Semantic Activation Alone Is Insufficient to Produce an

1
Semantic Activation Alone Is Insufficient to
Produce an Involuntary Attentional
Blink Veronica J. Dark and Amy L. Ramos Iowa
State University

• Introduction
• Pashler and Shiu (1999) showed that after
  people formed a mental image of an object, if a
  picture of the imagined object occurred in a
  subsequent RSVP stream of pictures, it would
  capture attention and cause an Attentional Blink
  (AB) in which subjects were less accurate in
  identifying the digit when the critical picture
  occurred before rather than after a digit target.
  
• Dark, Vochatzer, and VanVoorhis (1996) showed
  that semantic activation from silently reading a
  word was sufficiently strong to lead to
  "selection" of the word in a pair that was
  related to a preceding prime word that is,
  priming (or prior semantic activation) produced
  selective attention. Based on this finding, the
  current study asked whether semantic activation
  alone would be sufficient to produce the AB
  effect reported by Pashler and Shiu.
• Current Experiment
• Subjects performed one of the following four
  tasks on a word presented prior to each RSVP
  stream
• form an image of the word
• categorize the word as a living thing (or a
  part thereof)
• silently read the word, or read the word aloud
• If the AB is solely due to semantic activation's
  leading to the capture of attention, then all
  four groups should show an AB.

• Method
• Groups
• Three groups of 16 each were randomly assigned
  to the image, categorize and silent read word
  tasks. A subsequent group of 16 was assigned to
  read the word aloud. Each trial began with a
  word. Image subjects formed an image, which was
  rated for clarity. Categorization subjects
  indicated their response via a keypress. In both
  cases, the word stayed on the screen until a
  response. For both read groups, the word was
  presented for 1200 msec.
• Procedure
• Each RSVP stream consisted of four pictures
  before and four pictures after the digit plus
  mask. The critical picture was either picture 3
  (before) or picture 5 (after). Pictures were
  line drawings of common objects shown for 112
  msec. Each picture was seen only twice, once in
  the first block of 36 trials and once in the
  second block. Digit duration was individually
  set for each participant and averaged 61 msec
  with a 51 msec mask (the two summed to 112 msec).
  Displays were presented via E-Prime the screen
  refresh rate was 12 msec. Participants responded
  via the keypad and received accuracy feedback.
• Results
• Table 1. Proportion Correct Report of Digits as
  a Function of Group and Picture Location
• Image
  Categorize Silent Read Read
  Aloud
• M SE M
  SE M SE M SE
• Before .64 .017 .66 .017
  .69 .026 .69 .019
• After .71 .022 .67 .021
  .71 .02 .63 .022
• Difference .07 .028 .01 .021
  -.02 .026 .06 .026
• A two-way ANOVA with Word Task (image,
  categorize, silent read, or read aloud) as a
  between-subjects variable and critical picture
  Location (before or after) as a within-subject
  variable showed a main effect of Location, F (1,
  60) 6.72, p .012, and a Word Task x Location
  interaction, F (3, 60) 3.02, p .037, MSE
  .0051 for both. The simple main effect of
  location was reliable for the image and read
  aloud groups, but not the categorization and
  silent read groups.

• Results cont.
• After completing the task, subjects were asked
  whether they noticed that sometimes a picture of
  the word occurred in the digit task. The
  proportions responding that they noticed were
  78, 57, 38, and 63 respectively for the
  image, categorize, silent read, and read aloud
  groups.
• Discussion
• The image condition replicated the results of
  Pashler and Shiu. A picture of a just-imaged
  object appears to capture attention even when it
  is briefly presented and is not a target.
  Although the categorization response required
  access to the word's meaning, there was no
  evidence that a subsequent picture of the
  categorized word attracted attention. Thus,
  semantic activation alone is insufficient to
  produce an involuntary AB in the digit task.
• Dark et al. showed involuntary semantic
  selection following silent reading of a prime.
  In the current study, there was an AB with the
  read aloud condition, but not the silent read
  condition. Part of the difference may be due to
  instructions. The silent read group was told
  that they were a "control" group because they did
  not need to make a response to the word like
  other groups. Comments during the debriefing and
  the low proportion of subjects noticing the
  word-picture relationship suggest that the
  subjects may have actively ignored the word.
• Finally, we note that the two tasks producing
  an AB required overt responses that were unique
  to each word. This might be the property related
  to obtaining an AB.
• References
• Dark, V. J., Vochatzer, K., VanVoorhis, B.
  (1996) Semantic and spatial components of
• selective attention. Journal of
  Experimental Psychology Human Perception
  Performance,
• 22, 63-81
• Pashler, H. Shiu, L. (1999). Do images
  involuntarily trigger search? A test of
  Pillsbury's
• hypothesis. Psychonomic Bulletin Review,
  6, 445-448.
• Abstract Erratum

RSVP stream