Depth Cues Psychology
Depth cues in psychology refer to the visual cues that help us perceive depth and distance in our environment. These cues can be monocular, such as relative size and linear perspective, or binocular, such as retinal disparity and convergence. Understanding depth cues is important for our ability to navigate and interact with the world around us.
7 Key excerpts on "Depth Cues Psychology"
eBook - ePub- Hugh Foley, Margaret Matlin(Authors)
- 2015(Publication Date)
- Psychology Press(Publisher)
...Many of these monocular cues are also effective when looking at a two-dimensional representation of a three-dimensional world, such as realistic paintings or photographs. Other monocular cues to depth arise when stimuli move within a scene. We’ll next consider the contribution of our two eyes to depth perception. When you look at a nearby object, the image on your left retina differs from that on your right retina. This binocular cue only works because of the disparity between the images on your left and right retinas. We’ll also mention a couple of weaker cues to depth based on information from eye muscles. Finally, we’ll discuss several theoretical approaches to distance perception. As you learned in Chapter 5, researchers approach shape perception in a number of different ways. We’ll look at two approaches to depth perception before revisiting the computational approach as it applies to depth perception. Monocular Cues to Depth Most of our sources of information about distance are monocular. Lest you think of these monocular factors as “second-class citizens,” keep in mind that we all rely solely on monocular cues when judging the distance of objects that are far away. To illustrate the effectiveness of monocular cues to depth, consider professional athletes who have competed successfully even though they had vision in only one eye. In spite of relying totally on monocular cues, athletes such as Wesley Walker (football) and Eddie Shannon (basketball) have been quite successful. Figure 6.1 A classification scheme for retinal cues about depth and distance. Before exploring monocular depth cues that require motion, we’ll focus on monocular cues found in static scenes. Keep in mind that even though we discuss these cues separately, they most certainly work together to provide your sense of depth...
- Jessica Kuper, Jessica Kuper(Authors)
- 2015(Publication Date)
- Routledge(Publisher)
...Depth Perception DOI: 10.4324/9781315677101-44 Walter C. Gogel University of California, Santa Barbara A classical problem in visual perception is understanding how an observer can perceive the world as extended in three dimensions from information registered on the two-dimensional retinas of the eyes. Unlike horizontal and vertical extensions in the world which are represented by proportional retinal extents, information or cues regarding the dimension of distance are coded indirectly in the visual system. There are two kinds of distance cues. One kind, called egocentric cues, provides information as to the distance of objects from the observer. The other, termed exocentric cues, indicates the depth between objects. Two instances of egocentric cues to distance involve motor adjustments of the eyes. In one of these (the cue of vergence), the two eyes turn in opposite directions in order to position the image of the object being viewed on the most sensitive portion of each retina (the fovea). In the other (the accommodative cue), the curvature of the lens of the eye is adjusted in order to focus clearly the image on the retina. These oculomotor cues are ineffective for objects beyond about three metres from the observer. A possible egocentric cue that by definition is learned and can apply to both near and distant objects is the known size of familiar objects. In general, exocentric cues are more precise than egocentric cues and help to extend the perception of distance to far distances from the observer. Among the exocentric cues that have been identified is the cue of binocular disparity, which is a consequence of the two eyes being laterally separated in the head and thus receiving slightly different views of scenes extended in depth (Ogle, 1962). Another exocentric cue occurs between different successive views of the world as the head is moved laterally, and is called relative motion parallax (Hochberg, 1972)...
eBook - ePub- Hugh J. Foley(Author)
- 2019(Publication Date)
- Routledge(Publisher)
...As we mentioned in Chapter 5, the illusions are intrinsically interesting, but their major importance lies in what the illusions tell us about how the visual system must be functioning. We will begin our discussion by addressing the principles that give rise to the perception of depth or distance. Like most of your other perceptual experience, depth perception seems automatic—even unavoidable. Because of the immediacy of your experience of depth, you seldom think about the processes that might underlie this perceptual experience. Before you begin reading the next section, take a few minutes to look around you as if you were seeing for the first time. Note the vivid impression of depth that emerges and try to determine how you are able to see in depth. How can you tell which of two buildings or people is nearer to you? How can you catch a ball thrown at you, or judge the distance (or size) of a bird in flight? Join the psychologists who take a more analytic approach to the perception of depth, and you may discover many of the principles for yourself before we describe them to you. Perceiving a Three-Dimensional World How many cues to depth did you identify? We will now begin a systematic investigation of the major cues to depth or distance. First, however, let’s be a bit more specific about what we mean by distance perception. Distance perception (or depth perception) refers to your ability to perceive the distance relationships within the visual scene. We can think of three different types of distance or depth relationships. First, egocentric distance refers to the distance of an object from you, the observer. (You can remember the word egocentric because it literally means “self-centered.”) When you estimate how far you are from the car in front of you, you are judging egocentric distance. Second, relative distance refers to how far two objects are from each other...
eBook - ePubPerception
Theory, Development and Organisation
- Paul Rookes, Jane Willson(Authors)
- 2005(Publication Date)
- Routledge(Publisher)
...Our brain appears to be able to fuse the two images and this is called stereopsis. The brain uses this information about the differences in position of an object in the two images to give the impression of depth. The greater the difference in the position of the object, the nearer it is. Convergence Binocular vision provides another cue to depth in the form of convergence. The nearer an object is, the more the eyes have to turn inwards in order to focus on that object. Information from the orbital muscles which turn the eyes is therefore available as a further cue to depth. The two binocular cues described above depend on the interaction of both eyes. They both result from processes and structures which are inherent in human beings. They do not appear to be dependent on learning or experience. For this reason, they are called ‘primary cues’. It is obviously beneficial to human beings to use both eyes to process visual information. For example, common tasks involving judgements of relative depth (e.g. threading a needle, inserting coins into slots, etc.) are performed 30% faster and more accurately using both eyes than just one eye (Sheedy et al., 1986). However, if someone loses the sight of one eye or has one eye closed, it is still possible to make judgements about depth. This must mean that some depth cues are available to one eye working alone. These are called monocular cues. Monocular cues There are several monocular cues but only one is a primary cue (i.e. one that is independent of learning). This is accommodation. In order to focus on objects at different distances from the eye, the lens has to change. This occurs because of the movements of the muscles holding the lens in place. (These are autonomic responses and are not under conscious control.) The amount of accommodation of the lens provides feedback to the brain about the distance of the fixated object. However, according to Hochberg (1971), accommodation provides a fairly weak cue to distance...
