Perceptual simulation in property verification

If people represent concepts with perceptual simulations, two predictions follow in the property verification task (e.g., Isface a property of GORILLA?). First, perceptual variables such as property size should predict the performance of neutral subjects, because these variables determine the ease of processing properties in perceptual simulations (i.e., perceptual effort). Second, uninstructed neutral subjects should spontaneously construct simulations to verify properties and therefore perform similarly to imagery subjects asked explicitly to use images (i.e., instructional equivalence). As predicted, neutral subjects exhibited both perceptual effort and instructional equivalence, consistent with the assumption that they construct perceptual simulations spontaneously to verify properties. Notably, however, this pattern occurred only when highly associated false properties prevented the use of a word association strategy. In other conditions that used unassociated false properties, the associative strength between concept and property words became a diagnostic cue for true versus false responses, so that associative strength became a better predictor of verification than simulation. This pattern indicates that conceptual tasks engender mixtures of simulation and word association, and that researchers must deter word association strategies when the goal is to assess conceptual knowledge

Representing Properties Locally

Theories of knowledge such as feature lists, semantic networks, and localist neural nets typically use a single global symbol to represent a property that occurs in multiple concepts. Thus, a global symbol represents mane across HORSE, PONY, and LION. Alternatively, perceptual theories of knowledge, as well as distributed representational systems, assume that properties take different local forms in different concepts. Thus, different local forms of mane exist for HORSE, PONY, and LION, each capturing the specific form that mane takes in its respective concept. Three experiments used the property verification task to assess whether properties are represented globally or locally (e.g., Does a PONY have mane?). If a single global form represents a property, then verifying it in any concept should increase its accessibility and speed its verification later in any other concept. Verifying mane for PONY should benefit as much from having verified mane for LION earlier as from verifying mane for HORSE. If properties are represented locally, however, verifying a property should only benefit from verifying a similar form earlier. Verifying mane for PONY should only benefit from verifying mane for HORSE, not from verifying mane for LION. Findings from three experiments strongly supported local property representation and ruled out the interpretation that object similarity was responsible (e.g., the greater overall similarity between HORSE and PONY than between LION and PONY). The findings further suggest that property representation and verification are complicated phenomena, grounded in sensory-motor simulations

Role of mental imagery in a property verification task: fMRI evidence for perceptual representations of conceptual knowledge

Is our knowledge about the appearance of objects more closely related to verbal thought or to perception? In a behavioural study using a property verification task, Kosslyn (1976) reported that there are both amodal and perceptual representations of concepts, but that amodal representations may be more easily accessed. However, Solomon (1997) argued that due to the nature of Kosslyn’s stimuli, subjects may be able to bypass semantics entirely and perform this task using differences in the strength of association between words in true trials (e.g., cat–whiskers) and those in false trials (e.g., mouse–stinger). Solomon found no evidence for amodal representations when the task materials were altered to include associated false trials (e.g., cat–litter), which require semantic processing, as opposed to associative strategies. In the current study, we used fMRI to examine the response of regions of visual association cortex while subjects performed a property verification task with either associated or unassociated false trials. We found reliable activity across subjects within the left fusiform gyrus when true trials were intermixed with associated false trials but not when true trials were intermixed with unassociated false trials. Our data support the idea that conceptual knowledge is organised visually and that it is grounded in the perceptual system. One of the leading theories of the organisation o