The specificity of the search template Mary J. Bravo Hany Farid

1. The specificity of the search templateMary J. Bravo HanyFarid Leona Ryan, Ben Peterson, Josh Diton

2. Research Topic • The researchers wanted to learn how specific search templates are in a complex environment, like in everyday situations. • A lot of research has been shown that we use search templates, so it is known that they exist. How they function, what they use, and the characteristics were still unknown.

3. Important terms • Selective attention: The ability to attend to things that are important in the visual field and ignore those that aren’t • Search template: A stored representation of an object/ set of objects, that attention uses to selectively attend to objects • Perceptual Priming: An implicit memory effect that is driven by prior exposure

4. Previous Research • Bundesen, 1990: His work provided quantitative evidence that attention requires something, like a search template, to be as efficient as it is. • Other empirical support for the existence of a search template can be seen in Chelazzi et al. 1993. • Search templates were characterized as either generic or specific, there wasn’t consensus between different experimenters

5. Goals of the experiments • Are search templates represented of a specific image or set of general features? • Experimenters thought it was more likely that it was in between • Hypothesis: Search templates are specific to particular objects or types of objects, but can account for variation in size and orientation

6. Logic of the experiment • The authors wanted to explore the search template. There are two key points: • Complex/realistic stimuli • Avoiding/controlling for priming effects • So they decided to using naming cues instead of image cues • They used different species of fish as targets in a complex environment

7. Sample stimuli This is an example of some of the complex environments used in the study

8. Logic continued • Manipulated factors: • Presence of fish • Size/orientation of fish • Same species, different fish • Generic cue vs. specific cue • Data collected in the form of response time for correct responses

9. Methods • Participants: 20 elementary psychology students • The stimuli was a random composite of coral background images • On every image there were 11 sea creatures randomly selected and located on the image • On present trials there was 1 fish randomly selected from a pool of 100 fish from 10 species • The fish could be an exact image of the selected fish, a transformed image, or a different fish from the same species

10. Fish sample stimuli Here are a few of the exact fish species used in the experiment

11. Experiment 1 Procedure • Visual search task • It consisted of 14 blocks of 40 trials, the first block was practice • A fish was present on 50% of the trials, of these they were split into four conditions: • Exact image of the fish • Transformed image of the fish • A different fish from the same species • A nonspecific cue (the word fish) • Subjects were cued with 1 of 4 cues followed by a brief blank screen then followed by the search task

12. Experiment 1Results • Designed as a control for experiment 2 • Control for priming effects • An identical cue provided a large advantage • This is good evidence that selective attention, and not priming, is at work for the search task

13. Experiment 2 • Experiment 2 used name cues instead of image cues for all of it’s trials • Because of this, all observers were trained on word-image pairings of 5 different fish species • Training lasted 50 minutes • Everyone completed with at least 90% accuracy • Actual testing took place 1-2 days after the training period

14. Experiment 2 procedure • The same conditions were used from condition 1, with naming cues instead of image cues • Including one extra condition for a new fish species • The cueing time was lengthened because auditory cues take longer to process (Vickery et al.,2005; Wolfe et al., 2004) • As in experiment 1, there were 14 blocks of 40 trials each

15. Experiment 2 results • Identical and transformed conditions were much faster • Same species didn’t have any benefit from the cue There is a major error in the graph key

16. Results/discussion • The results support the experimenters’ hypothesis • The search template is specific to object identity, but invariant to the transformation/view point orientation • It is not general enough to account for differences within the same species • This experiment may contradict earlier experiments • Prior experiments used very general features, like color or orientation

17. Conclusions • Before this experiment there wasn’t consensus on how specific the search template was • This experiment provided significant evidence for their hypothesis • Their sample size could be an issue to external validity • It was unclear why a name cue was used for the unspecific cue in the image cue experiment

18. Ways to improve the experiment • A larger sample size would be desirable • The study only used 10 subjects in each experiment • Make sure the graphs are keyed correctly • In the image experiment it may be better to use an image for the nonspecific cue • Use a smaller selection of composite images to be able to examine cueing effects for individual trials

19. Proposed future studies • Experimenters suggest looking at real world objects instead of images • Objects provide virtually unlimited amounts of images from different orientations • Create a study to see if facial recognition uses the same mechanisms examined in this study