eBook - ePubAttention, Perception and Memory
An Integrated Introduction
- Elizabeth Styles(Author)
- 2004(Publication Date)
- Psychology Press(Publisher)
...Richard Gregory (1977) says that perception is ‘a dynamic searching for the best interpretation of the available data’. This interpretation includes using our expectations based on memory for previous experiences, as well as what are called visual cues. As the retina is essentially flat, the brain has to use clues and cues to construct a three-dimensional world. The two-dimensional retina has only length and breadth; the third dimension is depth. Depth perception—binocular cues Animals that hunt, move by arm-swinging through trees, or make fine manipulative movements with their forepaws or hands, have eyes that face forward, on the front of the face. Prey animals tend to have their eyes on the sides of their heads to give them better all-round vision. Humans have evolved along the first route and have forward-facing eyes that provide a number of cues to depth. Having two eyes facing forward gives an animal overlapping visual fields. That is, both eyes can see the same object or view, but from slightly different angles. When we look at, or fixate, an object or a point in space, our eyes automatically move so that the area of maximum sensitivity, the fovea, is where the image is focused. As the two eyes are separated on the face, each eye will be angled slightly differently, but the image of the point will be focused on the fovea of each eye. If you alternately close one eye and then the other you can notice these slightly different views, and the object you are looking at seems to be more to the left or the right depending on which eye is looking. This difference between the views is called horizontal disparity. Next, try this. Get a friend to hold their index finger in front of them at arm’s length, then ask them to gradually bring their finger toward their nose, and keep it in focus as they do so. If you watch their eyes you will see that their eyes move more and more inwards towards each other as the finger approaches the nose...
eBook - ePubFine Art and Perceptual Neuroscience
Field of Vision and the Painted Grid
- Paul Hackett(Author)
- 2014(Publication Date)
- Psychology Press(Publisher)
...There are other important cues to depth perception, and we are usually able to perceive depth effectively with just monocular perception. In the preceding sections of this chapter, I have provided information about visual depth perception and how diplopia distorts my depth perception. In the sections that follow, I will present how cognitive neuroscience and psychology: specifically Gestalt psychology. Figure 1.1 Projections of images on my retinas. GESTALT PSYCHOLOGY AND COGNITIVE NEUROSCIENCE In this section, I briefly present the approaches of Gestalt psychology and cognitive neuroscience as a conjoined perspective that I use to guide and to produce understanding the current research and practice. From several perspectives within empirical psychology, research has been conducted into the psychology of art including the researches by Fechner (see Solomon, 2011) and Arnheim (1943, 1966, 1969, 1974, 1986). One can understand Gestalt psychology and its principles as a theoretical and empirical basis for organizing, ordering, and simplifying human perception. In their seminal collection of writings on twentieth century art theory, Harrison and Wood (2003) present the competing ways in which artists and art critics have understood Gestalt psychology and the concept of the holistic ‘gestalt’ in their attempts to explicate twentieth century art. More precisely, Arthur Shimamura (2013) comments upon how Rudolf Arnheim broadens the scope of Gestalt psychology to provide understanding of how artists employ Gestalt grouping principles (a large amount of Gestalt psychology of perception is concerned with the grouping of objects and figure–ground relations) in their arrangement of objects and people in a scene. He used the term ‘perceptual forces’ to describe how artists create these forces through placement, balance, and harmony...
eBook - ePub- Diana Jackson-Dwyer, Craig Roberts(Authors)
- 2015(Publication Date)
- Psychology Press(Publisher)
...In the figure above, the blue line on the left is the outside of a building going away and hence gives the perception of being smaller as it is “going away from our eyes”. The blue line on the right is the corner of an inside room so the perception is that it is coming towards you and getting larger. Hence the right-hand line is perceived to be larger. The Ponzo illusion Which of the two blue rectangles is longer, A or B? Of course, both are of the same length! The two lines either side of A and B are converging into the distance, hence we perceive that the picture is going further away and are tricked into believing that A is longer. Depth cues • Linear perspective. With a railway line the tracks run in parallel, but when we look at the train tracks into the distance they seem to get closer and closer the further away they get from our eyes. This is called convergence. • Texture gradient. The fineness in detail decreases the further away the object is from the eye. • Superimposition. If one object hides part of another object, then the object that is still “complete” is perceived to be closer. • Height in plane. This follows the “rule” that the closer an object is to the horizon, the further away it is compared to other objects seen in the same picture or scene. • Relative size. An object’s smaller size on your retina when it is further away from you is called its relative size. Which depth cues are present in the figures on the opposite page? See pp. 241–243 of Psychology for GCSE Level, 2nd Edition, for more examples of depth cues. Role of experience in perception Nurture and perceptual abilities Study 1 (Man—Elephant—Antelope): Hudson (1960) Aim: To test out the depth-perceptual abilities in two-dimensional pictures of a varied group of people living in the southern regions of Africa. Method: 562 participants were shown a variety of pictures of the same hunting scene but with differing depth cues. They were shown a series of six pictures (see p...
