuli: Evidence for an attentional explanation. Psychological Research 67, 184-197], the other attributes it to nonspecific upgrading mediated by retino-thalamic and thalamo-cortical pathways [Bachmann, T. (1994). Psychophysiology of visual masking: The fine structure of conscious experience. Commack, NY: Nova Science Publishers]. The models make different predictions about the time course of perceptual latency priming. Four experiments test these predictions. The results provide more support for the attentional than for the upgrading model. The experiments further demonstrate that testing latency facilitation with temporal-order judgments may induce a methodological problem resulting in fairly low estimates. A method which provides a more exhaustive measure is suggested and tested.

Selection-for-action in visual search

Grasping an object rather than pointing to it enhances processing of its orientation but not its color. Apparently, visual discrimination is selectively enhanced for a behaviorally relevant feature. In two experiments we investigated the limitations and targets of this bias. Specifically, in Experiment 1 we were interested to find out whether the effect is capacity demanding, therefore we manipulated the set-size of the display. The results indicated a clear cognitive processing capacity requirement, i.e. the magnitude of the effect decreased for a larger set size. Consequently, in Experiment 2, we investigated if the enhancement effect occurs only at the level of behaviorally relevant feature or at a level common to different features. Therefore we manipulated the discriminability of the behaviorally neutral feature (color). Again, results showed that this manipulation influenced the action enhancement of the behaviorally relevant feature. Particularly, the effect of the color manipulation on the action enhancement suggests that the action effect is more likely to bias the competition between different visual features rather than to enhance the processing of the relevant feature. We offer a theoretical account that integrates the action-intention effect within the biased competition model of visual selective attention.