This article considers the role of the hippocampus in memory function. A central thesis is that work with rats, monkeys, and humans--which has sometimes seemed to proceed independently in 3 separate literatures--is now largely in agreement about the function of the hippocampus and related structures. A biological perspective is presented, which proposes multiple memory systems with different functions and distinct anatomical organizations. The hippocampus (together with anatomically related structures) is essential for a specific kind of memory, here termed declarative memory (similar terms include explicit and relational). Declarative memory is contrasted with a heterogeneous collection of nondeclarative (implicit) memory abilities that do not require the hippocampus (skills and habits, simple conditioning, and the phenomenon of priming). The hippocampus is needed temporarily to bind together distributed sites in neocortex that together represent a whole memory.

Memory and the hippocampus: A synthesis from findings with rats, monkeys, and humans.

Visual object recognition is of fundamental importance to most animals. The diversity of tasks that any biological recognition system must solve suggests that object recognition is not a single, general purpose process. In this review, we consider evidence from the fields of psychology, neuropsychology, and neurophysiology, all of which supports the idea that there are multiple systems for recognition. Data from normal adults, infants, animals, and brain-damaged patients reveal a major distinction between the classification of objects at a basic category level and the identification of individual objects from a homogeneous object class. An additional distinction between object representations used for visual perception and those used for visually guided movements provides further support for a multiplicity of visual recognition systems. Recent evidence from psychophysical and neurophysiological studies indicates that one system may represent objects by combinations of multiple views, or aspects, and another may represent objects by structural primitives and their spatial interrelationships.

/pdf/visual-object-recognition-46yfsn3ins.pdf

Visual Object Recognition

https://www.cell.com/neuron/pdf/S0896-6273(00)80832-6.pdf

Differential Processing of Objects under Various Viewing Conditions in the Human Lateral Occipital Complex

ly, so that it is sometimes difficult to appreciate what would count for or against it. A difficulty with the systems view is that the definition of the term \"system" is uncertain, and it is not always clear from studies of normal subjects when behavioral findings justify postulating a separate memory sys­ tem. The concept of brain systems, while not entirely free of problems itself, provides a more concrete and in the end a more satisfying basis for thinking about memory systems. This is because a long tradition of anatomical and physiological work on the structure and organization of the brain has con­ cerned itself with the identification and study of separable neural systems, sometimes independently of or in advance of any understanding of their func­ tional significance.

/pdf/the-structure-and-organization-of-memory-1jj7gotb8h.pdf

The Structure and Organization of Memory

fMR-adaptation: a tool for studying the functional properties of human cortical neurons.

The magnitude of priming resulting from perception of a briefly presented picture of an object in an earlier trial block, as assessed by naming reaction times (RTs), was independent of whether the primed object was presented at the same or a different size as when originally viewed. RTs and error rates for "same" responses for old-new shape judgments were much increased by a change in object size from initial presentation. We conjecture that this dissociation between the effects of size consistency on naming and old-new shape recognition may reflect the differential functioning of 2 independent systems subserving object memory: 1 for representing object shape and the other for representing its size, position, and orientation (metric attributes). Allowing for response selection, object naming RTs may provide a relatively pure measure of the functioning of the shape system. Both the shape and metric systems may affect the feelings of familiarity that govern old-new episodic shape judgments. A comparison of speeded naming and episodic recognition judgments may provide a behavioral, noninvasive technique for determining the neural loci of these 2 systems. The "recognition" latency of a shape originally viewed at one size is lengthened when that shape is presented at a different size (Jolicoeur, 1987). This result, and a number of others demonstrating time costs for comparing two simultaneously (or immediately sequential) presented shapes that differ in size (Besner, 1983; Bundesen & Larsen, 1975; Ellis, Allport, Humphreys, & Collis, 1989; Jolicoeur & Besner, 1987; Larsen, 1985; Larsen & Bundesen, 1978) have led to the belief that shapes are stored at a specified scale (Kosslyn, 1987; Ullman, 1989).' To achieve matching of the representation of that shape when it is presented at a different size, according to this view, scaling transformations are necessary (e.g., Ullman, 1989). Presumably, the additional time to perform these transformations is the reason why the match of a different-size shape requires more time. Recognition was placed in quotes in the previous paragraph because, curiously, the effects of size consistency on a relatively direct measure of object classification, basic-level naming, have never been assessed. Jolicoeur's (1987) measure of recognition was old-new discrimination. Jolicoeur himself cautioned that it was possible that the effects of size inconsistency in his experiment were not reflecting the perceptual representation used for pattern recognition of the object but rather the processes for episodic discrimination. We report here that Jolicoeur's disquiet was well founded: Size consistency does not affect basic-level naming reaction times (RTs). We used a picture-primin g task where it has been well documented that an object viewed on one occasion

