The development of reflexive and voluntary shifts of visual attention, as well as relations between the two forms of shifting, were examined in three groups of children (5, 7, and 9 years old), one group of young adults (24 years old), and two groups of senior adults (young seniors with an average age of 69 years, and old seniors with an average age of 81 years). The task entailed response to the detection of a target (black dot) in one of four possible locations in the visual field. Relations between reflexive and voluntary shifts of attention were gauged by the degree to which flash and arrow facilitation and inhibition were observed in response to the presentation of both arrow and flash cues together in one trial. All age groups oriented reflexively in response to a flash cue and utilized the arrow cue to orient attention strategically. When flash and arrow cues were presented in quick succession and thereby competed for attention, the youngest children and oldest seniors were least efficient and flexible in their approach to the orienting task as they had difficulty modulating visual reflexes.

Visual search for compound patterns was examined in observers aged 6, 8, 10, and 22 years. The main question was whether age-related improvement in search rate (response time slope over number of items) was different for patterns defined by short- versus long-range spatial relations. Perceptual access to each type of relation was varied by using elements of same contrast (easy to access) or mixed contrast (hard to access). The results showed large improvements with age in search rate for long-range targets; search rate for short-range targets was fairly constant across age. This pattern held regardless of whether perceptual access to a target was easy or hard, supporting the hypothesis that different processes are involved in perceptual grouping at these two levels. The results also point to important links between ontogenic and microgenic change in perception (H. Werner, 1948, 1957).

A forced-choice reaction time (RT) task was used to examine the relations between covert orienting (shifts of visual attention independent of eye movement) and filtering (the mhlbition of processing of melevant stllnu11) components of attention in pers'Jns with Down syndrome (n = 17} and children of average intelligence (n = 17) matched for mental age (MA), (MA = approximately 5 years). Conditions varied with regard ta presence or absl.::nce of distractors\ and the validity (valid, invalid, or neutraI) of location .;ues.RT/p(correct) scores of both groups were longer in distractor-present conditions and in conditions when the location cue provided incorrect information (invalid cue). In addition., RT/p(correct) scores of both groups were longer wh en it was nl~cessary to sirnultaneously search for a target :and filter out irn~lfvant information, than when each of these attention demanding tasks was utilized separately. However, there were lIO

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