Shape specific inhibition of return

How modality processing differences affect cross-modal nonspatial repetition inhibition

Although previous studies have demonstrated that identity-based repetition inhibition could occur across modalities, whether the modality processing difference or attentional set caused differences between the unimodal and cross-modal conditions was unknown. To investigate this question in both visual-auditory and auditory-visual patterns, the present study adopted a cross-modal "prime-neutral cue-target" priming paradigm, in which a neutral event was presented between the prime and the target. The relationships of the identities and modalities between the prime and the target were manipulated such that their modalities and identities could either be the same or different. Our results showed that (a) identity-based repetition inhibition occurred under both unimodal and cross-modal conditions, (b) response times to auditory targets were slower than those to visual targets, and (c) identity-based repetition inhibition was larger while discriminating repeated auditory targets than visual targets regardless of whether the prime was visual or auditory. These results suggested that nonspatial repetition inhibition can occur across modalities and that it was not in general larger or smaller than unimodal repetition inhibition, as this difference was due to modality processing differences.

Different visual and auditory latencies affect cross-modal non-spatial repetition inhibition

The present study examined the effect of different latencies for processing visual and auditory stimuli in cross-modal non-spatial repetition inhibition. In two experiments, the cue validity of modality and identity between the prime and the target was manipulated in a "prime-neutral cue-target" paradigm. A distinct neutral event was presented after the prime and before the onset of the target. The prime probe was visual in Experiment 1 and auditory in Experiment 2. The results in both experiments showed that RTs for identity-cued trials were significantly slower than RTs for identity-cued trials regardless of whether the modality of the target was visual or auditory. In addition, RTs for visual trials were significantly faster than RTs for auditory trials, indicating different latencies of processing visual and auditory stimuli. This latency difference affects cross-modal non-spatial repetition inhibition in two aspects: 1) creating a new representation (identity uncued) that is delivered via visual modality is easier under audio-visual conditions, and 2) retrieving an inhibited representation (identity cued) that is delivered via auditory modality is more difficult under visual-audio conditions. We propose that cross-modal non-spatial repetition inhibition, which is distinct from unimodal repetition inhibition, can be easily influenced by different latencies of processing visual and auditory stimuli.

Reprint of: Object-based attentional facilitation and inhibition are neuropsychologically dissociated

Salient peripheral cues produce a transient shift of attention which is superseded by a sustained inhibitory effect. Cueing part of an object produces an inhibitory cueing effect (ICE) that spreads throughout the object. In dynamic scenes the ICE stays with objects as they move. We examined object-centred attentional facilitation and inhibition in a patient with visual form agnosia. There was no evidence of object-centred attentional facilitation. In contrast, object-centred ICE was observed in 3 out of 4 tasks. These inhibitory effects were strongest where cues to objecthood were highly salient. These data are evidence of a neuropsychological dissociation between the facilitatory and inhibitory effects of attentional cueing. From a theoretical perspective the findings suggest that 'grouped arrays' are sufficient for object-based inhibition, but insufficient to generate object-centred attentional facilitation.

The Role of Surface Feature Continuity in Object-based Inhibition of Return

The contribution of surface feature continuity to object-based inhibition of return (IOR) was tested in three experiments. Participants executed a saccade to a previously fixated or unfixated colored disk after the object had moved to a new location. Object-based IOR was observed as lengthened saccade latency to a previously fixated object. The consistency of surface feature (color) and spatiotemporal information was manipulated to examine the feature used to define the persisting objects to which inhibition is assigned. If the two objects traded colors during motion, object-based IOR was reliably reduced (Experiment 2), suggesting a role for surface feature properties in defining the objects of object-based IOR. However, if the two objects changed to new colors during motion, object-based IOR was preserved (Experiment 1), and color consistency was not sufficient to support object continuity across a salient spatiotemporal discontinuity (Experiment 3). These results suggest that surface feature consistency plays a significant role in defining object persistence for the purpose of IOR, although surface features may be weighted less strongly than spatiotemporal features in this domain.