https://geon.usc.edu/%7Ebiederman/publications/Biederman_Cooper_Size_1992.pdf

Size invariance in visual object priming

The magnitude of priming on naming reaction times and on the error rates, resulting from the perception of a briefly presented picture of an object approximately 7 min before the primed object, was found to be independent of whether the primed object was originally viewed in the same hemifield, left—right or upper—lower, or in the same left—right orientation. Performance for same-name, different-examplar images was worse than for identical images, indicating that not only was there priming from block one to block two, but that some of the priming was visual, rather than purely verbal or conceptual. These results provide evidence for complete translational and reflectional invariance in the representation of objects for purposes of visual recognition. Explicit recognition memory for position and orientation was above chance, suggesting that the representation of objects for recognition is independent of the representations of the location and left—right orientation of objects in space.

Evidence for complete translational and reflectional invariance in visual object priming.

https://geon.usc.edu/%7Ebiederman/publications/Biederman%20Cooper%20Contour%20Deletion%20CogPsych%201991.pdf

Priming contour-deleted images: evidence for intermediate representations in visual object recognition.

Phenomenologically, human shape recognition appears to be invariant with changes of orientation in depth (up to parts occlusion), position in the visual field, and size. Recent versions of template theories (e.g., Ullman, 1989; Lowe, 1987) assume that these invariances are achieved through the application of transformations such as rotation, translation, and scaling of the image so that it can be matched metrically to a stored template. Presumably, such transformations would require time for their execution. We describe recent priming experiments in which the effects of a prior brief presentation of an image on its subsequent recognition are assessed. The results of these experiments indicate that the invariance is complete: The magnitude of visual priming (as distinct from name or basic level concept priming) is not affected by a change in position, size, orienta- tion in depth, or the particular lines and vertices present in the image, as long as representations of the same components can be activated. An implemented seven layer neural network model (Hummel & Bicderman, 1992) that captures these fundamental properties of human object recognition is described. Given a line drawing of an object, the model activates a viewpoint-inva riant structural descrip- tion of the object, specifying its parts and their interrelations. Visual priming is interpreted as a change in the connection weights for the activation of: a) cells, termed geon feature assemblies (GFAs), that conjoin the output of units that represent invariant, independent properties of a single geon and its relations (such as its type, aspect ratio, relations to other geons), or b) a change in the connection weights by which several GFAs activate a cell representing an object.

https://geon.usc.edu/%7Ebiederman/publications/Cooper_Biederman_Hummel_1992.pdf

Metric invariance in object recognition: a review and further evidence.

Three experiments investigated the role of visual attention in priming for object images and their left-right reflections. Objects to which participants attended were visually primed in both the same view and in the left-right reflected view; ignored objects were primed only in the same view. The effects of attention (attended vs. ignored) and view (same vs. reflected) were strictly additive. These results suggest that 2 separate representations mediate human object recognition (J.E. Hummel & B.J. Stankiewicz, 1996): One requires attention but is invariant with left-right reflection, whereas the other can be activated automatically but is sensitive to left-right reflection. Both representations appear to be invariant with translation across the visual field.

Eric E. Cooper

Papers

Size invariance in visual object priming

Evidence for complete translational and reflectional invariance in visual object priming.

Priming contour-deleted images: evidence for intermediate representations in visual object recognition.

Metric invariance in object recognition: a review and further evidence.

The role of attention in priming for left-right reflections of object images: evidence for a dual representation of object shape.