Article Figures & Data
Figures
- Figure 1.
Hypotheses. Different neural processes and their interactions may mediate the selection of behaviorally relevant information from natural scenes. In the example, people are the object category that is relevant to ongoing behavior (i.e., target category) and cars are the object category that was previously but is not presently relevant (i.e., distracter category), whereas all other object categories present in the scene are never task relevant (i.e., neutral category, such as trees). If visual search in natural scenes is accomplished solely through the enhancement of relevant information, processing of the target category should be enhanced relative to both neutral and distracter categories (left). If category detection additionally requires the suppression of a previous attentional set, distracter processing should be reduced compared with processing of the neutral categories (right).
- Figure 3.
Analytical approach. A, Definition of an ROI in OSC. OSC was defined separately in each individual participant by contrasting responses to intact and scrambled objects that were presented in an independent localizer experiment. The figure depicts the ventral cluster of the OSC ROI in a group-level analysis (at p < 0.001). B, Schematic overview of analysis approach. The general approach was to correlate multivoxel patterns evoked by scene images in the category detection task with response patterns from the independent category localizer. The example illustrates how information was calculated for the category people in a response pattern evoked by a scene containing people. The scene response pattern was first correlated with the people response pattern from the category localizer (black arrow; r(p scene, p); p, people category). Next, the correlations between the scene-elicited activation pattern and the tree and car response patterns were computed (gray arrows; r(p scene, tr), r(p scene, c); tr, tree category; c, car category). Categorical information related to people was then defined as the difference between the scene-people correlation and the average of the scene-car and scene-tree correlations.
- Figure 2.
Experimental design. A, Counterbalancing of object category to task relevance across participants. The assignment of the three object categories to their levels of behavioral relevance was counterbalanced across participants, creating three different participant groups. For group 1 (black), people and cars were the target and distracter categories, and trees were the neutral category. For group 2 (light gray), cars and trees were assigned to be the target and distracter categories, whereas people constituted the neutral category. For group 3 (dark gray), people and trees were the target and distracter categories, whereas cars constituted the neutral category. B, Trial structure. Participants indicated on each trial with a button press whether or not the target category was present in the photograph.
- Figure 4.
Category information in single-category scenes. Examples for single-category scenes are shown for a run in which people served as the target category, whereas trees constituted the neutral category and cars the distracter category. Category information was calculated by first computing the correlation between the scene response and the response elicited by the category present in the scene. Then the average of the correlations between the scene response and the responses evoked by the two non-present categories was subtracted. Response patterns in OSC carried significant information for the target and neutral categories but not for the distracter category. Error bars denote ±SEM corrected for within-subject comparisons.
- Figure 5.
Category information in scenes depicting two categories. Examples for two-category scenes are shown for a run in which people served as the target category, whereas trees constituted the neutral category and cars the distracter category. Category information was calculated separately for the two categories embedded in the scene. The correlation between the scene and the category not present in the scene was subtracted from the correlation between the scene and one of the two categories present in the scene. A, In T–N scenes, both the target and the neutral category were processed to the category level. B, In T–D, scenes the target but not the distracter category was processed to the category level. C, Information values did not differ for the neutral and distracter category in N–D scenes. Error bars denote ±SEM corrected for within-subject comparisons.
- Figure 6.
Category information in scenes depicting all three object categories. The correlation between the scene-elicited response pattern and the response pattern evoked by the neutral category was subtracted from the correlations involving the target and distracter categories. Target information was enhanced relative to the neutral category, whereas distracter information was reduced. Error bars denote ±SEM corrected for within-subject comparisons.
