Attentional processing of “unattended” flankers: Evidence for a failure of selective attention

Abstract

Results from research with the flanker task have been used to argue both that flankers are identified without attention and that flanker identificatin requires attention. In three experiments, we addressed this issue by examining flanker recall. In Experiment 1, we manipulated flanker redundancy, a variable that could influence attention to the flankers, in order to determine whether it affected the magnitude of the flanker effect, the magnitude of flanker recall, or both. Redundancy did not influence the flanker effect, and recall was high in both conditions, suggesting that the flankers were attended. The recall results contradicted those of Miller (1987), the only other study that we could find in which flanker recall was used. In Experiments 2 and 3, we examined differences between Miller's procedure and ours. Although flanker recall was lower when open-ended rather than forced recall was used and when the flanker task was made more complicated, flanker recall remained well above chance in all conditions. The data strongly suggest that in the typical correlated flanker task there is a failure of selective attention at some point during processing such that flankers receive attentional processing.

Flanker recall and the flanker validity effect may reflect different attentional processes

“…They used the argument previously applied to the Eriksen flanker task: Because a factor that allowed participants to focus their attention on just the target (i.e., location cuing) reduced the magnitude of the FVE, the FVE might be reflecting attentional processing of the flankers' identities that occurs because of a failure of selective attention (see, also, Stadler & Proctor, 1993). Schmidt and Dark (1998) offered further support for this interpretation. They used flanker recall as a measure of the attentional processing of the flankers' identities (cf.…”

“…The high flanker recall reported by Schmidt and Dark (1998) indicated that the identities offlankers in the correlated flanker task are attentionally processed, but it is not clear from the extant data whether the attentional processing of the flankers' identities is related to the FVE. The fact that flankers are receiving sufficient levels of attentional processing to be identified on a latter recall test does not, in itself, imply that the FVE depends on this processing.…”

“…First, the data showed that overall response times were roughly 60 msec slower during Block 2 than during Block 1. In the standard conditions run in our lab (see Schmidt & Dark, 1998) and in Miller's lab (see Miller, 1987, Experiment 2), the participants generally get faster from the first half to the second half of the experiment. The participants in Experiment 2 may have slowed down during Block 2, in order to figure out what the flankers were, in case they were asked to report them.…”

“…Of interest in the correlated flanker task are responses to two types of trials: valid trials, in which the flankers are highly correlated with the same response as that required by the target (and, therefore, validly cue the target response), and invalid trials, in which the flankers are highly correlated with the other response (and, therefore, invalidly cue the target response). Research with the correlated flanker task has shown that response times are slowed to targets on invalid trials, relative to valid trials (e.g., Carlson & Flowers, 1996;Miller, 1987Miller, , 1991Paquet & Lortie, 1990;Schmidt & Dark, 1998;Stadler & Proctor, 1993). That is, response times showed that participants are influenced by the flanker-response correlations.…”

“…Schmidt and Dark (1998) argued that flanker recall was a sensitive measure of trial-by-trial attentional processing of flanker identity, and they assumed that assessing flanker recall near the end of the experiment successfully tapped into the sum ofattentional processing ofthe flankers' identites over all trials. If, however, flanker recall, a discrete measure obtained at the end of the trials, only reflects the attentional processing of flankers' identities on an atypical subset of the trials, flanker recall may not provide information about attentional processing on the majority oftrials (i.e., the trials that contribute to the FVE).…”