Primary Characteristics of Students with Intellectual Disabilities

Academic Performance

Students who are identified with mild intellectual disabilities lag significantly behind grade-level peers in developing academic skills. Thus, students with mild intellectual disabilities are likely to be significantly delayed in learning to read and learning basic math skills (Taylor, Richards, & Brady, 2005). This delay in developing foundational skills in reading and math, coupled with delays in language skills, then results in delays in other academic areas that require the use of these skills (e.g., writing, spelling, science).

Students with intellectual disabilities continue to lag behind age-level peers in academic achievement throughout their school years. However, many students with mild intellectual disabilities develop basic literacy skills and functional mathematics skills. For example, most students with mild intellectual disabilities learn basic computational skills and functional arithmetic skills related to money, time, and measurement. However, most of these students continue to have difficulty with more advanced skills related to content, such as mathematical reasoning and applying concepts to solve problems (Beirne-Smith et al., 2006).

It is noteworthy that delayed language development, which is characteristic of students with mild intellectual disabilities, also has a negative influence on academic achievement. The academic area in which language delay has the most detrimental effect is reading (Torgesen, 2000). While students who are mildly intellectually disabled and who are poor readers share a deficit in phonological language skills similar to other students with disabilities (e.g., students with LD) (Fletcher, Scott, Blair, & Bolger, 2004), students with intellectual disabilities are also often significantly delayed in general oral language skills. Thus, even if students with mild intellectual disabilities develop the ability to read individual words and strategies for reading comprehension, they will have difficulty comprehending what they have read because of weak verbal skills in areas such as vocabulary. Therefore, teachers need to provide these students with instruction to address their phonological weaknesses as well as a broader range of language skills (e.g., vocabulary development) (Torgesen, 2000).

Cognitive Performance

Students with mild intellectual disabilities are characterized by general delays in cognitive development that influence the acquisition of language and academic skills. Moreover, while these students can learn much information that is part of the general education curriculum, they learn more slowly than do typical students. Deficits in specific cognitive skill areas also contribute to this delay. Three of the most important cognitive skill deficits exhibited by students with mild intellectual disabilities are related to attention, memory, and generalization.

Attention  Students with mild intellectual disabilities have difficulty with different types of attention, including orienting to a task, selective attention, and sustaining attention to a task (Wenar & Kerig, 2006). Orienting to a task requires a student to look in the direction of the task (e.g., a teacher demonstrating how to solve a math problem on an overhead projector in the front of the room). Selective attention requires that the student attend to relevant aspects of the task and not to unimportant task components (e.g., attending to one type of math problem on a page and completing the appropriate operation). Finally, sustained attention requires that the student continue to attend to a task for a period of time.

The attentional difficulties of students with mild intellectual disabilities have several implications for how they may be more effectively taught (Beirne-Smith et al., 2006, p. 277). For example, teachers should

1. present initial stimuli that vary in only a few dimensions,
2. direct the individual's attention to these critical dimensions,
3. initially remove extraneous stimuli that may distract the individual from attending
4. increase the difficulty of the task over time, and
5. teach the student decision-making rules for discriminating relevant from irrelevant stimuli.

Memory  Students with mild intellectual disabilities also have difficulty remembering information (i.e., short-term memory). For example, these students may have difficulty remembering math facts or spelling words; or if they remember this information one day, they may forget it the next. To some degree, memory problems are influenced by attentional difficulties. That is, students will have difficulty remembering information if they do not orient to the information, select the information that needs to be remembered, and maintain attention to the important material for a period of time.

However, distinct from attentional problems, students with mild intellectual disabilities have difficulty generating and using strategies that help facilitate short-term memory. For example, when students attempt to remember information, many use a rehearsal strategy (repeating information over and over) to facilitate learning (Kirk, Gallagher, Anastasiow, & Coleman, 2006). Teaching approaches to addressing short-term memory deficits include focusing on meaningful content during instruction and instructing students about strategies that they might use to facilitate remembering information (e.g., rehearsal, clustering information, using mnemonic devices) (Smith, Polloway, Patton, & Dowdy, 2004).

Generalization  A final area in which many students with mild intellectual disabilities have difficulty relates to the generalization of information to other material or settings (Wenar & Kerig, 2006). For example, a student may learn operations for addition and subtraction but may then have difficulty generalizing this information to a division problem. Similarly, a student may learn a new word when reading material in one subject area but may have difficulty reading the same word in other reading material. Students with mild intellectual disabilities also have difficulty generalizing material learned in one setting to another (e.g., from school to the community). Teaching strategies that may be used to address difficulties with generalization include teaching material in relevant contexts, reinforcing students for generalizing information across material or settings, reminding students to apply information they have learned in one setting to another, and teaching information in multiple settings (Smith et al., 2004).

Social Skills Performance

Many of the cognitive characteristics of students with mild intellectual disabilities may contribute to difficulty interacting socially. For example, a low level of cognitive development and delayed language development may cause a student with intellectual disability to have difficulty understanding the content of verbal interactions and understanding expectations (e.g., when to listen, when and how to respond) during verbal interactions. Similarly, difficulty with attention and memory impedes social interactions, as students with mild intellectual disabilities have difficulty attending to important aspects of social interactions, maintaining attention over time, and holding important aspects of what they observe in short-term memory.

In addition to social difficulties that result from general cognitive deficits, students with mild intellectual disabilities share many of the same social difficulties of students with learning disabilities, including the inability to read social cues and interact successfully in conversations, lack of affiliation in school activities, low social status, and negative self-concept.

As with students with LD, these characteristics often lead to lower social status in classrooms and, at times, alienation of students from teachers and peers and lack of affiliation or involvement in school. Moreover, social skills deficits may lead students with mild intellectual disabilities to feel that they are unimportant to peers and teachers and produce feelings that they are not involved in the social community of the school. These difficulties may lead students with mild intellectual disabilities to withdraw in social situations or seek attention in inappropriate ways. They may also behave inappropriately because they have difficulty distinguishing between acceptable and unacceptable standards of behavior (Beirne-Smith et al., 2006).

Directly teaching social skills is one approach that may be used to address the social skills deficits of students with mild intellectual disabilities. This may be necessary for many students with mild intellectual disabilities because their limited cognitive and language skills prevent them from developing these skills through spontaneous interactions with peers.

Students with mild intellectual disabilities have little opportunity to interact with age-level peers in school settings, due to the fact that they spend a large proportion of the school day in segregated school settings with other students with disabilities (Williamson, McLeskey, Hoppey, & Rentz, 2006). Extensive research evidence reveals that the social skills of students with mild intellectual disabilities tend to be improved when they are provided with appropriate supports and included in a general education classroom with age-appropriate peers for a large part of the school day (Freeman & Alkin, 2000).