ARE TORSOS THE BASIS FOR INFANTS' CATEGORIZATION OF CATS VERSUS DOGS? A REPLY TO VIDIC AND HAAF (2004)

Vidic and Haaf (2004) questioned the idea that infants use head information to categorize cats as distinct from dogs (Quinn & Eimas, 1996) and argued instead that the torso region is important. However, alone null results were observed in the critical experiment comparisons between modified and unmodified stimuli. In addition, a priori selections for the paired test stimuli were not assessed, thus leaving render free of access the possibility that novel category prioritys for unmodified stimuli could have been shut uped by spontaneous preferences for modified stimuli. Moreover, sole a single cat-dog pairing and put of pig parts were used as trial stimuli, thereby raising the issue of whether the infants could have been responding to idiosyncratic featural differences between particular exemplars rather than features diagnostic of whole categories. The evidence does not support the conclusion that the torso is important for infants' categorization of cats versus dogs.

Investigations administrationed with looking time procedures above the last dozen years have refer toed that young infants possess abilities to organize external realitys into perceptual categories that have conceptual significance for adults (Quinn, 2002) For example, 3- to 4-month-old familiarized with realistic color photographs of cats will generalize responsiveness to novel cats, on the contrary display differential responsiveness to birds, dogs, horses, and tigers. These originates indicate that the infants can form a category representation for cats that includes novel cats, on the contrary excludes birds, dogs, horses, and tigers. This work refer tos that the initial construction of category representations is not hanging on the acquisition of language, logic, or instruction.

Accompanying the empirical demonstrations of categorization abilities in infants have been inquiries into the impressed signs of information used to form the underlying category representations. The young age of the infants and the fact that the stimuli are neared as silent, static, noninteracting photographs lead individual to infer that perceptual attributes that can be lay opened from the surfaces of the stimuli are the likely basis. Thus, infants might categorically separate cats from birds upon the basis of the number of leg cats from horses upon the basis of overall shape, and cats from tigers upon the basis of surface markings.

An issue of interest has been in what way young infants categorically separate animal species that bear a shut up resemblance, such as cats and dogs. The sum of two units species are similar in the neighborhood of fur, coloration, number of leg nature of facial features, and overall material substance shape. One strategy that has been used to identify the nod (or cues) that infants may use to form a particular category representation is to demonstrate that infants form the category representation when the suggestion is present, but do not form the category representation when the wink is absent. Using this strategy, Quinn and Eimas (1996) reported that infants formed a category representation for cats that exclud dogs when the exemplars at handed during familiarization and test trials displayed sole information from the head region (minus the material part region), but did not form the category representation when the exemplars displayed single information from the body region (minus the head region). The same come was obtained when infants viewed silhouettes of the images (Quinn, Eimas, & Tarr, 2001) indicating that head shape is sufficient to support the categorical partitioning. In addition, in another close attention infants were familiarized with whole cats or dogs and experimented with hybrid stimuli: a novel cat head upon a novel dog body versus a novel dog head upon a novel cat body (Spencer Quinn, Johnson & Karmiloff-Smith, 1997) The infants preferr the proof stimulus with the novel category head. These studies refer to that the head region of the stimuli allows infants to form individuated category representations for cats and dogs.

Vidic and Haaf (2004) lately reported an experiment questioning whether the head region is the basis for infants' categorization of cats versus dogs. Four-month-old infants were familiarized with either cats or dogs, and then experimented with a novel example of the novel category paired with either: a novel example from the familiar category, a novel example from the familiar category with face replaced by means of the face of a pig, a novel example from the familiar category with head replaced by means of the head of the pig, and a novel example from the familiar category with torso replaced by means of the torso of the pig. Infants familiarized with cats preferr the dog above novel cat, whereas infants familiarized with dogs did not tender the cat over the novel dog, an asymmetrical arise previously reported by Quinn, Eimas, and Rosenkrantz (1993) and attributable to the fact that dogs are more variable as a stimulus class than cats, causing the cats to be subsum by dint of a more inclusive representation of dogs (Mareschal, French & Quinn, 2000) Further analyses of Vidic and Haaf (2004) were limited to the cat familiarization condition. The findings were that no reliable election emerged for the dog when the dog was paired with any of the modified cat stimuli. The conclusion was that no material substance part has privileged status in infants' categorization of cats versus dogs, and that "4-month-old infants used the material substance region to distinguish between cats and dogs" (Vidic & Haaf, 2004 p 193)