Visual Perception and the Pop-Out Effect

In experiment 1, participants were instructed to press a key to determine if the stimulus was red, blue, yellow, or green. On the second half of the experiment, the stimulus appeared in grey with only one colored letter which was positioned randomly. Error rates for the experiment were below 2.5% for each condition, which is quite low. Experiment 2 was the same as experiment 1 except that there were 114 data collections instead of 288 and there were 36 practice trials instead of 72. According to experiment 1 and 2 it is suggested that the effect of

The Stroop (1935) effect is the inability to ignore a color word when the task is to report the ink color of that word (i.e., to say "green" to the word RED in green ink). The present study investigated whether object-based processing contributes to the Stroop effect. According to this view, observers are unable to ignore irrelevant features of an attended object (Kahneman & Henik, 1981). In three experiments, participants had to name the color of one of two superimposed rectangles and to ignore words that appeared in the relevant object, in the irrelevant object, or in the background. The words were congruent,

Evidence for space-based attention comes primarily from a variety of cuing tasks, which assume that reaction time for detecting a target indicates processing efficiency. Since attention enhances processing efficiency, one would expect that reaction times are faster for attended features, and slower for unattended ones. For example, Posner (1980) showed that target letters were identified more quickly when they had been pre-cued by a dot in the same location. This suggests that attention was directed at the cued region of space. Egly and Homa (1984) used a task in which a general circular area was pre-cued. They found that stimulus detection was

Change blindness is a phenomenon in attention where drastic changes to a scene can go unnoticed. This is important to the field of Human Sensation and Perception because it helps illustrate how a visual scene is processed. Specifically it shows how even if there is direct attention to a scene, there are times when drastic changes can occur without perception of the change occurring. With extensive research already conducted illustrating this effect, new research has recently been conducted studying different types of scene changes in the hopes of understanding which changes are easier or harder to notice. The results of these studies were quantified by the measurement of change detection time (usually reported in seconds). This subset of change blindness research has far-reaching practical applications, especially in the field of security and law enforcement. By applying the knowledge of which type of stimuli lead to longer change detection times training programs could be developed that allow this population to improve their observation skills.

It was therefore hypothesised that the reaction times for global judgments would be faster than the reaction times of local judgments. It was also hypothesised that consistent stimuli would be faster than conflicting stimuli in the local tasks.

This was achieved by presenting central cues, indicating the position of the target letter thus increasing focus. Through these experiments they found that when a subject is in a diffuse attention state (unfocussed) SOD do cause attentional capture and increase reaction time. However, if the subject was presented with a cue this same increase in reaction time was not observed. This led them to conclude that attentional capture from SOD is not automatic and instead propose a priority based visual attention system. In 2006 Neo and Chua conducted research which built upon Yantis and Jonides’ to further demonstrate effects of attentional capture on reaction time. They investigated whether sporadic use of the SOD increased the effect of attentional capture as well as investigated whether maintaining the same position for the target letter decreased reaction times. They found that SOD attentional capture did affect reaction times and unlike in Yantis and Jonides’ experiment they concluded SOD did trigger an automaticity response when used

Three hypotheses were being tested. The first hypotheses was whether global is faster than local. The second hypothesis was if letters are faster than shapes. Finally, the third hypotheses was based on ‘Interaction’ which investigates

Powell (1986) conducted a study in which individuals viewed a photo or slide. Individuals were required to scan images and decide on an image for the entire display (Powell, 1986). Objects were pointed to, and subjects were asked to identify its location (Powell, 1986). The subject was asked to close his or her eyes and were shown another image. The subjects were to decide if the object was in the correct position (Powell, 1986). The subjects would hear one of the objects and was required to focus on the object while keeping the entire image in his or her mind (Powell, 1986). When the next object was identified, the subjects were to move from the first object to the second watching a black dot moving in a straight line (Powell, 1986).

Luck and Vogel's change detection experiment was made to determine exactly how much information can a person withhold from a quick flash of stimulus. They modified the previous change dtetction experiment alittle. Rather than asking the person if there was a change in the display only, they also ask the person to recall the amount of items

This experiment investigated the Stroop effect comparing response times between naming colour ink printed in colour-associated words and colour neutral words. Previous research of two-process theories which support Stroop's studies [cited in Edgar:2007] found that automatic processes can interfere with controlled processes. To test this interference further, colour-associated words were employed. Results of this experiment show a statistically significant difference in condition response times, with naming the colour ink printed in colour-associated words taking longer than those in colour

Overall what the study shows is that as the time between cue and target increases people's performance tends to shift inversely. This is displayed as shorter instances (100ms) found individuals responding faster, relative to when they were longer (500ms) to which individuals would respond slower if they appeared on the same side, with only a minor increase when they appeared on the opposite. Another interesting finding from the study was that trail validity had no statistically significant effect on response times, essentially meaning that how likely a target was to appear had no real effect on how well individuals performed in the study.

Overall, when comparing the reaction times of pictures to letters, picture reaction times are said to be generally greater.

Conjunction feature search involves visual features of objects in the environment which are processed together and does not depend on attention. However, the simple feature search requires features to combine to form objects, It requires attention to bind the primitive features into conjunctions. It is a slower process than conjunction search as it requires to scan the whole scene which is therefore time consuming (Gelade et al., 1980). The hypothesis of the present study predicts that the participants will react quicker to the simple feature condition compared to the conjunction feature condition when presented with targets in different display sizes. Also, that the display sizes would have a larger effect on the conjunction feature search compared to the simple feature

Research carried out on attention has mainly been associated with the selective processing of incoming sensory information. It proposes, to some degree, our awareness of the world depends on what we choose to focus on and not simply the stimulation received by our senses. Attention is often linked to a filter that screens out most potential stimuli whilst allowing a select few to pass through into our conscious awareness, however, a great deal of debate has been devoted to where the filter is situated in the information processing chain (Martindale, 1991). Psychologists have made extensive contributions to this subject matter in the past century. Notable examples include Donald Broadbent's filter theory of attention (1958), which set the

We are replicating J.R. Stroop’s original experiment The Stroop Effect (Stroop, 1935). The aim of the study was to understand how automatic processing interferes with attempts to attend to sensory information. The independent variable of our experiment was the three conditions, the congruent words, the incongruent words, and the colored squares, and the dependent variable was the time that it took participants to state the ink color of the list of words in each condition. We used repeated measures for the experiment in order to avoid influence of extraneous variables. The participants were 16-17 years of age from Garland High School. The participants will be timed on how long it takes them to say the color of the squares and the color of the words. The research was conducted in the Math Studies class. The participants were aged 16-17 and were students at Garland High School. The results showed that participants took the most time with the incongruent words.